reactions of tertiary phosphines with group 15

REACTIONS OF TERTIARY PHOSPHINES WITH

GROUP 15 TRIHALIDES AND RELATED SYSTEMS

A thesis submitted to The University of Manchester for the degree of

Doctor of Philosophy in the Faculty of Engineering and Physical Sciences

2012

Fatma Alhanash

School of Chemistry

2

Contents

Page

Contents 2

List of Tables 5

List of Figures 9

Abstract 16

Declaration 17

Copyright statement 18

Acknowledgements 19

1. Introduction

1.1. Group 15 elements 21

1.2. Phosphorus and its organophosphorus chemistry 21

1.2.1. Synthesis of tertiary phosphines 25

1.2.2. Reactions of tertiary phosphines (R3P) with halogens. 26

1.2.3. Reactions of tertiary phosphines (R3P) with interhalogens 38

1.2.4. Reactions of R3PX2 with Metal powders 39

1.2.5. Reactions of tertiary phosphine sulfides and selenides with halogens

and interhalogens 45

1.3. Synthesis and structures of arsenic, antimony and bismuth trihalides 56

1.3.1. Chemistry of arsenic, antimony and bismuth trihalides with macrocyclic

thio- and selenoether ligands 60

1.3.2. Reactions of arsenic(III) halides with thio- and seleno-ether ligands 60

1.3.3. Reactions of antimony(III) halides with bi- , tri-dentate and macrocyclic

thio- and seleno-ether ligands 64

1.3.4. Reactions of bismuth(III) halides with bi- , tri-dentate and macrocyclic

thio- and seleno-ether ligands 66

1.4. Reactions of arsenic, antimony and bismuth trihalides with P-donors 70

3

1.5. Reactions of arsenic, antimony and bismuth trihalides with P=E donors

(E = O, S, Se) 73

1.6. Aims and objectives 77

1.7. References 78

2. Experimental

2.1. General methods 85

2.2. Reactions of triaryl phosphines with iodine trichloride 87

2.3. Reactions of triaryl phosphines with dibromine/iodine monobromide 89

2.4. Reactions of phosphonium halides with dibromine/sulfuryl chloride 92

2.5 Reactions of tertiary phosphines with selenium tetrahalides 93

2.6. Reactions of tertiary phosphines with elemental selenium 97

2.7. Reactions of tri-o-tolylphosphine selenide, tri-p-tolylphosphine selenide

and triphenylphosphine selenide with main-group halides 102

2.8. Reactions of mixed aryl phosphine selenides and tris(4-fluorophenyl)

phosphine selenide with main group halides 111

2.9. Synthesis of mixed alkylaryl phosphine selenides with main group halides 117

2.10. Reactions of diphosphine diselenides with main group halides 122

3. Synthesis and characterisation of mixed tertiary phosphine interhalogen

Compounds

3.0 Mixed tertiary phosphine interhalogen compounds 138

3.1. Reactions of tertiary phosphines with iodine trichloride 138

3.2. Reactions of tertiary phosphines with Br2/ IBr 144

3.3. Reactions of phosphonium halides with dibromine/sulfuryl chloride 149

3.4 Conclusion 154

3.5. References 156

4. Synthesis and characterisation of tertiary phosphine selenium tetrahalides

4

4.0 Tertiary phosphine selenium tetrahalides 158

4.1. Reactions of tertiary phosphines with selenium tetrahalides 159

4.2. Conclusion 166

4.3. References 167

5. Synthesis and characterisation of phosphine selenides

5.0 Phosphine selenides 169

5.1. Reactions of tertiary phosphines with elemental selenium 169

5.2. Reactions of tris-p fluorophenylphosphine selenides with group

15 halides 173

5.3. Reactions of aryl phosphine selenides (Ph3PSe, (o-tolyl)3PSe,

(p-tolyl)3PSe) and mixed aryl ((o-tolyl)2PhP and (o-tolyl)Ph2P) with

group 15 halides 184

5.4. Reactions of alkyl/aryl phosphine selenides with group 15 halides 203

5.5. Reactions of diphosphine diselenides with group 15 halides 209

5.6. Interpretation of Raman spectroscopic data of some phosphine selenides

and phosphine diselenides 229

5.7. Conclusion 236

5.8. References 237

6. Appendix 239

Word count: 56,098

5

List of Tables

page

1.0. Comparison of P-I, I-I bonds and P-I-I angles in different R3PI2 compounds 34

1.1. 31P{1H} NMR spectroscopic data for Ar3P, Ar3PI2,

[Ar3PI]+, [Ar3POH]+/[{Ar3PO}2H]+ and [Ar3PH]+ species 37

1.2. The comparison of selected geometrical parameters for

crystallographically characterised tertiary phosphine sulfide

diiodide and iodine monobromide compounds 46

1.3. 31P NMR shifts (ppm) and coupling constants 1J(SeP) (Hz) of

phosphine selenides R2R'PSe (R, R' = iPr or tBu) and

phosphine selenide dibromides. 49

1.4. Comparison of bond lengths and bond angles in R3PSeBr2

compounds from DFT calculations. 51

1.5. Melting or boiling points of trihalides of arsenic, antimony

and bismuth. 56

1.6. Approximate differences between the primary and secondary

M-X bonds (Δ) for MX3 trihalides. 57

3.0. Elemental analysis data for [R3PCl][ICl2] 139

3.1 31P {1H} NMR chemical shifts and Raman bands for [R3PCl][ICl2] 139

3.2. Selected bond lengths selected bond lengths (Å) and angles (°) of

[(p-FC6H4)3PCI][ICl2], 2 141


CH3Ph2PCl][ICl2], 7 143


[(o-CH3C6H4)3PBr][Br3], 11 146

3.5 31P {1H} NMR chemical shifts and Raman bands for [R3PBr][Br3] 147

3.6. Elemental analysis data for [R3PBr][Br3] 148

3.7. Elemental analysis data for [Ph3PCH3][X'X2] and [(CH3)4P][Br3] 150

3.8. 31P {1H} NMR chemical shifts and Raman bands for [Ph3PCH3][X'X2]

6

and [(CH3)4P][Br3]. 150


[Ph3PCH3][ICl2], 15 151


[Ph3PCH3]2[Br3]Br, 16 152

4.0. Elemental analysis of [R3PX][SeX3] complexes 160

4.1. Selected bond lengths (Å) and angles (°) of [(p-OCH3C6H4)3PCl][SeCl3], 19 162

4.2. Selected bond lengths (Å) and angles (°) of [(o-SCH3C6H4)3PCl][SeCl3], 21 164

4.3. Raman spectroscopic data for [R3PX][SeX3] compounds. 165

4.4. 31P{1H} NMR chemical shifts of [R3PX][SeX3] compounds. 166

5.0. 31P{1H} NMR chemical shifts of the starting phosphines and their selenides,

as well as their coupling constants 1J(PSe) Hz. 170

5.1. Elemental analysis data of phosphine selenides and diselenides. 173

5.2. Elemental analysis data of [MX3{Se=(p-FC6H4)3}] compounds 174

5.3. Spectroscopic data of p-fluorophenyl phosphine selenide compounds 175

5.4. Selected bond lengths (Å) and angles (°) of [BiCI3{Se=P(p-FC6H4)3}], 44 176

5.5. Selected bond lengths (Å) and angles (°) of [BiBr3{Se=P(p-FC6H4)3}], 45 177

5.6. Selected bond lengths (Å) and angles (°) of [SbCI3{Se=P(p-FC6H4)3}], 46 178

5.7. Selected bond lengths (Å) and angles (°) of [AsBr3{Se=P(p-FC6H4)3}], 49. 180

5.8. Comparison of Raman data of M-X stretches of p-fluorophenyl

phosphine selenide compounds to parent trihalides MX3 184

5.9. Elemental data for [MX3{Se=PPh3}] and [MX3{Se=PPh3}2] 186

5.10. Selected bond lengths (Å) and angles (°) of [BiCl3{(SePPh3)}2], 50 187

5.11. Selected bond lengths (Å) and angles (°) of [SbBr3{Se=PPh3}], 55 188

7

5.12. Spectroscopic data of [MX3{Se=PPh3}] and [MX3{Se=PPh3}2] 189

5.13. Elemental analysis data for [MX3{Se=P(o-tolyl)3}], [MX3{Se=P(o-tolyl)3}2],

[MX3{Se=P(p-tolyl)3}] and [MX3{Se=P(p-tolyl)3}2] compounds. 190

5.14. Selected bond lengths (Å) and angles (°) of [SbCI3{Se=P(o-tolyl)3}], 60 191

5.15. Selected bond lengths (Å) and angles (°) of dimer B of

[AsCI3{Se=P(o-tolyl)3}], 63 194

5.16. Selected bond lengths (Å) and angles (°) of dimer A of

[AsCI3{Se=P(o-tolyl)3}], 63 195

5.17. Selected bond lengths (Å) and angles (°) of [BiCI3{Se=P(p-tolyl)3}2], 66 196

5.18. Selected bond lengths (Å) and angles (°) of [BiBr3{Se=P(p-tolyl)3}], 67 197

5.19. Spectroscopic data for [MX3{Se=P(o-tolyl)3}],

[MX3{Se=P(o-tolyl)3}2], [MX3{Se=P(p-tolyl)3}] and [MX3{Se=P(p-tolyl)3}2]. 198

5.20. Elemental analysis data for [MX3{Se=PPh(o-tolyl)2}] and

[SbX3{Se=PPh2(o-tolyl)}2]. 200

5.21. Selected bond lengths (Å) and angles (°) of

[SbBr3{Se=PPh2(o-tolyl)}].CH2Cl2, 80 201

5.22 Spectroscopic data of mixed aryl phosphine selenides 203

5.23. Elemental analysis data for [MX3{Se=PPh(CH3)2}] and

[MX 3{Se=PPh2CH3}]. 204

5.24. Selected bond lengths (Å) and angles (°) of [SbBr3{Se=PPh(CH3)2}], 86 205

5.25 Selected bond lengths (Å) and angles (°) of [BiCl3{Se=PPh2CH3}], 89 207

5.26 Spectroscopic data for [MX3{Se=PPh(CH3)2}] and [MX 3{Se=PPh2CH3}] 209

5.27. Elemental analysis data for [MX3{Ph2P(Se)CH2P(Se)Ph2}] 211


8

[SbBr3{Ph2P(Se)CH2P(Se)Ph2}], 98 212

5.29 Spectroscopic data for [MX3{Ph2P(Se)CH2P(Se)Ph2}] 213

5.30. Elemental analysis data for [MX3{Ph2P(Se)CH2CH2P(Se)Ph2}] 214

5.31. Spectroscopic data for [MX3{Ph2P(Se)CH2CH2P(Se)Ph2}] 215


[SbCl3{Ph2P(Se)CH2CH2P(Se)Ph2}]n.0.5CH2Cl2, 106 217

5.33. Elemental analysis data of [MX3{Ph2P(Se)(CH2)6P(Se)Ph2}] 219

5.34. Spectroscopic data for [MX3{Ph2P(Se)(CH2)6P(Se)Ph2}] 219

5.35. Elemental analysis data for [MX3{cis-Ph2P(Se)CH=CHP(Se)Ph2}] and

[MX3{trans-Ph2P(Se)CH=CHP(Se)Ph2}]. 221

5.36. Spectroscopic data for [MX3{cis-Ph2P(Se)CH=CHP(Se)Ph2}] and

[MX3{trans-Ph2P(Se)CH=CHP(Se)Ph2}]. 222

5.37. Selected bond lengths (Å) and angles (°) of [SbBr3{trans-

Ph2P(Se)CH=CHP(Se)Ph2}]n, 130. 227

5.38. Geometric parameters of Sb-Se and Sb-Br bonds found in

crystallographically characterised complexes of different phosphine

selenide ligands with SbBr3. 228

5.39 Selected Raman stretches for phosphine selenide and phosphine

diselenides of BiCl3, SbCl3 and AsCl3 compounds. 230

5.40. Raman stretches ν (M-X) reported for parent MX3 halides 232

5.41. Selected Raman stretches for phosphine selenide and phosphine

diselenides of BiBr3, SbBr3 and AsBr3 compounds. 232

5.42. Selected Raman stretches for phosphine selenide and

phosphine diselenides of BiI3 and SbI3. 235

9

List of Figures

page

1.0. Some structures of phosphorus compounds 22

1.1 (a) Ligand angle measuring device and (b) cone angle,

taken from ref [12(a)]. 24

1.1 (c) A schematic definition of electronic and steric effects, taken

from ref [12(a)]. 24

1.2. Possible structures of R3PX2 compounds 27

1.3. X-ray crystal structure of [Ph3PCl+···Cl-···+ClPPh3]Cl.CH2Cl2,

taken from ref [26]. 28

1.4. X-ray crystal structure of trigonal bipyramidal Ph3PCl2,


1.5 (a) X-ray crystal structure of Ph3P.Br2, taken from ref [21] 30

1.5 (b) Molecular orbital diagram showing the donation of :PR3 into

σ* orbital of X2 31

1.6. A representation of the structure of Ph3PI2, taken from ref [27] 32

1.7. Molecular structure of (m-tolyl)3PI2, taken from ref [55]. 33

1.8. Molecular structure of (p-tolyl)3PI2, taken from ref [55]. 34

1.9. Molecular structure of ((p-FC6H4)3PI2 (1), taken from ref [56]. 35

1.10. Molecular structure of ((p-FC6H4)3PI2 (2), taken from ref [56]. 36

1.11. X-Ray crystal structure of Ph3PI1.29Br0.71, taken from [67]. 38

1.12. X-ray crystal structure of [PPh3I][Co(PPh3)I3].OEt2, taken from

ref [73(b)]. 41

10

1.13. X-ray crystal structure of [Zn(PEt3)I2]2, taken from ref [78]. 42

1.14. X-ray crystal structure of [MnI2(PPh3)2], taken from ref [73(a)]. 43

1.15. X-ray crystal structure of [AuI3(PMe3)2], taken from ref [90]. 44

1.16. The structures of (a) tertiary phosphine sulfide and (b) tertiary

phosphine selenides (R = aryl, alkyl group). 45

1.17. The molecular CT structures of: (a) (Ph3PS)2(I2)3 and (b) Ph3PSI2,


1.18. The structure of [{(Me2N)3PS}2S][Br3]2, taken from ref [98] 47

1.19 (a) The 'spoke' structure of (Me2N)3PSeI2 and (b) the T-shaped

structure of (Me2N)3PSeBr2, taken from ref [93 & 97]. 47

1.20. The molecular structure of iPr3PSeBr2, taken from ref [99]. 50

1.21 (a) The molecular structure of iPr3PSeI2 (b) Cation-anion interactions

of iPr3PSeI2, taken from ref [105]. 52

1.22. The molecular structure of (p-FC6H4)3PSe, taken from ref [106]. 53

1.23. The molecular structure of (p-FC6H4)3PS, taken from ref [106]. 54

1.24. The molecular structure of (p-FC6H4)3PSeI2, taken from ref [106]. 55

1.25. The molecular structure of (p-FC6H4)3PSI2, taken from ref [106]. 56

1.26 (a) The structure of BiCl3 with three directly bonded chlorine atoms

and (b) secondary bonds to the five chlorine atoms with bond

lengths and angles, taken from ref [115]. 58

1.27. ORTEP diagram of the bicapped trigonal prism of chlorine atoms

in the structure of SbCl3(a) bonded chlorine atoms projection (b)

11

perspective view, taken from ref [116]. 58

1.28 (a) AsCl3 molecule (b) projection of the structure (c) closest

environment of AsCl3 molecule, E is the lone pair, taken

from ref [117]. 59

1.29. Crystal structure of [AsCl3([9]aneS3)], taken from ref [130]. 61

1.30. The ladder structure of [(AsCl3)([8]aneSe2)], taken from ref [131]. 61

1.31. Crystal structure of [(AsCl3)4([24]aneSe6)], taken from ref [130]. 62

1.32 (a) Structure of [(AsCl3)2{1,2,4,5-C6H2(CH2SMe)4}] (b) polymeric

chain structure, taken from [132]. 63

1.33 (a) Structure of [(AsCl3)2{1,2,4,5-C6H2(CH2SeMe)4}] (b) polymeric

chain structure, taken from [132]. 63

1.34. One-dimensional structure of [SbCl3{MeSe(CH2)3SeMe}], taken

from ref [128]. 64

1.35 (a) [SbCl3([8]aneSe2)] dimer (b) infinite ladder structure formed

from weakly associated dimers, taken from ref [131]. 65

1.36 (a) Structure of [SbCl3{o-C6H4(SMe)2}] (b) polymeric chain, taken

from ref [132]. 66

1.37. Structure of [BiCl3{MeSe(CH2)3SeMe}], taken from ref [126]. 67

1.38. Structure of [BiBr3{MeSe(CH2)3SeMe}], taken from ref [126]. 68

1.39. (a) Structure of [(BiCl3)2{o-C6H4(CH2SMe)2}3] (b) polymeric chain,


1.40. (a) Structure of [(BiCl3)4{o-C6H4(CH2SeMe)2}3] (b) polymeric chain,


12

1.41. Molecular structure of [Bi4Br12(PEt3)4], taken from ref [138]. 70

1.42. Crystal structure of [Sb2I6(PMe3)2] showing three dimer units and

three thf molecules of crystallization, taken from ref [138]. 71

1.43. Structure of [Sb2Br6{o-C6H4(PPh2)2}2], taken from ref [143]. 71

1.44. Isomer A geometry 72

1.45 (a) Independent dimeric units in [AsCl3(PMe3)](b) Crystal packing

showingAs(1)···Cl(5) interaction, taken from ref [144]. 72

1.46. Structure of [{BiI3(Ph3PO)2}2], taken from ref [152]. 73

1.47. Structure of [(Me2N)3PSeSeP(NMe2)3]2+, taken from ref [142]. 74

1.48. Structure of polymeric halide polymeric anion, [(BiCl4)2]n2n-, taken

from ref [142]. 74

1.49. Dimeric structure of [SbI3{SePPh3}], taken from ref [153]. 75

1.50. Structure of [SbF3{Ph2P(O)CH2P(O)Ph2}], taken from ref [156]. 76

1.51. Dimeric structure of [SbF3{Me2P(O)CH2P(O)Me2}], taken

from ref [156]. 77

3.0. ORTEP representation of the molecular structure of

[(p-FC6H4)3PCI][ICl2],2. 141

3.1. Crystal packing of [(p-FC6H4)3PCI][ICl2], 2, showing H···Cl and F···H

contacts. 142

3.2. ORTEP representation of the molecular structure of [CH3Ph2PCl][ICl2],7,

C(13)/Cl(1) and C(14)/Cl(2) are 50 % CH3 and 50 % Cl. 143

3.3. Crystal packing of [CH3Ph2PCl][ICl2], 7, showing Cl···H contacts 144

3.4. ORTEP representation of [(o-CH3C6H4)3PBr][Br3], 11 146

13

3.5. Crystal packing of [(o-CH3C6H4)3PBr][Br3], 11 viewed down the

crystallographic b axis. 147

3.6. ORTEP representation of [Ph3PCH3][ICl2], 15 151

3.7. ORTEP representation of [Ph3PCH3]2[Br3]Br, 16. 152

3.8 Crystal packing of [Ph3PCH3]2[Br3][Br], 16 viewed down the

crystallographic a-axis. 153

3.9 Crystal packing of [Ph3PCH3]2[Br3][Br], 16 showing weak

Br···H contacts 154

4.0. Solid state structure of [Ph3PCl][SeCl3], taken from ref [1]. 158

4.1. ORTEP representation of [(p-OCH3C6H4)3PCl][SeCl3], 19 162

4.2. Crystal packing of [(p-OCH3C6H4)3PCl][SeCl3], 19 showing short contacts

and one-side hydrogen bonding between the anion and cation. 163

4.3. ORTEP representation of [(o-SCH3C6H4)3PCl][SeCl3], 21 164

5 (a) 31P{1H} NMR spectrum of (CH3)2PhP (b) 31P{1H} NMR spectrum of

(CH3)2PhP=Se and (c) 77Se{1H} NMR spectrum of (CH3)2PhP=Se in CDCl3. 171

5.1. 31P{1H} NMR spectrum of [Ph2P(Se)(CH2)2P(Se)Ph2](dppeSe2), 40 172

5.2. ORTEP representation of [BiCI3{Se=P(p-FC6H4)3}], 44 176

5.3. ORTEP representation of [BiBr3{Se=P(p-FC6H4)3}], 45 177

5.4. ORTEP representation of [SbCI3{Se=P(p-FC6H4)3}], 46 178

5.5. ORTEP representation of [SbCl3(mbts)(μ-mbts)2SbCl3(mbts)],


5.6. ORTEP representation of [AsBr3{Se=P(p-FC6H4)3}], 49. 180

5.7. Octahedral coordination [3 + 3] environment in

14

[AsBr3{Se=P(p-FC6H4)3}], 49, showing primary AsBr3 fragment with

three Se=P(p-FC6H4)3 molecules. 181

5.8. Generation of the As4Se4 cuboid motif in the structure of

[AsBr3{Se=P(p-FC6H4)3}], 49. 182

5.9. Crystal packing of [AsBr3{Se=P(p-FC6H4)3}], 49, showing the As···Se, F···F

and F···H interactions in the extended structure of the co-crystal. 183

5.10. ORTEP representation of [BiCl3{(SePPh3)}2], 50 187

5.11. ORTEP representation of [SbBr3{Se=PPh3}], 55 188

5.12. ORTEP representation of [SbCI3{Se=P(o-tolyl)3}], 60 191

5.13. ORTEP representation of [AsCI3{Se=P(o-tolyl)3}], 63 192

5.14. Interaction of molecules A and B in [AsCI3{Se=P(o-tolyl)3}], 63 193

5.15. ORTEP representation of dimer B of [AsCI3{Se=P(o-tolyl)3}], 63 194

5.16. ORTEP representation of dimer A of [AsCI3{Se=P(o-tolyl)3}], 63 195

5.17. ORTEP representation of [BiCI3{Se=P(p-tolyl)3}2], 66 196

5.18. ORTEP representation of [BiBr3{Se=P(p-tolyl)3}], 67 197

5.19. ORTEP representation of [SbBr3{Se=PPh2(o-tolyl)}].CH2Cl2, 80 201

5.20. Crystal packing of [SbBr3{Se=PPh2(o-tolyl)}].CH2Cl2, 80 showing the

weak Br···Br interactions between dimers. 202

5.21. ORTEP representation of [SbBr3{Se=PPh(CH3)2}], 86 205

5.22. Crystal packing of [SbBr3{Se=PPh(CH3)2}], 86 206

5.23. ORTEP representation of tetramer of [BiCl3{Se=PPh2CH3}], 89 207

5.24. Crystal packing of the tetramer [Bi4Cl12{Se=PPh2(CH3}4], 89 along the

crystallographic c-axis. 208

15

5.25. ORTEP representation of [SbBr3{Ph2P(Se)CH2P(Se)Ph2}], 98 212

5.26. 31P{1H} NMR spectrum of [AsI3{Ph2P(Se)CH2CH2P(Se)Ph2}] 111

in CDCl3 216

5.27. ORTEP representation of

[SbCl3{Ph2P(Se)CH2CH2P(Se)Ph2}]n.0.5CH2Cl2, 106 217

5.28. Polymeric chain of [SbCl3{Ph2P(Se)CH2CH2P(Se)Ph2}]n.0.5CH2Cl2, 106 218

5.29. 31P{1H} NMR spectrum of {trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}, 42 in CDCl3 223

5.30. 31P{1H} NMR spectrum of [AsCl3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}], 123

in CDCl3. 224

5.31 31P{1H} NMR spectrum of [AsBr3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}2], 124

in CDCl3. 225

5.32. 31P{1H} NMR of {trans-Ph2P(Se)CH=CHP(Se)Ph2}, 43 in CDCl3. 226

5.33. ORTEP representation of [SbBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}]n, 130. 227

5.34. Polymeric chain of [SbBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}]n, 130. 228

5.35. Raman spectrum of [BiBr3{Se=P(p-tolyl)3}], 67 233

5.36. Raman spectrum of [SbBr3{Se=P(p-tolyl)3}], 70 233

5.37. Raman spectrum of [SbBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}]n, 130. 234

5.38. Raman spectrum of [SbI3{Se=P(p-tolyl)3}], 71 235

16

Reactions of tertiary phosphines with group 15 trihalides

and related systems

Fatma Alhanash

Thesis submitted for the degree of Doctor of Philosophy

The University of Manchester

2012

Abstract

The direct reaction of a series of R3P compounds with ICl3 has been shown to be an effective route for the synthesis of [R3PCl][ICl2] salts. Two of these salts have been structurally characterised and represent the first reported structural data for these systems. A two step route of R3P + Br2 + IBr does not yield the intended [R3PBr][IBr2] salts, instead [R3PBr][Br3] compounds are formed.

The reactions of R3P with SeX4 have been studied. A redox reaction occurs, with oxidation of R3P to [R3PX]+ and reduction of SeX4 to [SeX3]–. The structures of two [R3PCl][SeCl3] salts are reported. In [(p–OCH3C6H4)3PCl][SeCl3] the anion dimerizes in the solid–state to [Se2Cl6]2– via secondary Se···Cl interactions, whilst in [(o–SCH3C6H4)3PCl][SeCl3] dimerization does not occur as there is an unusual S···Se interaction between the cation and anion.

The versatile coordination chemistry of tertiary phosphine selenides (monodentate and bidentate) to group 15 centres (As, Sb, Bi) has been examined. Most Ar3PSe ligands yield 1:1 [MX3{SePAr3}] compounds which form dimers linked by M–X bridges. The asymmetry of these bridges is dependent on the nature of M and X. The aryl rings are usually located over the vacant coordination site occupied by the lone pair on the square pyramidal As, Sb or Bi atom. The weaker donor SeP(p–FC6H4)3 forms co–crystals with MX3 (M = As, Sb, Bi; X = Cl, Br) which link to form highly unusual distorted M4Se4 cuboids of high symmetry.

Mixed alkyl/aryl phosphine selenides form compounds with different types of structures. The reaction of BiCl3 with SePPh2CH3 forms a tetrameric compound, [Bi4Cl12{SePPh2CH3}4] with octahedral bismuth centres. In contrast, the 1:1 [SbBr3{SePPh(CH3)2}] compound is a chain polymer with bridging phosphine selenide ligands.

Polymeric chain structures are usually formed when bidentate phosphine diselenides Ph2P(Se)(CH2)n(Se)PPh2 (n = 1, 2, 6) or trans Ph2P(Se)CH=CH(Se)PPh2 complex to MX3, (M = As, Sb, Bi).

17

DECLARATION

No portion of the work referred to in the thesis has been submitted in support of an application for another degree or qualification of this or any other university or other institute of learning.

Signature

Date

18

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19

ACKNOWLEDGEMENTS

The work presented in this thesis could not be completed only with the help of others.

I would like to express my great thanks to my supervisor, Dr. Alan Brisdon for his

continuous help and patience throughout this work and also for training on the FT

Raman spectrometer.

Thanks also to Dr. Stephen Godfrey who welcomed me as a PhD student and has

deceased for one year now.

Special and Particular thanks goes to Dr. Nicholas Barnes for his great help, patience,

guidance in all areas throughout this work including practical and theoretical inputs,

especially in X-ray crystallography.

Thanks to Anthony Thomas for his help.

Thanks to the microanalysis Lab for their help in analyzing all samples for elemental

analysis.

Thanks to Dr. Robin Pritchard for solving crystal structures.

I don't really know how to express my feelings to thank my parents for their

continuous encouragement, support and guidance through these years of my study.

Great thanks to all my sisters and brothers and their families especially my sister

Sumaya for her kind hospitality and great help where I felt as if I was back home and

of course my sister Hana who was not only as a very close sister but where we were

both very close together through these years and always, her continuous

encouragement and great help and I would also like to thank her husband Ragiab,

wishing him success in his PhD. Congratulations to my sister Hana who has very

recently completed her PhD.

Thanks to the Libyan government for the funding.

20

1.0. Introduction

1.1. Group 15 elements

1.2. Phosphorus and its organophosphorus chemistry

1.3. Synthesis and structures of arsenic, antimony and bismuth trihalides

1.4. Reactions of arsenic, antimony and bismuth trihalides with P-donors

1.5. Reactions of arsenic, antimony and bismuth trihalides with P=E donors

(E = O, S, Se)

1.6. Aims and objectives

1.7. References

21

1.0. Introduction

1.1. Group 15 elements

Group 15 constitutes the third column of the p-block of the periodic table and

comprises the elements nitrogen, phosphorus, arsenic, antimony and bismuth

(together they are called pnictogens or pnictides).[1-8] For all of these elements, the

ground state electronic configuration is ns2np3 which results in common oxidation

states of +3(III) and +5(V) although the relative stabilities of these differ for the various

elements. Despite being in the same group, however, the properties of the elements

vary a considerable degree as the group is descended. Thus, whereas nitrogen and

phosphorus are typical non-metals, arsenic and antimony are more usually described

as metalloids or semi-metals, and bismuth has many properties associated with

metallic behaviour. Indeed, group 15 (together with groups, 14 and 16) exhibits the full

range of element chemistries from non-metallic, through semi-metallic, to metallic in a

single group.

1.2. Phosphorus and its organophosphorus chemistry

Phosphorus has an extensive and varied chemistry which exceeds the

boundaries of inorganic chemistry not only because of its preference to form

innumerable covalent ''organophosphorus'' compounds, but also because of the

numerous and important roles it plays in the biochemistry of all living things. The

element was first isolated by Hennig Brandt in 1669 as a white waxy substance that

glowed in the dark when exposed to air[9] and in 1680 Robert Boyle improved the

process and in subsequent years made the oxide and phosphoric acid.

The organic chemistry of phosphorus is based on the existence of numerous

stable functional groups that form carbon-phosphorus bonds and are organic

derivatives of inorganic phosphorus acids. There are now numerous commercial

applications of organophosphorus compounds, and many cases in which these

compounds are used as valuable reagents in the synthesis of non phosphorus organic

compounds, which taken together has made organophosphorus chemistry a lively and

interesting field in which to conduct research. As with much of organic chemistry,

organophosphorus chemistry had its beginnings in the nineteenth century. The

increase in research activity has not lessened over the intervening years and many new

22

uses for organophosphorus compounds have been discovered. Some of these uses[10]

can be summarized as follows:

Agricultural chemicals, including insecticides, herbicides, and plant regulators.

Medicinal compounds, including anticancer, and antibacterial agents and

agents for the treatment of bone diseases.

Catalyst systems based on metal-coordinated tertiary phosphines used for

many industrial processes (Oxo hydroformylation, olefin hydrogenation, Reppe

olefin polymerization, etc.) and in a new asymmetric syntheses using

complexes of optically active phosphines.

Flame retardants for fabrics and plastics.

Plasticizing and stabilizing agents in the plastics industry.

Selective extractants of metal salts from ores, especially those of uranium.

Additives in the petroleum products field.

Corrosion inhibitors.

Many of these compounds are based on structures possessing three or four bonds of

the type shown in Fig. 1.0 (e.g. tertiary phosphines, 1 and phosphites, 2; trialkyl

phosphates, 3 phosphonic acids, 4 and quaternary phosphonium salts, 5).

1 2 3 4 5

Fig. 1.0. Some structures of phosphorus compounds

Phosphorus can form stable structures (as well as reaction intermediates or

transition states) with five and even six bonds and now hundreds of such compounds

(mostly with five bonds) are known. The discovery that phosphorus could form stable

molecules with multiple bonds led to the addition of many new functional groups to

phosphorus chemistry. Until about 1950, all reported organophosphorus compounds

had either three atoms or four atoms attached directly to phosphorus and were known

respectively as tricovalent (or trivalent) or tetracovalent (or tetravalent or sometimes

pentavalent if the phosphoryl group P=O was present).

23

The most common coordination numbers for organophosphorus compounds are three

and four as represented by tertiary phosphines and their complexes, and quaternary

cations such as [PMe4]+ and [PPh4]+.[2] The 3-coordinate phosphorus species with a lone

electron pair are invariably capable of oxidation to the phosphoryl (P=O) structure. The

literature refers to all such 3-coordinate species as having oxidation state P(III),

regardless of whether P bears an electron-releasing group such as H or methyl. There

are very important structures in organophosphorus chemistry that can be formally

described as 1,2-dipoles, in which a phosphorus atom with a unit positive charge is

attached directly to another atom bearing a unit negative charge .

When the negative charge is on carbon, the structure is more commonly called

an ylide; this is the key reactant in the familiar Wittig olefin synthesis as shown in the

reaction

ylide ylene

Wittig reaction

The Wittig reaction is the reaction of an aldehyde or ketone with a triphenyl

phosphonium ylide (often referred to as a Wittig reagent) to give an alkene and

triphenyl phosphine oxide.

The chemistry of tertiary phosphines, although extensive and of great practical

importance, is centered on the lone pair and its availability for the formation of new

bonds to phosphorus. An excellent summary of understanding structure and bonding

in phosphines is provided by Gilheany.[11] Interactions in molecules are frequently

classified as being steric or geometrical on one hand and electronic on the other hand

(Fig. 1.1 (c)). The steric demand of the phosphine ligands was first quantified by the

cone angle concept stated by Tolman[12a] for tertiary phosphine complexes of the

Ni(CO)3 fragment as shown in Fig. 1.1 (a) and (b) where the metal phosphorus bond is

2.28 Å. It is known that the cone angles in tertiary phosphines expand as group size, R,

24

increases, the smallest value is 118° in Me3P whereas the largest reported so far is

212° for (2,4,6-Me3C6H2)3P. This concept has been extended to cover the heavier group

15 atoms (As, Sb, Bi) by Imyanitov.[13]

(a) (b)

Fig. 1.1 (a) Ligand angle measuring device and (b) cone angle, taken from ref

[12(a)].

Molecular structures, rate and equilibrium constants, NMR chemical shifts and

even relative infrared intensities have been correlated with cone angles.[12(a)]

ELECTRONIC STERIC

Fig. 1.1 (c) A schematic definition of electronic and steric effects, taken from ref

[12(a)].

Electronic effects occur as a result of transmission along chemical bonds, e.g. changing

from P(p-C6H4OCH3)3 to P(p-C6H4Cl)3. It was shown by Strohmeier[12(b)] that phosphorus

ligands can be ranked in an electronic series (based on CO stretching frequencies) for a

wide variety of mono-substituted transition metal carbonyls, e.g. Ni(CO)3L in CH2Cl2.

This may be explained on going from P(p-tolyl)3 to PMe3, where ν = 2066.7 and

2064.1 cm-1 respectively. Tertiary phosphines act as powerful nucleophiles in many

25

reactions. The nucleophilicity is greatest for trialkylphosphines and decreases for

secondary and primary phosphines as the electron-release by the alkyl group

diminishes. Phenyl substitution decreases the nucleophilicity; nevertheless triphenyl

phosphine (unlike triphenylamine), is a useful nucleophile. The nucleophilicity of their

reactions with alkyl halides has been studied extensively and placed on a quantitative

basis by Henderson and Buckler,[14] and quaternization is one of their most

characteristic reactions as shown below

Triarylphosphines are also easily oxidized by chemical reagents to give

phosphine oxides, but less readily by the atmosphere, so that they can be handled

without special precautions. Primary and secondary phosphines are more rapidly

oxidized and so require care in handling. They then have the potential of undergoing

additional changes, after the attachment of oxygen to phosphorus. Many discoveries

of powerful catalytic activity of metal coordination complexes of phosphines have

been published.[10]

Phosphorus chemistry has shared in the enormous benefits that spectroscopic

techniques offer in the determination of structure and the characterization of

compounds. Nuclear magnetic resonance spectroscopy is important because

phosphorus itself is NMR active (31P 100 % abundance and has spin 1/2) and gives

characteristic signals.

1.2.1. Synthesis of tertiary phosphines

There are various ways to synthesize tertiary phosphines, one of which is via the

reduction of phosphine oxides, phosphine sulfides and some halogenophosphines.

Phosphine oxides have been reduced with LiAlH4, Ca(AlH4)2, CaH2, silanes, boranes and

alanes (R3Al) and perchloropolysilanes[15] to yield tertiary phosphines. However, the

most common preparative method is the use of organometallic reagents such as

Grignard or organolithium compounds with halogenophosphines which can be mono-,

di-, or tri-halide derivatives, for example the preparation of triphenylphosphine is

based on PCl3 according to the following equation:

26

The yield of these reactions can be improved by using a large excess of the Grignard

reagent and a low reaction temperature, or by heating to obtain better efficiency.[15]

One of the first and most widely used methods for the synthesis of tertiary phosphines

is the reaction of alkylating agents with metallated phosphines,[15] as the phosphide

anions are excellent nucleophiles and react with a wide range of alkylating agents.

Triphenylphosphine may be used as a starting product as the reaction with lithium

metal results in the formation of lithium diphenyl phosphide in ethereal solvents or

dry tetrahydrofuran. Different alkylating agents can be used with metallated

phosphines, as shown below, where M is a metal and X is a halogen (Cl, Br or I).

1.2.2. Reactions of tertiary phosphines (R3P) with halogens (Cl, Br, I)

Tertiary phosphines react readily with halogens to form R3PX2 compounds,

according to the equation:

When R = Ph and X = Cl, Br or I, the products in the solid state may have ionic

phosphonium salt structures R3PX+X–, as has been demonstrated by solid state 31P

NMR spectroscopy.[16, 17] For more than hundred years ago, Michaelis[18] studied the

chemistry of the nature of triorganophosphorus dihalogen compounds which was of

great interest to both inorganic and organic chemists.

There has been much previous work on dihalogen adducts of tertiary

phosphines, such as the solution studies by Harris and his co-workers[19] and by Du

Mont.[20] For dihalogenophosphoranes, there are essentially three types of structures,

(Fig. 1.2) the predominant solution phase species which is ionic, R3PX+X– (6), the

traditionally accepted five co-ordinated molecular solid-state structure R3PX2 (7) and

the molecular solid-state 'spoke' structure R3P-X-X (8).[19(h), 21]

27

(6) (7) (8)

Fig. 1.2. Possible structures of R3PX2 compounds

A large number of triorganophosphorus dichloride compounds, R3PCl2, (R3 =

substituted aryl, mixed aryl-alkyl or triaryl) have been synthesized in diethyl ether and

characterised by analytical and 31P-{1H} NMR data in CDCl3 solution. Detailed 31P-{1H}

NMR investigations[22-25] have concluded that R3PCl2 are ionic, [R3PCl]Cl, in MeCN or

CH2Cl2 solution which agree with conductivity studies on Ph3PCl2 in MeCN solution by

Harris and co-workers[19(c), 19(e)] who also concluded an ionic formulation [Ph3PCl]Cl.

It was reported in 1996, by Godfrey and co-workers[26] that a crystallographic

study of Ph3PCl2 which was prepared from the direct 1:1 reaction of PPh3 and

dichlorine in dichloromethane solution according to the following reaction

results in an unusual dinuclear ionic compound, [Ph3PCl+···Cl-···+ClPPh3]Cl.CH2Cl2,

(Fig. 1.3) and not the trigonal bipyramidal, nor molecular charge-transfer Ph3P-Cl-Cl

nor the simple ionic species [Ph3PCl]Cl.

28

Fig. 1.3. X-ray crystal structure of [Ph3PCl+···Cl-···+ClPPh3]Cl.CH2Cl2, taken from ref [26].

The 31P{1H} NMR spectra of the unusual dinuclear ionic compound recorded in

CDCl3 and CD3CN gave single resonances at δ 65.5 and 66.5 ppm, respectively, these

values being similar to the values quoted for simple ionic species [Ph3PCl]Cl which gave

a single resonance at δ 62 ± 8 ppm. Considering the widespread use of Ph3PCl2 as a

chlorinating agent, the structural nature of the reagent is of great importance since the

structure may influence its effectiveness as a chlorinating agent and, possibly, the

mechanism of chlorination. Consequently, the choice of solvent employed for a given

chlorination reaction utilising Ph3PCl2 may be of fundamental importance. However,

Godfrey and co-workers[27] also prepared triphenylphosphine dichloride Ph3PCl2 from

the direct reaction of Ph3P and dichlorine in diethyl ether in a 1:1 stoichiometric ratio

according to the following equation

The X-ray crystal structure of Ph3PCl2 was the first example of a molecular

trigonal bipyramidal R3PCl2 compound (Fig. 1.4) and not the ionic structure,

[Ph3PCl···Cl···ClPPh3]Cl.2CH2Cl2, obtained in dichloromethane solution. The 31P{1H} NMR

spectra of the product Ph3PCl2 recorded in C6D6 exhibits a single resonance at δ -47

ppm which is different to any reported value for the ionic

29

[Ph3PCl···Cl···ClPPh3]Cl.2CH2Cl2 or any previous R3PCl2 compound. This value of δ - 47

ppm is comparable to analogous difluorophosphoranes, R3PF2, which are known to

retain a molecular five-coordinate geometry in solution, e.g. MePh2PF2 (δ - 43.2 ppm)

and Ph3PF2 (δ – 58.1 ppm).[27]

Fig. 1.4. X-ray crystal structure of trigonal bipyramidal Ph3PCl2, taken from ref [27].

It can be concluded that polarity of the solvent plays an important role in the

balance between ionic and covalent forms for Ph3PCl2 i.e. in the more polar solvent,

CH2Cl2, an ionic structure is adopted whereas in diethyl ether a molecular form is seen.

Thus, the solvent of preparation is critical in determining the structure of Ph3PCl2. A

molecular form persists in solvents of low polarity but is converted into an ionic form

in solvents of higher polarity, any structure adopted will certainly have an effect on the

chlorinating ability of the reagent, and, possibly, the nature of any products formed. It

was also noted that (C6F5)3PCl2 and (C6F5)Ph2PCl2 exhibit trigonal-bipyramidal

structures in CH2Cl2 whereas Ph3PCl2 adopts an ionic structure, the reason may be due

to the acidity of the parent tertiary phosphine since both (C6F5)3P and (C6F5)Ph2P are

more acidic than Ph3P for a given solvent and thus it can also be concluded that the

nature of R group plays an important role for the determination of the structure.

The wide range of applications and uses of the triphenylphosphorus-dibromine

such as a synthetic reagent,[20, 28, 29] as well as a reagent for bond cleavage,[30, 31]

displacement reactions[32, 33] and in the synthesis of novel transition metal complexes

30

of tertiary phosphine ligands[34] has made it of significant importance in organic

chemistry. Triorganophosphorus dibromide compounds of formula, R3PBr2 (R3 =

substituted aryl, mixed aryl/alkyl, triaryl or trialkyl substituents) have been synthesized

from diethyl ether solution. These compounds were characterised by analytical and

31P{1H} NMR data in CDCl3 solution. Solution 31P{1H} NMR studies regarding R3PBr2 are

limited to Ph3PBr2,[16] Bun3PBr2, Pri

3PBr2[22] as well as the nitrogen containing

compounds (Et2N)3PBr2, (Me2N)3PBr2 and Me(Me2N)2PBr2.[35] All the compounds were

assigned to an ionic structure [R3PBr]Br in acetonitrile solution, and are in agreement

with conductimetric studies by Harris and co-workers,[19(a-g)] also carried out in

acetonitrile.

Solid state investigations of R3PBr2 compounds are limited to an infrared study

of Me3PBr2[36] and a solid state 31P{1H} NMR study of Ph3PBr2 prepared in

nitrobenzene,[35] both compounds were again assigned an ionic structure [R3PBr]Br (R=

Me or Ph) in agreement with solution phase studies. Charge transfer complexes

involving dibromine are much less common than for the diiodide analogues which are

more recognized.[37-42] McAuliffe and co-workers reported the first X-ray crystal

structure of [Ph3P.Br2], Figure 1.5(a) which shows a lengthening of the Br-Br bond with

respect to molecular bromine (3.12 Å compared to 2.28 Å) which is expected with the

donation of electron density from the electron donor to the σ* antibonding orbital of

the X2 molecule as shown in Fig. 1.5 (b).

Fig.1.5 (a) X-ray crystal structure of Ph3P.Br2, taken from ref [21]

31

Fig. 1.5 (b) Molecular orbital diagram showing the donation of :PR3 into σ* orbital of X2

In 1997, du Mont and co-workers[43] reported the crystal structure of the

solvated compound iPr3PBr2.0.5CH2Cl2 which exhibits an ionic structure. With the

exception of (C6F5)3PBr2 and (CF3)3PBr2, all reported R3PBr2 compounds exhibit high

positive 31P{1H} NMR resonances which are indicative of ionic structures in CDCl3

solution. The 31P{1H} NMR resonance for (C6F5)3PBr2 is δ -59.1 ppm, which is unusual

since it arises from the R3PBr2 compound which contains the more acidic (or least

basic) parent tertiary phosphine. The value of δ -59.1 ppm was similar to δ -64.5 ppm

recorded for (CF3)3PBr2 by Cavell et al.,[44] who assigned it to a trigonal bipyramidal

structure. However, in 1998, Godfrey and co-workers[45] were the first to report an

X-ray crystallographic study that the crystal structure of (C6F5)3PBr2 was trigonal

bipyramidal. It is therefore, concluded that the nature of R group plays an important

role for the determination of the structure in R3PBr2.

Diiodotriphenylphosphorane is useful in many conversion and synthetic organic

reactions such as conversion of alcohols, phenols to iodides,[46, 47] vicinal diols into

32

olefins,[48] in the synthesis of halohydrins [49] as well as in the transformation of

aliphatic sulfonic acids, sulfinic acids, thiols, sulfinates, thiosulfonates and disulfides

into the corresponding alkyl iodides.[50] Nineteen diiodophosporanes, R3PI2 (R3 = Ph3,

substituted triaryl, mixed aryl alkyl, or trialkyl substituents) have been reported by

Bricklebank and co-workers.[51] NMR data suggest an ionic [R3PI]I structure in CDCl3

solution but solid-state 31P{1H} magic angle spinning (MAS) NMR data for R3PI2 (R3 =

Ph3, PhMe2 or Me3) suggest a molecular four co-ordinate R3P-I-I structure, strongly

suggesting that this is the common structure of diiodophosphoranes, and not the five

co-ordinate trigonal bipyramid. The solid-state structure of Ph3PI2 (Fig. 1.6) exists as a

molecular four co-ordinate compound, isostructural with Ph3P-Br-Br[21] and

Ph3As-I-I,[52, 53] all of which have the linear 'spoke' structure R3E-X-X.

Fig. 1.6. A representation of the structure of Ph3PI2, taken from ref [27]

Ten other new compounds of stoichiometry R3PI2 [R3 = (o-MeOC6H4)3, (o-

MeOC6H4)2Ph, (o-MeOC6H4)Ph2, (p-FC6H4)2Ph, (p-FC6H4)Ph2, (p-CH2=CHC6H4)Ph2,

(CH2=CHCH2)2Ph, (PhCH2CH2)3 and (Me2N)3] were prepared by the direct reaction of

the appropriate phosphine and I2 in diethyl ether solution.[54] The compounds have

been characterised by Raman and solid-state 31P{1H} MAS and solution NMR

spectroscopy. Solid-state 31P{1H} MAS NMR studies indicate that the predominant

solid-state species is the molecular 'spoke' structure R3P-I-I where in some cases, a

minor peak was assignable to the ionic species, [R3PI]I; however, solid-state 31P{1H}

MAS NMR studies indicate that (Me2N)3PI2 and (CH2=CHCH2)2PhPI2 are ionic species,

[R3PI]I. It is concluded that the structures adopted by R3PI2 compounds (ionic or

covalent) as for the other halides are clearly critically dependent on R.

Barnes et al reported a number of o-, m-, and p-tolyl substituted R3PI2

compounds[55] as well as other tertiary aryl substituted Ar3PI2 compounds[56]

[Ar = o-OCH3C6H4, m-OCH3C6H4, p-OCH3C6H4, o-SCH3C6H4, p-SCH3C6H4, m-FC6H4,

33

p-FC6H4, p-ClC6H4] which were all prepared in 1:1 ratio by the direct reaction of the

phosphine and di-iodine in diethyl ether solution. The compounds were characterised

by elemental analysis, multi-nuclear spectroscopy, Raman spectroscopy and in some

cases by single X-ray crystallography. All the compounds are 1:1 adducts as determined

from the elemental analysis results. The Raman spectroscopic data shows that

o-OCH3C6H4, m-OCH3C6H4, p-OCH3C6H4, p-FC6H4, p-ClC6H4 tertiary aryl substituted

Ar3PI2 compounds exhibit peaks between 130 and 160 cm-1 which have been assigned

as v(P-I) stretches by comparison with previously reported R3PI2 compounds[51, 54, 57, 58]

while (p-SCH3C6H4)3PI2 and (m-FC6H4)3PI2 fluoresced and (o-SCH3C6H4)PI2 showed an

intense peak at 160 cm-1 which may be due to be v(I-I) rather than v(P-I). In free I2, v(I-I)

stretch is at 180 cm-1[59] which shifts to lower frequencies when co-ordinated.[60, 61, 62]

All the compounds exhibit the charge transfer 'spoke' structure with a linear

P-I-I angle. The magnitude of the P-I and I-I bonds depends on the nature of the R

groups, the more donating R groups, the shorter the P-I and the longer the I-I bond.

The structures of the m-, p-tolyl substituted, anisyl and thioanisyl compounds (Figs. 1.7

& 1.8) shows similar P-I and I-I bond lengths as Ph3PI2[19(h)] as shown in Table 1.0 with

shorter P-I bonds and longer I-I bonds compared with Ph3PI2, whereas in (o-tolyl)3PI2,

the P-I bond is longer and I-I bond is shorter, this may be due to the bulky groups of

the ortho tolyl group.

Fig. 1.7. Molecular structure of (m-tolyl)3PI2, taken from ref [55].

34

Fig. 1.8. Molecular structure of (p-tolyl)3PI2, taken from ref [55].

Table 1.0 shows a comparison of the P-I, I-I bonds and P-I-I angles in a number of

different R3PI2 compounds.

Table 1.0. Comparison of P-I, I-I bonds and P-I-I angles in different R3PI2 compounds

Compound P-I bond (Å) I-I bond (Å) P-I-I (°)

Ph3PI2 2.481(4) 3.161(2) 178.22(7)

(o-tolyl)3PI2 2.5523(12) 3.0727(4) 174.32(3)

(m-tolyl)3PI2 2.479(3) 3.1815(13) 173.82(8)

(p-tolyl)3PI2 2.472(5) 3.1809(17) 178.75(9)

(m-OCH3C6H4)3PI2 2.454(2) 3.2123(7) 177.42(5)

(p-OCH3C6H4)3PI2 2.448(4) 3.2575(15) 170.75(12)

(p-SCH3C6H4)3PI2 2.468(2) 3.1946(8) 173.55(5)

(p-FC6H4)3PI2 (1) 2.460(3) 3.1985(11) 171.91(8)

(p-FC6H4)3PI2 (2)A 2.507(3)

2.461(3)

3.0807(12)

3.1529(11)

177.76(7)

173.07(7)

(m-FC6H4)3PI2B 2.476(4)

2.475(4)

3.1347(13)

3.1500(14)

177.58(10)

174.10(10)

(p-ClC6H4)3PI2 2.488(2) 3.1332(9) 178.86(6)

A and B - two independent molecules in the asymmetric unit, (1) & (2) refer to two different

polymorphs of (p-FC6H4)3PI2.

The halo-substituted aryl phosphine diiodide compounds ((m-FC6H4)3PI2, (p-FC6H4)3PI2

and (p-ClC6H4)3PI2)) were crystallographically characterised and the structures of

35

(p-FC6H4)3PI2 are shown Figs. 1.9 & 1.10 where a mixture of two different polymorphs

were obtained ((p-FC6H4)3PI2 (1) and (p-FC6H4)3PI2 (2)) which show differences in their

P-I and I-I bonds. The structure of the (p-FC6H4)3PI2 (1) contains one independent

molecule with a short P-I bond length of 2.460(3) Å and longer I-I bond length of

3.1985(11) Å compared with the analogous Ph3P diiodide compound.

Fig. 1.9. Molecular structure of ((p-FC6H4)3PI2 (1), taken from ref [56].

However, the structure of the other form of p-fluoro-substituted triphenyl phosphine

diodide (p-FC6H4)3PI2 (2) is quite different, it contains two independent molecules with

d(P-I): 2.461(3) Å and d(I-I): 3.1529(11) Å in one molecule and d(P-I): 2.507(3) Å and

d(I-I): 3.0807(12) Å in the second molecule. The bond length variations may be due to

different conformations of the (p-FC6H4) rings in the (p-FC6H4)3PI2 molecules which

affect the steric bulk of the (p-FC6H4)3P fragment.

36

Fig. 1.10. Molecular structure of ((p-FC6H4)3PI2 (2), taken from ref [56].

Early 31P{1H} NMR spectroscopic studies concluded that all R3PI2 compounds ionized in

CDCl3 to [R3PI]I, and the chemical shifts were dependent on the nature of R; when R

was an aryl group the chemical shifts for [Ar3PI]+ cations were between 40 and

50 ppm.[19(h), 51, 54] In contrast, 31P{1H} MAS NMR studies in the solid state showed that

for R3PI-I spoke compounds, the chemical shifts are at lower frequencies, e.g. -17.8

ppm for Ph3PI2[51] in its charge transfer form.

The reaction of Ph3P with differing ratios of I2 was followed using 31P{1H} NMR

spectroscopy by Deplano et al.[63] It was concluded that the chemical shifts changed

with an increase in the Ph3P:I2 ratio, starting from -7.7 ppm for Ph3P to -23.4 ppm for

1:1 ratio and 12.0 ppm for 2:1 ratio suggesting that the correct shift for the [Ph3PI]+

cation is 12.0 ppm and not 44.8 as first reported. The initially reported shifts

(40-50 ppm) for Ar3PI2 cations are believed not to be correct and are maybe due to the

presence of the hydrolysed cationic products, [Ar3POH]+ or [{Ar3PO}2H]+ which are the

most dominant cations formed when R3PI2 compounds are exposed to moist air or

water.[64] In order to confirm the new chemical shifts of the Ar3PI2 cations, the 31P{1H}

NMR spectroscopic studies were performed for the tertiary aryl substituted Ar3PI2

compounds in comparison with Ph3PI2 and o-, m- and p-tolyl substituted R3PI2

37

compounds in anhydrous/anaerobic and moist conditions over several days. The

chemical shifts of the compounds under anhydrous conditions exhibited a broad peak

in the range from -10 to -35 ppm which are shifted to lower frequencies from their

starting phosphines, except (o-CH3C6H4)3PI2 and (o-OCH3C6H4)3PI2 where they are

shifted to higher frequencies, as shown in Table 1.1.[56] The broad peaks were mistaken

in initial reports as unreacted starting material. However, under moist conditions, two

peaks were observed, one for the spoke compound and a second peak was between

-20 and 0 ppm except for ((m-FC6H4)3PI2, (p-FC6H4)3PI2 and (p-ClC6H4)3PI2) which

showed broad peaks for spoke compounds and a second distinguishable peak at 40-45

ppm for hydrolysed products.

Table 1.1. 31P{1H} NMR spectroscopic data for Ar3P, Ar3PI2, [Ar3PI]+,

[Ar3POH]+/[{Ar3PO}2H]+ and [Ar3PH]+ species

Ar3P δP R3P δP R3PI2

spoke

δPA

[R3PI]+

δP

[Ar3POH]+/[{Ar3PO}2H]+

δP [R3PH]+

(1JPH)

Ph3P -7.7 -23.4 12.0 44.7 -5.1 (514)

(o-CH3C6H4)3PI2 -37.2 -21.5 -8.6 48.6 -10.9 (504)

(m-CH3C6H4)3PI2 -10.2 -13.1 6.0 48.2 -5.6 (518)

(p-CH3C6H4)3PI2 -7.3 -11.1 4.6 47.3 -5.0 (513)

(o-OCH3C6H4)3PI2 -39.2 -34.6 -15.8 56.5 -17.9 (551)

(m-OCH3C6H4)3PI2 -2.6 -18.5 5.5 47.8 -5.6 (525)

(p-OCH3C6H4)3PI2 -9.5 -12.7 5.7 50.9 -8.6 (531)

(o-SCH3C6H4)3PI2 -30.6 -31.4 - 40.7 -12.9 (548)

(p-SCH3C6H4)3PI2 -8.3 -16.3 5.9 47.9 -3.8 (515)

(m-FC6H4)3PI2 -5.6 -29.8 -14.7 40.6 -

(p-FC6H4)3PI2 -8.4 -20.2 -4.2 39.8 -

(p-ClC6H4)3PI2 -7.8 -14.1 -5.1 35.0 - A [R3PI]+ cationic species data from reported [R3PI][I3]. [65]

The chemical shifts for [Ar3PI]+ cations in [Ar3PI][I3] typically lie in the range between

10 and -10 ppm[64] and the previously reported chemical shifts between -20 and 0 ppm

were suggested to be due to the ionized [Ar3PH][I] species. In the 31P proton coupled

NMR spectra the resonances are seen as doublets with coupling constants in the range

500-560 Hz, which is in agreement with [R3PH]+ cations. Very few data have been

reported for [R3PH]+ species, for example data for [Ph3PH][HBr2] δP = -4.6 ppm, (1J(PH):

532Hz) and [{p-CH3C6H4)3PH][HBr2] δP = -4.2 ppm, (1J(PH): 529Hz in CD2Cl2)[66] are

38

similar to the second peaks observed for Ph3PI2 and (p-CH3C6H4)3PI2, as shown in Table

1.1.

Investigation of the 31P{1H} NMR spectra after some time in air showed peaks

in the range from 35 to 50 ppm which represent the hydrolysed cations

[Ar3POH]+/[{Ar3PO}2H]+,[64] these peaks are also seen after several days for compounds

performed in anaerobic/anhydrous conditions except for (m-FC6H4)3PI2, (p-FC6H4)3PI2

and (p-ClC6H4)3PI2) which show these peaks after several hours due to their high

moisture sensitivity. It can be concluded that Ar3PI2 compounds are rapidly hydrolysed

forming initially [Ar3PH]+ cations followed by slower hydrolysis to

[Ar3POH]+/[{Ar3PO}2H]+, as in previous studies, resonances described as being due to

[Ar3PI]I are infact the hydrolysed [Ar3POH]+ or [{Ar3PO}2H]+ cations.

1.2.3. Reactions of tertiary phosphines (R3P) with interhalogens

Harris and co-workers[19(a, c, f, g)] reported compounds of stoichiometry R3PX(X')

(where R = Ph; X = Br, X' = I) using conductimetric titration methods in MeCN solution

where ionic products were formed. The reaction of Ph3P with IBr to produce Ph3PIBr

was unsuccessful but instead a product with the formula, Ph3PI1.5Br0.5 was isolated.

A number of products were also isolated from the 2:1 ratio reaction of IBr and PPh3,

all of which were assigned ionic structures, R3PXnX'4-n, (n = 1 or 3) based on

conductimetric results. The compounds Ph3PI3Br and Ph3PBr3 were also assigned an

ionic structure. The crystal structure obtained[67] is shown in Fig. 1.11.

Fig. 1.11. X-Ray crystal structure of Ph3PI1.29Br0.71, taken from [67].

X-ray analysis results showed that this compound has the empirical formula

Ph3PI1.29Br0.71 and was proved to be more complex than expected. Although existing

predominantly as Ph3P-I-Br (the heavier halogen bound to the phosphorus), there was

39

evidence for presence of Ph3PI2, Ph3Br2 and /or Ph3P-Br-I within the cell. It was

concluded from crystallographic and spectroscopic evidence that R3PIBr compounds

have complicated structures and contain molecules with various halogen combinations

and are not structurally described by the simple formula R3PIBr.

The compounds R3PIBr appear to be more complicated than suggested by

Dillon and Lincoln[68] and Ph3PIBr has clearly been shown to adopt the molecular four

co-ordinate structure Ph3P-X-X' and is isostructural with both Ph3PI2 and Ph3PBr2. In

solution, there is evidence for [R3PI]Br and no [R3PBr]I and the single peak in the

31P{1H} NMR spectra of all R3PIBr compounds indicates that considerable halogen

exchange occurs in solution, in agreement with the work of Harris[19(a, c, f, g)] and

Schmutzler and co-workers.[69]

1.2.4. Reactions of R3PX2 with Metal powders

The chemistry of transition-metal complexes of tertiary phosphines is the

widest and most actively studied area of inorganic chemistry. The usual method of

synthesis is the reaction of a metal salt, i.e. an oxidised metal, with phosphine.[70] In

1991, Godfrey and co-workers developed a novel synthetic route to existing and

unusual phosphine complexes[34, 71-73(a)] starting with an oxidized ligand, e.g. a

dihalotriorganophosphorus compound R3PX2 (X = Br[21] or I) and metal powders, rather

than an oxidised metal. Other oxidised Group 15 ligands, R3AsX2 and R3SbX2 can also be

used with crude metal powders[73(b)][equation (1)].

This type of reaction can be thought of as analogous to a Grignard reaction

Although reaction (2) frequently needs an additional reagent, e.g. MeI or I2, to

activate the magnesium whereas equation (3) needs no additional reagents, which is

highly unusual and quite unexpected. The use of metallic reagents is rare, but not

unknown, in inorganic chemistry, but all previous work employed 'activated' metals.

Thus, Timms[74] and Green[75] and their co-workers have produced metal complexes by

40

employing metal vapours, whilst Hudnall and Rieke[76] used finely dispersed metals.

Tuck and co-workers[77] developed the electrolytic reaction of anodic or cathodic

metals to produce Schiff-base and other complexes. These techniques all involve

experimental difficulties or limitations.

Vapour-phase reactions require high temperatures in order to volatilise the

reactants and very low temperatures to co-condense the vapours whilst involatile

ligands can be treated with dispersed metals in solution, the formation of these

solutions can be laborious. Electrolytic syntheses are quite straightforward, but the

range of applicable ligands is limited. As previously stated, Godfrey and co-workers

have studied the reaction of dihalogenophosphoprus compounds, R3PX2 (X = Br or I)

with unactivated coarse-grain transition metal[34, 71-73(a)] and main-group[21] metal

powders to produce metal phosphine complexes and so far, results have shown that

novel isomers of known complexes[34] and complexes containing the metal atom in an

unusually high oxidation state[34, 72] are all available from this synthetic route.

Reaction of coarse unactivated reagent-grade cobalt metal powder with 2 mol

equivalents of the R3PI2 compounds [R3 = (m-MeC6H4)3, (o-, m- or p-MeC6H4)Ph2, Ph3,

(PhCH2CH2)3, Ph2Prn, PhMe2, Ph2Me, Bun3, Prn

3 or Et3] in diethyl ether yielded the

complexes [PR3I][Co(PR3)I3][73(b)] according to the following equation:

The X-ray crystal structure of ionic [PPh3I][Co(PPh3)I3].OEt2 showed a

tetrahedral Co(II) anion, the charge being balanced by the iodophosphonium cation,

[PPh3I]+ (Fig. 1.12). All the complexes [PR3I][Co(PR3)I3] have also been studied using

Raman and visible spectroscopy, the latter confirming the tetrahedral geometry of the

cobalt anion.

41

Fig. 1.12. X-ray crystal structure of [PPh3I][Co(PPh3)I3].OEt2, taken from ref [73(b)].

A special case is seen when R3 = PhMe2, producing both the ionic complex

[PPhMe2I][Co(PPhMe2)I3] and the cobalt(III) complex [Co(PPhMe2)2I3], an equilibrium is

set up and both the cobalt-(II) and –(III) complexes may be isolated from the same

reaction mixture. The reaction of the analogous R3PBr2 with cobalt metal powder

either does not proceed at all or results in the detection of a trace quantity of a

cobalt(II) complex, possibly analogous to the corresponding iodo-complexes since

dibromophosphoranes react readily with other metals (e.g. iron, manganese and

nickel) to produce metal complexes. The mixed-halogeno ligand Ph3PIBr reacts with

cobalt powder to produce [PPh3I][Co(PPh3)IBr2].

Bricklebank and co-workers[78] reported the reaction of R3PI2 (R = Me, Et, Prn,

Bun) with zinc powder to yield the unexpected 1:1 phosphine complexes [Zn(PR3)I2]2

according to the following equation:

In the case of R = Et, recrystallisation of the white powder from dry diethyl ether

yielded moisture sensitive colourless needles suitable for single X-ray analysis. In 1992

[Zn(PEt3)I2]2 was the first, simple, zinc(II) tertiary phosphine to be crystallographically

42

characterised (Fig. 1.13) which shows that it has a dimeric structure containing both

bridging and terminal iodide ligands.

Fig. 1.13. X-ray crystal structure of [Zn(PEt3)I2]2, taken from ref [78].

The novel reaction of crude manganese metal powder with dibromo- and diiodo-

phosphoranes, R3PX2[73(a)] has been studied. Reaction of the R3PI2 adduct (R = phenyl or

substituted aryl) with manganese gives the monomeric tetrahedral complexes

[MnI2(PR3)2] and MnI2 according to the following equation:

In the case of R = Ph, the complex [MnI2(PPh3)2] has been crystallographically

characterised (Fig. 1.14) and shown to exist as a monomeric tetrahedral species with

bond lengths and angles similar to those reported by Kohler and co-workers[79] for

[MnI2(PEt3)2].

43

Fig. 1.14. X-ray crystal structure of [MnI2(PPh3)2], taken from ref [73(a)].

However, reaction of R3PX2 (R3 = mixed aryl/alkyl, trialkyl; X = Br or I) with manganese

gives polymeric complexes [{MnX2(PR3)}n]. When R3 = Ph2Me an equilibrium exists and

both types of complex, [MnI2(PPh2Me)2] and [{MnI2(PPh2Me)}n], can be detected from

the same reaction.

There is a limited number of reports concerning tertiary phosphine complexes

of tin(II) halides.[80, 81] The novel reaction of some R3PX2 compounds (X = Br or I; R3 =

Ph3, Ph2Me or PhMe2) with unactivated coarse-grain tin metal powder has been

investigated.[82] Initially a tin(II) species results which is further oxidized forming both

cis- and trans-[Sn(PR3)2I4]. The reactions of tin powder with R3PBr2 and PhMe2PI2 seem

to be straightforward, yielding compounds of stoichiometry [Sn(PR3)2X4] (X = Br, R3 =

Ph3, Ph2Me or PhMe2; X = I, R3 = PhMe2) which are mixtures of both the cis- and trans-

isomers according to the following equation:

In contrast, reactions of Ph3PI2 or Ph2MePI2 with tin produced compounds of slightly

different elemental analysis each time the reaction was repeated, typically indicating

compounds of formula Sn2(PR3)3I8 (X = I, R = Ph3 or Ph2Me) where further

44

investigations showed that these compounds are mixtures of three products, the tin(II)

species [PR3I][SnI3] and cis- and trans-[Sn(PR3)2I4] as shown in the following equation:

Evidence is provided by the 31P{1H} NMR spectra, which all contain a resonance which

can be assigned to the [PR3X]+ cation in the tin(II) species [PR3X][SnX3].

Historically, gold has always been considered as being amongst the most noble

of all metals. The chemistry of gold complexes containing tertiary phosphine ligands

has been well studied and is well understood.[83-89] The use of certain chelating agents

can force the gold to adopt distorted trigonal-bipyramidal or, more commonly, square-

pyramidal coordination geometry due to the steric requirements of the ligand. The

novel compounds, [AuI3(AsMe3)] and [AuI3(PMe3)2] have been synthesized by the

reaction of coarse-grain gold powder and Me3EI2 (E = P, As). The compound

[AuI3(PMe3)2][90] (Fig. 1.15) was crystallographically characterised and shown to have a

trigonal-bipyramidal geometry. This is the first trigonal bipyramidal complex of gold(III)

containing ligands that do not impose any particular steric demands on the metal

centre.

Fig. 1.15. X-ray crystal structure of [AuI3(PMe3)2], taken from ref [90].

45

This novel reaction provided a new path to gold complexes and for the synthesis of

complexes not accessible by the conventional reaction of gold halides with tertiary

phosphines.

1.2.5. Reactions of tertiary phosphine sulfides and selenides with halogens and

interhalogens

Tertiary phosphine sulfides and selenides have the general structures shown in

Fig. 1.16 and consist of a phosphine group linked to a chalcogen atom by a P=S or P=Se

double bond.

(a) (b)

Fig. 1.16. The structures of (a) tertiary phosphine sulfide and (b) tertiary phosphine

selenides (R = aryl, alkyl group).

There are few crystallographic reports of tertiary phosphine sulfide dihalide or

interhalide compounds. It was initially believed that triphenylphosphine sulfide

diiodide could not be isolated, although the charge transfer (CT) compound

(Ph3PS)2(I2)3 was structurally characterised and found to consist of two CT Ph3P=S-I-I

moieties linked by a diiodide molecule to form an I6 polyiodide chain.[91] It was 30 years

after this discovery that the molecular charge transfer structure of Ph3PSI2 was

reported[92] and found to adopt a molecular CT 'spoke' arrangement, in agreement

with previous IR and UV-vis spectroscopic studies concerning that molecule and other

compounds of stoichiometry R3PSI2 [93] (Fig. 1.17).

46

Fig. 1.17. The molecular CT structures of: (a) (Ph3PS)2(I2)3 and (b) Ph3PSI2,

taken from ref [98].

The compounds, (Me2N)3PSI2 and Ph3PSIBr have also been described[94] and were

found to be isostructural with Ph3PSI2. As with other CT systems, bond distances yield

information about the strength (or stability) of the complex. However, for tertiary

phosphine chalcogenides, three important changes should be considered on

coordination, i.e. in d(I-X) (where X = I, Br), d(E-I) and d(P-E) (where E = S, Se).

Table 1.2 shows a comparison of selected geometrical parameters for

crystallographically characterised tertiary phosphine sulfide compounds[91, 93, 95]. The

stability of the compounds is said to increase across the table, i.e. the 2:3 product of

Ph3PS and I2 can be considered a stronger donor-acceptor system than the 1:1 product

due to the shorter (and therefore stronger) d(S-I) and the longer (and therefore

weaker) d(I-I) in (Ph3PS)2(I2)3 with respect to Ph3PSI2.

Table 1.2. Comparison of selected geometrical parameters for crystallographically

characterised tertiary phosphine sulfide diiodide and iodine monobromide compounds

Geometrical

parameters

(Å or °)

Ph3PS Ph3PSI2 (Ph3PS)2(I2)3 (Me2N)3PSI2 Ph3PSIBr

d(P-S) 1.950(3) 1.998(2) 2.007(3) 2.014(4) 2.007(1)

d(S-I) - 2.753(2) 2.729(2) 2.705(3) 2.656(1)

d(I-I) - 2.8230(11) 2.838(1) 2.856(1) -

d(I-Br) - - - - 2.6832(6)

S-I-X (X =I, Br) - 175.51(3) 175.23(5) 177.98(6) 175.13(2)

47

It can be seen that (Me2N)3PS is a better donor molecule than Ph3PS and that Ph3PSIBr

is stronger than others, as shown by its shorter (S-I) distance. There have been no

crystallographic reports of an iodine monochloride, dichloride or difluoride compound

of a tertiary phosphine sulfide. However, it has been found[93] that when Ph3PS is

reacted with dibromine, two products form, Ph3PBr2 and elemental sulfur; this

phenomenon was also noted in solution (using 31P-NMR spectroscopy) for the product

of the reaction of (C6H11)3PS with dibromine, but interestingly not in the solid state for

which there is evidence that (C6H11)3PSBr2 forms. Surprisingly, the reaction of

(Me2N)3PS with dibromine produced the unusual ionic compound [{(Me2N)3PS}2S][Br3]2

as one of the products and not the expected (Me2N)3PSBr2 (Fig. 1.18).

Fig. 1.18. The structure of [{(Me2N)3PS}2S][Br3]2, taken from ref [98]

The reaction of Ph3PSe and (C6H11)3PSe with diiodine, iodine monobromide and

iodinemonochloride produces stable 1:1 adducts which were spectroscopically

characterised.[92] It was shown that R3PSeI2 (R = Ph, Me2N, Et2N) compounds adopt a

CT molecular spoke structure[96] analogous to Ph3PSI2[91] and (Me2N)3PSI2,[93] while the

compounds (Me2N)3PSeBr2 and (C6H11)3PSeBr2 were shown to adopt a T-shaped

geometry.[97] Fig. 1.19 shows these two structural types, in the case of (Me2N)3PSeI2

and (Me2N)3PSeBr2.

(a) (b)

Fig. 1.19 (a) The 'spoke' structure of (Me2N)3PSeI2 and (b) the T-shaped structure of

(Me2N)3PSeBr2, taken from ref [93 & 97].

48

The I-I bond length of the diiodide compounds increases in the order Ph3PSeI2 <

(Me2N)3PSeI2 < (Et2N)3PSeI2, with d(I-I) of 2.881(2), 2.959(2) and 2.985(2) Å

respectively, reflecting increasing CT to the I2 acceptor. When comparing these values

to d(I-I) of the corresponding tertiary phosphine sulfide diiodine compounds

(Table 1.2), it can clearly be seen that compounds of the form R3PSe are superior

donors to R3PS; i.e. the greater lengthening of the diiodide bond in the tertiary

phosphine selenide compound compared to the tertiary phosphine sulfide reflects the

greater donor power of selenium towards diiodine compared to sulfur.

The iodine-iodine bond length in the CT complexes R3PSeI2 is also sensitive to

the nature of R, d(I-I) for Ph3PSeI2 is 2.881(2) Å whereas d(I-I) for (Et2N)3PSeI2 is

2.985(2) Å, illustrating that the R groups on the parent tertiary phosphine significantly

affect the donor power of selenium atom towards diiodine, despite the fact that they

are not directly bound to this group.

The reaction of bulky trialkyl phosphine selenides with one equivalent of bromine

results in the formation of T-shaped products R2R'PSeBr2 (R, R' = iPr or tBu).[99] These

trialkyl phosphine selenides include tBu3PSe, iPr3PSe and mixed groups such as

tBu2(iPr)Se and tBu(iPr)2PSe. The dibromide complexes were formed according to the

following reaction

where R,R' = tBu; R,R' = iPr; R = tBu, R' = iPr; R = iPr, R' = tBu.

The addition of Br2 to phosphine selenide solutions of tBu3PSe, iPr3PSe, (tBu)2iPrPSe or

iPr2tBuPSe in dichloromethane lead to a single 31P NMR signal with a pair of Se

satellites, and 1J(SeP) decreases with increasing amounts of Br2. The 77Se NMR signal of

the brominated products cannot easily be resolved as it broadens on addition of an

excess of the Br2. However, pure iPr3PSeBr2 and tBu(iPr)2PSeBr2 in CD2Cl2 solutions

49

show a doublet in the 77Se NMR spectrum while tBu2iPrPSeBr2 shows a single broad

resonance. The 31P resonances of the brominated trialkylphosphine selenides and the

trialkylphosphine selenides are about 30-50 ppm downfield from the parent

trialkylphosphine as is shown in Table 1.3,[100] but the brominated products are slightly

shifted upfield towards trialkylphosphine selenides.

Table 1.3. 31P NMR shifts (ppm) and coupling constants 1J(SeP) (Hz) of phosphine

selenides R2R'PSe (R, R' = iPr or tBu) and phosphine selenide dibromides.

R2R'P

δ 31P

R2R'PSe R2R'PSeBr2

δ 31P, 1J(SeP) δ 31P, 1J(SeP)

tBu3P 62.0[a] 93.8, 709[a]

93.3, 693[b]

83.0, 514[c]

tBu2(iPr)P 46.9[a] 84.6, 706[a]

70.6, 692[b]

82.9, 520[b]

tBu(iPr)2P 33.3[a] 79.9, 713[a]

84.4, 688[b]

77.4, 526[b]

iPr3P 19.3[a] 71.1, 709[a]

79.5, 696[b]

69.8, 521[c]

[a] C6D6, [b] CD2Cl2, [c] CH2Cl2/C6D6

The Raman spectra of the T-shaped products (containing a linear and symmetric

Br-E-Br group (E = S, Se)), exhibit a strong peak at around 160 cm-1 in the Raman

spectrum due to the symmetric stretching vibration of the Br-E-Br system, and a peak

at around 190 cm-1 due to the antisymmetric vibration which is seen when the Br-E-Br

system is asymmetric, which is similar to [Br-X-Br]- (X = I, Br) anions.[101, 102] The FT-

Raman spectra of iPr3PSeBr2 and (tBu)2iPrPSeBr2 show strong peaks at 169 and 163

cm-1 respectively[99] and weaker peaks at around 190 cm-1, iPr2tBuPSeBr2 also shows a

peak at 163.9 cm-1 but of low intensity and a weaker peak at 190 cm-1.

The brominated trialkylphosphine selenides, iPr3PSeBr2, (tBu)2iPrPSeBr2 and

iPr2tBuPSeBr2 were characterised crystallographically. The structure of iPr3PSeBr2 exists

in two crystalline forms. One of these forms consists of one molecule in the

asymmetric unit while the other form shows two independent molecules within the

asymmetric unit. The monomeric molecule (Fig. 1.20) contains iPr3P groups bonded to

the Se atom with an almost linear Br-Se-Br angle, (the bonding described by the

notation 10-Se-3: 10 valence electrons at the central Se atom which has 3

50

substituents)[103] the T–shaped structure has unequal Se-Br bond lengths and PSeBr

angles that are greater than 90°. The P=Se bond in the starting phosphine selenides,

iPr3PSe, is 2.1244(9) Å which is increased (as is usually observed in for R3PSeBr2

compounds[97]) to 2.2681(5) Å. The Se-Br bond lengths are unequal with Se-Br(1):

2.6435(3) Å and Se-Br(2): 2.5252(3) Å respectively and the angles P-Se-Br(1):

96.743(16)° and P-Se-Br(2): 95.485(16)° differ. The Br(1)-Se-Br(2) angle is 167.209(11)°

which deviates from linearity.

Fig. 1.20. The molecular structure of iPr3PSeBr2, taken from ref [99].

Mkadmh and co-workers[104] conducted density functional studies on a number of

trialkyl phosphine selenide dibromide compounds R3PSeBr2 (R= H, Me, Et, N(CH3)2,

N(C2H5)2, Ph and C6H11) which suggested that these compounds may exhibit two

geometries, T-shaped or molecular spoke geometries, with pseudo trigonal

bipyramidal or bent angular structures respectively around the Se atom. The structure

of the T-shaped form is consistent with (Me2N)3PSeBr2 which was crystallographically

characterised by Godfrey et al.[97] In the T-shaped structures, the Se-Br bond lengths

and two Br-Se-P angles are unequal and the Br-Se-Br angles in the T-shaped structures

and Se-Br-Br in the spoke structures deviate slightly from linearity (as shown in

51

Table 1.4) which shows the comparison of bond lengths and bond angles of some

R3PSeBr2 compounds. The authors report that the inequivalence of the Se-Br bond

lengths may be due to geometrical orientation of Br atoms to the Se and orientation of

Se-Br bonds to the whole molecule.[104]

Table 1.4. Comparison of bond lengths and bond angles in R3PSeBr2 compounds from

DFT calculations.

Structure R H CH3 C2H5 N(CH3)2 N(C2H5)2 Ph C6H11

T d(Se-Br(2))/ Å 2.552 2.602 2.609 2.619 2.608 2.595 2.533

d(Se-Br(3))/ Å 2.719 2.679 2.682 2.681 2.680 2.671 2.487

Br-Se-Br / ° 167.9 179.0 176.6 174.1 168.9 173.5 170.2

spoke d(Se-Br(2))/ Å 2.465 2.510 2.513 2.535 2.522 2.511 2.512

d(Br(2)-Br(3))/ Å 2.910 2.818 2.815 2.785 2.797 2.812 2.764

Se-Br-Br / ° 177.3 178.9 179.7 179.1 178.8 178.3 178.3

The reactions of trialkyl phosphine selenides with diiodine have also been

reported.[105] These reactions were performed using different ratios of I2 resulting in

the formation of compounds having chemical formula R3PSeIn where n = 2-7 and R3 is

tBu3, iPr3 and mixed groups such as tBu2(iPr) and tBu(iPr)2. The structures of the trialkyl

phosphine selenide diiodides (1:1 ratio) are ionic and feature weak intermolecular I···I

interactions and Se···I interactions between cations and anions.

The structure of iPr3PSeI2 consists of [(iPr3PSe)2I]+ cations and [I3]¯ anions within the

asymmetric unit (Fig. 1.21(a)) where the Se···I3 distance is 3.8644(7) Å resulting in a

···Se-I-Se···I-I-I··· motif with almost linear I3···Se-P (173.27(3)° and bent I2-I3···Se

(114.579(15)° (Fig. 1.21(b)).

52

Fig. 1.21 (a) The molecular structure of iPr3PSeI2 (b) Cation-anion interactions of

iPr3PSeI2, taken from ref [105].

The reactions of tris-(p-fluorophenyl)phosphine chalcogenides (p-FC6H4)3PE (E = Se, S)

with diiodine have been studied resulting in 1:1 charge-transfer compounds (p-

FC6H4)3PSeI2 and (p-FC6H4)3PSI2 which have a linear E-I-I motif.[106] These compounds

were synthesized according to the following reactions

where E = Se, S.

The 31P{1H} NMR spectrum shows that resonances of the starting phosphine

(p-FC6H4)3P, δ : -8.8[107] is shifted to higher frequencies for the corresponding

tris-(p-fluorophenyl)phosphine selenide (p-FC6H4)3PSe δ: 33.6 and sulfide (p-FC6H4)3PS

δ: 42.2 ppm respectively. The 31P{1H} spectrum of (p-FC6H4)3PSe also shows Se

satellites with a coupling constant of 1J(SeP) = 741 Hz which is in agreement with

53

previously reported data,[107-109] as well as 77Se NMR spectrum which displays a doublet

(1J(SeP) = 741 Hz) resonance at δ: -246.1 ppm.

The tris-(p-fluorophenyl)phosphine selenide and sulfide have been characterised

crystallographically. The structure of (p-FC6H4)3PSe contains two independent

molecules in the asymmetric unit (Fig. 1.22) with very similar P=Se bonds in both

molecules P(1)-Se(1): 2.1100(13) Å, P(2)-Se(2): 2.1115(12) Å. These P=Se bond lengths

are similar to those found in other Ar3PSe systems, for example in Ph3PSe, the P=Se

bond is 2.106(1) Å.[110]

Fig. 1.22. The molecular structure of (p-FC6H4)3PSe, taken from ref [106].

54

The structure of (p-FC6H4)3PS contains only one independent molecule as shown in

Fig. 1.23. The P=S bond length in (p-FC6H4)3PS, P(1)-S(1): 1.9540(9) Å is also similar to

previous reported Ar3PS systems, e.g. d(P=S) is 1.950(3) Å in Ph3PS[111] and 1.947(4) Å in

(o-CH3C6H4)3PS.[112]

Fig. 1.23. The molecular structure of (p-FC6H4)3PS, taken from ref [106].

The reactions of the compounds (p-FC6H4)3PSe and (p-FC6H4)3PS with diiodine in a 1:1

ratio resulted in the following products, (p-FC6H4)3PSeI2 and (p-FC6H4)3PSI2.[106] The

31P{1H} NMR spectra of these products showed resonances shifted slightly to higher

frequencies than their starting phosphine chalcogenides, (p-FC6H4)3PSe δ : 33.6 to 44.5

ppm and (p-FC6H4)3PS δ : 42.2 to 47.5 ppm. The 77Se NMR spectra could not be

obtained due to the poor solubility of (p-FC6H4)3PSeI2 in deuterated solvents.

The diiodide products were crystallographically characterised. The structure of

(p-FC6H4)3PSeI2[106] (Fig. 1.24) contains two independent molecules within the

asymmetric unit, both of which display a near linear Se-I-I bond angle;

Se(1)-I(1)-I(2): 178.17(2)° and Se(2)-I(3)-I(4): 178.02(2)°. There is a slight difference in

55

the I-I distances and Se-I distances between the molecules, I(1)-I(2): 2.8888(12),

I(3)-I(4): 2.8950(11) Å and Se(1)-I(1): 2.8153(12), Se(2)-I(3): 2.8198(12) Å. The I-I

distances in (p-FC6H4)3PSeI2 are shorter than those in trialkyl or tris(alkylamino)

substituted R3PSeI2 systems where the I-I bond length is 2.985(2) Å in (Et2N)3PSeI2,

which is expected as the weak donor ability of (p-FC6H4)3PSe results in a weaker Se-I

interaction, and stronger I-I bond.

Fig. 1.24. The molecular structure of (p-FC6H4)3PSeI2, taken from ref [106].

The structure of (p-FC6H4)3PSI2[106] (Fig. 1.25) also contains two independent molecules

within the asymmetric unit with both molecules showing an essentially linear S-I-I

motif, S(1)-I(1)-I(2): 177.88(10)°, S(2)-I(3)-I(4): 178.94(9)°. There is a significant

difference in the I-I distances in the two molecules, I(1)-I(2): 2.8042(17) Å and

I(3)-I(4): 2.835(2) Å. The S-I bond lengths S(1)-I(1): 2.787(5) Å and S(2)-I(3): 2.792(6) Å

are longer than in Ph3PSI2, d(S-I): 2.753(2) Å as expected due to the weaker donor

power of (p-FC6H4)P compared to Ph3P. There is also a lengthening in the P-S bonds in

(p-FC6H4)3PSI2, P(1)-S(1): 1.997(6) and P(2)-S(2): 1.984(5) Å with respect to

(p-FC6H4)3PS, d(P-S): 1.9540(9) Å, similar to the analogous phosphine selenide system.

56

Fig. 1.25.The molecular structure of (p-FC6H4)3PSI2, taken from ref [106].

1.3. Synthesis and structures of arsenic, antimony and bismuth trihalides

There are two main types of halides in group 15: MX3 and MX5 (M = As, Sb and Bi). The

trihalides are prepared by direct halogenation with an excess of the element while the

pentahalides may be prepared by treatment of the elements with an excess of the

halogen. The trihalides, AsF3 and AsCl3 are volatile and hydrolyse quickly in water.

Table 1.5[113] shows some examples of the trihalides of arsenic, antimony and bismuth

and their melting or boiling points.

Table 1.5. Melting or boiling points of trihalides of arsenic, antimony and bismuth.

Fluorides °C Chlorides °C Bromides °C Iodides °C AsF3 b 62.8 AsCl3 b 103.2 AsBr3 m

b 31.2

221.0 AsI3 m 140.0

SbF3 m 292.0 SbCl3 m 73.17 SbBr3 m 97.0 SbI3 m 171.0

BiF3 m 725.0 BiCl3 m 233.5 BiBr3 m 219.0 BiI3 m 408.6 b: boiling point °C, m: melting point °C.

57

In most cases, the MX3 trihalides feature trigonal pyramidal MX3 units with primary

bonds, and short intermolecular contacts or secondary bonds. Table 1.6 shows the

approximate differences between the primary and secondary M-X bond lengths (Δ) of

MX3 trihalides.

A primary bond is usually defined as the normal covalent bond with usual bond

lengths while the secondary bond is a longer interaction with bond lengths within the

sum of the van der Waals radii for the elements concerned.[114] The difference

between the primary and secondary bond lengths decreases down the group from As >

Sb > Bi as can be seen from Table 1.6 and it also decreases on going to heavier halides

such as from BiCl3 to BiBr3 and BiI3.

Table 1.6. Approximate differences between the primary and secondary M-X bonds (Δ)

for MX3 trihalides

M-F Δ (Å) M-Cl Δ (Å) M-Br Δ (Å) M-I Δ (Å)

As-Br 1.40 As-I 0.90

Sb-F 0.70 Sb-Cl 1.25 Sb-Br 1.25 (α), 1.10 (β) Sb-I 0.45, 0.91

Bi-F Bi-Cl 0.85 Bi-Br 0.65 (α), 0 (β) Bi-I 0

Bismuth trichloride has been characterised crystallographically and its structure

consists of BiCl3 molecules where each bismuth atom is bonded to three chlorine

atoms resulting in a distorted trigonal pyramidal geometry (Fig. 1.26 (a)).[115] Two bond

lengths in BiCl3 are almost equal while the third bond is slightly shorter, Bi-Cl(2): 2.513

(7) Å, Bi-Cl(3): 2.518 (7) Å and Bi-Cl(1): 2.468 (3) Å. A similar pattern is observed for the

angles, Cl(1)-Bi-Cl(3): 94.9 (3)°, Cl(1)-Bi-Cl(2): 93.2 (3)° and one much smaller Cl(2)-Bi-

Cl(3): 84.45 (14)°. There are also five more chlorine atoms which form secondary

bonds at bond lengths ranging from 3.216 (9) Å to 3.450 (9) Å (Fig. 1.26(b)) resulting in

an overall geometry of trigonal prismatic with a coordination number of 8.

58

(a) (b)

Fig. 1.26 (a) The structure of BiCl3 with three directly bonded chlorine atoms and (b)

secondary bonds to the five chlorine atoms with bond lengths and angles, taken from

ref [115].

Antimony trichloride was also characterised crystallographically, the structure

consists of SbCl3 molecules with pyramidal geometry with two equal Sb-Cl bond

lengths, Sb-Cl(2) and Sb-Cl(2I) = 2.368 (1) Å while the third bond, Sb-Cl(1) = 2.340 (2) Å

is shorter. A similar pattern is observed with the angles, Cl(2I)-Sb-Cl(1): 95.70(5)° and

two equal Cl(2I)-Sb-Cl(2): 90.98(5)°. This is similar to the BiCl3 structure. There are also

secondary bonds to five chlorine atoms resulting in a coordination number of 8 for the

Sb atom which is in a bicapped trigonal prismatic geometry (Fig. 1.27 (a) and (b)).[116]

The bond lengths of these secondary Sb-Cl bonds range from 3.457 (1) Å to 3.736 (1) Å

and are within the sum of the van der Waals radii of Sb and Cl atoms (4.0 Å).

(a) (b)

Fig. 1.27. ORTEP diagram of the bicapped trigonal prism of chlorine atoms in the

structure of SbCl3(a) bonded chlorine atoms projection (b) perspective view, taken

from ref [116].

59

Arsenic(III) chloride has also been crystallographically characterised. The structure

consists of AsCl3 molecules with the arsenic atom bonded directly to three chlorine

atoms and six secondary chlorines positioned in a triangular shape.[117] The three As-Cl

distances are almost the same, two As-Cl bond lengths are equal, As-Cl2 and

As-Cl3 = 2.163(3) Å, and the third As-Cl1 = 2.158(2) Å. The angles are similar, Cl1-As-

Cl2: 98.4(1)°, Cl2-As-Cl3: 97.5(1)° and Cl3-As-Cl1: 97.8(1)° respectively. There are As-Cl

interactions with three adjacent molecules resulting in a tricapped triangular prism

geometry, as shown in Fig 1.28.

Fig. 1.28 (a) AsCl3 molecule (b) projection of the structure (c) closest

environment of AsCl3 molecule, E is the lone pair, taken from ref [117].

60

There are two different structures for antimony tribromide, α-SbBr3 and β-SbBr3.[118]

The α-SbBr3[119] structure is isomorphous with AsBr3

[120] with MX3 pyramidal geometry

having only three short intermolecular contacts rather than five as in BiCl3 and SbCl3.

The primary and secondary Sb-Br bond lengths average to 2.50 Å and 3.75 Å

respectively (in α-SbBr3), while in AsBr3 the As-Br bonds average 2.36 Å and 3.77 Å.

Bismuth tribromide also has two different structures, α-BiBr3 and β-BiBr3.[121] The

structure of α-BiBr3 contains BiBr3 molecules with the bismuth atom bonded to three

bromine atoms with an average Bi-Br bond length of 2.663 Å giving a trigonal

pyramidal geometry and three longer secondary bonds of an average of 3.316 Å,

whereas β-BiBr3 has an octahedral geometry with an average Bi-Br distance of 2.81 Å.

The structures of SbI3,[122] AsI3[123] and BiI3

[122] also give octahedral geometries

with different primary and secondary bond lengths. The structure of AsI3 contains AsI3

molecules with three As-I bonds of 2.591 Å and three secondary As-I contacts of

3.467 Å, however in BiI3, all six Bi-I bonds are equal, Bi-I: 3.1 Å and in SbI3, there are

short and long Sb-I bonds ranging from 2.868 Å to 3.32 Å.

1.3.1. Chemistry of arsenic, antimony and bismuth trihalides with macrocyclic thio-

and selenoether ligands

The coordination chemistry of polydentate and macrocyclic thio- and

selenoether ligands has been investigated by Levason et al[124] with a series of main

group elements including the group 15 elements arsenic(III), antimony(III) and

bismuth(III). Their structures range from six-coordinate monomers through to one-,

two- or three-dimensional network infinite polymers with structural motifs very

different to those of d-block elements. The structures are based on a combination of

primary M-X (X = Cl, Br or I) and secondary M···E (E = S or Se) interactions and, in some

cases, secondary M···X interactions.[125-129]

1.3.2. Reactions of arsenic(III) halides with thio- and seleno-ether ligands

Arsenic(III) halide complexes with thio- and seleno-ether ligands have been

reported, these include complexes with MeS(CH2)2SMe, [9]aneS3, [14]aneS4, [8]aneSe2

(1,5-diselenacyclooctane), [16]aneSe4 (1,5,9,13-tetraselenacyclohexadecane) and

61

[24]aneSe6 (1,5,9,13,17,21-hexaselenacyclotetracosane).[130] Complexes with

MeSe(CH2)2SeMe and MeC(CH2EMe)3 (E = S or Se) resulted in oils which could not be

isolated, which may reflect the poorer acidity of AsX3 compared to BiX3 and SbX3 where

a number of solid complexes have been isolated. The complex [AsCl3([9]aneS3)] has

been crystallographically characterised. The structure (Fig. 1.29) shows the complex is

a six-coordinate monomer involving distorted octahedral S3X3 coordination at As(III).

Fig. 1.29. Crystal structure of [AsCl3([9]aneS3)], taken from ref [130].

The crystal structure of [(AsCl3)([8]aneSe2][131] (Fig. 1.30) shows an infinite one

dimensional ladder with near-planar As2Cl6 units linked by bridging [8]aneSe2

molecules, which was the first example of an AsX3-selenoether complex. The terminal

As-Cl bonds (As(1)-Cl(1): 2.2821(17) and As(1)-Cl(2): 2.2734 Å) are shorter than the

bridging As-Cl bonds (As(1)-Cl(3): 2.7766(19) and As(1)-Cl(3'): 2.7451(18) Å). This

structure is similar to the Bi(III) analogue [BiCl3([8]aneSe2)].[127]

Fig. 1.30. The ladder structure of [(AsCl3)([8]aneSe2)], taken from ref [131].

62

The complex, [(AsCl3)4([24]aneSe6)] (Fig. 1.31) is unusual, showing a new structural

type which shows both endo and exo coordination of As(III) centres and forms discrete

molecules. The unusual feature is the asymmetric As2Cl6 µ-chloro bridged dinuclear

unit coordinated within the macrocyclic ring.

Fig. 1.31. Crystal structure of [(AsCl3)4([24]aneSe6)], taken from ref [130]. The acyclic dithio-ether complexes isolated are [AsX3{MeS(CH2)2SMe}] where (X = Cl, Br

or I). The bromo and iodo species adopt discrete asymmetric µ-dibromo bridged As2X6

units with a chelating dithioether on each As centre.[124] The tetrathioether

[(AsCl3)2{1,2,4,5-C6H2(CH2SMe)4}] and tetraselenoether [(AsCl3)2{1,2,4,5-

C6H2(CH2SeMe)4}] complexes of AsCl3 have been reported and crystallographically

characterised.[132] The structure of the tetrathioether, [(AsCl3)2{1,2,4,5-

C6H2(CH2SMe)4}] consists of AsCl3 pyramidal units each weakly linked to two S-donor

atoms from two different thioether ligands forming a polymeric chain as shown in

Fig. 1.32 (b).

63

Fig. 1.32. (a) Structure of [(AsCl3)2{1,2,4,5-C6H2(CH2SMe)4}] (b) polymeric chain

structure, taken from [132].

The tetraselenoether complex [(AsCl3)2{1,2,4,5-C6H2(CH2SeMe)4}] showed an unusual

structure (Fig. 1.33 (b)) where the Se atoms in the 2,4- and 1,5-positions of the

selenother ligand are linked to pyramidal AsCl3 units giving a polymeric chain resulting

in a distorted octahedral geometry at each As atom through three primary As-Cl bonds

and three weak secondary As···Se interactions.

Fig. 1.33. (a) Structure of [(AsCl3)2{1,2,4,5-C6H2(CH2SeMe)4}] (b) polymeric chain

structure, taken from [132].

http://pubs.acs.org/action/showImage?doi=10.1021/ic101296e&iName=master.img-007.jpg&type=master


64

1.3.3. Reactions of antimony(III) halides with bi- , tri-dentate and macrocyclic thio- and seleno-ether ligands

Antimony(III) halides react with thio-, seleno- and telluroether ligands forming unusual

infinite one- or two dimensional networks, even though only a few complexes have

been reported. The first examples of Sb(III) selenoether complexes are

[(SbBr3)2([16]aneSe4)] and [SbCl3{MeSe(CH2)3SeMe}].[128]

The bromo complex, [(SbBr3)2([16]aneSe4)] adopts a two-dimensional network

with exocyclic macrocyclic coordination giving a square pyramidal geometry at Sb(III),

whereas the chloro complex adopts an infinite one-dimensional chain with a distorted

octahedral geometry at Sb(III),[128] as shown in Fig. 1.34.

Fig. 1.34. One-dimensional structure of [SbCl3{MeSe(CH2)3SeMe}], taken from ref [128].

The crystal structure of the complex [SbCl3([8]aneSe2)] consists of [Sb2Cl6([8]aneSe2)]

dimers involving edge-bridged square pyramids with [8]aneSe2 ligands as shown in

Fig. 1.35 (a), the dimers are linked into an infinite ladder structure through long Sb···Se

interactions involving the remaining Se atoms as shown in Fig. 1.35 (b).

65

Fig. 1.35 (a) [SbCl3([8]aneSe2)] dimer; (b) infinite ladder structure formed from weakly

associated dimers, taken from ref [131].

The crystal structure of [SbCl3([8]aneSe2)] is similar to the structures observed for

[(AsCl3)([8]aneSe2)] and [BiCl3([8]aneSe2)]. The bond lengths and angles in

[SbCl3([8]aneSe2)] are much less regular than in the arsenic and bismuth analogues

with the asymmetric bridging Sb-Cl bonds (Sb(1)-Cl(1): 2.881(2) and Sb(1)-Cl(1'):

2.751(2) Å) and terminal Sb-Cl bonds (Sb(1)-Cl(2): 2.499(2) and Sb(1)-Cl(3): 2.438(2) Å);

Sb(1)-Se(1): 2.7839(13) and Sb(1)-Se(2''): 3.2904(13) Å. This irregularity is possibly due

to a greater stereochemical activity of the lone pair in this complex, compared to the

arsenic and bismuth complexes.

It was not found possible to isolate a solid product from the reaction of SbCl3

with MeSe(CH2)2SeMe but instead an orange oil was obtained. The thioether species

are more stable than the selenoether species, which decomposed and darkened within

a week,[129] thus the compounds [SbCl3{MeC(CH2SMe)3}], [SbBr3{MeC(CH2SeMe)3}] and

[SbI3{MeC(CH2SMe)3}] were obtained and their structures exhibited different structural

motifs. All the structurally characterised Sb(III) complexes reported by Levason et al[129]

repeat infinitely along one-, two or three-dimensions with no discrete dimers. In all the

antimony complexes the coordinated S or Se atoms lie cis whereas both cis and trans

dispositions have been seen for the analogous bismuth systems.[127]

66

A number of complexes were recently reported following the reaction of antimony

trihalides with a series of aromatic dithio-, tetrathio-, diseleno-, tetraselenoethers[132]

ligands resulting in complexes such as [SbCl3{o-C6H4(SMe)2}], [SbCl3{o-C6H4(CH2SEt)2}]

and [{SbCl3(MeCN)}2{1,2,4,5-C6H2(CH2SMe)4}]. The diselenoether complex, [SbCl3{o-

C6H4(SeMe)2}] was an oily product. The structure of [SbCl3{o-C6H4(SMe)2}] contains

Sb2Cl6 dimers linked to weakly bridging dithioethers which form a polymeric chain

structure as shown in Fig. 1.36.

Fig. 1.36 (a) Structure of [SbCl3{o-C6H4(SMe)2}] (b) polymeric chain, taken from ref

[132].

1.3.4. Reactions of bismuth(III) halides with bi- , tri-dentate and macrocyclic thio- and

seleno-ether ligands

Bismuth trihalides (BiX3, X = Cl, Br or I) react with a series of thio- and seleno-ether

ligands to yield complexes in different ratios. The synthesis and characterization of a

number of Bi(III) compounds has been reported which include the crystal structures of


67

[BiBr3{MeS(CH2)3SMe}], [BiCl3{MeSe(CH2)3SeMe}], [BiBr3{MeSe(CH2)3SeMe}],

[BiBr3{MeS(CH2)2SMe}2], [Bi2Br6{PhS(CH2)2SPh}] and [BiCl3{MeC(CH2SeMe)3}].[126]

A small number of macrocyclic thioether complexes have been structurally

characterised which include [BiCl3([12]aneS4)], [BiCl3([15]aneS5)], [BiCl3([18]aneS6)] and

[(BiCl3)2([24]aneS8)] ([12]aneS4 = 1,4,7,10-tetrathiacyclododecane, [15]aneS5 =

1,4,7,10,13-pentathiacyclopentadecane, [18]aneS6 = 1,4,7,10,13,16-hexathiacycloocta

decane, [24]aneS8 = 1,4,7,10,13,16,19,22-octathiacyclotetracosane).[133-135] The

structure of [BiCl3{MeSe(CH2)3SeMe}] (Fig. 1.37) is similar to [BiBr3{MeS(CH2)3SMe}]

and adopts a two-dimensional sheet structure with edge-shared bioctahedral Bi2Cl6

dimers linked by diselenoether ligands bridging Bi2Cl6 units, with Bi-Se distances of

3.036(2) and 2.988(2) Å.

Fig. 1.37. Structure of [BiCl3{MeSe(CH2)3SeMe}], taken from ref [126].

The compound [BiBr3{MeSe(CH2)3SeMe}] (Fig. 1.38) is also isostructural with

[BiBr3{MeS(CH2)3SMe}] with Bi-Se bond lengths of 3.028(2) and 2.978(3) Å, these

compounds are the first bismuth thio- and seleno-ether complexes to be characterised

structurally.

68

Fig. 1.38. Structure of [BiBr3{MeSe(CH2)3SeMe}], taken from ref [126].

There is also a variety of bismuth chloride complexes with a series of aromatic dithio-,

tetrathio-, diseleno- and tetraselenoether[132] ligands such as [BiCl3{o-C6H4(SMe)2}],

[BiCl3{o-C6H4(SeMe)2}], [(BiCl3)2{o-C6H4(CH2SMe)2}3], [BiCl3{o-C6H4(CH2SEt)2}] and

[(BiCl3)4{o-C6H4(CH2SeMe)2}3]. The structure of the 2:3 M:L complex

[(BiCl3)2{o-C6H4(CH2SMe)2}3] (Fig. 1.39) shows that the dithioether ligands bridge two

different BiCl3 molecules, resulting in a distorted seven co-ordinate geometry at the Bi

atom.

Fig. 1.39 (a) Structure of [(BiCl3)2{o-C6H4(CH2SMe)2}3] (b) polymeric chain, taken from

ref [132].


69

The 4:3 M:L complex [(BiCl3)4{o-C6H4(CH2SeMe)2}3] had a very unusual structure which

consists of two independent molecules within the asymmetric unit. Each of these

contain four BiCl3 units as shown in Fig. 1.40 (a), with an octahedral BiCl6 located in the

centre linked to three other bismuth atoms through bridging chlorine atoms

(Bi1-Cl1: 2.697(5) Å and Bi2-Cl1: 2.974(6) Å). The outer bismuth atoms are linked to

two diselenoether ligands and two terminal chlorine atoms (Bi2-Se1: 3.006(2) Å,

Bi2-Cl2: 2.494(5) Å).

Fig. 1.40. (a) Structure of [(BiCl3)4{o-C6H4(CH2SeMe)2}3] (b) polymeric chain, taken from

ref [132].


70

1.4. Reactions of arsenic, antimony and bismuth trihalides with P-donors

Norman and co-workers[136-139] and others[140] have reported the chemistry of

bismuth(III) and antimony(III) halides with monodentate and bidentate phosphines.

The reaction of Bi(III) bromide with PMe3 formed [PMe3H][Bi2Br7(PMe3)2].2(MeCN)

which was the first bismuth phosphine complex characterised crystallographically.[141]

The structure consists of a polymeric anion, the monomeric unit contains a planar

Bi2Br6 arrangement where each bismuth is further bonded to a PMe3 ligand and an

additional bromide. Bi(III) bromide reacts with two equivalents of PEt3 resulting in a

1:1 complex BiBr3(PEt3),[142] its structure as shown in Fig. 1.41 and consists of a

tetrameric association of BiBr3(PEt3) units, i.e. [Bi4Br12(PEt3)4] where there are two

pairs of bismuth atoms Bi(1) and Bi(2) each bonded to one phosphine and five

bromines.

Fig. 1.41. Molecular structure of [Bi4Br12(PEt3)4], taken from ref [138].

The reaction of SbI3 and PMe3 in thf yielded [Sb2I6(PMe3)2].thf[139] where its

crystal structure is described as a polymer of dimers with one un-coordinated thf

molecule of crystallization per dimer unit as shown in Fig. 1.42, each antimony atom

has a square-based pyramidal co-ordination geometry with a PMe3 ligand in the apical

site and four iodides in the basal plane. The terminal Sb-I lengths, [Sb(1)-I(3): 2.836(2)

Å and Sb(2)-I(5): 2.847(2) Å] are shorter than the bridging Sb-I bonds, [Sb(1)-I(1):

3.225(2) Å, Sb(2)-I(1): 3.092(2) Å and Sb(1)-I(2): 3.016(2) and Sb(2)-I(2): 3.230(2) Å].

71

Fig. 1.42. Crystal structure of [Sb2I6(PMe3)2] showing three dimer units and

three thf molecules of crystallization, taken from ref [138].

The reactions of SbX3 or BiX3 (X =Cl, Br or I) with the diphosphines o-C6H4(PMe2)2 or

o-C6H4(PPh2)2 (L)[143] resulted in complexes of 1:1 stoichiometry MX3L irrespective of

the reactant ratios used. The complex [SbBr3{o-C6H4(PPh2)2] was crystallographically

characterised and found to be dimeric as shown in Fig 1.43 with the isomer A structure

(Fig. 1.44) observed[138] previously for [E2Br6(Me2PCH2CH2PMe2)2] (E = Sb or Bi).

Fig. 1.43. Structure of [Sb2Br6{o-C6H4(PPh2)2}2], taken from ref [143].

72

Fig. 1.44. Isomer A geometry

The reaction of AsX3 with PMe3 yielded products of formula [AsX3(PMe3)2] and

[AsX3(PMe3)] using 1:2 and 1:1 AsX3:PMe3 ratios respectively.[144] The structure

(Fig. 1.45) shows two independent AsCl3(PMe3) moieties in the asymmetric unit which

form a µ-dichloro-bridged dimer. The two As-P distances are essentially similar in the

two dimers, being 2.380(5) and 2.388(5) Å.

Fig. 1.45 (a) Independent dimeric units in [AsCl3(PMe3)] (b) Crystal packing showing

As(1)···Cl(5) interaction, taken from ref [144].

73

1.5. Reactions of arsenic, antimony and bismuth trihalides with P=E donors (E = O, S,

Se)

Few studies have been reported on group 15 trihalides (M = As, Sb or Bi, X = Cl, Br, I)

with R3P=O, R3P=S and R3P=Se, the compounds formed were usually MX3 : 2L

stoichiometry.[145-149] The reactions of triphenylphosphine oxide with MX3 trihalides

have been studied[146-150] resulting in the observation of a number of complexes such

as [SbCl3(Ph3PO)2], [SbBr3(Ph3PO)2], [SbI3(Ph3PO)2], [BiCl3(Ph3PO)3], [BiBr3(Ph3PO)2] and

[BiI3(Ph3PO)2], which were investigated by vibrational spectroscopy.

The two complexes [SbCl3(Ph3PO)2][147, 151] and [BiI3(Ph3PO)2][152] were

crystallographically characterised. The structure of [BiI3(Ph3PO)2], as shown in Fig. 1.46,

is binuclear with bridging iodides and cis triphenylphosphine oxide ligands. The Bi-I

bond lengths for the terminal Bi-I bonds are 2.901(2) and 2.947(1) Å and the bridging

Bi-I distances are 3.050(1) and 3.353(2) Å respectively. The P-O bond lengths are

1.499(7) and 1.508(6) Å, which is longer than the P=O bond in Ph3PO which is 1.46(1)

Å.[146]

Fig. 1.46. Structure of [{BiI3(Ph3PO)2}2], taken from ref [152].

74

Bismuth(III) chloride reacts with the monodentate selenium donor,[142]

tris(dimethylamino)phosphane selenide Se=P(NMe2)3, forming

[(Me2N)3PSeSeP(NMe2)3]2+[(BiCl4)2]n2n- the cation of which is shown in Fig. 1.47, its

structure consists of discrete [(Me2N)3PSeSeP(NMe2)3]2+ cations and two independent

but equivalent two-dimensional polymeric anion chains, [(BiCl4)2]n2n- as shown in

Fig. 1.48 where the dimeric (BiCl4)2 units are linked by further Bi-Cl bridges giving

separate infinite chains of edge-sharing octahedral bismuth atoms.

Fig. 1.47. Structure of [(Me2N)3PSeSeP(NMe2)3]2+, taken from ref [142].

Fig. 1.48. Structure of polymeric halide polymeric anion, [(BiCl4)2]n2n-, taken

from ref [142].

75

There are two terminal Bi-Cl bonds, which range between 2.497(9) to 2.528(9) Å and

four bridging Bi-Cl links of lengths which range between 2.65(1) to 3.02(1) Å within

each chain of the two Bi atoms.

Antimony (III) iodide reacts with Ph3PSe forming a 1:1 complex as shown in

Fig. 1.49 consisting of two T-shaped [SbI3{SePPh3}] units dimerising through halogen

bridges, to give a square-pyramidal geometry at antimony which was reported by

Haase and co-workers.[148, 153] The dimer consists of terminal Sb-I bonds,

d(Sb-I) = 2.7287(19) and 2.818(3) Å and bridging Sb-I links of lengths 3.047(3) and

3.323(3) Å, the bond length of the Sb(1)-Se(1) bond is 2.861(2) Å. The dimer also shows

that the one of the phenyl rings is oriented over the vacant coordination site of the Sb

centre.

Fig 1.49. Dimeric structure of [SbI3{SePPh3}], taken from ref [153].

The complex [Sb4Br12(SPMe2Ph)4][148] also has a similar tetrameric structure to

[Bi4Br12(PEt3)4] with bridging phosphine sulfide ligands.

Phosphine oxide complexes of the pentachlorides of arsenic and antimony are

known[155] but the AsCl5 complexes are thermally unstable. Antimony pentachloride

forms a series of complexes with R3PO, R3PS and R3PSe where R = Me, Ph and also with

bidentate ligands such as Ph2P(O)CH2P(O)Ph2, Ph2P(O)(CH2)2P(O)Ph2, Ph2P(S)CH2P(S)Ph2

and o-C6H4(P(O)Ph2)2.[155] However the R3PSe complexes seemed to be unstable and

rapidly decomposed.

76

Recently, Levason et al[156] have reported the coordination chemistry of arsenic and

antimony trifluorides with R3PO where R = Ph, Me and bidentate ligands such as

R2P(O)(CH2)nP(O)R2 (R = Ph or Me when n = 1; R = Ph when n = 2) which were the first

examples to be studied. No complexes were formed with bismuth trifluoride.

Attempted to form complexes with sulfide donors were unsuccessful.

From crystallographic data, it has been shown that the antimony complexes

consist of a square pyramidal SbF3O2 arrangement with an apical F atom which is

similar to SbF5 in various fluoroantimonate(III) structures.[157] The structure of

[SbF3{Ph2P(O)CH2P(O)Ph2}] as shown in Fig. 1.50 contains distorted square pyramidal

SbF3O2 with a chelating diphosphine dioxide ligand and Sb-O bond lengths of 2.306(3)

and 2.593(3) Å, whereas the structure of the methyl analogue,

[SbF3{Me2P(O)CH2P(O)Me2}] also exhibits a square pyramidal geometry but this time

with a bridging diphosphine dioxide ligand to give a dimeric structure resulting in a

twelve-membered ring (Fig. 1.51).

Fig. 1.50. Structure of [SbF3{Ph2P(O)CH2P(O)Ph2}], taken from ref [156].

77

Fig. 1.51. Dimeric structure of [SbF3{Me2P(O)CH2P(O)Me2}], taken from ref [156].

1.6. Aims and objectives

Previous work has been carried out the reaction of tertiary phosphines

(R3P = substituted aryl, mixed aryl/alkyl, triaryl or trialkyl) with halogens (X2 , X = Cl, Br

or I) and a number of the interhalogens interhalogens (IX) resulting in products of

formula, R3PX2 and R3PIX. The R3PBr2 and R3PI2 compounds usually exhibited spoke

structure with a linear P-X-X arrangement, however the R3PCl2 compound (R = PPh3)

gave an unusual dinuclear ionic structure in DCM and a trigonal bipyramidal structure

in diethyl ether. Thus, the nature of the R3PX2 compound formed is dependent on the

nature of R and the solvent used in its synthesis. This work is concerned with extending

this work to the reactions of a series of tertiary phosphines with ICl3, Br2/IBr and SeX4.

The coordination chemistry of P-S and P-Se donors, R3P=E (R3P = alkyl, aryl; E = S or Se)

with halogens and interhalogens has also been investigated extending previous reports

that compounds of this type have different structural motifs such as (Me2N)3PSeI2 has

a spoke structure whereas (Me2N)3PSeBr2 adopts a T-shaped geometry.

78

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Chem., 1975, 27, 363. 111. P. W. Codding, K.A. Kerr, Acta Crystallogr., Sect. B; Struct. Crystallogr. Cryst. Chem., 1978, 34, 3785. 112. T. S. Cameron, B. Dahlen, J. Chem. Soc., Dalton Trans. 1975, 2, 1737. 113. F. A. Cotton, G. Wilkinson, Advanced Inorganic Chemistry, 4th, 1980, John Wiley & sons, New York. 114. G. A. Fisher and N. C. Norman, Advances in Inorganic Chemistry, 41. 115. S. C. Nyburg, G. A. Ozin, and J. T. Szymański, Acta Crystallogr., Sect. B; Struct. Crystallogr. Cryst. Chem., 1971, 27, 2298. 116. A. Lipka, Acta Crystallogr., Sect. B; Struct. Crystallogr. Cryst. Chem., 1979, 35, 3020. 117. J. Galy, R. Enjalbert, P. Lecante and A. Burian, Inorg. Chem. 2002, 41, 693. 118. D. W. Cushen and R. Hulme, J. Chem. Soc. 1962, 2218. 119. D. W. Cushen and R. Hulme, J. Chem. Soc. 1964, 4162. 120. J. Trotter, Z. Kristallogr. 1965, 122, 230. 121. H. von Benda, Z. Kristallogr. 1980, 151, 271. 122. J. Trotter and T. Zobel, Z. Kristallogr. 1966, 123, 67. 123. R. Enjalbert and J. Galy, Acta Crystallogr., Sect. B; Struct. Crystallogr. Cryst. Chem., 1980, 36, 914. 124. N. J. Hill, W. Levason and G. Reid, Inorg. Chem. 2002, 41, 2070. 125. A. R. J. Genge, W. Levason and G. Reid, Chem. Commun., 1998, 2159. 126. A. J. Barton, A. R. J. Genge, W. Levason and G. Reid, J. Chem. Soc., Dalton Trans., 2000, 859. 127. A. J. Barton, A. R. J. Genge, W. Levason and G. Reid, J. Chem. Soc., Dalton Trans., 2000, 2163. 128. A. J. Barton, N. J. Hill, W. Levason, B. Patel and G. Reid, Chem. Commun., 2001, 95. 129. A. J. Barton, N. J. Hill, W. Levason and G. Reid, J. Chem. Soc., Dalton Trans., 2001, 1621. 130. W. Levason and G. Reid, J. Chem. Soc., Dalton Trans., 2001, 2953. 131. N. J. Hill, W. Levason, R. Patel, G. Reid and M. Webster, Dalton Trans., 2004,

980. 132. W. Levason, S. Maheshwari, R. Ratnani, G. Reid, M. Webster and W. Zhang., Inorg. Chem. 2010, 49, 9036. 133. G. R. Willey, M. T. Lakin and N. W. Alcock, J. Chem. Soc., Dalton Trans., 1992, 591. 134. G. R. Willey, M. T. Lakin and N. W. Alcock, J. Chem. Soc., Dalton Trans., 1992, 1251. 135. A. J. Blake, D. Fenske, W. S. Li, V. Lippolis and M. Schroder, J. Chem. Soc., Dalton Trans., 1998, 3968. 136. W. Clegg, R. J. Errington, R. J. Flynn, M. E. Green, D. C. R. Hockless, N. C. Norman, V. C. Gibson and K. Tavakkoli, J. Chem. Soc., Dalton Trans., 1992, 1753. 137. W. Clegg, M.R. J. Elsegood, N. C. Norman and N. L. Pickett, J. Chem. Soc., Dalton Trans., 1994, 1753. 138. W. Clegg, M. R. J. Elsegood, V. Graham, N. C. Norman, N. L. Pickett and K. Tavakkoli, J. Chem. Soc., Dalton Trans., 1994, 1743. 139. W. Clegg, M. R. J. Elsegood, V. Graham, N. C. Norman and N. L. Pickett, J. Chem.

Soc., Dalton Trans., 1993, 997.

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140. G. R. Willey, L. T. Daly and M. G. B. Drew, J. Chem. Soc., Dalton Trans.,1996, 1063 141. W. Clegg, R. J. Errington, G. A. Fisher, M. E. Green, D. C. R. Hockless, N. C. Norman, Chem. Ber., 1991, 124, 2457. 142. G. R. Willey, J. R. Barras, M. D. Rudd and M. G. B. Drew, J. Chem. Soc., Dalton Trans., 1994, 3025. 143. A. R. J. Genge, N. J. Hill, W. Levason and G. Reid, J. Chem. Soc., Dalton Trans., 2001, 1007. 144. N. J. Hill, W. Levason and G. Reid, J. Chem. Soc., Dalton Trans., 2002, 1188. 145. M. Zackrisson, K. I. Anden, Acta. Chem. Scand., 1960, 14, 994. 146. S. Milićev, D. Hadži, Inorg. Chim. Acta., 1977, 21, 201. 147. L. Golič, S. Milićev, Acta Crystallogr., Sect. B: Struct. Crystallogr. Cryst. Chem.,

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Chapter 2. Experimental

2.1. General methods

2.2. Reactions of triaryl phosphines with iodine trichloride

2.3. Reactions of triaryl phosphines with dibromine/iodine monobromide

2.4. Reactions of phosphonium halides with dibromine/sulfuryl chloride

2.5 Reactions of tertiary phosphines with selenium tetrahalides

2.6. Reactions of tertiary phosphines with elemental selenium

2.7. Reactions of tri-o-tolylphosphine selenide, tri-p-tolylphosphine selenide

and triphenylphosphine selenide with main-group halides

2.8. Reactions of mixed aryl phosphine selenides and tris(4-fluorophenyl)phosphine

selenide with main group halides

2.9. Reactions of mixed alkylaryl phosphine selenides with main group halides

2.10. Reactions of diphosphine diselenides with main group halides

85

Chapter 2. Experimental

2.1. General methods

Most of the compounds studied in this report are moisture sensitive, additionally a few

are air sensitive, therefore strict anhydrous and anaerobic conditions were used in

their synthesis and studies. The air/ moisture sensitive materials were either syringed

or weighed from their bottles in a glove box (Belle technology).

2.1.1. Glassware

All glassware used was connected to a vacuum /N2 line where it was dried using a heat

gun, cooled under vacuum and then filled with dry nitrogen. This procedure was

repeated two times before undertaking any reaction.

2.1.2. Chemicals

Tri-o-tolyl phosphine, tri-m-tolyl phosphine, bis(diphenylphosphino)methane,

triphenylphosphine sulfide, methyltriphenylphosphonium iodide, methyl-

triphenylphosphonium bromide, tris(4-fluorophenyl)phosphine, tris(2,6-

dimethylphenyl) phosphine, sulfuryl chloride, bismuth triiodide, bismuth tribromide,

iodine, iodine monobromide, iodine trichloride, antimony tribromide, antimony

triiodide, selenium tetrachloride, selenium tetrabromide, toluene (Aldrich),

methyldiphenylphosphine, dimethylphenylphosphine, tetramethylphosphonium

bromide, antimony trichloride, bismuth trichloride, tris(4-methoxyphenyl) phosphine,

selenium powder (Alfa Aesar), triphenyl phosphine, triphenyl phosphine selenide, cis-

1,2-bis(diphenylphosphino)ethylene, trans-1,2-bis(diphenylphosphino)ethylene

(Lancaster), 1,2-bis(diphenyl phosphino)ethane (Avocado), arsenic tribromide (Acros

Organic), arsenic triiodide (Strem Chemicals), tris(2-methoxyphenyl)phosphine, 1,4-

bis(diphenyl phosphino)butane, bromine, di-o-tolylphenyl phosphine, o-tolyldiphenyl

phosphine tri-o-tolyl phosphine selenide, tri-p-tolyl phosphine selenide tris-o-

thioanisylphosphine, 1,6-(diphenylphosphino)hexane, tri-p-tolyl phosphine and arsenic

trichloride were used as supplied.

86

2.1.3. The Drying of solvents

Dried solvents (diethyl ether, dichloromethane and pentane) were collected directly

from a commercial solvent purification system in which HPLC grade solvents are dried

over alumina columns.

2.1.4. Spectroscopic techniques and physical properties

a) NMR spectroscopy

The 1H, 13C, 31P and 77Se NMR spectra were recorded on a Bruker Avance III 400 MHz

spectrometer with operating frequencies of 1H: 400.1 MHz, 13C: 100.6 MHz, 31P: 162.0

MHz, 77Se: 76.3 MHz and recorded at 300K using CDCl3 as the solvent unless otherwise

specified. The peak positions are quoted relative to TMS (1H & 13C), 85% H3PO4 (31P)

and Me2Se (77Se), unless otherwise stated NMR signals are singlets.

b) Elemental analysis

All the micro analytical analyses were carried out by the micro analytical laboratory at

the School of Chemistry-University of Manchester. Carbon, hydrogen and nitrogen (C,

H, N) on a Thermo Scientific, Flass 2000 organic elemental analyser; Halides (Cl, Br & I)

on a Metrohm 686 Titroprocessor, 665 Dosimat elemental analyser and Phosphorus on

an ICP/OES Fisons Horizon Instrument.

c) Raman Spectroscopy

All the Raman spectra were run as solid samples recorded on a Nicolet Nexus

combined FT-IR/ FT-Raman spectrometer using the OMNIC E.S.P. 5.1 software

package. The values given in bold are the peaks which are most intense.

d) X-ray Crystallography

X-ray data for the compounds were recorded on a Nonius k-CCD 4-circle

diffractometer using graphite monochromated Mo-Kα radiation (λ= 0.71073 Å).

The structural data for all the compounds were solved by direct methods (SHELXS97).

CIF files for all structures in this thesis can be found on the enclosed CD.

87

2.2. Reactions of triaryl phosphines with iodine trichloride

Synthesis of [R3PCl][ICl2] where R3P = Ph3P, (p-FC6H4)3P, (o-SCH3C6H4)3P, (o-CH3C6H4)3P,

[(2,6-OCH3)2C6H3]3P, CH3Ph2P, (CH3)2PhP. These [R3PCl][ICl2] compounds were

synthesized by reacting equimolar quantities of R3P with ICl3 in diethyl ether under

anhydrous and anaerobic conditions.

2.2.1. Synthesis of [Ph3PCl][ICl2]

Triphenyl phosphine (0.5 g, 1.9 mmoles) was added to anhydrous diethyl ether (50 ml)

in a Rotaflo tube with stirring against a stream of dry nitrogen. Iodine trichloride (0.444

g, 1.9 mmoles) was added and the colour of the solution changed to orange-brown.

The reaction was left stirring for 2 days. The solid product was isolated using standard

Schlenk techniques and dried in vacuo for two hours. The dry solid product (dark

yellow) was transferred to pre-dried sample tubes in the glove box.

[Ph3PCl][ICl2] : Calculated for C18H15Cl3IP: C, 43.60; H, 3.05; Cl, 21.47; I, 25.62 %; Found:

C, 46.58; H, 3.10; Cl, Approx. 17; I, Approx. 23 %. 1H NMR (CDCl3): δ 7.5-7.65 (m, 8H,

ArH), 7.7-7.8 (m, 2H, ArH), 7.8-7.95 (m, 4H, ArH), 7.97-8.07 (m, 1H, ArH), 13C{1H} NMR

(CDCl3): δ 118.5 (d, Ci, J(PC) = 93.2 Hz), 129.6 (d, Cm, J(PC) = 12.2 Hz), 131.2 (d, Co, J(PC)

= 13.7 Hz), 134.45 (d, Cp, J(PC) = 2.68 Hz), 31P{1H} NMR (CDCl3): δ 43.9, 66.0. Raman

(cm-1): 3066, 1588, 1573, 1185, 1162, 1027, 998, 688, 615, 313, 294, 274, 188.

2.2.2. Synthesis of [(p-FC6H4)3PCl][ICl2]

In a procedure analogous to 2.2.1, [(p-FC6H4)3PCl][ICl2] (as a yellow solid) was prepared

using tris(4-fluorophenyl)-phosphine (0.5 g, 1.58 mmoles) and iodine trichloride (0.368

g, 1.58 mmoles).

[(p-FC6H4)3PCl][ICl2]: Calculated for C18H12F3Cl3IP: C, 39.32; H, 2.20; Cl, 19.36; I, 23.10 %;

Found: C, 40.28; H, 2.03; Cl, Approx.17; I, Approx. 22 %. 1H NMR (CDCl3): δ 7.2-7.4 (m,

6H, ArH), 7.5-7.7 (m, 6H, ArH), 31P{1H} NMR (CDCl3): δ 64.6. Raman (cm-1): fluoresced.

2.2.3. Synthesis of [(o-SCH3C6H4)3PCl][ICl2]

In a procedure analogous to 2.2.1, [(o-SCH3C6H4)3PCl][ICl2] (as an orange solid) was

prepared using tris-o-thioanisyl phosphine (0.5 g, 1.25 mmoles) and iodine trichloride

(0.291 g, 1.25 mmoles).

88

[(o-SCH3C6H4)3PCl][ICl2]: Calculated for C21H21Cl3IPS3: C, 39.79; H, 3.34; Cl, 16.79; I,

20.04; S, 15.14 %; Found: C, 41.37; H, 3.40; Cl, Approx. 14; I, Approx. 19; S, 15.28 %. 1H

NMR (CDCl3): δ 2.45 (s, br, 9H, SCH3), 7.52-7.63 (m, 5H, ArH), 7.6-7.8 (m, 4H, ArH), 7.86-

7.95 (m, 3H, ArH), 31P{1H} NMR (CDCl3): δ 36.9*, 56.9. Raman (cm-1): 3059, 2983, 2917,

1576, 1554, 1440, 1417, 1274, 1170, 1107, 1041, 708, 651, 430, 264, 149, 116.

2.2.4. Synthesis of [(o-CH3C6H4)3PCl][ICl2]

In a procedure analogous to 2.2.1, [(o-CH3C6H4)3PCl][ICl2] (as a brown solid) was

prepared using tri-o-tolyl phosphine (0.5 g, 1.6 mmoles) and iodine trichloride (0.383 g,

1.6 mmoles).

[(o-CH3C6H4)3PCl][ICl2]: Calculated for C21H21Cl3IP: C, 46.89; H, 3.94; Cl, 19.79; I, 23.61

%; Found: C, 50.69; H, 4.12; Cl, Approx. 16; I, Approx. 23 %. 1H NMR (CDCl3): δ 2.43 (s,

9H, CH3), 7.38-7.45 (m, 3H, ArH), 7.60-7.66 (m, 3H, ArH), 7.68-7.76 (m, 3H, ArH), 7.89-

7.95 (m, 3H, ArH), 13C{1H} NMR (CDCl3): δ 23.0 (d, CCH3, J(PC) = 5 Hz), 116.4 (d, Ci, J(PC) =

89.0 Hz), 128.5 (d, Cm, J(PC) = 15.2 Hz), 132.7 (d, Co, J(PC) = 11.2 Hz), 134.8 (d, Cm, J(PC)

= 12.2 Hz), 137.7 (s, Cp), 144.4 (d, Co, J(PC) = 10.0 Hz) 31P{1H} NMR (CDCl3): δ 44.1*,

64.4. Raman (cm-1): 3055, 1591, 1566, 1386, 1166, 1047, 840, 799, 692, 664, 262, 189.

2.2.5. Synthesis of [((2,6-OCH3)2C6H3)3PCl][ICl2]

In a procedure analogous to the above, [((2,6-OCH3)2C6H3)3PCl][ICl2] (as a yellow solid)

was prepared using tris(2,6-dimethylphenyl) phosphine (0.332 g, 0.75 mmoles) and

iodine trichloride (0.175 g, 0.75 mmoles).

[((2,6-OCH3)2C6H3)3PCl][ICl2]: Calculated for C24H27Cl3IO6P: C, 42.64; H, 4.03; Cl, 15.75; I,

18.79 %; Found: C, 43.16; H, 3.98; Cl, Approx. 15; I, Approx. 20 %. 1H NMR (CDCl3): δ

3.66 (s, 18H, 6CH3), 6.55-6.65 (m, 2H, ArH), 6.65-6.8 (m, 4H, ArH), 7.51-7.6 (m, 1H,

ArH), 7.6-7.78 (m, 2H, ArH), 31P{1H} NMR (CDCl3): δ 36.4. Raman (cm-1): 3081, 3021,

3005, 2939, 2839, 1585, 1576, 1463, 1447, 1295, 1287, 1249, 1186, 1060, 1045, 751,

425, 372, 277, 264, 146, 140, 125, 117.

2.2.6. Synthesis of [CH3Ph2PCl][ICl2]

Methyldiphenylphosphine (0.2 ml, 1.06 mmoles) was syringed into 50 ml of anhydrous

pentane in a Rotaflo tube in the glove box, the reaction was then stirred under

89

nitrogen. Iodine trichloride (0.248 g, 1.06 mmoles) was added and the colour of the

solution changed to yellow. The reaction was left stirring for 4 days. The product was

isolated using standard Schlenk techniques and dried in vacuo for two hours. The dry

solid product (yellow) was transferred to pre-dried sample tubes in the glove box.

31P{1H} NMR (CDCl3): δ 48.5.

2.2.7. Synthesis of [(CH3)2PPhCl][ICl2]

In a procedure analogous to 2.2.6, [(CH3)2PPhCl][ICl2] (as a dark orange product) was

prepared using dimethylphenylphosphine (0.2 ml, 1.4 mmoles) and iodine trichloride

(0.327 g, 1.4 mmoles).

[(CH3)2PPhCl][ICl2]: Calculated for C8H11Cl3IP: C, 25.85; H, 2.99; Cl, 28.64; I, 34.18; P,

8.34 %; Found: C, 34.53; H, 4.14; Cl, Approx. 20; I, Approx. 27 %. 31P{1H} NMR (CDCl3): δ

53.4, 79.8. Raman (cm-1): 3065, 2972, 2906, 1549, 1161, 1028, 996, 683, 479, 415, 273,

246, 160, 141, 109.

2.3. Reactions of triaryl phosphines with dibromine/iodine monobromide

The syntheses of these compounds was undertaken via a two step reaction. In the first

step, Br2 and R3P were reacted in a 1:1 ratio, followed by the addition of iodine

monobromide the next day.

Attempts were made to prepare [R3PX][IX2] where R3P = Ph3P, (p-FC6H4)3P, (o-

SCH3C6H4)3P, (o-CH3C6H4)3P, (p-CH3C6H4)3P, (o-OCH3C6H4)3P and X = Br.

2.3.1. Attempted synthesis of [Ph3PBr][IBr2]

Triphenyl phosphine (1.0 g, 3.8 mmoles) was added to anhydrous diethyl ether (50 ml)

in a Rotaflo tube and stirred under nitrogen. Bromine (0.195 ml, 3.8 mmoles) was

added and the colour of the solution changed to pale yellow. The reaction was left

stirring for 24 hrs. Iodine monobromide (0.78 ml, 3.8 mmoles) was syringed into the

Rotaflo tube, and the colour of the solution remained yellow. The reaction was left

stirring for 2 days. The product was isolated using standard Schlenk techniques and

dried in vacuo for two hours. The dry solid product (yellow) was transferred to pre-

dried sample tubes in the glove box.

90

[Ph3PBr][IBr2]: Calculated for C18H15Br3IP: C, 34.34; H, 2.38; Br, 38.11; I, 20.17 %;

Found: C, 46.85; H, 3.41; Br, Approx. 44; I, Approx. 3 %. The actual product is

[Ph3PBr][Br3]: Calculated for C18H15Br4P: C, 37.13; H, 2.60; Br, 54.94 %. Found: C, 46.85;

H, 3.41; Br, Approx. 44 %. 1H NMR (CDCl3): 7.37-7.55 (m, 4H, ArH), 7.51-7.7 (m, 10H,

ArH), 7.7-7.81 (m, 1H, ArH), 13C{1H} NMR (CDCl3): δ 118.5 (d, Ci, J(PC) = 93.2 Hz), 129.6

(d, Cm, J(PC) = 12.2 Hz), 131.2 (d, Co, J(PC) = 13.7 Hz), 134.45 (d, Cp, J(PC) = 2.68 Hz),

31P{1H} NMR (CDCl3): δ 51.6. Raman (cm-1): fluoresced.

2.3.2. Attempted synthesis of [(o-OCH3C6H4)3PBr][IBr2]

In a procedure analogous to 2.3.1, [(o-OCH3C6H4)3PBr][IBr2] (as a yellow solid) was

attempted using tris(2-methoxyphenyl) phosphine (0.611 g, 1.7 mmoles), bromine

(0.08 ml, 1.7 mmoles) and Iodine monobromide (0.35 ml, 1.7 mmoles).

[(o-OCH3C6H4)3PBr][IBr2]: Calculated for C21H21Br3IO3P: C, 35.06; H, 2.94; Br, 33.35; I,

17.66 %; Found: C, 40.11; H, 3.42; Br, Approx. 10; I, Approx. 6 %. The actual product is

[(o-OCH3C6H4)3PBr][Br3]: Calculated for C21H21Br4O3P: C, 37.51; H, 3.15; Br, 47.58 %.

Found: C, 40.11; H, 3.42; Br, Approx. 10 %. 1H NMR (CDCl3): (m, 4H, ArH), 7.51-7.7 (m,

10H, ArH), 7.7-7.81 (m, 1H, ArH), 13C{1H} NMR (CDCl3): δ 57 (s, COCH3), 106.5 (d, Ci, J(PC)

= 96 Hz), 113.5 (d, Cm, J(PC) = 7.4 Hz), 122.4 (d, Co, J(PC) = 15.6 Hz), 135.1(d, Cm, J(PC) =

11.7 Hz), 139.0 (d, Cp, J(PC) = 1.8 Hz), 161.8 (d, Co, J(PC) = 2.7 Hz) 31P{1H} NMR (CDCl3): δ

37.7, 51.6. Raman (cm-1): 3071, 2944, 2839, 1591, 1255, 1171, 1141, 1040, 912, 791,

727, 672, 253, 240, 177, 165.

2.3.3. Attempted synthesis of [(p-FC6H4)3PBr][IBr2]

In a procedure analogous to 2.3.1, [(p-FC6H4)3PBr][IBr2] (as a dark yellow solid) was

attempted using tris(4-fluorophenyl) phosphine (0.80 g, 2.52 mmoles), bromine (0.130

ml, 2.52 mmoles) and iodine monobromide (0.52 ml, 2.52 mmoles).

[(p-FC6H4)3PBr][IBr2]: Calculated for C18H12F3PBr3I: C, 31.64, H, 1.77; Br, 35.11; I, 18.59

%; Found: C, 39.38; H, 2.12; Br, Approx. 42; I, Approx. 3 %. The actual product is

[(p-FC6H4)3PBr][Br3]: Calculated for C18H12F3Br4P: C, 33.98; H, 1.90; Br, 50.28 %; Found:

C, 39.38; H, 2.12; Br, Approx. 42 %. 1H NMR (CDCl3): 7.3-7.38 (m, 2H, ArH), 7.5-7.6 (m,

4H, ArH), 7.76-7.86 (m, 2H, ArH), 7.86-7.98 (m, 4H, ArH), 31P{1H} NMR (CDCl3): δ 46.8,

91

47.7. Raman (cm-1): 3068, 1591, 1303, 1232, 1168, 1159, 1118, 1097, 822, 626, 353,

220, 165.

2.3.4. Attempted synthesis of [(o-CH3C6H4)3PBr][IBr2]

In a procedure analogous to 2.3.1, [(o-CH3C6H4)3PBr][IBr2] (as a dark yellow solid) was

attempted using tri-o-tolyl phosphine (0.80 g, 2.62 mmoles), bromine (0.134 ml, 2.62

mmoles) and iodine monobromide (0.54 ml, 2.62 mmoles).

[(o-CH3C6H4)3PBr][IBr2]: Calculated for C21H21PBr3I: C, 37.57; H, 3.16; Br, 35.74; I, 18.92

%; Found: C, 40.01, H, 3.35; Br, Approx. 52, I, Approx. 3 %. The actual product is [(o-

CH3C6H4)3PBr][Br3]: Calculated for C21H21PBr4: C, 40.40; H, 3.39; Br, 51.24 %. Found: C,

40.01, H, 3.35; Br, Approx. 52 %. 1H NMR (CDCl3): 2.49 (s, 9H, CH3), 7.42-7.53 (m, 3H,

ArH), 7.57-7.64 (m, 3H, ArH), 7.64-7.72 (m, 3H, ArH), 7.84-7.91 (m, 3H, ArH), 13C{1H}

NMR (CDCl3): δ 23.1(d, CCH3, J(PC) = 4.8 Hz), 116.4 (d, Ci, J(PC) = 90.7 Hz), 128.4 (d, Cm,

J(PC) = 16.5 Hz), 132.7 (d, Co, J(PC) = 11.8 Hz), 134.8 (d, Cm, J(PC) = 11.8 Hz), 137.3 (d,

Cp, J(PC) = 3.1 Hz), 144.3 (d, Co, J(PC) = 9.5 Hz), 31P{1H} NMR (CDCl3): δ 45.3. Raman (cm-

1): 1586, 1565, 1381, 1278, 1225, 1198, 1167, 1135, 1048, 802, 663, 549, 531, 514, 475,

425, 405, 237, 168, 157.

2.3.5. Attempted synthesis of [(p-CH3C6H4)3PBr][IBr2]

In a procedure analogous to 2.3.1, [(p-CH3C6H4)3PBr][IBr2] (as a dark yellow solid) was

attempted using tri-p-tolyl phosphine (0.60 g, 1.97 mmoles), bromine (0.10 ml, 1.97

mmoles) and iodine monobromide (0.40 ml, 1.97 mmoles).

[(p-CH3C6H4)3PBr][IBr2]: Calculated for C21H21PBr3I: C, 37.57; H, 3.16; Br, 35.74; I, 18.92

%; Found: C, 40.26, H, 3.17; Br, Approx. 38, I, Approx. 3 %. The actual product is

[(p-CH3C6H4)3PBr][Br3]: Calculated for C21H21PBr4: C, 40.40; H, 3.39; Br, 51.24 %. Found:

C, 40.26, H, 3.17; Br, Approx. 38 %. 31P{1H} NMR (CDCl3): δ 52.4, 52.9. Raman (cm-1):

fluoresced.

2.3.6. Attempted synthesis of [(o-SCH3C6H4)3PBr][IBr2]

In a procedure analogous to the 2.3.1, [(o-SCH3C6H4)3PBr][IBr2] (as a dark yellow solid)

was attempted using tris-o-thioanisyl phosphine (0.80 g, 2.0 mmoles), bromine (0.10

ml, 2.0 mmoles) and iodine monobromide (0.41 ml, 2.0 mmoles).

92

[(o-SCH3C6H4)3PBr][IBr2]: Calculated for C21H21PBr3IS3: C, 32.87; H, 2.76, Br, 31.26; I,

16.55; S, 12.51 %; Found: C, 34.92: H, 3.02; Br, Approx. 43; I, Approx. 3; S, 13.07 %. The

actual product is [(o-SCH3C6H4)3PBr][Br3]: Calculated for C21H21PBr4S3: C, 35.02; H, 2.94;

Br, 44.41; S, 13.33 %. Found: C, 34.95, H, 3.02; Br, Approx. 43; S, 13.33 %. 31P{1H} NMR

(CDCl3): δ 56.6*, 48.3. Raman (cm-1): 3052, 2988, 2918, 1570, 1547, 1278, 1173, 1113,

1098, 1040, 240, 156.


Synthesis of [R3PR'][IX2] where R= Ph3, R'= CH3 and X = Cl, Br.

2.4.1. Synthesis of [Ph3PCH3][IBr2]

Methyltriphenylphosphonium iodide (1.0 g, 2.4 mmoles) was added to anhydrous

diethyl ether (50 ml) in a Rotaflo tube and stirred under nitrogen. Bromine (0.126 ml,

2.4 mmoles) was added and the colour of the solution changed to pale orange. The

reaction was left stirring for 2 days. The product was isolated using standard Schlenk

techniques and dried in vacuo for two hours. The dry orange brown solid product was

transferred to pre-dried sample tubes in the glove box.

[Ph3PCH3][IBr2]: Calculated for C19H18Br2IP: C, 40.44; H, 3.22; Br, 28.34; I, 22.51; P, 5.49

%. Found: C, 45.05; H, 3.34; Br, Approx. 22; I, Approx. 21.0; P, 5.91 %. 31P{1H} NMR

(CDCl3): δ 21.4. Raman (cm-1): 3052, 2967, 2897, 1590, 1573, 1190, 1161, 1106, 1028,

998, 675, 380, 278, 273, 257, 177, 151, 132.

2.4.2. Synthesis of [Ph3PCH3][ICl2]

In a procedure analogous to 2.4.1, [Ph3PCH3][ICl2] (as a yellow solid) was prepared

using methyltriphenylphosphonium iodide (1.0 g, 2.4 mmoles) and sulfuryl chloride

(0.19 ml, 2.4 mmoles) which was added dropwise.

[Ph3PCH3][ICl2]: Calculated for C19H18Cl2IP: C, 48.01; H, 3.82; Cl, 14.93; I, 26.72; P, 6.52

Found: C, 48.39; H, 3.68; Cl, App. 13; I, App. 26.0; P, 6.48 %. 31P{1H} NMR (CDCl3): δ

21.3. Raman (cm-1): 3065, 3048, 2973, 2900, 1586, 1165, 1106, 1028, 999, 675, 614,

268, 181, 154.

93

2.4.3. Synthesis of [Ph3PCH3][Br3]

In a procedure analogous to 2.4.1, [Ph3PCH3][Br3] (as a yellow solid) was prepared

using methyltriphenylphosphonium bromide (0.30 g, 0.84 mmoles) and bromine

(0.043 ml, 0.84 mmoles).

[Ph3PCH3][Br3]: Calculated for C19H18Br3P: C, 44.12; H, 3.51; Br, 46.38; P, 5.99 %.

Found: C, 45.30; H, 3.47; Br, 45.40; P, 6.25 %. 31P{1H} NMR (CDCl3): δ 21.2.

Raman (cm-1): 3060, 2966, 2894, 1586, 1028, 999, 675, 260, 166.

2.4.4. Attempted synthesis of [(CH3)4P][Br3]

In a procedure analogous to 2.4.1, [(CH3)4P][Br3] (as a yellow solid) was attempted

using tetramethylphosphonium bromide (0.20 g, 1.1 mmoles) and bromine (0.06 ml,

1.1 mmoles).

[(CH3)4P][Br3]: Calculated for C4H12Br3P: C, 14.51; H, 3.66; Br, 72.47; P, 9.36 %. Found:

C, 28.32; H, 7.07; Br, 46.80; P, 17.86 %. The actual product is starting material

[(CH3)4PBr]: Calculated for C4H12PBr: C, 28.07; H, 7.07; Br, 46.74; P, 18.12 %. Found: C,

28.32; H, 7.07; Br, 46.80; P, 17.86 %. 31P{1H} NMR (CDCl3): δ 23.8. Raman (cm-1): 2970,

2906, 773, 695, 690, 642, 278.

2.5 Reactions of tertiary phosphines with selenium tetrahalides

Syntheses of [R3PX][SeX3] where R3P = (o-tolyl)3P, (p-tolyl)3P, (o-OCH3C6H4)3P, (p-

OCH3C6H4)3P, (o-SCH3C6H4)3P, (p-FC6H4)3P, Me2PhP and X = Cl, Br. The [R3PX][SeX3] salts

were synthesized by reacting equimolar quantities of R3P with either SeCl4 or SeBr4 in

diethyl ether under anhydrous and anaerobic conditions.

2.5.1. Synthesis of [(o-tolyl)3PCl][SeCl3]

Tris-o-tolylphosphine (0.50 g, 1.64 mmoles) was added to anhydrous diethyl ether (50

ml) in a Rotaflo tube with stirring against a stream of dry nitrogen. Selenium

tetrachloride (0.36 g, 1.64 mmoles) was added to give a white-coloured solution which

after 5 minutes changed to a very pale yellow colour. The reaction was left stirring for

2 days. The product was isolated using standard Schlenk techniques and dried in vacuo

for two hours. The dry very pale yellow solid product ( 0.678 g, 79 %) was transferred

to pre-dried sample tubes in the glove box.

94

[(o-tolyl)3PCl][SeCl3]: Calculated for C21H21PSeCI4: C, 48.01,; H, 4.03; CI, 27.02; P, 5.90

%; Found: C, 53.71; H, 4.47; Cl, 24.48; P, 6.47 %. 31P{1H} NMR (CDCl3): δ 64.4, 47.9,

43.5*. Raman (cm-1): 3058, 2921, 1590, 1560, 1386, 1286, 1195, 1165, 1133, 1074,

1047, 800, 604 528, 500, 430, 319, 281, 260, 227, 163, 144.

2.5.2. Synthesis of [(p-tolyl)3PCl][SeCl3]

As described in section 2.5.1, [(p-tolyl)3PCl][SeCl3] as a yellow solid (0.792 g, 92 %) was

prepared using tris-p-tolylphosphine (0.50 g, 1.64 mmoles) and selenium tetrachloride

(0.36 g, 1.64 mmoles).

[(p-tolyl)3PCl][SeCl3]: Calculated for C21H21PSeCI4: C, 48.01; H, 4.03; CI, 27.02; P, 5.90 %;

Found: C, 51.60; H, 4.40; Cl, 21.11; P, 6.35 %. 31P{1H} NMR (CDCl3): δ 66.0, 37.9*.

Raman (cm-1): 3047, 2918, 1600, 1563, 1375, 1316, 1216, 1195, 1114, 1098, 808, 797,

668, 650, 634, 570, 489, 383, 346, 277, 232, 174.

2.5.3. Synthesis of [(p-OCH3C6H4)3PCl][SeCl3]

As described in section 2.5.1, [(p-OCH3C6H4)3PCl][SeCl3] as a yellow solid (0.464 g, 71 %)

was prepared using tris-(4-methoxyphenyl)phosphine (0.40 g, 1.13 mmoles) and

selenium tetrachloride (0.25 g, 1.13 mmoles).

[(p-OCH3C6H4)3PCl][SeCl3]: Calculated for C21H21PO3SeCI4: C, 43.99; H, 3.69; CI, 24.75; P,

5.41 %; Found: C, 49.99; H, 4.40; Cl, 16.35; P, 6.27 %. 31P{1H} NMR (CDCl3): δ 64.3,

40.7*. Raman (cm-1): 3074, 2942, 2837, 1587, 1563, 1450, 1437, 1313, 1268, 1192,

1114, 1101, 1001, 800, 625, 563, 370, 330, 278, 195, 187.

2.5.4. Synthesis of [(o-OCH3C6H4)3PCl][SeCl3]

As described in section 2.5.1, [(o-OCH3C6H4)3PCl][SeCl3] as a very pale yellow solid

(0.104 g, 64 %) was prepared using tris-(2-methoxyphenyl)phosphine (0.1 g, 0.28

mmoles) and selenium tetrachloride (0.06 g, 0.28 mmoles).

[(o-OCH3C6H4)3PCl][SeCl3]: Calculated for C21H21PO3SeCI4: C, 43.99; H, 3.69; CI, 24.75; P,

5.41 %; Found: C, 52.67; H, 4.35; Cl, 14.95; P, 6.90 %. 31P{1H} NMR (CDCl3): product

insufficiently soluble. Raman (cm-1): 3071, 3017, 2945, 2837, 1590, 1474, 1448, 1251,

1165, 1138, 1039, 794, 671, 257, 235, 195, 149.

95

2.5.5. Synthesis of [(o-SCH3C6H4)3PCl][SeCl3]

As described in section 2.5.1, [(o-SCH3C6H4)3PCl][SeCl3] as a yellow solid (0.619 g, 80 %)

was prepared using tris-o-thioanisylphosphine (0.50 g, 1.25 mmoles) and selenium

tetrachloride (0.27 g, 1.25 mmoles).

[(o-SCH3C6H4)3PCl][SeCl3]: Calculated for C21H21PS3SeCI4: C, 40.59; H, 3.41; CI, 22.84, P,


36.9*. Raman (cm-1): 3052, 2990, 2921, 1569, 1550, 1442, 1421, 1276, 1165, 1136,

1101, 1034, 749, 703, 663, 585, 426, 351, 273, 257, 176, 155.

2.5.6. Synthesis of [(o-tolyl)3PBr][SeBr3]

In a procedure analogous to 2.5.1, the reaction of tris-o-tolylphosphine (0.50 g, 1.64

mmoles) and selenium tetrabromide (0.65 g, 1.64 mmoles) gave [(o-tolyl)3PBr][SeBr3]

as a dark yellow solid. (0.913 g, 79 %).

[(o-tolyl)3PBr][SeBr3]: Calculated for C21H21PS3SeBr4: C, 35.86; H, 3.01; Br, 45.48, P, 4.41

%; Found: C, 42.68; H, 3.42; Br, 42.19; P, 5.40 %. 31P{1H} NMR (CDCl3): δ 54.9. Raman

(cm-1): fluoresced.

2.5.7. Synthesis of [(p-tolyl)3PBr][SeBr3]

In a procedure analogous to 2.5.1, the reaction of tris-p-tolylphosphine (0.50 g, 1.64

mmoles) and selenium tetrabromide (0.65 g, 1.64 mmoles) gave [(p-tolyl)3PBr][SeBr3]

as a light brown solid (1.06 g, 93 %).

[(p-tolyl)3PBr][SeBr3]: Calculated for C21H21PS3SeBr4: C, 35.86; H, 3.01; Br, 45.48, P, 4.41

%; Found: C, 36.88; H, 2.86; Br, 44.42; P, 4.56 %. 31P{1H} NMR (CDCl3): δ 52.60. Raman

(cm-1): 3044, 2915, 1595, 1378, 1313, 1214, 1196, 1094, 809, 630, 530, 477, 365, 243,

193.

2.5.8. Synthesis of [(p-OCH3C6H4)3PBr][SeBr3]

In a procedure analogous to 2.5.1, the reaction of tris-(4-methoxyphenyl)phosphine

(0.40 g, 1.13 mmoles) and selenium tetrabromide (0.45 g, 1.13 mmoles) gave [(p-

OCH3C6H4)3PBr][SeBr3] as a light brown solid (0.585 g, 69 %).

96

[(p-OCH3C6H4)3PBr][SeBr3]: Calculated for C21H21PO3SeBr4: C, 33.57; H, 2.82; Br, 42.58;

P, 4.13 %; Found: C, 37.51; H, 3.05; Br, 31.46; P, 4.60 %. 31P{1H} NMR (CDCl3): δ 49.9,

51.8, 39.9*. Raman (cm-1): 3073, 3021, 2943, 2837, 1591, 1566, 1527, 1453, 1440,

1410, 1312, 1301, 1261, 1190, 1100, 1003, 840, 800, 668, 626, 531, 497, 329, 228, 182,

163.

2.5.9. Synthesis of [(o-OCH3C6H4)3PBr][SeBr3]

As described in section 2.5.1, [(o-OCH3C6H4)3PBr][SeBr3] as a dark yellow solid (0.582 g,

68.3 %) was prepared using tris-(2-methoxyphenyl)phosphine (0.40 g, 1.13 mmoles)

and selenium tetrabromide (0.45 g, 1.13 mmoles).

[(o-OCH3C6H4)3PBr][SeBr3]: Calculated for C21H21PO3SeBr4: C, 33.57; H, 2.82; Br, 42.58;


48.3. Raman (cm-1): 3066, 2990, 2939, 2834, 1587, 1566, 1477, 1281, 1255, 1160,

1136, 1042, 792, 671, 461, 432, 237, 165, 145.

2.5.10. Synthesis of [(o-SCH3C6H4)3PBr][SeBr3]

As described in section 2.5.1, [(o-SCH3C6H4)3PBr][SeBr3] was prepared as a brown solid

(0.699 g, 70 %) using tris-o-thioanisylphosphine (0.50 g, 1.25 mmoles) and selenium

tetrabromide (0.49 g, 1.25 mmoles).

[(o-SCH3C6H4)3PBr][SeBr3]: Calculated for C21H21PS3SeBr4: C, 31.55; H, 2.65; Br, 40.02; P,

3.88 %; Found: C, 32.86; H, 2.64; Br, 39.54; P, 4.20 %. 31P{1H} NMR (CDCl3): δ 48.7.

Raman (cm-1): 3058, 2988, 2915, 1571, 1547, 1270, 1254, 1172, 1098, 1050, 1035, 710,

647, 544, 443, 417, 379, 281, 255, 229, 195, 155.

2.5.11. Synthesis of [(p-FC6H4)3PCl][SeCl3]

As described in section 2.5.1, [(p-FC6H4)3PCl][SeCl3] as very pale yellow solid (0.676 g,

80 %) was prepared using tris(4-fluorophenyl)phosphine (0.50 g, 1.58 mmoles) and

selenium tetrachloride (0.35 g, 1.58 mmoles).

[(p-FC6H4)3PCl][SeCl3]: Calculated for C18H12F3PSeCI4: C, 40.24; H, 2.25; CI, 26.42; P,

5.77 %; Found: C, 41.04; H, 2.06; Cl, 21.97; P, 6.00 %. 31P{1H} NMR (CDCl3): δ 31.9.

Raman (cm-1): 3069, 1592, 1167, 1097, 830, 627, 570, 351, 285, 230, 174.

97

2.5.12. Synthesis of [(p-FC6H4)3PBr][SeBr3]

As described in section 2.5.1, [(p-FC6H4)3PBr][SeBr3] as an orange brown solid (1.013 g,

90 %) was prepared using tris(4-fluorophenyl)phosphine (0.50 g, 1.58 mmoles) and

selenium tetrabromide (0.63 g, 1.58 mmoles).

[(p-FC6H4)3PBr][SeBr3]: Calculated for C18H12F3PSeBr4: C, 30.23; H, 1.69; Br, 44.72; P,

4.33 %; Found: C, 30.72; H, 1.48; Br, 41.64; P, 4.51 %. 31P{1H} NMR (CDCl3): δ 48.4

Raman (cm-1): 3065, 1588, 1171, 1093, 831, 625, 531, 499, 247, 222, 201.

2.5.13. Synthesis of [Me2PhPCl][SeCl3]

As described in section 2.5.1, [Me2PhPCl][SeCl3] as a dark grey solid (1.203 g, 93 %) was

prepared using dimethylphenyl phosphine (0.51 ml, 3.62 mmoles) and selenium

tetrachloride (0.799 g, 3.62 mmoles).

[Me2PhPCl][SeCl3]: Calculated for C8H11PSeCl4: C, 26.75; H, 3.09; Cl, 39.52; P, 8.63 %;

Found: C, 33.40; H, 3.75; Cl, 28.66; P, 10.60 %. 31P{1H} NMR (CDCl3): δ 57.0, 79.9*.

Raman (cm-1): 3056, 2981, 2965, 2894, 1580, 1023, 991, 551, 278, 235, 139.

2.5.14. Synthesis of [Me2PhPBr][SeBr3]

As described in section 2.5.1, [Me2PhPBr][SeBr3] as an orange solid (1.563 g, 80 %) was

prepared using dimethylphenyl phosphine (0.51 ml, 3.62 mmoles) and selenium

tetrabromide (1.442 g, 3.62 mmoles).

[Me2PhPBr][SeBr3]: Calculated for C8H11PSeBr4: C, 17.89; H, 2.07; Br, 59.56; P, 5.77 %;

Found: C, 23.96; H, 2.58; Br, 54.29; P, 7.38 %. 31P{1H} NMR (CDCl3): δ 67.6.

Raman (cm-1): fluoresced.


A series of tertiary triaryl phosphine, mixed aryl, mixed aryl/alkyl and di phosphine

selenides were prepared by refluxing the tertiary phosphines with selenium powder in

toluene at 90°C for 24 hrs, then filtering off the excess of selenium from the product.

The solvent was then evaporated using a rotary evaporator. The phosphine selenides

were synthesized in 1:1 ratios for (p-tolyl)3P, p-FC6H4)3P, (o-tolyl)2PhP, (o-tolyl)Ph2P,

(CH3)2PhP, Ph2CH3P and 1:2 ratios for bis(diphenylphosphino)methane(dppm),

98

1,2-bis(diphenylphosphino)ethane(dppe), 1,6-(diphenylphosphino)hexane(dpph), cis-

1,2-bis(diphenylphosphino)ethylene and trans-1,2-bis(diphenylphosphino)ethylene.

2.6.1. Synthesis of [(p-FC6H4)3P=Se]

Tris(4-fluorophenyl)phosphine (3.50 g, 11.06 mmoles) and selenium powder (0.873 g,

11.05 mmoles) were refluxed in toluene (200 ml) for 24 hrs, the product was filtered

and the filtrate evaporated using a rotary evaporator. A white waxy solid was

obtained. (4.12 g, 94 %).

[(p-FC6H4)3P=Se]: Calculated for C18H12F3PSe: C, 54.68; H, 3.06; P, 7.84 %; Found: C,

54.92; H, 2.74; P, 7.94 %. 1H NMR (CDCl3): δ 7.13-7.22 (m, 6H, ArH), 7.63-7.78 (m, 6H,

ArH), 31P{1H} NMR (CDCl3): δ 32.3, 77Se{1H} NMR (CDCl3): δ -251.4, d, 1J(SeP) = 742 Hz.

2.6.2. Synthesis of [(p-tolyl)3P=Se]

In a procedure analogous to 2.6.1, [(p-tolyl)3PSe] as a shiny white solid (3.73 g, 97 %)

was prepared using tri p-tolyl phosphine (3.07 g, 10.08 mmoles) and selenium powder

(0.796 g, 10.08 mmoles).

[(p-tolyl)3P=Se]: Calculated for C21H21PSe: C, 65.78; H, 5.52; P, 8.09 %; Found: C, 65.99;

H, 5.36; P, 8.11 %. 31P{1H} NMR (CDCl3): δ 33.7,77Se{1H} NMR (CDCl3): δ -262.7, d, 1J(SeP)

= 718 Hz. Raman (cm-1): 3195, 3049, 3022, 2975, 2917, 2864, 1597, 1560, 1539, 1496,

1446, 1378, 1308, 1211, 1185, 1120, 1096, 807, 646, 631, 621, 570, 540, 478, 364, 319,

238, 221.

2.6.3. Synthesis of [(o-tolyl)2PhP=Se]

In a procedure analogous to 2.6.1, [(o-tolyl)2PhP=Se] as a pink solid (5.84 g, 92 %) was

prepared using di-o-tolylphenyl phosphine (5.0 g, 17.24 mmoles) and selenium powder

(1.361 g, 17.23 mmoles).

[(o-tolyl)2PhP=Se]: Calculated for C20H19PSe: C, 65.03; H, 5.19; P, 8.39 %; Found: C,

65.00; H, 5.21; P, 8.31 %. 1H NMR (CDCl3): δ 2.06 (s, br, 6H, CH3), 7.07-7.16 (m, 2H,

ArH), 7.17-7.26 (m, 4H, ArH), 7.3-7.36 (m, 2H, ArH), 7.36-7.49 (m, 3H, ArH), 7.67-7.76

(m, 2H, ArH), 31P{1H} NMR (CDCl3): δ 29.1, 1J(SeP) = 713 Hz. Raman (cm-1): 3050, 2954,

2922, 1587, 1564, 1385, 1283, 1203, 1178, 1163, 1132, 1097, 1046, 995, 805, 672, 575,

540, 509, 490, 439, 257, 272, 196, 135.

99

2.6.4. Synthesis of [(o-tolyl)Ph2P=Se]

In a procedure analogous to 2.6.1, [(o-tolyl)Ph2P=Se] as a yellowish white solid (1.69 g,

85 %) was prepared using o-tolyldiphenyl phosphine (1.5 g, 5.45 mmoles) and selenium

powder (0.43 g, 5.44 mmoles).

[(o-tolyl)Ph2P=Se]: Calculated for C19H17PSe: C, 64.21; H, 4.83; P, 8.72 %; Found: C,

65.14; H, 4.95; P, 8.77 %. 1H NMR (CDCl3): δ 2.42 (s, br, 3H, CH3), 7.25-7.31 (m, 2H,

ArH), 7.37-7.43 (m, 1H, ArH), 7.45-7.57 (m, 6H, ArH), 7.58-7.75 (m, 1H, ArH), 7.82-7.91

(m, 4H, ArH), 31P{1H} NMR (CDCl3): δ 31.9, 1J(SeP) = 724 Hz. Raman (cm-1): 3046, 2915,

1585, 1572, 1200, 1179, 1160, 1130, 1093, 1051, 1029, 993, 803, 675, 617, 571, 544,

500, 438, 284, 248, 236, 205, 171.

2.6.5. Synthesis of [(CH3)2PhP=Se]

In a procedure analogous to 2.6.1, [(CH3)2PhP=Se] as a viscous yellow liquid (5.4 g, 98

%) was prepared using dimethylphenyl phosphine (3.60 ml, 25.33 mmoles) and

selenium powder (2.0 g, 25.33 mmoles).

[(CH3)2PhP=Se]: 1H NMR (CDCl3): δ 2.05 (d, 6H, CH3, J(PH) = 13.4 Hz), 7.35-7.41 (m, 3H,

ArH), 7.77-7.84 (m, 2H, ArH), 13C{1H} NMR (CDCl3): δ 23.2 (d, PCH3, J(PC) = 50.5 Hz),

128.7 (d, CAr, J(PC) = 11.4 Hz), 130.5 (d, CAr, J(PC) = 9.8 Hz), 131.7 (d, CAr, J(PC) = 3.6 Hz),

132.2 (d, Ci, 1J(PC) = 72 Hz), 31P{1H} NMR (CDCl3): δ 16.0, 1J(SeP) = 703 Hz, 77Se{1H} NMR

(CDCl3): δ -287.2, d, 1J(SeP) = 703 Hz. Raman (cm-1): 3051, 2980, 2905, 1588, 1419,

1404, 1209, 1190, 1158, 1112, 1026, 998, 784, 743, 688, 487, 382, 248, 217, 202.

2.6.6. Synthesis of [Ph2CH3P=Se]

In a procedure analogous to 2.6.1, [Ph2CH3P=Se] as a viscous yellow liquid (6.81 g, 98

%) was prepared using diphenylmethyl phosphine (4.7 ml, 24.98 mmoles) and


[Ph2CH3P=Se]: 1H NMR (CDCl3): δ 2.46 (d, 3H, CH3, J(PH) = 13.2 Hz, 3H), 7.41-7.52 (m,

6H, ArH), 7.80-7.90 (m, 4H, ArH], 13C{1H} NMR (CDCl3): δ 22.2 (d, PCH3, J(PC) = 52.7 Hz),

128.7 (d, CAr, J(PC) = 13.7 Hz), 131.2 (d, CAr, J(PC) = 12.3 Hz), 131.64 (d, CAr, J(PC) = 2.8

Hz), 132.7 (d, Ci, 1J(PC) = 73 Hz), 31P{1H} NMR (CDCl3): δ 23.3, 1J(SeP) = 718 Hz, 77Se{1H}

NMR (CDCl3): δ -276.7, d, 1J(SeP) = 718 Hz. Raman (cm-1): fluoresced.

100

2.6.7. Synthesis of [Ph2P(Se)CH2P(Se)Ph2] (dppmSe2)

In a procedure analogous to 2.6.1, [Ph2P(Se)CH2P(Se)Ph2] as an off white solid (6.56 g,

93 %) was prepared using bis(diphenylphosphino)methane (5.0 g, 13.0 mmoles) and


[Ph2P(Se)CH2P(Se)Ph2](dppmSe2): Calculated for C25H22P2Se2: C, 55.35; H, 4.09; P, 11.43

%; Found: C, 55.47; H, 3.92; P, 11.32 %. 31P{1H} NMR (CDCl3): δ 25.0, 1J(SeP) = 745 Hz,

77Se{1H} NMR (CDCl3): δ -239.7, d, 1J(SeP) = 745 Hz. Raman (cm-1): 3048, 2933, 2884,

1584, 1183, 1158, 1101, 1027, 1001, 618, 530, 501, 385, 270, 250, 233, 184, 131.

2.6.8. Synthesis of [Ph2P(Se)CH2CH2P(Se)Ph2] (dppeSe2)

In a procedure analogous to 2.6.1, [Ph2P(Se)CH2CH2P(Se)Ph2] as a pink solid (13.82 g,

99 %) was prepared using 1,2-bis(diphenylphosphino)ethane (10.0 g, 25.09 mmoles)

and selenium powder (3.96 g, 50.18 mmoles).

[Ph2P(Se)CH2CH2P(Se)Ph2](dppeSe2): Calculated for C26H24P2Se2: C, 56.11; H, 4.35; P,

11.14 %; Found: C, 58.13; H, 4.49; P, 10.46 %. 1H NMR (CDCl3): δ 2.78 (d, 4H, PCH2CH2,

J(PH) = 2.3 Hz), 7.33-7.45 (m, 12H, ArH), 7.70-7.78 (m, 8H, ArH], 31P{1H} NMR (CDCl3): δ

35.9, 1J(SeP) = 735 Hz; 3J(PP) = 64.8 Hz and 4J(PSe) = 6.4 Hz,77Se{1H} NMR (CDCl3): δ -

352.5, dd, 1J(PSe) = 735 Hz; 4J(PSe) = 5.6 Hz.

2.6.9. Synthesis of [Ph2P(Se)(CH2)6P(Se)Ph2] (dpphSe2)

1,6-(diphenylphosphino)hexane (3.0 g, 6.40 mmoles) and selenium powder (1.01 g,

12.80 mmoles) were refluxed in toluene (200 ml) for 48 hrs, initially, the colour of the

solution was grey but changed to greyish white after about an hour. The product was

filtered and the solvent removed using a rotary evaporator. An off-white coloured solid

was obtained (1.28 g, 33 %). There was some residue left in the funnel which was

dissolved in dichloromethane and filtered, the filtrate was evaporated yielding a dark

pinkish solid (1.867 g, 48 %).

[Ph2P(Se)(CH2)6P(Se)Ph2] (dpphSe2)-off-white product: 31P{1H} NMR (CDCl3): δ 34.1,

77Se{1H} NMR (CDCl3): insufficiently soluble.

[Ph2P(Se)(CH2)6P(Se)Ph2]: (dpphSe2)-dark pinkish product.

101

[Ph2P(Se)(CH2)6P(Se)Ph2]: Calculated for C26H24P2Se2: C, 58.81; H, 5.27; P, 10.12 %;

Found: C, 59.01; H, 5.31; P, 9.90 %.31P{1H} NMR (CDCl3): δ 34.1, 77Se{1H} NMR (CDCl3): δ

-345, d, 1J(PSe)= 720 Hz. Raman (cm-1): 3048, 2893, 1587, 996, 902, 724, 259, 238.

2.6.10. Attempted synthesis of [cis-Ph2P(Se)CH=CHP(Se)Ph2]

In a procedure analogous to 2.6.1, a mixture of trans and cis-Ph2P(Se)CH=CHP(Se)Ph2

were formed as a pale yellow solid (4.57 g) in approximately 4:1 ratio was prepared

using cis-1,2-bis(diphenylphosphino)ethylene (3.50 g, 8.82 mmoles) and selenium

powder (1.394 g, 17.65 mmoles).

[trans/cis-Ph2P(Se)CH=CHP(Se)Ph2]: Calculated for C26H22P2Se2: C, 56.31; H, 4.00; P,

11.18 %; Found: C, 56.39; H, 3.81; P, 11.21 %. 1H NMR (CDCl3): δ 7.45-7.57 (m, 12H,

ArH), 7.72-7.81 (m, 8H, ArH), 7.93 (vt, J = 23 Hz, 2H), 13C{1H} NMR (CDCl3): δ 129 (vt,

J(PC) = 7 Hz), 130.4-131.6 (m, C=C), 131.9 (vt, J(PC) = 6 Hz), 132 (s, CpAr), 142.4 (m, Ci),

31P{1H} NMR (CDCl3): δ 22.6*, 28.5, 1J(SeP) = 753 Hz, 3J(PP) = 60.6 Hz and 4J(PSe) = 6.0

Hz, 77Se{1H} NMR (CDCl3): δ -325.4, dd, 1J(PSe) = 753 Hz; 4J(PSe) = 5.8 Hz, 278.8, d,

J(PSe) = 737 Hz. Raman (cm-1): 3166, 3142, 3053, 3003, 2988, 2965, 2948, 1585, 1571,

1259, 1226, 1187, 1160, 1098, 1026, 1001, 811, 702, 614, 553, 530, 258, 197.

2.6.11. Synthesis of [trans-Ph2P(Se)CH=CHP(Se)Ph2]

In a procedure analogous to 2.6.1, [trans-Ph2P(Se)CH=CHP(Se)Ph2] as a beige solid

(4.96 g, 100 %) was prepared using trans-1,2-bis(diphenylphosphino)ethylene (3.50 g,

8.82 mmoles) and selenium powder (1.394 g, 17.65 mmoles).

[trans-Ph2P(Se)CH=CHP(Se)Ph2]: Calculated for C26H22P2Se2: C, 56.31; H, 4.00; P, 11.18

%; Found: C, 59.32; H, 4.22; P, 10.18 %. 1H NMR (CDCl3): δ 7.45-7.57 (m, 12H, Ar), 7.73-

7.8 (m, 8H, Ar), 7.94 (vt, J = 22.2 Hz, 2H), 13C{1H} NMR (CDCl3): δ 129 (vt, J(PC) = 7 Hz),

130.4-131.6 [m, C=C], 131.9 (vt, J(PC) = 6 Hz), 132 (s, CpAr), 142.4 [m, Ci], 31P{1H} NMR

(CDCl3): δ 28.6, 1J(SeP) = 753 Hz; 3J(PP) = 60.6 Hz and 4J(PSe) = 6.0 Hz, 77Se{1H} NMR

(CDCl3): δ -325.8, dd, 1J(PSe) = 753 Hz; 4J(PSe) = 5.6 Hz. Raman (cm-1): 3164, 3139,

3048, 2986, 2955, 2912, 1582, 1435, 1378, 1336, 1265, 1211, 1183, 1161, 1097, 1030,

998, 815, 784, 704, 617, 536, 518, 491, 458, 428, 281, 258, 219, 199, 181.

102

2.7. Reactions of tri-o-tolylphosphine selenide, tri-p-tolylphosphine selenide and

triphenylphosphine selenide with main-group halides

Syntheses of [MX3{Se=PR3}m] where M = Bi, Sb & As; X = Cl, Br, I and R= (o-tolyl)3, (p-

tolyl)3 & Ph3; m = 1 or 2.

2.7.1. Synthesis of [BiCl3{Se=P(o-tolyl)3}]

Tri-o-tolylphosphine selenide (0.50 g, 1.3 mmoles) was added to anhydrous diethyl

ether (50 ml) in a Rotaflo tube with stirring against a stream of dry nitrogen. Bismuth

trichloride (0.205 g, 0.65 mmoles) was added and the colour of the solution changed to

pale yellow. The reaction was left stirring for 2 days. The product was isolated using

standard Schlenk techniques and dried in vacuo for two hours. The dry white solid

product (0.461 g, 65 %) was stored in pre-dried sample tubes in the glove box.

[BiCl3{Se=P(o-tolyl)3}]: Calculated for C21H21PSeBiCl3: C, 36.08; H, 3.03; Cl, 15.23, P, 4.43

%; Found: C, 35.43; H, 2.93; Cl, 15.19; P, 4.30 %. 31P{1H} NMR (CDCl3): product

insufficiently soluble. Raman (cm-1): 3056, 2921, 1588, 1566, 1389, 1279, 1200, 1163,

1133, 1044, 800, 666, 532, 513, 324, 266, 236, 196, 147.

2.7.2. Synthesis of [BiBr3{Se=P(o-tolyl)3}]

In a procedure analogous to 2.7.1, the reaction of tri-o-tolylphosphine selenide (0.50 g,

1.3 mmoles) and bismuth tribromide (0.292 g, 0.65 mmoles) gave [BiBr3{Se=P(o-

tolyl)3}] as a yellow solid. (0.244 g, 31 %).

[BiBr3(Se=P(o-tolyl)3)]: Calculated for C21H21PSeBiBr3: C, 30.30; H, 2.54; Br, 28.82; P,


Raman (cm-1): 3053, 2915, 1585, 1560, 1200, 1163, 1044, 797, 663, 535, 440, 403, 236,

217, 178.

2.7.3. Attempted synthesis of [BiI3{Se=P(o-tolyl)3}]


1.3 mmoles) and bismuth triiodide (0.384 g, 0.65 mmoles) gave [BiI3(Se=P(o-tolyl)3)] as

a greyish-black solid. (0.246 g).

103

[BiI3{Se=P(o-tolyl)3}]: Calculated for C21H21PSeBiI3: C, 37.17; H, 3.1; I, 28.08; P, 4.57 %

Found: C, 1.46; H, <0.3; I, 62.24; P, <0.3 %. The elemental analysis shows that the

product is bismuth triiodide, BiI3: Calculated for BiI3: I, 64.56 %; Found: I, 62.24 %.

31P{1H} NMR (CDCl3): product insufficiently soluble. Raman (cm-1): 141, 117.

2.7.4. Synthesis of [SbCl3{Se=P(o-tolyl)3}]


1.3 mmoles) and antimony trichloride (0.148 g, 0.64 mmoles) gave [SbCl3{Se=P(o-

tolyl)3}] as a white solid. (0.353 g, 54 %).

[SbCl3{Se=P(o-tolyl)3}]: Calculated for C21H21PSeSbCl3: C, 41.23; H, 3.46; Cl, 17.40; P,


Raman (cm-1): 3056, 2915, 1588, 1563, 1390, 1286, 1200, 1163, 1133, 1047, 797, 678,

663, 559, 535, 519, 483, 349, 306, 236, 217, 162.

2.7.5. Synthesis of [SbBr3{Se=P(o-tolyl)3}]


1.3 mmoles) and antimony tribromide (0.235 g, 0.65 mmoles) gave [SbBr3{Se=P(o-

tolyl)3}] as a very pale yellow solid. (0.435 g, 59 %).

[SbBr3{Se=P(o-tolyl)3}]: Calculated for C21H21PSeSbBr3: C, 33.85; H, 2.84; Br, 32.20; P,

4.16 %; Found: C, 33.89; H, 2.78; Br, 32.46; P, 4.15 %. 31P{1H} NMR (CDCl3): δ 29.2,

1J(SeP) = 662 Hz. Raman (cm-1): 3053, 2912, 1585, 1560, 1197, 1163, 1133, 1044, 797,

709, 660, 532, 407, 242, 203.

2.7.6. Synthesis of [SbI3{Se=P(o-tolyl)3}]


1.3 mmoles) and antimony triiodide (0.327 g, 0.65 mmoles) gave [SbI3{Se=P(o-tolyl)3}]

as a dark yellow solid. (0.431 g, 52.1 %).

[SbI3{Se=P(o-tolyl)3}]: Calculated for C21H21PSeSbI3: C, 28.46; H, 2.39; I, 42.99; P, 3.50 %;

Found: C, 28.18; H, 2.53; I, 43.22; P, Approx. 3 %. 31P{1H} NMR (CDCl3): δ 29.2. Raman

(cm-1): 3050, 2918, 1585, 1559, 1377, 1202, 1047, 799, 531, 478, 230, 184, 168.

104

2.7.7. Synthesis of [AsCl3{Se=P(o-tolyl)3}]

Tri-o-tolylphosphine selenide (0.35 g, 0.91 mmoles) was added to anhydrous diethyl

ether (50 ml) in a Rotaflo tube with stirring against a stream of dry nitrogen. Arsenic

trichloride (0.038 ml, 0.45 mmoles) was added The reaction was left stirring for 2 days.

As the product was soluble in diethyl ether, it was evaporated under vacuum until

about 5 ml was left, 15 ml of dry pentane was added which resulted in the

precipitation of a solid, which was isolated using standard Schlenk techniques and

dried in vacuo for two hours. The dry white solid product (0.278 g, 64 %) was


[AsCl3{Se=P(o-tolyl)3}]: Calculated for C21H21PSeAsCI3: C, 44.65; H, 3.75; Cl, 18.85; P,


1J(SeP) = 703 Hz. Raman (cm-1): 3047, 2922, 1587, 1568, 1385, 1284, 1198, 1159, 1128,

1050, 798, 686, 665, 571, 553, 534, 521, 485, 388, 365, 302, 268, 240, 187, 164.

2.7.8. Synthesis of [AsBr3{Se=P(o-tolyl)3}2]


0.91 mmoles) and arsenic tribromide (0.143 g, 0.45 mmoles) gave [AsBr3{Se=P(o-

tolyl)3)}2] as a pale yellow solid. (0.375 g, 38 %).

[AsBr3{Se=P(o-tolyl)3}2]: Calculated for C42H42P2Se2AsBr3: C, 46.63; H, 3.92; Br, 22.18; P,

5.73 %; Found: C, 44.31; H, 3.39; Br, 24.87; P, 5.41%. 31P{1H} NMR (CDCl3): δ 28.1,

1J(SeP) = 700 Hz. Raman (cm-1): 3050, 2915, 1591, 1568, 1385, 1280, 1194, 1163, 1128,

1048, 804, 664, 567, 548, 532, 519, 481, 435, 277, 254, 237, 205, 169.

2.7.9. Synthesis of [AsI3{Se=P(o-tolyl)3}2]


1.3 mmoles) and arsenic triiodide (0.297 g, 0.65 mmoles) gave [AsI3{Se=P(o-tolyl)3)}2]

as an orange solid. (0.344 g, 21.6 %).

[AsI3{Se=P(o-tolyl)3}2]: Calculated for C42H42P2Se2AsI3: C, 41.25; H, 3.46; I, 31.16; P, 5.07

%; Found: C, 40.94; H, 3.49; I, 30.79; P, 4.77 %. 31P{1H} NMR (CDCl3): δ 29.1, 1J(SeP) =

711 Hz. Raman (cm-1): fluoresced.

105

2.7.10. Synthesis of [BiCl3{Se=P(p-tolyl)3}2]

Tri-p-tolylphosphine selenide (0.50 g, 1.3 mmoles) was added to anhydrous diethyl

ether (50 ml) in a Rotaflo tube with stirring against a stream of dry nitrogen. Bismuth

trichloride (0.205 g, 0.65 mmoles) was added, the reaction was to stir for 2 days. The

solvent was evaporated under vacuum until dryness and product left in vacuo for two

hours. The dry yellow solid product (0.44 g, 32 % ) was transferred to pre-dried sample

tubes in the glove box.

[BiCI3{Se=P(p-tolyl)3}2]: Calculated for C42H42P2Se2BiCl3: C, 46.60; H, 3.91; Cl, 9.83; P,

5.73 %; Found: C, 45.83; H, 3.87; Cl, 9.93; P, 5.71 %. 31P{1H} NMR (CDCl3): δ 32.5, 1J(SeP)

= 671 Hz. Raman (cm-1): 3050, 2914, 1596, 1457, 1381, 1305, 1209, 1186, 1093, 809,

644, 538, 478, 300, 283, 234.

2.7.11. Synthesis of [BiBr3{Se=P(p-tolyl)3}]

In a procedure analogous to 2.7.1, the reaction of tri-p-tolylphosphine selenide (0.50 g,

1.3 mmoles) and bismuth tribromide (0.292 g, 0.65 mmoles) gave [BiBr3{Se=P(p-

tolyl)3}] as a dark yellow solid. (0.324 g, 41 %).

[BiBr3{Se=P(p-tolyl)3}]: Calculated for C21H21PSeBiBr3: C, 30.30; H, 2.54; Br, 28.82; P,


Raman (cm-1): 3053, 2974, 2918, 2858, 1595, 1565, 1377, 1308, 1213, 1190, 1096, 806,

634, 525, 472, 235, 191.

2.7.12. Synthesis of [BiI3{Se=P(p-tolyl)3}]


1.3 mmoles) and bismuth triiodide (0.384 g, 0.65 mmoles) gave [BiI3{Se=P(p-tolyl)3}] as

a red brick solid. (0.5 g, 57 %).

[BiI3{Se=P(p-tolyl)3}]: Calculated for C21H21PSeBiI3: C, 25.90; H, 2.18; I, 39.14; P, 3.18 %;

Found: C, 25.25; H, 2.00; I, 39.79; P, 3.03 %. 31P{1H} NMR (CDCl3): δ 33.7. Raman (cm-1):

3044, 2974, 2918, 1596, 1559, 1400, 1374, 1308, 1212, 1186, 1096, 806, 657, 639, 634,

613, 528, 505, 468, 450, 323, 236, 225, 150, 136, 115.

106

2.7.13. Synthesis of [SbCl3{Se=P(p-tolyl)3}]


1.30 mmoles) and antimony trichloride (0.148 g, 0.65 mmoles) gave [SbCl3{Se=P(p-

tolyl)3}] as a white solid. (0.466 g, 58 %).

[SbCl3{Se=P(p-tolyl)3}]: Calculated for C21H21PSeSbCl3: C, 41.23; H, 3.46; Cl, 17.40, P,



2862, 1595, 1561, 1375, 1309, 1214, 1189, 1096, 799, 635, 619, 535, 478, 434, 338,

320, 264, 233, 220, 151, 135.

2.7.14. Synthesis of [SbBr3{Se=P(p-tolyl)3}]


1.30 mmoles) and antimony tribromide (0.235 g, 0.65 mmoles) gave [SbBr3{Se=P(p-

tolyl)3}] as a very pale yellow solid. (0.325 g, 33 %).

[SbBr3{Se=P(p-tolyl)3}]: Calculated for C21H21PSeSbBr3: C, 33.85; H, 2.84; Br, 32.20, P,



2860, 1593, 1561, 1497, 1442, 1375, 1309, 1213, 1190, 1096, 801, 636, 533, 476, 318,

234, 178.

2.7.15. Synthesis of [SbI3{Se=P(p-tolyl)3}]

In a procedure analogous to 2.7.1, the reaction of tri-p-tolyl phosphine selenide (0.50

g, 1.30 mmoles) and antimony triiodide (0.32 g, 0.65 mmoles) gave [SbI3{Se=P(p-

tolyl)3}] as a orange solid. (0.514 g, 45 %).

[SbI3{Se=P(p-tolyl)3}]: Calculated for C21H21PSeSbI3: C, 28.46; H, 2.39; I, 42.99; P, 3.50 %;

Found: C, 27.91; H, 2.18; I, 42.71; P, 3.38 %. 31P{1H} NMR (CDCl3): δ 34.4, 77Se{1H} NMR

(CDCl3): insufficiently soluble. Raman (cm-1): 3045, 2977, 2918, 2863, 1594, 1559, 1398,

1374, 1310, 1212, 1187, 1093, 807, 655, 631, 528, 469, 322, 224, 180, 160.

107

2.7.16. Attempted synthesis of [AsCl3{Se=P(p-tolyl)3}]


g, 1.30 mmoles) and arsenic trichloride (0.05 ml, 0.65 mmoles) gave [AsCl3{Se=P(p-

tolyl)3}] as a pink solid. (0.292 g).

[AsCl3{Se=P(p-tolyl)3}]: Calculated for C21H21PSeAsCl3: C, 53.19; H, 4.47; Cl, 18.85; P,

5.49 %; Found: C, 63.81; H, 5.21; Cl, none; P, 8.03 %. The elemental analysis shows that

the product is [(Se=P(p-tolyl)3]; Calculated for C21H21PSe: C, 65.78; H, 5.52; P, 8.09 %;

Found: C, 63.81; H, 5.21; P, 8.03 %. 31P{1H} NMR (CDCl3): δ 33.7, 77Se{1H} NMR (CDCl3): δ

-262.8, d, 1J(SeP) = 718 Hz. Raman (cm-1): fluoresced.

2.7.17. Attempted synthesis of [AsBr3{Se=P(p-tolyl)3}]


g, 1.30 mmoles) and arsenic tribromide (0.20 g, 0.65 mmoles) gave [AsBr3{Se=P(p-

tolyl)3}] as a very pale pink solid. (0.326 g).

[AsBr3{Se=P(p-tolyl)3}]: Calculated for C21H21PSeAsCl3: C, 46.63; H, 3.92; Br, 22.18; P,

5.73 %; Found: C, 64.99; H, 5.36; Br, none; P, 7.77 %. 31P{1H} NMR (CDCl3): δ 33.7,

77Se{1H} NMR (CDCl3): δ -262.4, d, 1J(SeP) = 718 Hz. Raman (cm-1): fluoresced. The

elemental analysis shows that the product is [(Se=P(p-tolyl)3]; Calculated for C21H21PSe:

C, 65.78; H, 5.52; P, 8.09 %; Found: C, 64.99; H, 5.36; P, 7.77 %.

2.7.18. Synthesis of [AsI3{Se=P(p-tolyl)3}]


1.3 mmoles) and arsenic triiodide (0.297g, 0.65 mmoles) gave [AsI3{Se=P(p-tolyl)3}] as

an orange solid. (0.024 g, 3 %).

[AsI3{Se=P(p-tolyl)3}]: Calculated for C21H21PSeAsI3: C, 30.05; H, 2.52; I, 45.39; P, 3.69 %;

Found: C, 31.60; H, 2.82; l, 38.19; P, 3.83 %. 31P{1H} NMR (CDCl3): δ 33.7.

2.7.19. Synthesis of [BiCl3{Se=PPh3}2]

In a procedure analogous to 2.7.7, triphenylphosphine selenide (0.50 g, 1.46 mmoles)

and bismuth trichloride (0.231 g, 0.732 mmoles) gave [BiCl3{Se=PPh3}2] as a yellow

solid.

108

[BiCl3{Se=PPh3}2]: Calculated for C36H30P2Se2BiCl3: C, 43.31; H, 3.03; Cl, 10.66; P, 6.21 %;

Found: C, 44.20; H, 2.74; Cl, 9.86; P, 6.43 %. 31P{1H} NMR (CDCl3): δ 33.8, 1J(SeP) = 672

Hz. Raman (cm-1): 3057, 1583, 1571, 1479, 1435, 1184, 1162, 1094, 1026, 997, 615,

551, 452, 262, 247, 197, 170, 150.

2.7.20. Synthesis of [BiCI3{Se=PPh3}]

In a procedure analogous to 2.7.1 but using pentane as solvent, triphenylphosphine

selenide (0.50 g, 1.46 mmoles) and bismuth trichloride (0.462 g, 1.46 mmoles) gave

[BiCl3{Se=PPh3}] as a yellow solid. (0.741 g, 77.10 %).

[BiCI3(Se=PPh3)]: Calculated for C18H15PSeBiCl3: C, 32.91; H, 2.30; Cl, 16.20; P, 4.72 %;

Found: C, 33.75; H, 1.96; Cl, 13.83; P, 4.82 %. 31P{1H} NMR (CDCl3): δ 33.8.

Raman (cm-1): 3058, 1583, 1184, 1159, 1093, 1027, 997, 559, 283, 268, 250, 180.

2.7.21. Synthesis of [BiBr3{Se=PPh3}2]

In a procedure analogous to 2.7.7, using anhydrous dichloromethane instead of

anhydrous diethyl ether, [BiBr3{Se=PPh3}2] (as a yellow solid) was prepared using

triphenyl phosphine selenide (0.50 g, 1.4 mmoles) and bismuth tribromide (0.328 g,

0.73 mmoles).

[BiBr3{Se=PPh3}2]: Calculated for C36H30Br3P2Se2Bi: C, 38.20; H, 2.67; Br, 21.20; P, 5.48

% Found: C, 37.70; H, 2.55; Br, 21.85; P, 5.28 %. 31P{1H} NMR (CDCl3): δ 33.8. Raman

(cm-1): 3166, 3142, 3053, 3004, 2988, 2952, 1583, 1571, 1480, 1436, 1184, 1161, 1093,

1027, 997, 690, 615, 550, 450, 247, 232, 218, 196, 174, 161, 144.

2.7.22. Synthesis of [Bil3{Se=PPh3}]

In a procedure analogous to 2.7.1, [BiI3{Se=PPh3}] (as a very dark grey solid) was

prepared using triphenyl phosphine selenide (0.50 g, 1.46 mmoles) and bismuth

triiodide (0.432 g, 0.73 mmoles).

[Bil3{Se=PPh3}]: Calculated for C18H15BiI3PSe: C, 23.21; H, 1.62; I, 40.90; P, 3.33 %;

Found: C, 26.61; H, 1.72; I, 35.86; P, 4.04 %. 31P{1H} NMR (CDCl3): δ 35.5. Raman (cm-1):

3056, 1582, 1572, 1432, 1157, 1096, 1035, 999, 617, 557, 458, 281, 272, 245, 233, 220,

199.

109

2.7.23. Synthesis of [SbCl3{Se=PPh3}2]


anhydrous diethyl ether, triphenyl phosphine selenide (0.50 g, 1.46 mmoles) and

antimony trichloride (0.167 g, 0.732 mmoles) gave [SbCl3{Se=PPh3}2] as a white solid.

(0.42 g, 32 %).

[SbCl3{Se=PPh3}2]: Calculated for C36H30P2Se2SbCl3: C, 47.46; H, 3.32; Cl, 11.69, P, 6.81

%; Found: C, 46.62; H, 3.15; Cl, 12.23, P, 6.28 %. 31P{1H} NMR (CDCl3): δ 34.8, 77Se{1H}

NMR (CDCl3): δ -200.3, d, 1J(SeP) = 701 Hz. Raman (cm-1): 3168, 3139, 3057, 3003,

2985, 2949, 1583, 1480, 1431, 1183, 1158, 1097, 1027, 998, 615, 558, 546, 337, 268,

250, 199, 149.

2.7.24. Synthesis of [SbBr3{Se=PPh3}2]


anhydrous diethyl ether, triphenyl phosphine selenide (0.50 g, 1.46 mmoles) and

antimony tribromide (0.264 g, 0.732 mmoles) gave [SbBr3{Se=PPh3}2] as an off-white

solid (0.5 g, 33 %).

[SbBr3{Se=PPh3}2]: Calculated for C36H30P2Se2SbBr3: C, 41.40; H, 2.90; Br, 22.97, P, 5.94

%; Found: C, 40.33; H, 2.66; Br, 25.43, P, 5.28 %. 31P{1H} NMR (CDCl3): δ 35.0, 77Se{1H}

NMR (CDCl3): δ -205, d, 1J(SeP) = 701 Hz. Raman (cm-1): 3167, 3141, 3059, 2999, 2986,

2951, 1582, 1181, 1159, 1095, 1028, 999, 545, 269, 251, 236, 221, 195, 167.

2.7.25. Synthesis of [SbI3{Se=PPh3}]


anhydrous diethyl ether, [SbI3{Se=PPh3}] (as an orange solid) was prepared using

triphenyl phosphine selenide (0.30 g, 0.879 mmoles) and antimony triiodide (0.441g,

0.879 mmoles).

[SbI3{Se=PPh3}]: Calculated for C18H15PSeSbI3: C, 25.61; H, 1.79; I, 45.13 %; Found: C,

15.37; H, 0.99; I, 53.55 %. 31P{1H} NMR (CDCl3): δ 33.2.

110

2.7.26. Attempted synthesis of [AsCl3{Se=PPh3}2]

In a procedure analogous to 2.7.1, the reaction of triphenylphosphine selenide (0.50 g,

1.46 mmoles) and arsenic trichloride (0.061 ml, 0.73 mmoles) gave a pink solid

(0.236 g).

[AsCl3{Se=PPh3}2]: Calculated for C36H30P2Se2AsCI3: C, 50.04; H, 3.50; Cl, 12.32; P, 7.17

%; Found: C, 63.29; H, 3.96; Cl, none; P 9.15 %. The elemental analysis shows the

product to be triphenylphosphine selenide [Ph3PSe]: Calculated for C18H15PSe: C,

63.33; H, 4.43; P, 9.08 %; Found: C, 63.29; H, 3.96; P, 9.15 %. 31P{1H} NMR (CDCl3): δ

35.3, 1J(SeP) = 728 Hz. Raman (cm-1): 3056, 1582, 1572, 1432, 1157, 1096, 1035, 999,

617, 557, 458, 281, 272, 245, 233, 220, 199.

2.7.27. Attempted synthesis of [AsBr3{Se=PPh3}2]


1.46 mmoles) and arsenic tribromide (0.230 g, 0.73 mmoles) gave a white solid

(0.18 g).

[AsBr3{Se=PPh3}2]: Calculated for C36H30P2Se2AsBr3: C, 43.34; H, 3.03; Br, 24.05; P, 6.22;

Found: C, 63.33; H, 4.35; Br, none; P, 8.65 %. The elemental analysis shows the product

to be triphenylphosphine selenide [Ph3PSe]: Calculated for C18H15PSe: C, 63.33; H, 4.43;

P, 9.08 %; Found: C, 63.33; H, 4.35; P, 8.65 %. 31P{1H} NMR (CDCl3): δ 35.2, 1J(SeP) = 729

Hz. Raman (cm-1): 3045, 1587, 1572, 1182, 1159, 1097, 1031, 999, 617, 562, 461, 278,

274, 251, 239, 220, 196.

2.7.28. Synthesis of [AsI3{Se=PPh3}2]


1.46 mmoles) and arsenic triiodide (0.333 g, 0.73 mmoles) gave [AsI3{Se=PPh3}2] as an

orange solid (0.434 g, 26 %) using dichloromethane as solvent.

[AsI3{Se=PPh3}2]: Calculated for C36H30P2Se2AsI3: C, 37.97; H, 2.66; I, 33.46; P, 5.44;

Found: C, 39.07; H, 2.72; I, 31.83, P 8.65 %. 31P{1H} NMR (CDCl3): δ 35.1, 77Se{1H} NMR

(CDCl3): insufficiently soluble. Raman (cm-1): fluoresced.

111

2.8. Reactions of mixed aryl phosphine selenides and tris(4-fluorophenyl)phosphine

selenide with main group halides

Syntheses of [MX3{Se=PR3}] where M = Bi, Sb & As; X = Cl, Br, I and R3 = (o-tolyl)2Ph,

(o-tolyl)Ph2 and (p-FC6H4)3.

2.8.1. Synthesis of [BiCl3{Se=PPh(o-tolyl)2}]

Di-o-tolylphenyl phosphine selenide (0.50 g, 1.35 mmoles) was added to anhydrous

diethyl ether (50 ml) in a Rotaflo tube with stirring against a stream of dry nitrogen.

Bismuth trichloride (0.21 g, 0.67 mmoles) was added and the colour of the solution

became yellowish-white. The reaction was left stirring for 2 days. The product was

isolated using standard Schlenk techniques and dried in vacuo for two hours. The dry

yellowish white solid product (0.382 g, 54 %) was transferred to pre-dried sample

tubes in the glove box.

[BiCl3{Se=PPh(o-tolyl)2}]: Calculated for C20H19PSeBiCl3: C, 35.07; H, 2.80; Cl, 15.54, P,


Raman (cm-1): (the sample fluoresced but gave the following peaks) 3059, 2912, 1582,

1200, 1163, 1044, 993, 797, 324, 266, 236,193, 141.

2.8.2. Synthesis of [BiBr3{Se=PPh(o-tolyl)2}]

In a procedure analogous to 2.8.1, the reaction of di-o-tolylphenyl phosphine selenide

(0.50 g, 1.35 mmoles) and bismuth tribromide (0.30 g, 0.67 mmoles) gave

[BiBr3{Se=PPh(o-tolyl)2}] as a yellow solid. (0.378 g, 47 %).

[BiBr3{Se=PPh(o-tolyl)2}]: Calculated for C20H19PSeBiBr3: C, 29.35; H, 2.34; Br, 29.31; P,


Raman (cm-1): 3056, 2921, 1591, 1563, 1199, 1160, 1133, 1048, 1026, 996, 803, 669,

533, 242, 198.

2.8.3. Synthesis of [BiI3{Se=PPh(o-tolyl)2}]


(0.50 g, 1.35 mmoles) and bismuth triiodide (0.40 g, 0.67 mmoles) gave [BiI3{Se=PPh(o-

tolyl)2}] as a dark brown solid. (0.431 g, 48 %).

112

[BiI3{Se=PPh(o-tolyl)2}]: Calculated for C20H19PSeBiI3: C, 25.03; H, 2.00; I, 39.71; P, 3.23

%; Found: C, 15.40; H, 0.95; I, 49.17; P, 1.99 %. 31P{1H} NMR (CDCl3): δ 29.1, 1J(SeP) =

711 Hz. Raman (cm-1): (the sample fluoresced but gave the following peaks) 3053,

1585, 144, 117.

2.8.4. Attempted synthesis of [SbCl3{Se=PPh(o-tolyl)2}]


(0.50 g, 1.35 mmoles) and antimony trichloride (0.154 g, 0.67 mmoles) gave a white

solid. (0.10 g).

[SbCl3{Se=PPh(o-tolyl)2}]: Calculated for C20H19PSeSbCI3: C, 40.19; H, 3.21; CI, 17.81, P,

5.19 %; Found: C, 63.28; H, 4.94; Cl, None; P, 8.28%. The elemental analysis shows the

starting phosphine selenide [(Se=PPh(o-tolyl)2]: Calculated for C20H19PSe: C, 65.03; H,

5.19; P, 8.39 %; Found: C, 63.28; H, 4.94; P, 8.28 %. 31P{1H} NMR (CDCl3): δ 29.1, 1J(SeP)

= 712 Hz. Raman (cm-1): 3053, 3007, 2947, 2918, 1586, 1562, 1388, 1282, 1275, 1202,

1181, 1159, 1130, 1092, 1069, 1046, 1026, 995, 804, 535, 520, 505, 486, 442, 261, 245,

204.

2.8.5. Synthesis of [SbBr3{Se=PPh(o-tolyl)2}]


(0.50 g, 1.35 mmoles) and antimony tribromide (0.244 g, 0.67 mmoles) gave

[SbBr3{Se=PPh(o-tolyl)2}] as a dusty white solid. (0.238 g, 28 %).

[SbBr3{Se=PPh(o-tolyl)2}]: Calculated for C20H19PSeSbBr3: C, 32.85; H, 2.62; Br, 32.81, P,


1J(SeP) = 671 Hz. Raman (cm-1): 3056, 2914, 1589, 1569, 1391, 1282, 1199, 1159, 1047,

1023, 994, 799, 670, 533, 481, 432, 397, 237, 211.

2.8.6. Synthesis of [SbI3{Se=PPh(o-tolyl)2}]


(0.50 g, 1.35 mmoles) and antimony triiodide (0.34 g, 0.67 mmoles) gave

[SbI3{Se=PPh(o-tolyl)2}] as an orange solid. (0.242 g, 29 %).

[SbI3{Se=PPh(o-tolyl)2}]: Calculated for C20H19PSeSbI3: C, 27.54; H, 2.20; I, 43.68, P, 3.55

%; Found: C, 26.01; H, 1.85; I, 45.08; P, 3.41. %. 31P{1H} NMR (CDCl3): δ 29.7. Raman

113

(cm-1): 3050, 2918, 1582, 1559, 1377, 1202, 1047, 997, 799, 571, 531, 435, 327, 188,

179, 158, 148, 130.

2.8.7. Attempted synthesis of [AsCl3{Se=PPh(o-tolyl)2}]


(0.50 g, 1.35 mmoles) and arsenic trichloride (0.05 ml, 0.67 mmoles) gave a pale pink

solid. (0.25 g).

[AsCl3{Se=PPh(o-tolyl)2}]: Calculated for C20H19PSeAsCl3: C, 43.61; H, 3.48; Cl, 19.33; P,

5.63 %; Found: C, 64.66; H, 5.15; Br, none; P, 8.18 %. The elemental analysis shows

that the product is unreacted [(Se=PPh(o-tolyl)2]; Calculated for C20H19PSe: C, 65.03; H,

5.19; P, 8.39 %; Found: C, 64.66; H, 5.15; P, 8.18 %. 31P{1H} NMR (CDCl3): δ 29.1. 1J(SeP)

= 711 Hz. Raman (cm-1): 3170, 3131, 3053, 3010, 2951, 2920, 1587, 1566, 1384, 1279,

1201, 1181, 1161, 1131, 1094, 1045, 997, 805, 533, 504, 487, 442, 258, 245, 196, 135.

2.8.8. Attempted synthesis of [AsBr3{Se=PPh(o-tolyl)2}]


(0.50 g, 1.35 mmoles) and arsenic tribromide (0.213 g, 0.67 mmoles) gave a pinkish

white solid. (0.124 g).

[AsBr3{Se=PPh(o-tolyl)2}]: Calculated for C20H19PSeAsBr3: C, 35.10; H, 2.80; Br, 35.06; P,

4.53 %; Found: C, 64.18; H, 5.16; Br, none; P, 8.50 %. The elemental analysis shows

that the product is unreacted [(Se=PPh(o-tolyl)2]; Calculated for C20H19PSe: C, 65.03; H,

5.19; P, 8.39 %; Found: C, 64.18; H, 5.16; P, 8.50 %. 31P{1H} NMR (CDCl3): δ 29.1. 1J(SeP)

= 711 Hz. Raman (cm-1): 3047, 2918, 1588, 1560, 1389, 1282, 1203, 1163, 1203, 1133,

1094, 1048, 1029, 999, 800, 675, 535, 483, 440, 260, 245, 199, 129.

2.8.9. Synthesis of [AsI3{Se=PPh(o-tolyl)2}]


(0.50 g, 1.35 mmoles) and antimony triiodide (0.30 g, 0.67 mmoles) gave a dark yellow

solid. (0.181 g, 22 %).

[AsI3{Se=PPh(o-tolyl)2}]: Calculated for C20H19PSeAsI3: C, 29.10; H, 2.32; I, 46.16, P, 3.76

%; Found: C, 25.13; H, 1.54; I, 48.91; P, 3.21 %. 31P{1H} NMR (CDCl3): δ 28.4.

Raman (cm-1): fluoresced.

114

2.8.10. Synthesis of [SbCl3{Se=PPh2(o-tolyl)}2]

In a procedure analogous to 2.7.7, [SbCl3{Se=PPh2(o-tolyl)}2] was prepared as an off

white solid (0.282 g, 21 %) using diphenyl-o-tolylphosphine selenide (0.50 g, 1.40

mmoles) and antimony trichloride (0.16 g, 0.70 mmoles).

[SbCl3{Se=PPh2(o-tolyl)}2]: Calculated for C38H34P2Se2SbCl3: C, 48.60; H, 3.65; Cl, 11.34;

P, 6.60 %; Found: C, 47.64; H, 3.38; Cl, 12.05; P, 6.40 %. 31P{1H} NMR (CDCl3): δ 31.8.

1J(SeP) = 706 Hz. Raman (cm-1): fluoresced.

2.8.11. Synthesis of [SbBr3{Se=PPh2(o-tolyl)}2]

In a procedure analogous to 2.7.7, [SbBr3{Se=PPh2(o-tolyl)}2] was prepared as a pale

yellow solid (0.263 g, 17 %) using diphenyl-o-tolylphosphine selenide (0.50 g, 1.40

mmoles) and antimony tribromide (0.254 g, 0.70 mmoles).

[SbBr3{Se=PPh2(o-tolyl)}2]: Calculated for C38H34P2Se2SbBr3: C, 42.55; H, 3.20; Br, 22.37;


1J(SeP) = 700 Hz. Raman (cm-1): 3056, 2921, 1588, 1569, 1203, 1182,1165, 1096, 1049,

1029, 994, 803, 537, 250, 234, 224, 211, 163.

2.8.12. Attempted synthesis of [SbI3{Se=PPh2(o-tolyl)}]

In a procedure analogous to 2.7.10, the synthesis of [SbI3{Se=PPh2(o-tolyl)}2] was

attempted using diphenyl-o-tolylphosphine selenide (0.50 g, 1.40 mmoles) and

antimony triiodide (0.353 g, 0.70 mmoles). A small amount of a red-brown solid was

obtained.

[SbI3{Se=PPh2(o-tolyl)}]: Calculated for C19H17PSeSbI3: C, 26.59; H, 2.00; I, 44.40; P, 3.61

%; Found: C, 18.98; H, 1.05; I, 54.59; P, 2.48 %. 31P{1H} NMR (CDCl3): δ 31.4. Raman

(cm-1): 3056, 1588, 1002, 239, 181.

2.8.13. Synthesis of [BiCl3{Se=P(p-FC6H4)3}]

In a procedure analogous to 2.7.7, [BiCl3{Se=P(p-FC6H4)3}] was prepared as a pale

yellow solid (0.33 g, 41 %) using tris(4-fluorophenyl)phosphine selenide (0.45 g, 1.13

mmoles) and bismuth trichloride (0.36 g, 1.13 mmoles).

115

[BiCl3{Se=P(p-FC6H4)3}]: Calculated for C18H12PSeF3BiCl3: C, 30.41; H, 1.70; Cl, 14.97; P,


Raman (cm-1): (the sample fluoresced and gave the following peaks) 3078, 1595, 1502,

1394, 1300, 1234, 1167, 1092, 828, 636, 531, 494, 413, 337, 298, 274, 238, 219.

2.8.14. Synthesis of [BiBr3{Se=P(p-FC6H4)3}]

In a procedure analogous to 2.7.7, [BiBr3{Se=P(p-FC6H4)3}] was prepared as a yellow

solid (0.342 g, 32 %) using tris(4-fluorophenyl)phosphine selenide (0.5 g, 1.26 mmoles)

and bismuth tribromide (0.56 g, 1.26 mmoles).

[BiBr3{Se=P(p-FC6H4)3}]: Calculated for C18H12PSeF3BiBr3: C, 25.60; H, 1.43; Br, 28.41; P,


Raman (cm-1): 3076, 1591, 1495, 1394, 1298, 1232, 1163, 1093, 827, 634, 530, 488,

415, 337, 237, 199, 187.

2.8.15. Attempted synthesis of [BiI3{Se=P(p-FC6H4)3}]

In a procedure analogous to 2.7.7, a dark grey solid (0.381 g) was obtained from the

reaction of tris(4-fluorophenyl)phosphine selenide (0.5 g, 1.26 mmoles) and bismuth


[BiI3{Se=P(p-FC6H4)3}]: Calculated for C18H12PSeF3BiI3: C, 21.94; H, 1.23; I, 38.66; P, 3.15

%; Found: C, 0.43; H, none; I, 64.28; P, none. The elemental analysis shows that the

product is BiI3; Calculated for BiI3: I, 64.56 %; Found: I, 64.28 %. 31P{1H} NMR (CDCl3):

insufficiently soluble. Raman (cm-1): (the sample fluoresced but gave the following

peaks) 149, 117.

2.8.16. Synthesis of [SbCl3{Se=P(p-FC6H4)3}]

In a procedure analogous to 2.7.7, [SbCl3{Se=P(p-FC6H4)3}] was prepared as a white

solid (0.567 g, 80 %) using tris(4-fluorophenyl)phosphine selenide (0.45 g, 1.13


[SbCl3{Se=P(p-FC6H4)3}]: Calculated for C18H12PSeF3SbCl3: C, 34.66; H, 1.94; Cl, 17.07; P,


Raman (cm-1): 3074, 1591, 1490, 1299, 1237, 1161, 1097, 828, 641, 536, 497, 327, 307,

242, 217, 152, 127.

116

2.8.17. Synthesis of [SbBr3{Se=P(p-FC6H4)3}]

In a procedure analogous to 2.7.1, [SbBr3{Se=P(p-FC6H4)3}] was prepared as a yellow


and antimony tribromide (0.45 g, 1.26 mmoles).

[SbBr3{Se=P(p-FC6H4)3}]: Calculated for C18H12PSeF3SbBr3: C, 28.55; H, 1.60; Br, 31.69; P,


Raman (cm-1): 3072, 1591, 1298, 1232, 1167, 1093, 827, 634, 615, 530, 492, 411, 337,

222, 214, 168.

2.8.18. Attempted synthesis of [SbI3{Se=P(p-FC6H4)3}]

In a procedure analogous to 2.7.1, an orange solid (0.013 g) was obtained from the

reaction of tris(4-fluorophenyl)phosphine selenide (0.5 g, 1.26 mmoles) and antimony


[SbI3{Se=P(p-FC6H4)3}]: Calculated for C18H12PSeF3SbI3: C, 24.07; H, 1.35; I, 42.42; P,

3.45 %; Found: C, 1.06; H, none; I, 72.97; P, trace. The elemental analysis shows that

the product is SbI3; Calculated for SbI3: I, 75.77 %; Found: I, 72.97 %. 31P{1H} NMR

(CDCl3): insufficiently soluble.

2.8.19. Synthesis of [AsCl3{Se=P(p-FC6H4)3}]

In a procedure analogous to 2.7.7, [AsCl3{Se=P(p-FC6H4)3}] was prepared as a white


and arsenic chloride (0.10 ml g, 1.26 mmoles).

[AsCl3{Se=P(p-FC6H4)3}]: Calculated for C18H12PSeF3AsCl3: C, 37.48; H, 2.10; Cl, 18.46; P,


1J(SeP) = 740 Hz, 77Se{1H} NMR (CDCl3): δ -248.3, d, 1J(SeP) = 740 Hz. Raman (cm-1):

3076, 1591, 1302, 1228, 1167, 1093, 827, 638, 538, 499, 364, 337, 241, 218, 187, 156.

2.8.20. Synthesis of [AsBr3{Se=P(p-FC6H4)3}]

In a procedure analogous to 2.7.7, [AsBr3{Se=P(p-FC6H4)3}] was prepared a white solid

(0.347 g, 39 %) using tris(4-fluorophenyl)phosphine selenide (0.5 g, 1.26 mmoles) and

arsenic tribromide (0.4 g, 1.26 mmoles).

117

[AsBr3{Se=P(p-FC6H4)3}]: Calculated for C18H12PSeF3AsBr3: C, 30.44; H, 1.70; Br, 33.78; P,


1J(SeP) = 740 Hz, 77Se{1H} NMR (CDCl3): δ -249.4, d, 1J(SeP) = 740 Hz. Raman (cm-1):

3072, 1591, 1302, 1228, 1167, 1093, 827, 638, 619, 534, 496, 341, 253, 218.

2.8.21. Attempted synthesis of [AsI3{Se=P(p-FC6H4)3}]

In a procedure analogous to 2.7.1, an orange solid (0.254 g) was obtained from the

reaction of tris(4-fluorophenyl)phosphine selenide (0.5 g, 1.26 mmoles) and arsenic


[AsI3{Se=P(p-FC6H4)3}]: Calculated for C18H12PSeF3AsI3: C, 25.39; H, 1.42; I, 44.76; P,

3.64 %; Found: C, 0.5; H, none; I, 78.33; P, < 0.3 %. The elemental analysis shows that

the product is AsI3; Calculated for AsI3: I, 83.56 %; Found: I, 78.33 %. 31P{1H} NMR

(CDCl3): insufficiently soluble. Raman (cm-1): (the sample fluoresced but gave the

following peaks) 209, 190.

2.9. Synthesis of mixed alkylaryl phosphine selenides with main group halides

Syntheses of [MX3{Se=PR3}] where M = Bi, Sb & As; X = Cl, Br, I and R3 = (CH3)2Ph and

Ph2CH3.

2.9.1. Synthesis of [BiCl3{Se=PPh(CH3)2}]

Dimethylphenyl phosphine selenide (0.35 ml, 2.30 mmoles) was added to anhydrous

diethyl ether (50 ml) in a Rotaflo tube with stirring against a stream of dry nitrogen.

Bismuth trichloride (0.726 g, 2.30 mmoles) was added to give a yellow-coloured

solution. The next day, the colour of the solution was dark brown. The reaction was

left stirring for 3 days. The product was isolated using standard Schlenk techniques and

dried in vacuo for two hours. The dark brown solid product (0.341 g, 28 %) was


[BiCl3{Se=PPh(CH3)2}]: Calculated for C8H11PSeBiCl3: C, 18.03; H, 2.08; Cl, 19.98; P, 5.82

%; Found: C, 18.48; H, 1.88; Cl, 18.91; P, 5.86 %. 31P{1H} NMR (CDCl3): δ 16.3, 77Se{1H}

NMR (CDCl3): insufficiently soluble. Raman (cm-1): fluoresced.

118

2.9.2. Synthesis of [BiBr3{Se=PPh(CH3)2}]

In a procedure analogous to 2.9.1, the reaction of dimethylphenyl phosphine selenide

(0.35 ml, 2.30 mmoles) and bismuth tribromide (1.03 g, 2.30 mmoles) gave

[BiBr3{Se=PPh(CH3)2}] as a yellow solid. (1.294 g, 84 %).

[BiBr3{Se=PPh(CH3)2}]: Calculated for C8H11PSeBiCl3: C, 14.42; H, 1.67; Br, 36.01; P, 4.65

%; Found: C, 14.45; H, 1.50; Br, 36.47; P, 4.69 %. 31P{1H} NMR (CDCl3): insufficiently

soluble, 77Se{1H} NMR (CDCl3): insufficiently soluble. Raman (cm-1): fluoresced.

2.9.3. Synthesis of [BiI3{Se=PPh(CH3)2}]


(0.35 ml, 2.30 mmoles) and bismuth triiodide (1.35 g, 2.30 mmoles) gave

[BiI3{Se=PPh(CH3)2}] as a red brown solid. (1.462 g, 79 %).

[BiI3{Se=PPh(CH3)2}]: Calculated for C8H11PSeBiI3: C, 11.90; H, 1.37; I, 47.19; P, 3.84 %;



2.9.4. Synthesis of [SbCl3{Se=PPh(CH3)2}]


(0.35 ml, 2.30 mmoles) and antimony trichloride (0.52 g, 2.30 mmoles) gave

[SbCl3{Se=PPh(CH3)2}] as a cream solid. (0.571 g, 56 %).

[SbCl3{Se=PPh(CH3)2}]: Calculated for C8H11PSeSbCl3: C, 21.57; H, 2.49; Cl, 23.89; P, 6.96



2.9.5. Synthesis of [SbBr3{Se=PPh(CH3)2}]


(0.35 ml, 2.30 mmoles) and antimony tribromide (0.832 g, 2.30 mmoles) gave

[SbCl3{Se=PPh(CH3)2}] as a yellow solid. (0.711 g, 53 %).

[SbBr3{Se=PPh(CH3)2}]: Calculated for C8H11PSeSbBr3: C, 16.60; H, 1.92; Br, 41.44; P,

5.35 %; Found: C, 17.07; H, 1.09; Br, 41.30; P, 4.92 %. 31P{1H} NMR (CDCl3): δ 17.1

119

77Se{1H} NMR (CDCl3): insufficiently soluble. Raman (cm-1): 3051, 2979, 2904, 1585,

1109, 1028, 998, 480, 437, 366, 250, 216, 186.

2.9.6. Synthesis of [SbI3{Se=PPh(CH3)2}]


(0.35 ml, 2.30 mmoles) and antimony triiodide (1.15 g, 2.30 mmoles) gave

[SbI3{Se=PPh(CH3)2}] as a yellow solid. (1.28 g, 77 %).

[SbI3{Se=PPh(CH3)2}]: Calculated for C8H11PSeSbI3: C, 13.34; H, 1.54; I, 52.91; P, 4.31 %;



2.9.7. Attempted synthesis of [AsCl3{Se=PPh(CH3)2}]


(0.35 ml, 2.30 mmoles) and arsenic trichloride (0.193 ml, 2.30 mmoles) gave no solid

product. A dark pink clear solution was obtained from which the solvent was removed

under vacuum and attempts were made to grow crystals using dry dichloromethane

and dry pentane.

2.9.8. Attempted synthesis of [AsBr3{Se=PPh(CH3)2}]


(0.35 ml, 2.30 mmoles) and arsenic tribromide (0.724 g, 2.30 mmoles) gave no solid

product. A clear solution was obtained from which the solvent was removed under

vacuum and attempts were to grow crystals from dry dichloromethane and dry

pentane.

2.9.9. Synthesis of [AsI3{Se=PPh(CH3)2}]


(0.35 ml, 2.30 mmoles) and arsenic triiodide (1.04 g, 2.30 mmoles) gave a sticky, brick

red solid (0.619 g, 40 %).

[AsI3{Se=PPh(CH3)2}]: Calculated for C8H11PSeAsI3: C, 14.27; H, 1.65; I, 56.60; P, 4.60 %;



120

2.9.10. Synthesis of [BiCl3{Se=PPh2CH3}]

In a procedure analogous to 2.9.1, the reaction of diphenylmethyl phosphine selenide

(0.33 ml, 2.30 mmoles) and bismuth trichloride (0.564 g, 2.30 mmoles) gave a greenish

brown solid (0.8 g, 75 %).

[BiCl3{Se=PPh2CH3}]: Calculated for C13H13PSeBiCl3: C, 26.25; H, 2.20; Cl, 17.89; P, 5.21



2.9.11. Synthesis of [BiBr3{Se=PPh2CH3}]


(0.33 ml, 2.30 mmoles) and bismuth tribromide (0.803 g, 2.30 mmoles) gave a yellow

solid (0.875 g, 67 %).

[BiBr3{Se=PPh2CH3}]: Calculated for C13H13PSeBiBr3: C, 21.44; H, 1.80; Br, 32.94; P, 4.26

%; Found: C, 21.39; H, 1.83; Br, 34.11; P, 4.30 %. 31P{1H} NMR (CDCl3): insufficiently

soluble, 77Se{1H} NMR (CDCl3): insufficiently soluble. Raman (cm-1): 3060, 2987, 2910,

1585, 1190, 1164, 1103, 1028, 997, 272, 248, 219, 185, 160.

2.9.12. Synthesis of [BiI3{Se=PPh2CH3}]


(0.33 ml, 2.30 mmoles) and bismuth triiodide (1.056 g, 2.30 mmoles) gave a red brick

solid (1.339 g, 86 %).

[BiI3{Se=PPh2CH3}]: Calculated for C13H13PSeBiI3: C, 17.96; H, 1.51; I, 43.82; P, 3.57 %;



1027, 998, 685, 510, 254, 145, 117.

2.9.13. Attempted synthesis of [SbCl3{Se=PPh2CH3}]


(0.33 ml, 2.30 mmoles) and antimony trichloride (0.408 g, 2.30 mmoles) gave no

product, the solvent was removed under vacuum until left with ~ 2 ml residue,

colourless crystals subsequently have appeared in the Rotaflo tube.

121

2.9.14. Synthesis of [SbBr3{Se=PPh2CH3}]


(0.33 ml, 2.30 mmoles) and antimony tribromide (0.647 g, 2.30 mmoles) gave a pale

yellow solid (0.48 g, 42 %).

[SbBr3{Se=PPh2CH3}]: Calculated for C13H13PSeSbBr3: C, 24.36; H, 2.05; Br, 37.43; P, 4.84

%; Found: C, 24.53; H, 2.05; I, 37.41; P, 4.75 %. 31P{1H} NMR (CDCl3): δ 24.3, 77Se{1H}

NMR (CDCl3): -158.4, d, 1J(SeP) = 668 Hz. Raman (cm-1): 3168, 3144, 3056, 2978, 2897,

1585, 1188, 1164, 1141, 1027, 997, 771, 688, 613, 512, 480, 438, 358, 258, 238, 213,

171, 150, 126.

2.9.15. Synthesis of [SbI3{Se=PPh2CH3}]


(0.33 ml, 2.30 mmoles) and antimony triiodide (0.899 g, 2.30 mmoles) gave a dark

yellow solid (1.04 g, 75 %).

[SbI3{Se=PPh2CH3}]: Calculated for C13H13PSeSbI3: C, 19.96; H, 1.68; I, 48.72; P, 3.96 %;



1103, 1028, 997, 251, 222, 170.

2.9.16. Attempted synthesis of [AsCl3{Se=PPh2CH3}]


(0.33 ml, 2.30 mmoles) and arsenic trichloride (0.899 g, 2.30 mmoles) gave no solid

product, the solvent was removed under vacuum and 20 ml of dry pentane was added,

but no solid product formed.

2.9.17. Attempted synthesis of [AsBr3{Se=PPh2CH3}]


(0.33 ml, 2.30 mmoles) and arsenic tribromide (0.563 g, 2.30 mmoles) gave no solid

product, the solvent was removed under vacuum and 20 ml of dry pentane was added,

but no solid product formed.

122

2.9.18. Attempted synthesis of [AsI3{Se=PPh2CH3}]


(0.33 ml, 2.30 mmoles) and arsenic triiodide (0.816 g, 2.30 mmoles) gave an orange

solid product (0.454 g).

[AsI3{Se=PPh2CH3}]: Calculated for C13H13PSeAsI3: C, 21.23; H, 1.78; I, 51.82; P, 4.22 %;

Found: C, 1.75; I, 81.74; P, < 0.3 %. The elemental analysis shows that the product is

AsI3; Calculated for AsI3: I, 83.56 %; Found: I, 81.74 %.

2.10. Reactions of diphosphine diselenides with main group halides

Syntheses of [MX3{Se2P2R}] using bidentate phosphines where M = Bi, Sb & As; X = Cl,

Br, I and R= Ph2(CH2)nPh2 (n = 1, 2 & 6), cis-Ph2CH=CHPh2 and trans- Ph2CH=CHPh2.

2.10.1. Synthesis of [BiCl3{Ph2P(Se)CH2P(Se)Ph2}]

Bis(diphenylphosphino)methane diselenide (dppmSe2) (0.5 g, 0.92 mmoles) was added

to anhydrous diethyl ether (50 ml) in a Rotaflo tube with stirring against a stream of

dry nitrogen. Bismuth trichloride (0.29 g, 0.92 mmoles) was added to give a yellow-

coloured solution. The next day, the colour of the solution had become pale yellow.

The reaction was left stirring for 3 days. The product was isolated using standard

Schlenk techniques and dried in vacuo for two hours. The pale yellow solid product

(0.751 g, 95 %) was transferred to pre-dried sample tubes in the glove box.

[BiCl3{Ph2P(Se)CH2P(Se)Ph2}]: Calculated for C25H22P2Se2BiCl3: C, 34.99; H, 2.59; Cl,

12.41; P, 7.23 %; Found: C, 34.80; H, 2.41; Cl, 12.65; P, 7.25 %. 31P{1H} NMR (CDCl3):

insufficiently soluble, 77Se{1H} NMR (CDCl3): insufficiently soluble. Raman (cm-1):

fluoresced.

2.10.2. Synthesis of [BiBr3{Ph2P(Se)CH2P(Se)Ph2}]

As described in section 2.10.1, [BiBr3{Ph2P(Se)CH2P(Se)Ph2}] as a dark yellow solid

(0.815 g, 89 %) was prepared using bis(diphenylphosphino)methane diselenide (0.50 g,

0.92 mmoles) and bismuth tribromide (0.41 g, 0.92 mmoles).

[BiBr3{Ph2P(Se)CH2P(Se)Ph2}]: Calculated for C25H22P2Se2BiBr3: C, 30.28; H, 2.24; Br,

24.20; P, 6.25 %; Found: C, 31.08; H, 2.12; Br, 24.12; P, 6.25 %. 31P{1H} NMR (CDCl3):

123

insufficiently soluble, 77Se{1H} NMR (CDCl3): insufficiently soluble. Raman (cm-1): 3055,

2891, 2836, 1585, 1436, 1190, 1163, 1094, 1028, 997, 526, 510, 480, 440, 378, 278,

254, 219, 168.

2.10.3. Synthesis of [BiI3{Ph2P(Se)CH2P(Se)Ph2}]

As described in section 2.10.1, [BiI3{Ph2P(Se)CH2P(Se)Ph2}] as an orange solid (0.942 g,

90 %) was prepared using bis(diphenylphosphino)methane diselenide (0.50 g, 0.92

mmoles) and bismuth triiodide (0.543 g, 0.92 mmoles).

[BiI3{Ph2P(Se)CH2P(Se)Ph2}]: Calculated for C25H22P2Se2BiBr3: C, 26.51; H, 1.96; I, 33.64;

P, 5.47 %; Found: C, 26.11; H, 1.66; I, 34.57; P, 5.71 %. 31P{1H} NMR (CDCl3): δ 25.1,

77Se{1H} NMR (CDCl3): insufficiently soluble. Raman (cm-1): 3052, 2887, 2840, 1583,

1481, 1436, 1188, 1163, 1095, 1027, 998, 524, 512, 485, 379, 278, 244, 218, 133.

2.10.4. Synthesis of [SbCl3{Ph2P(Se)CH2P(Se)Ph2}]

As described in section 2.10.1, [SbCl3{Ph2P(Se)CH2P(Se)Ph2}] as a white solid (0.625 g,

88 %) was prepared using bis(diphenylphosphino)methane diselenide (0.50 g, 0.92


[SbCl3{Ph2P(Se)CH2P(Se)Ph2}]: Calculated for C25H22P2Se2SbCl3: C, 38.95; H, 2.88; Cl,


insufficiently soluble, 77Se{1H} NMR (CDCl3): insufficiently soluble. Raman (cm-1): 3058,

2932, 2887, 1582, 1433, 1192, 1164, 1098, 1026, 995, 534, 512, 459, 375, 313, 295,

257, 238, 209, 176, 157.

2.10.5. Synthesis of [SbBr3{Ph2P(Se)CH2P(Se)Ph2}]

As described in section 2.10.1, [SbBr3{Ph2P(Se)CH2P(Se)Ph2}] as a pale yellow solid


0.92 mmoles) and antimony tribromide (0.333 g, 0.92 mmoles).

[SbBr3{Ph2P(Se)CH2P(Se)Ph2}]: Calculated for C25H22P2Se2SbBr3: C, 33.20; H, 2.45; Br,

26.53; P, 6.86 %; Found: C, 33.56; H, 2.25; Br, 26.52; P, 6.39 %. 31P{1H} NMR (CDCl3): δ

25.1. Raman (cm-1): 3053, 2925, 2872, 1583, 1435, 1188, 1163, 1097, 1026, 999, 529,

510, 461, 375, 289, 257, 209, 155, 136.

124

2.10.6. Synthesis of [SbI3{Ph2P(Se)CH2P(Se)Ph2}]

As described in section 2.10.1, [SbI3{Ph2P(Se)CH2P(Se)Ph2}] as a pale orange solid


0.92 mmoles) and antimony triiodide (0.463 g, 0.92 mmoles).

[SbI3{Ph2P(Se)CH2P(Se)Ph2}]: Calculated for C25H22P2Se2SbI3: C, 28.72; H, 2.12; I, 36.45;

P, 5.93 %; Found: C, 28.76; H, 2.06; I, 36.25; P, 5.70 %. 31P{1H} NMR (CDCl3): δ 24.8.

Raman (cm-1): 3054, 2882, 2831, 1580, 1432, 1343, 1187, 1161, 1091, 1029, 997, 526,

508, 475, 375, 246, 227, 155, 131.

2.10.7. Synthesis of [AsCl3{Ph2P(Se)CH2P(Se)Ph2}]

As described in section 2.10.1, [AsCl3{Ph2P(Se)CH2P(Se)Ph2}] as a pale pink solid (0.564

g, 85 %) was prepared using bis(diphenylphosphino)methane diselenide (0.50 g, 0.92

mmoles) and arsenic trichloride (0.077 ml, 0.92 mmoles).

[AsCl3{Ph2P(Se)CH2P(Se)Ph2}]: Calculated for C25H22P2Se2AsCl3: C, 41.48; H, 3.07; Cl,

14.70; P, 8.56 %; Found: C, 41.86; H, 2.86; Cl, 14.53; P, 8.81 %. 31P{1H} NMR (CDCl3): δ

25.0, 1J(SeP) = 743 Hz, 77Se{1H} NMR (CDCl3): insufficiently soluble. Raman (cm-1): 3054,

2892, 1583, 1572, 1161, 1099, 1026, 997, 900, 793, 766, 617, 526, 491, 469, 438, 397,

373, 354, 335, 303, 284, 259, 235, 220, 183, 155, 125.

2.10.8. Synthesis of [AsBr3{Ph2P(Se)CH2P(Se)Ph2}2]

As described in section 2.10.1, [AsBr3{Ph2P(Se)CH2P(Se)Ph2}2] as a very pale yellow

solid (0.563 g, 44 %) was prepared using bis(diphenylphosphino)methane diselenide

(0.50 g, 0.92 mmoles) and arsenic tribromide (0.29 g, 0.92 mmoles).

[AsBr3{Ph2P(Se)CH2P(Se)Ph2}2]: Calculated for C50H44P4Se4AsBr3: C, 42.90; H, 3.17; Br,


δ 25.0, 1J(SeP) = 743 Hz, 77Se{1H} NMR (CDCl3): δ -238, d, 1J(SeP) = 743 Hz. Raman

(cm-1): fluoresced.

125

2.10.9. Synthesis of [AsI3{Ph2P(Se)CH2P(Se)Ph2}]

As described in section 2.10.1, [AsI3{Ph2P(Se)CH2P(Se)Ph2}] as a dark yellow solid (0.868

g, 94 %) was prepared using bis(diphenylphosphino)methane diselenide (0.50 g, 0.92

mmoles) and arsenic triiodide (0.42 g, 0.92 mmoles).

[AsI3{Ph2P(Se)CH2P(Se)Ph2}]: Calculated for C25H22P2Se2AsI3: C, 30.07; H, 2.22; I, 38.16;


1J(SeP) = 737 Hz, 77Se{1H} NMR (CDCl3): insufficiently soluble. Raman (cm-1): fluoresced.

2.10.10. Synthesis of [BiCl3{Ph2P(Se)CH2CH2P(Se)Ph2}]

In a procedure analogous to 2.10.1, the reaction of 1,2-bis(diphenylphosphino)ethane

diselenide (0.50 g, 0.89 mmoles) and bismuth trichloride (0.28 g, 0.89 mmoles) gave

[BiCl3{Ph2P(Se)CH2CH2P(Se)Ph2}] as a yellow solid (0.612 g, 78 %).

[BiCl3{Ph2P(Se)CH2CH2P(Se)Ph2}]: Calculated for C26H24P2Se2BiCl3: C, 35.80; H, 2.78; Cl,

12.21; P, 7.11; Found: C, 35.43; H, 2.42; Cl, 12.34; P, 6.95 %. 31P{1H} NMR (CDCl3):


peaks) 3055, 2943, 2896, 1584, 1573, 1104, 998, 522, 498, 445, 281, 262, 252, 239.

2.10.11. Synthesis of [BiBr3{Ph2P(Se)CH2CH2P(Se)Ph2}]


diselenide (0.50 g, 0.89 mmoles) and bismuth tribromide (0.40 g, 0.89 mmoles) gave

[BiBr3{Ph2P(Se)CH2CH2P(Se)Ph2}] as a dark yellow solid (0.836 g, 93 %).

[BiBr3{Ph2P(Se)CH2CH2P(Se)Ph2}]: Calculated for C26H24P2Se2BiBr3: C, 31.05; H, 2.41; Br,


δ 35.9. Raman (cm-1): 3053, 2889, 1584, 1103, 1001, 497, 448, 252, 191, 175, 148.

2.10.12. Synthesis of [Bil3{Ph2P(Se)CH2CH2P(Se)Ph2}]


diselenide (0.50 g, 0.89 mmoles) and bismuth triiodide (0.52 g, 0.89 mmoles) gave

[Bil3{Ph2P(Se)CH2CH2P(Se)Ph2}] as a dark orange solid (0.914 g, 89 %).

[Bil3{Ph2P(Se)CH2CH2P(Se)Ph2}]: Calculated for C26H24P2Se2BiI3: C, 27.23; H, 2.11; l,

33.23; P, 5.41 %; Found: C, 27.35; H, 1.94; l, 33.62; P, 5.26 %. 31P{1H} NMR (CDCl3):

126

δ 35.9. Raman (cm-1): 3059, 2885, 1585, 1574, 1268, 1186, 1159, 1099, 1031, 996, 878,

523, 495, 448, 423, 253, 153, 138, 115.

2.10.13. Synthesis of [SbCl3{Ph2P(Se)CH2CH2P(Se)Ph2}]


diselenide (0.50 g, 0.89 mmoles) and antimony trichloride (0.20 g, 0.89 mmoles) gave

[SbCl3{Ph2P(Se)CH2CH2P(Se)Ph2}] as a white solid (0.53 g, 76 %).

[SbCl3{Ph2P(Se)CH2CH2P(Se)Ph2}]: Calculated for C26H24P2Se2SbCl3: C, 39.79; H, 3.08; Cl,

13.56; P, 7.90 %; Found: C, 38.54; H, 2.71; Cl, 14.94; P, 6.52 %. 31P{1H} NMR (CDCl3): δ

36.0. Raman (cm-1): 3058, 2931, 2887, 1585, 1156, 1105, 1096, 1026, 999, 790, 696,

615, 526, 502, 456, 336, 314, 290, 258, 207, 168, 147, 127.

2.10.14. Synthesis of [SbBr3{Ph2P(Se)CH2CH2P(Se)Ph2}]


diselenide (0.50 g, 0.89 mmoles) and antimony tribromide (0.32 g, 0.89 mmoles) gave

[SbBr3{Ph2P(Se)CH2CH2P(Se)Ph2}] as a pale yellow solid (0.714 g, 87 %).

[SbBr3{Ph2P(Se)CH2CH2P(Se)Ph2}]: Calculated for C26H24P2Se2SbBr3: C, 34.00; H, 2.64; Br,

26.13; P, 6.75 %; Found: C, 31.80; H, 2.17; Br, 29.12; P, 5.13 %. 31P{1H} NMR (CDCl3): δ

35.9. Raman (cm-1): 3055, 3038, 2887, 1585, 1102, 1094, 997, 498, 451, 254, 222, 212,

201.

2.10.15. Synthesis of [SbI3{Ph2P(Se)CH2CH2P(Se)Ph2}]


diselenide (0.50 g, 0.89 mmoles) and antimony triiodide (0.45 g, 0.89 mmoles) gave

[SbI3{Ph2P(Se)CH2CH2P(Se)Ph2}] as a turmeric-coloured solid (0.817 g, 86 %).

[SbI3{Ph2P(Se)CH2CH2P(Se)Ph2}]: Calculated for C26H24P2Se2SbI3: C, 29.48; H, 2.29; I,

35.97; P, 5.85 %; Found: C, 27.85; H, 1.79; I, 37.42; P, 5.01 %. 31P{1H} NMR (CDCl3):

δ 35.2. Raman (cm-1): fluoresced.

127

2.10.16. Synthesis of [AsCl3{Ph2P(Se)CH2CH2P(Se)Ph2}]


diselenide (0.50 g, 0.89 mmoles) and arsenic trichloride (0.075 ml, 0.89 mmoles) gave

[AsCl3{Ph2P(Se)CH2CH2P(Se)Ph2}] as a white solid (0.373 g, 56 %).

[AsCI3{Ph2P(Se)CH2CH2P(Se)Ph2}]: Calculated for C26H24P2Se2AsCl3: C, 42.31; H, 3.28; Cl,


δ 35.9, 1J(SeP) = 734 Hz; 3J(PP) = 64.1 Hz and 4J(PSe) = 6.6 Hz; 77Se{1H} NMR (CDCl3):

δ -349.4, dd, 1J(PSe) = 734 Hz; 4J(PSe) = 5.6 Hz. Raman (cm-1): 3055, 3037, 2929, 2889,

1584, 1574, 1188, 1164, 1104, 1094, 1028, 999, 887, 786, 698, 614, 528, 504, 460, 372,

349, 323, 256, 211, 184, 171, 152, 125.

2.10.17. Synthesis of [AsBr3{Ph2P(Se)CH2CH2P(Se)Ph2}]


diselenide (0.50 g, 0.89 mmoles) and arsenic tribromide (0.28 g, 0.89 mmoles) gave

[AsBr3{Ph2P(Se)CH2CH2P(Se)Ph2}] as a very pale yellow solid (0.442 g, 57 %).

[AsBr3{Ph2P(Se)CH2CH2P(Se)Ph2}]: Calculated for C26H24P2Se2AsBr3: C, 35.83; H, 2.78; Br,

27.53; P, 7.11; Found: C, 35.91; H, 2.18; Br, 27.92; P, 7.01 %. 31P{1H} NMR (CDCl3):


δ -349.1, dd, 1J(PSe) = 734 Hz; 4J(PSe) = 5.6 Hz. Raman (cm-1): 3056, 2929, 2887, 1584,

1187, 1157, 1102, 1029, 998, 886, 784, 692, 617, 526, 500, 452, 255, 232, 168, 127.

2.10.18. Synthesis of [AsI3{Ph2P(Se)CH2CH2P(Se)Ph2}]


diselenide (0.50 g, 0.89 mmoles) and arsenic triiodide (0.40 g, 0.89 mmoles) gave

[AsI3{Ph2P(Se)CH2CH2P(Se)Ph2}] as a dark yellow solid (0.723 g, 80 %).

[AsI3{Ph2P(Se)CH2CH2P(Se)Ph2}]: Calculated for C26H24P2Se2AsI3: C, 30.84; H, 2.39; l,



δ -341.5, dd, 1J(PSe) = 730 Hz; 4J(PSe) = 7.6 Hz Raman (cm-1): (the sample fluoresced

and gave the following peaks) 3049, 2882, 1582, 1101, 1000, 881, 522, 497, 450, 252,

199, 191.

128

2.10.19. Synthesis of [BiCl3{Ph2P(Se)(CH2)6P(Se)Ph2}2]

In a procedure analogous to 2.10.1, the reaction of 1,6-(diphenylphosphino)hexane

diselenide (0.4 g, 0.63 mmoles) and bismuth trichloride (0.20 g, 0.63 mmoles) gave a

yellow solid product (0.482 g, 49 %).

[BiCl3{Ph2P(Se)(CH2)6P(Se)Ph2}2]: Calculated for C60H64P4Se4BiCl3: C, 46.77; H, 4.19; Cl,


δ 34.0, 1J(SeP) = 718 Hz; 77Se{1H} NMR (CDCl3): insufficiently soluble. Raman (cm-1):

fluoresced.

2.10.20. Synthesis of [BiBr3{Ph2P(Se)(CH2)6P(Se)Ph2}2]


diselenide (0.4 g, 0.63 mmoles) and bismuth tribromide (0.286 g, 0.63 mmoles) gave a

dark yellow solid product (0.519 g, 49 %).

[BiBr3{Ph2P(Se)(CH2)6P(Se)Ph2}2]: Calculated for C60H64P4Se4BiBr3: C, 43.04; H, 3.86; Br,



3052, 3007, 2972, 2937, 2919, 2894, 998, 220, 191, 168, 155, 120.

2.10.21. Synthesis of [BiI3{Ph2P(Se)(CH2)6P(Se)Ph2}]


diselenide (0.3 g, 0.47 mmoles) and bismuth triiodide (0.282 g, 0.47 mmoles) gave a

grey solid product (0.478 g, 81 %).

[BiI3{Ph2P(Se)(CH2)6P(Se)Ph2}]: Calculated for C30H32P2Se2BiI3: C, 29.95; H, 2.68; I, 31.68;


1J(SeP) = 720 Hz. Raman (cm-1): 3049, 2933, 2918, 2895, 2852, 1586, 994, 258, 249,

232, 157, 148, 141, 133, 118.

5.10.22. Attempted synthesis of [SbCl3{Ph2P(Se)(CH2)6P(Se)Ph2}]

In a procedure analogous to 2.10.1, the reaction of 1,6-(diphenyl phosphino)hexane

selenide (0.3 g, 0.47 mmoles) and antimony trichloride (0.11 g, 0.47 mmoles) gave a

white solid product (0.247 g).

129

[SbCl3{Ph2P(Se)(CH2)6P(Se)Ph2}]: Calculated for C30H32P2Se2SbCl3: C, 42.85; H, 3.84; Cl,

12.66; P, 7.37 %; Found: C, 58.58; H, 5.27; Cl, none; P, 10.28 %. The elemental analysis

shows that the product is Ph2P(Se)(CH2)6P(Se)Ph2; Calculated for C30H32P2Se2: C, 58.81;

H, 5.27; P, 10.12 %; Found: C, 58.58; H, 5.27; P, 10.28 %. 31P{1H} NMR (CDCl3): δ 34.0,

1J(SeP) = 720 Hz; 77Se{1H} NMR (CDCl3): δ - 343, d, 1J(PSe) = 720 Hz. Raman (cm-1): 3052,

3008, 2935, 2897, 1587, 1171, 1103, 1031, 1001.

2.10.23. Attempted synthesis of [SbBr3{Ph2P(Se)(CH2)6P(Se)Ph2}]


diselenide (0.3 g, 0.47 mmoles) and antimony tribromide (0.173 g, 0.47 mmoles) gave

an off white solid product (0.271 g).

[SbBr3{Ph2P(Se)(CH2)6P(Se)Ph2}]: Calculated for C30H32P2Se2SbBr3: C, 36.98; H, 3.31; Br,

24.62; P, 6.36 %; Found: C, 57.09; H, 5.29; Br, 2.22; P, 9.85 %. The elemental analysis


H, 5.27; P, 10.12 %; Found: C, 57.09; H, 5.29; P, 9.85 %. 31P{1H} NMR (CDCl3): δ 34.0.

1J(SeP) = 719 Hz; 77Se{1H} NMR (CDCl3): δ -341.8, d, 1J(PSe) = 719 Hz. Raman (cm-1):

3051, 2936, 2910, 2899, 1588, 1576, 1558, 1118, 1088, 996, 977, 704, 276, 262, 249,

225.

2.10. 24. Synthesis of [SbI3{Ph2P(Se)(CH2)6P(Se)Ph2}]


diselenide (0.3 g, 0.47 mmoles) and antimony triiodide (0.24 g, 0.47 mmoles) gave an

orange solid product (0.442 g, 81 %).

[SbI3{Ph2P(Se)(CH2)6P(Se)Ph2}]: Calculated for C30H32P2Se2SbI3: C, 32.30; H, 2.89; I,



noisy spectra.

2.10.25. Attempted synthesis of [AsCl3{Ph2P(Se)(CH2)6P(Se)Ph2}]


diselenide (0.3 g, 0.49 mmoles) and arsenic trichloride (0.041 ml, 0.485 mmoles) gave a

very pale pink solid product (0.23 g).

130

[AsCl3{Ph2P(Se)(CH2)6P(Se)Ph2}]: Calculated for C30H32P2Se2AsCl3: C, 45.37; H, 4.06; Cl,

13.41; P, 7.81 %; Found: C, 57.34; H, 4.87; Cl, none; P, 9.96 %. The elemental analysis




3050, 2937, 2921, 2899, 2858, 1589, 1575, 1182, 1159, 1098, 1060, 1028, 996, 618,

538, 502, 481, 451, 287, 274, 256, 232, 219, 211, 201, 195.

2.10.26. Attempted synthesis of [AsBr3{Ph2P(Se)(CH2)6P(Se)Ph2}]


diselenide (0.3 g, 0.49 mmoles) and arsenic tribromide (0.154 g, 0.49 mmoles) gave a

very pale pink solid product (0.253 g).

[AsBr3{Ph2P(Se)(CH2)6P(Se)Ph2}]: Calculated for C30H32P2Se2AsBr3: C, 38.85; H, 3.48; Br,

25.87; P, 6.68 %; Found: C, 57.53; H, 5.17; Br, app. 1; P, 9.94 %. The elemental analysis




fluoresced.

2.10.27. Synthesis of [AsI3{Ph2P(Se)(CH2)6P(Se)Ph2}2]

In a procedure analogous to 2.10.1, the reaction of 1,6-(diphenyl phosphino)hexane

diselenide (0.3 g, 0.49 mmoles) and arsenic triiodide (0.223 g, 0.49 mmoles) gave a

turmeric-coloured solid product (0.371 g, 45 %).

[AsI3{Ph2P(Se)(CH2)6P(Se)Ph2}2]: Calculated for C60H64P4Se4AsI3: C, 42.86; H, 3.84; I,


δ 34.0, 1J(SeP) = 720 Hz; 77Se{1H} NMR (CDCl3): δ -335, d, 1J(PSe) = 720 Hz. Raman

(cm-1): fluoresced.

2.10.28. Attempted synthesis of [BiCI3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}]

In a procedure analogous to 2.10.1, [BiCl3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}] was

prepared as a dark brown solid (0.30 g) using trans/cis-1,2-

131

bis(diphenylphosphino)ethylene diselenide (0.40 g, 0.72 mmoles) and bismuth

trichloride (0.22 g, 0.72 mmoles).

[BiCl3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}]: Calculated for C26H22P2Se2BiCl3: C, 35.89; H,

2.55; Cl, 12.23; P, 7.13 %; Found: C, 36.13; H, 2.38; Cl, 11.36; P, 6.77 %. 31P{1H} NMR

(CDCl3): δ 28.6, 39.0*. Raman (cm-1): 3058, 2961, 1581, 1573, 1185, 1165, 1108, 1025,

999, 813, 526, 482, 452, 298, 270, 252, 197, 181, 169.

2.10.29. Attempted synthesis of [BiBr3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}]

In a procedure analogous to 2.10.1, [BiBr3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}] was

prepared as a pale green solid (0.564 g) from trans/cis-1,2-


tribromide (0.32 g, 0.72 mmoles).

[BiBr3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}]: Calculated for C26H22P2Se2BiBr3: C, 31.12; H,

2.21; Br, 23.91; P, 6.18 %; Found: C, 26.39; H, 1.56; Br, 28.65; P, 5.16 %. 31P{1H} NMR

(CDCl3): δ 28.6, 39.1*. Raman (cm-1): 3060, 3050, 1585, 1270, 1157, 1101, 1026, 999,

190, 179, 155.

2.10.30. Attempted synthesis of [BiI3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}]

In a procedure analogous to 2.10.1, [BiI3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}] was

prepared as an orange red solid (0.739 g) using trans/cis-1,2-



[BiI3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}]: Calculated for C26H22P2Se2BiI3: C, 27.28; H,

1.94; I, 33.29; P, 5.42 %; Found: C, 25.62; H, 1.71; I, 35.69; P, 6.21 %. 31P{1H} NMR

(CDCl3): δ 28.6. Raman (cm-1): 3168, 3142, 3051, 2954, 1641, 1584, 1571, 1479, 1434,

1333, 1269, 1187, 1160, 1101, 1025, 997, 817, 614, 543, 523, 477, 446.

2.10.31. Attempted synthesis of [SbCl3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}2]

In a procedure analogous to 2.10.1, [SbCl3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}2] was

prepared as a pale yellow solid (0.28 g) from trans/cis-1,2-

bis(diphenylphosphino)ethylene diselenide (0.40 g, 0.72 mmoles) and antimony


132

[SbCI3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}2]: Calculated for C52H44P4Se4SbCI3: C, 46.70;

H, 3.32; CI, 7.96; P, 9.27 %; Found: C, 47.73; H, 3.05; CI, 7.36; P, 8.84 %. 31P{1H} NMR

(CDCl3): δ 28.6, 21.2*. Raman (cm-1): 3054, 2969, 1585, 1572, 1264, 1188, 1166, 1160,

1097, 1026, 1000, 819, 704, 617, 534, 351, 331, 296, 264, 183.

2.10.32. Attempted synthesis of [SbBr3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}]

In a procedure analogous to 2.10.1, [SbBr3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}] was

prepared as a pale yellow solid (0.192 g) from trans/cis-1,2-



[SbBr3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}]: Calculated for C26H22P2Se2SbBr3: C, 34.08; H,

2.42; Br, 26.18; P, 6.77; Found: C, 34.34; H, 2.11; Br, 26.04; P, 6.58 %. 31P{1H} NMR

(CDCl3): δ 28.6, 19.6*. Raman (cm-1): 3055, 2985, 1582, 1569, 1024, 996, 550, 211, 194.

2.10.33. Attempted synthesis of [SbI3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}]

In a procedure analogous to 2.10.1, [SbI3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}] was

prepared as a yellow solid (0.496 g) using trans/cis-1,2-



[SbI3{trans/cis-Ph2P(Se)CHCHP(Se)Ph2}]: Calculated for C26H22P2Se2SbI3: C, 29.53; H,


(CDCl3): δ 28.6. Raman (cm-1): 3073, 3051, 3002, 2980, 2947, 1580, 1436, 1259, 1184,

1162, 1100, 1024, 998, 826, 742, 613, 539, 262, 227, 214, 183, 168.

2.10.34. Attempted synthesis of [AsCl3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}]

In a procedure analogous to 2.10.1, [AsCl3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}] was

prepared as a dark pink solid (0.337 g) using trans/cis-1,2-

bis(diphenylphosphino)ethylene diselenide (0.40 g, 0.72 mmoles) and arsenic

trichloride (0.06 ml, 0.72 mmoles).

[AsCl3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}]: Calculated for C26H22P2Se2AsCl3: C, 42.43; H,


(CDCl3): δ 28.5, 22.4* 1J(SeP) = 752 Hz, 3J(PP) = 61.1 Hz and 4J(PSe) = 6.1; 77Se{1H} NMR

133

(CDCl3): δ -322.8, dd, 1J(PSe) = 752 Hz, 4J(PSe) = 6.3 Hz. Raman (cm-1): 3065, 3047, 2955,

1586, 1264, 1188, 1162, 1107, 1025, 998, 812, 531, 488, 457, 426, 384, 353, 324, 252,

198, 186, 154.

2.10.35. Attempted synthesis of [AsBr3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}2]

In a procedure analogous to 2.10.1, [AsBr3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}2] was

prepared as a pale yellow solid (0.347 g) using trans/cis-1,2-



[AsBr3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}2]: Calculated for C52H44P4Se4AsBr3: C, 44.55;

H, 1.58; Br, 17.12; P, 8.85 %; Found: C, 43.87; H, 2.71; Br, 17.33; P, 8.82 %. 31P{1H} NMR

(CDCl3): δ 28.7, 39.3*, 1J(SeP) = 753 Hz, 3J(PP) = 60 Hz and 4J(PSe) = 6.0 Hz; 77Se{1H}

NMR (CDCl3): δ -325, dd, 1J(PSe)= 753 Hz, 4J(PSe) = 5.8 Hz . Raman (cm-1): fluoresced.

2.10.36. Attempted synthesis of [AsI3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}]

In a procedure analogous to 2.10.1, [AsI3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}] was

prepared as an orange solid (0.486 g) using trans/cis-1,2-

bis(diphenylphosphino)ethylene diselenide (0.40 g, 0.72 mmoles) and arsenic triiodide

(0.328 g, 0.72 mmoles).

[AsI3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}]: Calculated for C26H22P2Se2AsI3: C, 30.90; H,


(CDCl3): δ 28.4, 77Se{1H} NMR (CDCl3): insufficiently soluble. Raman (cm-1): fluoresced.

2.10.37. Synthesis of [BiCl3{trans-Ph2P(Se)CH=CHP(Se)Ph2}]

In a procedure analogous to 2.10.1, [BiCl3{trans-Ph2P(Se)CH=CHP(Se)Ph2}] was

prepared as a yellow solid (0.508 g, 81 %) from trans-1,2-



[BiCl3{trans-Ph2P(Se)CHCHP(Se)Ph2}]: Calculated for C26H22P2Se2BiCl3: C, 35.89; H, 2.55;

Cl, 12.23; P, 7.13 %; Found: C, 34.98; H, 1.87; Cl, 12.27; P, 6.96 %. 31P{1H} NMR (CDCl3):


peaks) 3055, 2978, 1584, 998, 547, 272, 253, 196, 187.

134

2.10.38. Synthesis of [BiBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}]

In a procedure analogous to 2.10.1, [BiBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}] was

prepared as a yellow solid (0.481 g, 67 %) using trans-1,2-



[BiBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}]: Calculated for C26H22P2Se2BiBr3: C, 31.12; H,


(CDCl3): δ 28.6. Raman (cm-1): 3050, 1587, 1573, 1267, 1160, 1098, 1028, 999, 819,

616, 546, 524, 477, 450, 254, 193, 174, 156.

2.10.39. Synthesis of [BiI3{trans-Ph2P(Se)CH=CHP(Se)Ph2}]

In a procedure analogous to 2.10.1, [BiI3{trans-Ph2P(Se)CH=CHP(Se)Ph2}] was prepared

as an orange brown solid (0.580 g, 70 %) using trans-1,2-



[BiI3{trans-Ph2P(Se)CH=CHP(Se)Ph2}]: Calculated for C26H22P2Se2BiI3: C, 27.28; H, 1.94; I,


δ 28.6, 77Se{1H} NMR (CDCl3): insufficiently soluble. Raman (cm-1): 3052, 2956, 1582,

1570, 1479, 1432, 1268, 1186, 1158, 1100, 1024, 996, 816, 542, 522, 476, 448, 272,

256, 138, 118.

2.10.40. Synthesis of [SbCl3{trans-Ph2P(Se)CH=CHP(Se)Ph2}2]

In a procedure analogous to 2.10.1, [SbCl3{trans-Ph2P(Se)CH=CHP(Se)Ph2}2] was

prepared as a greyish white solid (0.274 g, 28 %) using trans-1,2-



[SbCl3{trans-Ph2P(Se)CH=CHP(Se)Ph2}2]: Calculated for C52H44P4Se4SbCl3: C, 46.70; H,


(CDCl3): δ 28.6. Raman (cm-1): 3052, 2964, 1587, 1571, 1188, 1157, 1100, 1026, 999,

531, 348, 333, 262, 196, 182, 136.

135

2.10.41. Synthesis of [SbBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}]

In a procedure analogous to 2.10.1, [SbBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}] was

prepared as a yellow solid (0.481 g, 73 %) using trans-1,2-



[SbBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}]: Calculated for C26H22P2Se2SbBr3: C, 34.08; H,

2.42; Br, 26.18; P, 6.77; Found: C, 34.31; H, 1.99; Br, 25.54; P, 5.67 %. 31P{1H} NMR

(CDCl3): δ 28.7. Raman (cm-1): 3055, 1585, 1572, 1184, 1160, 1105, 1096, 1025, 999,

615, 549, 521, 213, 197.

2.10.42. Synthesis of [SbI3{trans-Ph2P(Se)CH=CHP(Se)Ph2}]

In a procedure analogous to 2.10.1, [SbI3{trans-Ph2P(Se)CH=CHP(Se)Ph2}] was prepared

as a yellow solid (0.575 g, 75 %) using trans-1,2-bis(diphenylphosphino)ethylene

diselenide (0.40 g, 0.72 mmoles) and antimony triiodide (0.362 g, 0.72 mmoles).

[SbI3{trans-Ph2P(Se)CH=CHP(Se)Ph2}]: Calculated for C26H22P2Se2SbI3: C, 29.53; H, 2.10;

I, 36.04; P, 5.86 %; Found: C, 24.08; H, 1.49; I, 44.51; P, 4.90 %. 31P{1H} NMR (CDCl3):

δ 28.6, 77Se{1H} NMR (CDCl3): insufficiently soluble. Raman (cm-1): 3052, 2977, 1580,

1260, 1183, 1160, 1100, 1024, 995, 922, 826, 539, 261, 237, 226, 213, 183, 168, 136,

114.

2.10.43. Synthesis of [AsCl3{trans-Ph2P(Se)CH=CHP(Se)Ph2}]

In a procedure analogous to 2.10.1, [AsCl3{trans-Ph2P(Se)CH=CHP(Se)Ph2}] was

prepared as a pink solid (0.397 g, 75 %) using trans-1,2-


trichloride (0.06 ml, 0.72 mmoles).

[AsCl3{trans-Ph2P(Se)CH=CHP(Se)Ph2}]: Calculated for C26H22P2Se2AsCl3: C, 42.43; H,


(CDCl3): δ 28.7, 1J(SeP) = 753 Hz; 3J(PP) = 60.5 Hz and 4J(PSe) = 6 Hz; 77Se{1H} NMR

(CDCl3): δ -319, dd, 1J(PSe) = 753 Hz, 4J(PSe) = 6 Hz. Raman (cm-1): 3065, 3048, 2956,

1585, 1265, 1186, 1161, 1104, 1026, 996, 810, 703, 616, 530, 487, 457, 427, 382, 354,

325, 254, 199, 185, 154, 123.

136

2.10.44. Synthesis of [AsBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}]

In a procedure analogous to 2.10.1, [AsBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}] was

prepared as a very pale yellow solid (0.346 g, 55 %) using trans-1,2-



[AsBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}]: Calculated for C26H22P2Se2AsBr3: C, 35.92; H,


(CDCl3): δ 28.8, 1J(SeP) = 753 Hz, 3J(PP) = 61 Hz and 4J(PSe) = 6.1 Hz; 77Se{1H} NMR

(CDCl3): δ-323.7, dd, 1J(PSe) = 753 Hz, 4J(PSe) = 6 Hz. Raman: 3049, 2955, 1584, 1264,

1187, 1160, 1100, 1025, 996, 810, 533, 488, 451, 260, 237, 198.

2.10.45. Synthesis of [AsI3{trans-Ph2P(Se)CH=CHP(Se)Ph2}]

In a procedure analogous to 2.10.1, [AsI3{trans-Ph2P(Se)CH=CHP(Se)Ph2}] was prepared

as a dark yellow solid (0.256 g, 35 %) using trans-1,2-bis(diphenylphosphino)ethylene

diselenide (0.40 g, 0.72 mmoles) and arsenic triiodide (0.328 g, 0.72 mmoles).

[AsI3{trans-Ph2P(Se)CH=CHP(Se)Ph2}]: Calculated for C26H22P2Se2AsI3: C, 30.90; H, 2.20;

I, 37.71; P, 6.14 %; Found: C, 29.52; H, 1.85; I, 40.18; P, 5.67 %. 31P{1H} NMR (CDCl3):

δ 28.4, 77Se{1H} NMR (CDCl3): insufficiently soluble. Raman (cm-1): Raman (cm-1):

fluoresced.

137

Chapter 3. Synthesis and Characterisation of mixed tertiary phosphine interhalogen compounds

3.0. Mixed tertiary phosphine interhalogen compounds

3.1. Reactions of tertiary phosphines with iodine trichloride

3.2. Reactions of tertiary phosphines with Br2/ IBr


3.4. Conclusion

3.5. References

138

3.0. Mixed tertiary phosphine interhalogen compounds

Tertiary phosphines react with halogens forming compounds which have been of great

importance and interest in organic and inorganic chemistry over a long period of

time.[1] These compounds show interesting structural motifs, some of which are ionic,

having formula of [R3PX][X], five co-ordinated molecular solid-state R3PX2 compounds

(trigonal bipyramidal) and spoke structure R3P-X-X.[2, 3] There have been very few

studies of tertiary phosphines with interhalogens such as IBr and ICl, especially

regarding their solid-state structural chemistry.[4]

3.1. Reactions of tertiary phosphines with iodine trichloride

Work in this section is concerned with the synthesis of some mixed tertiary phosphine

interhalogen complexes, [R3PCl][ICl2] by the direct reaction of the tertiary phosphines

with iodine trichloride in diethyl ether according to the equation:

where R3P = Ph3P, (p-FC6H4)3P, (o-SCH3C6H4)3P, (o-CH3C6H4)3P, {(2,6-OCH3)2C6H3}3P,

CH3Ph2P, (CH3)2PhP.

The preparation of these compounds was carried out by reacting equimolar

quantities of R3P with ICl3 in diethyl ether under anhydrous and anaerobic conditions.

In all cases, coloured precipitates (usually yellow to orange) were formed which were

filtered off under nitrogen and stored in glass vials in a glove box. The products were

characterised by elemental analysis, 31P{1H} NMR and Raman spectroscopy. The results

of the elemental analysis and 31P{1H} NMR chemical shifts/ Raman bands are shown in

Tables 3.0 & 3.1, respectively.

139

Table 3.0. Elemental analysis data for [R3PCl][ICl2]

% E cal % E found (E = S or

P)

% I cal % I found

% Cl cal % Cl found

% H cal % H found

% C cal % C found

Colour Compound

- - - - dark yellow

[Ph3PCl][ICl2], 1

23.10 App. 22

19.36 App. 17

2.20 2.03

39.32 40.28

yellow [(p-FC6H4)3PCl][ICl2], 2

15.14 15.28

20.04 App. 19

16.79 App. 14

3.34 3.40

39.79 41.37

orange [(o-SCH3C6H4)3PCl][ICl2], 3

- - - - brown [(o-CH3C6H4)3PCl][ICl2], 4

18.79 App. 20

15.75 App. 15

4.03 3.98

42.64 43.16

yellow [{(2,6-OCH3)2C6H3}3PCl][ICl2], 5

- - - - dark orange

[(CH3)2PhPCl][ICl2], 6

App. = Approximate value, an approximate value is given because of mixed halides in the sample, so an

exact value for each halide separately cannot be accurately determined (% accuracy : ± 2 %).

For compounds 2, 3, and 5, good agreement between the calculated and observed

elemental analysis figures was found. For compounds 1, 4 and 6 the analysis figures

were unsatisfactory.

Table 3.1 31P{1H} NMR chemical shifts and Raman bands for [R3PCl][ICl2]

(* = low intensity peak).

Characteristic Raman bands [ICl2

-] (cm-1)

31P{1H} δ (ppm) Compound

274 43.9, 66.0 [Ph3PCl][ICl2], 1

- 64.6 [(p-FC6H4)3PCl][ICl2], 2

264 36.9*, 56.9 [(o-SCH3C6H4)3PCl][ICl2], 3

262 44.1*, 64.4 [(o-CH3C6H4)3PCl][ICl2], 4

264 36.4 [{(2,6-OCH3)2C6H3}3PCl][ICl2], 5

273 53.4, 79.8 [(CH3)2PhPCl][ICl2], 6

- 48.5 [CH3Ph2PCl][ICl2], 7

The 31P{1H} NMR spectra of 1-7 were recorded in CDCl3. Unfortunately, some of the

materials were poorly soluble, resulting in noisy spectra. It has previously been

reported that the observed chemical shift range for [R3PCl]+ is 60-80 ppm[5] which is

dependent on the nature of the R group. Thus, the 31P{1H} NMR spectroscopic data is

consistent for compounds 1, 2, 3, 4 and 6. Compounds 1, 3, 4 & 6 additionally show

peaks at 43.9, 36.9, 44.1 and 53.4 ppm respectively even though these peaks for 3 & 4

140

are of low intensity which may indicate some hydrolysis of the desired product in

solution. For 5, a single peak is observed at 36.4 ppm, this is outside the usual chemical

shift range for [R3PCl]+ cations, however, the elemental analysis was satisfactory for

this complex, so it may reflect the influence of the methoxy groups on the aromatic

rings where the presence of the two groups may cause an increased shift which has

been observed for other methoxy substituted aryl phosphine compounds. NMR

spectroscopic data was also obtained for 7, for which insufficient sample was isolated

to allow for elemental analysis. A single sharp peak is observed at 48.5 ppm which is

found at lower frequency than expected, 70.3 ppm for [CH3Ph2Cl]+ cation, therefore

the peak at 48.5 ppm suggests that hydrolysis has occurred in solution.

Solid state FT Raman studies of 1-6 in sealed glass tubes were undertaken.

Compound 2 fluoresced and so suitable spectra could not be obtained. A linear [ICl2]–

ion should show one Raman active I-Cl stretching mode. Previously, this mode has

been observed between 250-270 cm-1.[6] As can be seen from the data in Table 3.1,

compounds 1, 3, 4 and 5 all show peaks within this range, which can be assigned to the

[ICl2]– anion. Compound 6 also exhibited a peak within the range, however, the

spectrum is too noisy to allow confidence in its assignment.

Crystals suitable for X-ray diffraction were grown using dry dichloromethane/

diethyl ether layered solutions of the compounds. For compounds 2 and 7, it was

possible to obtain X-ray crystal data, their resulting molecular structures are shown in

Figs 3.0 & 3.1, with selected bond lengths and angles given in Tables 3.2 & 3.3. These

confirm the presence of [R3PCl][ICl2] species.

For compound 2, as expected, the cation adopts an approximately tetrahedral

arrangement around the phosphorus atom (angles, 106.3(3), 107.1(3), 112.5(5) and

111.1(4)°), whilst the anion is essentially linear (Cl(1)-I(1)-Cl(2) = 178.64(9)°) with two

asymmetric I-Cl bond distances of 2.537(3) and 2.569(3) Å, the asymmetry of the I-Cl

bonds was also observed in [Me3PN(H)PMe3][ICl2]2[7] which consisted of two [ICl2]–

anions where one of the [ICl2]– anions was linked to N-H with I-Cl bond lengths of

2.477(2) and 2.609(2) Å while the other independent [ICl2]– anion, the I-Cl bonds were

2.512(2) and 2.585(2) Å, the angles, Cl-I-Cl angles were 176.96(7) and 178.33(7)°

respectively.

141

Fig. 3.0. ORTEP representation of the molecular structure of [(p-FC6H4)3PCI][ICl2], 2.

Table 3.2. Selected bond lengths (Å) and angles (°) of [(p-FC6H4)3PCI][ICl2], 2

Bond Length (Å) Angle Angle (°)

I(1)-Cl(2) 2.569(3) Cl(1)-I(1)-Cl(2) 178.64(9)

I(1)-Cl(1) 2.537(3) Cl(3)-P(1)-C(7) 107.1(3) Cl(3)-P(1) 2.008(4) Cl(3)-P(1)-C(13) 108.5(3)

P(1)-C(7) 1.762(10) C(1)-P(1)-C(7) 111.0(5)

P(1)-C(1) 1.777(10) C(1)-P(1)-C(13) 111.1(4)

P(1)-C(13) 1.771(10) C(7)-P(1)-C(13) 112.5(5)

F(1)-C(4) 1.361(12) Cl(3)-P(1)-C(1) 106.3(3)

F(2)-C(10) 1.344(11)

F(3)-C(16) 1.343(13)

The X-ray crystal packing of compound 2 shows that there is no significant Cl···Cl

contact between the P-Cl bond of the cation and the [ICl2]– anion, each of the chlorine

atoms in the anion participate in three weak, non–classical Cl···H hydrogen bonds, as

shown in Fig. 3.1. In addition, there are also F-H contacts which link the [(p-FC6H4)3PCI]+

cations, with F(1)···H(18) contacts of 2.41 Å (sum of the van der Waals radii of

hydrogen and fluorine is 2.67 Å).

142

Fig. 3.1. Crystal packing of [(p-FC6H4)3PCI][ICl2], 2, showing H···Cl and F···H

contacts.

Compound 7 also shows a tetrahedral arrangement around the phosphorus atom. The

I-Cl bond lengths of the [ICl2]– anion are more symmetric in compound 7, I(1)-Cl(3):

2.5468(19) and I(1)-Cl(4): 2.558(2) Å than in compound 2, symmetric I-Cl bond lengths,

I-Cl: 2.571(2) Å and Cl-I-Cl angle: 178.10(6)° was observed in the [ICl2]– anion of

[PPh4][ICl2].[8]

The X-ray crystal packing diagram for compound 7 shows that there is disorder

in this structure with the atoms labeled as C(13) and C(14) exhibiting partial carbon

and partial chlorine occupancy, Cl(1) and Cl(2) so little significance can be attached to

these distances. Indeed, they are observed to be intermediate between typical P-Cl

and P-C bond lengths.

143

Fig. 3.2. ORTEP representation of the molecular structure of [CH3Ph2PCl][ICl2],7,

C(13)/Cl(1) and C(14)/Cl(2) are 50 % CH3 and 50 % Cl.

Table 3.3. Selected bond lengths (Å) and angles (°) of [CH3Ph2PCl][ICl2], 7


I(1)-Cl(3) 2.5468(19) Cl(3)-I(1)-Cl(4) 178.48(6)

I(1)-Cl(4) 2.558(2) Cl(1)-P(1)-C(7) 109.3(3) Cl(1)-P(1) 1.963(4) Cl(1)-P(1)-C(14) 111.76(17)

Cl(2)-P(1) 1.964(4) Cl(1)-P(1)-C(1) 107.9(3)

P(1)-C(1) 1.792(8) C(1)-P(1)-C(14) 110.1(3)

P(1)-C(13) 1.963(4) Cl(2)-P(1)-C(1) 110.1(3) P(1)-C(14) 1.964(4) C(1)-P(1)-C(7) 110.5(3)

P(1)-C(7) 1.783(7) C(7)-P(1)-C(14) 107.4(3)

Cl(2)-P(1)-C(7) 107.4(3) C(7)-P(1)-C(13) 109.3(3)

Cl(2)-P(1)-C(13) 111.76(17)

C(1)-P(1)-C(13) 107.9(3)

It is also observed from X-ray crystal packing diagram shown in Fig. 3.3 for compound 7

that the hydrogen bonding is less than in compound 2 with only one Cl···H hydrogen

bond Cl(4)···H(13A): 2.89 Å at one end of the [ICl2]– anion, and two at the other end,

Cl(3)···H(3): 2.92 Å and Cl(3)···H(4): 2.85 Å. The Cl···H bonds are also weaker than in the

144

[(p-FC6H4)3PCI][ICl2], 2 which may be explain the more symmetric I-Cl bonds observed

in [CH3Ph2PCl][ICl2],7.

Fig. 3.3. Crystal packing of [CH3Ph2PCl][ICl2], 7, showing Cl···H contacts

3.2. Reactions of tertiary phosphines with Br2/ IBr

Work in this section is concerned with the syntheses of some mixed tertiary phosphine

interhalogen compounds, [R3PBr][IBr2] by the two step reaction of tertiary phosphines

with bromine in diethyl ether followed by the addition of IBr2 the next day, according

to the equation:

where R3P = Ph3P, (o-OCH3C6H4)3P, (p-FC6H4)3P, (o-CH3C6H4)3P, (p-CH3C6H4)3P,

(o-SCH3C6H4)3P.

The preparation of these compounds was carried out by initially reacting

equimolar quantities of R3P with Br2 in diethyl ether under anhydrous and anaerobic

conditions, followed by IBr the next day. In all cases, coloured precipitates (yellow to

orange) were formed which were filtered off under nitrogen and stored in glass vials in

145

a glove box. The results were characterised by elemental analysis, 31P{1H} NMR and

Raman spectroscopy.

Crystals suitable for X-ray diffraction were grown using dry

dichloromethane/diethyl ether layered solution of the compound,

[(o-CH3C6H4)3PBr][Br3], 11, so it was possible to obtain crystal data and its molecular

structure, this is shown in Fig. 3.4, and selected bond lengths and angles are given in

Table 3.4. The solid state structure of the product from the reaction of (o-CH3C6H4)3P

with Br2 and IBr showed it to contain the [Br3]– anion such that the product obtained is

the fully brominated compound [(o-CH3C6H4)3PBr][Br3] and not the expected mixed

interhalogen compound, [(o-CH3C6H4)3PBr][IBr2]. This suggests that the formation of

[R3PBr][Br] may not be favoured instead reaction with an additional equivalent of Br2

occurs to give [R3PBr][Br3] as it is difficult to stop the reaction at one equivalent.

Raman studies showed the presence of a band assignable to the [Br3]– ion, see later.

Compound 11 shows a tetrahedral arrangement around the phosphorus atom (angles

106.0(3), 107.1(3), 114.9(4), 111.4(5)°) and the Br3– anion is essentially linear

(Br(2)-Br(1)-Br(3) = 177.14(5)°) with asymmetrical Br-Br distances of 2.5576(14) and

2.6126(13) Å. The P-Br bond length for the [(o-CH3C6H4)3PBr]+ cation in compound 11,

[(o-CH3C6H4)3PBr][Br3] is 2.180(2) Å which is similar to m- and p-substituted

phenylphosphine bromide cations in [{m-CH3C6H4)3PBr}2Br3][Br3] and

[{p-CH3C6H4)3PBr}2Br3][Br3][9] of 2.175(6) and 2.179(3) Å respectively, but is longer than

the P-Br bond length of 2.1588(9) Å observed for the [(o-CH3C6H4)3PBr]+ cation in

[(o-CH3C6H4)3PBr][Cu2Br6](Br2),[10] and for the [Ph3PBr]+ cations in [Ph3PBr][Br3], d(P-Br):

2.134(7) and 2.145(7) Å,[11] or [Ph3PBr][SeBr3], d(P-Br): 2.1512(17) Å.[12]

146

Fig. 3.4. ORTEP representation of [(o-CH3C6H4)3PBr][Br3], 11

Table 3.4. Selected bond lengths (Å) and angles (°) of [(o-CH3C6H4)3PBr][Br3], 11


Br(4)-P(1) 2.180(2) Br(2)-Br(1)-Br(3) 177.14(5)

Br(1)-Br(3) 2.5576(14) Br(4)-P(1)-C(8) 106.0(3)

Br(1)-Br(2) 2.6126(13) Br(4)-P(1)-C(15) 107.1(3)

P(1)-C(15) 1.808(10) C(1)-P(1)-C(8) 114.9(4) P(1)-C(8) 1.792(9) C(1)-P(1)-C(15) 111.4(5)

P(1)-C(1) 1.778(10) C(8)-P(1)-C(15) 109.6(4)

Br(4)-P(1)-C(1) 107.4(3)

The X-ray crystal packing diagram (Fig. 3.5) shows some non-bonded interactions of

the [Br3]– ion with the phosphorus centre, with Br···Br contact distance of 3.3332(13) Å

and the P-Br···Br angle is 165.19(8)°.

147

Fig. 3.5. Crystal packing of [(o-CH3C6H4)3PBr][Br3], 11 viewed down the crystallographic

b axis.

The packing shows that [(o–CH3C6H4)3PBr]+ cations pack in a side-to-side and anti-

parallel fashion. There is one offset face-to-face and two edge-to-face embraces of the

tolyl rings which is common in halo-tris–aryl phosphonium salts.[9(a), 13, 14] The packing

of the cations form a square like packing motif with the tribromide anions sandwiched

between the cations.

The results of the 31P{1H} NMR chemical shifts / Raman bands and elemental analysis

are shown in Tables 3.5 & 3.6, respectively.

Table 3.5 31P{1H} NMR chemical shifts and Raman bands for [R3PBr][Br3]

(* = low intensity peak).

Characteristic Raman bands (cm-1)

31P {1H} δ (ppm) Compound

165 51.6 [Ph3PBr][Br3], 8

165 37.7*, 49.5 [(o-OCH3C6H4)3PBr][Br3], 9

165 46.8, 47.7 [(p-FC6H4)3PBr][Br3], 10

168 45.3 [(o-CH3C6H4)3PBr][Br3], 11

- 52.4, 52.9 [(p-CH3C6H4)3PBr][Br3], 12

240 56.6*, 48.3 [(o-SCH3C6H4)3PBr][Br3], 13

148

Solid state FT Raman studies of 8-13 in sealed glass tubes were undertaken. Compound

12 fluoresced and so suitable spectra could not be obtained. A linear [Br3]– ion should

show one Raman active stretching band, previously this has been observed at

163 cm-1.[15] As can be seen from the data in Table 3.5, compounds 8, 9, 10 and 11 all

show peaks within this range, which can be assigned to the [Br3]– anion. However,

compound 13 exhibits an intense peak at 240 cm-1 which is outside of the expected

range. Earlier studies[9(b)] have shown that the [Br3]– anion in [(o-SCH3C6H4)3PBr][Br3],

13 is very asymmetric [Br-Br···Br] so Br-Br band is close to Br2 which is in the range of

250-300 cm-1 found in Me2S.Br2.[16]

The 31P{1H} NMR spectra of 8-13 were recorded in CDCl3. Unfortunately, some

of the materials were poorly soluble, resulting in noisy spectra. It has previously been

reported that the observed chemical shift range for [R3PBr]+ is 40-60 ppm.[17] Thus, the

31P NMR data is consistent for all of the complexes.

The elemental analysis of the compounds were recalculated assuming the composition

of the type [R3PBr]+[Br3]– , in light of the structure of [(o-CH3C6H4)3PBr][Br3], 11, which

gave evidence for the formation of the fully brominated product. Now, the agreement

between calculated and observed figures is excellent for 11 (Calculated C, 40.40; H,

3.39; Br, 51.24 %; Found : C, 40.01, H, 3.35; Br, App. 52 %) and 13 (Calculated C, 35.02;

H, 2.94; Br, 44.41; S, 13.33 %; Found : C, 34.92, H, 3.02; Br, App. 43; S, 13.07 %).

Table 3.6. Elemental analysis data for [R3PBr][Br3]

% S cal % S found

% Br cal % Br found

% H cal % H found

% C cal % C found

Colour Compound

- - - -

yellow [Ph3PBr][Br3], 8

- - - -

yellow [(o-OCH3C6H4)3PBr][Br3], 9

- - - - dark yellow

[(p-FC6H4)3PBr][Br3], 10

- 51.24 App. 52

3.39 3.35

40.40 40.01

dark yellow

[(o-CH3C6H4)3PBr][Br3], 11

- 51.24 App. 38

3.39 3.17

40.40 40.26

dark yellow

[(p-CH3C6H4)3PBr][Br3], 12

13.33 13.07

44.41 App. 43

2.94 3.02

35.02 34.92

dark yellow

[(o-SCH3C6H4)3PBr][Br3], 13

149

For compound 12, the elemental analysis figures are reasonable for C, H, Br and not for

I which has a very low value (app. 3 %) and is also observed for all other compounds (8,

10, 11 and 13), compound 9 also a low value of app. 6 %). Taken together, this appears

to suggest that iodine is not significantly incorporated in the resulting products, and

that the tribromides are formed instead.


In this section, work was concerned with the syntheses of tetraphosphonium

interhalogen compounds, [R3PR'][X'X2] by the direct reaction of the

methyltriphenylphosphonium halide (where halide is I and/or Br) with bromine and/or

sulfuryl chloride according to the following reaction:

where X' = I, Br and X2 = Br2, SO2Cl2

A similar reaction was performed for the synthesis of tetramethylphosphonium

tribromide by the direct reaction of tetramethylphosphonium bromide with bromine

according to the following reaction:

The preparation of these compounds was carried out by direct reaction of equimolar

quantities of tetramethylphosphonium iodide/bromide with bromine/sulfuryl chloride

in diethyl ether under anhydrous and anaerobic conditions. In all cases, coloured

precipitates were formed which were filtered off under nitrogen and stored in glass

vials in a glove box.

The resulting products were characterised by elemental analysis, 31P NMR and Raman

spectroscopy. Table 3.7 shows the elemental analysis data for the [Ph3PCH3][X'X2] and

[(CH3)4P][Br3] compounds.

150

Table 3.7. Elemental analysis data for [Ph3PCH3][X'X2] and [(CH3)4P][Br3]

% Pcal % Pfound

% I cal % I found

% X cal % X found

(X = Cl or Br)

% H cal % H found

% C cal % C found

Colour Compound

- - - - - Orange-brown

[Ph3PCH3][IBr2], 14

6.52 6.48

26.72 App. 26

14.93 App. 13

3.82 3.68

48.01 48.39

yellow [Ph3PCH3][ICl2], 15

5.99 6.25

46.38 45.40

3.51 3.47

44.12 45.30

yellow [Ph3PCH3][Br3], 16

9.36 17.86

72.47 46.80

3.66 7.07

14.51 28.32

white [(CH3)4P][Br3], 17

Compounds 15 and 16 showed good agreement in the results while compound 14

showed unsatisfactory figures. The values obtained for complex 17 were significantly

high for C, H, P and about half the expected value for Br, these suggest some changes

have occurred, which is consistent with observations during the reaction, the colour of

the reaction mixture was yellow at the beginning and then it became paler and paler

until finally a white precipitate was obtained. The actual product of compound 17 is

the starting tetramethylphosphonium bromide [(CH3)4PBr] (C, 28.07; H, 7.07; Br, 46.74;

P, 18.12 %. Found: C, 28.32; H, 7.07; Br, 46.80; P, 17.86 % which is clear from the

recalculated elemental analysis.

Table 3.8. 31P{1H} NMR chemical shifts and Raman bands for [Ph3PCH3][X'X2] and

[(CH3)4P][Br3].

Characteristic Raman bands (cm-1)

31P{1H} δ (ppm) Compound

177, 151 21.4 [Ph3PCH3][IBr2], 14

268 21.3 [Ph3PCH3][ICl2], 15

166 21.24, 21.28 [Ph3PCH3][Br3], 16

278 23.8 [(CH3)4P][Br3], 17

The 31P{1H} NMR spectra of 14-17 were recorded in CDCl3. Unfortunately, some of the

materials were poorly soluble, resulting in noisy spectra. It has previously been

reported that the observed chemical shift range for quaternary phosphonium salts is

19-36 ppm.[18] Thus, the 31P{1H} NMR data are consistent for all of the compounds.

151

Fortunately, the reaction of [Ph3PCH3]I with SO2Cl2 to give 15 and [Ph3PCH3]Br with Br2

to give 16 resulted in crystals suitable for X-ray diffraction and their molecular

structures are shown in Figs 3.6 & 3.7 respectively and selected bond lengths and

angles are listed in Tables 3.9 & 3.10.

The crystal structure of 15 shows the [Ph3PCH3]+ cation with the phosphorus

atom in a tetrahedral geometry (C-P-C angles 110.6(5), 110.2(5), 108.4(5) and

109.7(5)°) while the [ICl2]– anion is linear (angle Cl(1)-I(1)-Cl(2) = 178.79(10)°) with two

slightly asymmetric I-Cl distances of 2.525(3) and 2.557(3) Å.

Fig. 3.6. ORTEP representation of [Ph3PCH3][ICl2], 15

Table 3.9. Selected bond lengths (Å) and angles (°) of [Ph3PCH3][ICl2], 15


I(1)-Cl(2) 2.525(3) Cl(1)-I(1)-Cl(2) 178.79(10)

I(1)-Cl(1) 2.557(3) C(1)-P(1)-C(13) 108.9(5) P(1)-C(7) 1.800(11) C(1)-P(1)-C(19) 110.2(5)

P(1)-C(1) 1.780(12) C(1)-P(1)-C(7) 108.4(5)

P(1)-C(19) 1.775(11) C(7)-P(1)-C(19) 109.0(5)

P(1)-C(13) 1.797(10) C(13)-P(1)-C(19) 110.6(5)

C(7)-P(1)-C(13) 109.7(5)

152

The crystal structure of 16 shows two independent methyltriphenylphosphonium ions,

a bromide and a linear tribromide anion with a Br(1)-Br(2)-Br(3) angle of 176.97(2)°

Fig. 3.7. ORTEP representation of [Ph3PCH3]2[Br3]Br, 16.

Table 3.10. Selected bond lengths (Å) and angles (°) of [Ph3PCH3]2[Br3]Br, 16

Bond Length (Å) Angle Angle (°) Br(1)-Br(2) 2.5131(6) Br(1)-Br(2)-Br(3) 176.97(2)

Br(2)-Br(3) 2.5812(6) C(1)-P(1)-C(7) 110.94(19)

P(1)-C(7) 1.791(5) C(1)-P(1)-C(13) 109.18(19)

P(1)-C(1) 1.799(4) C(7)-P(1)-C(13) 106.97(19) P(1)-C(19) 1.786(4) C(7)-P(1)-C(19) 110.5(2)

P(1)-C(13) 1.799(4) C(13)-P(1)-C(19) 108.9(2)

P(2)-C(38) 1.774(4) C(26)-P(2)-C(38) 110.3(2) P(2)-C(20) 1.795(4) C(32)-P(2)-C(38) 110.4(2)

P(2)-C(32) 1.797(4) C(26)-P(2)-C(32) 109.7(2)

P(2)-C(26) 1.792(4) C(20)-P(2)-C(26) 107.31(19)

C(20)-P(2)-C(32) 109.27(19) C(20)-P(2)-C(38) 110.3(2)

153

The X-ray crystal packing diagram of [Ph3PCH3]2[Br3][Br] (Fig. 3.8) viewed down the a–

axis shows an unusual packing arrangement of four [Ph3PCH3]+ cations around the [Br]–

anions in the centre of the cell. This arrangement appears to be directed by non–

classical BrH hydrogen bonding between methyl or aryl protons on the cation and

the [Br]– anions. There is also BrH hydrogen bonding to the [Br3]– anions, but this is

weaker and the methyl groups prefer to hydrogen bond to the [Br]– anions as shown in

Fig. 3.9.

Fig. 3.8. Crystal packing of [Ph3PCH3]2[Br3][Br], 16 viewed

down the crystallographic a-axis.

154

Fig. 3.9. Crystal packing of [Ph3PCH3]2[Br3][Br], 16 showing weak Br···H contacts

Interestingly, the empirical formula of the single crystals [Ph3PCH3]2[Br3]Br does not

agree with that found for the bulk material sent for elemental analysis [Ph3PCH3][Br3].

This may mean that the product has lost bromine during crystallization, or that this

product crystallises more readily than [Ph3PCH3][Br3].

However, the observation of two phosphonium centres in the single crystal X-ray

structure appears to be consistent with the 31P{1H} NMR data, where two peaks of

similar intensity with very similar chemical shifts are observed.

3.4. Conclusion

A series of tertiary phosphines (where R3P is Ph3P, (p-FC6H4)3P, (o-SCH3C6H4)3P,

(o-CH3C6H4)3P, {(2,6-OCH3)2C6H3}3P, CH3Ph2P, (CH3)2PhP) have been reacted with iodine

trichloride to yield compounds of the formula [R3PCl][ICl2]. Two of these compounds

have been characterised crystallographically, [(p-FC6H4)3PCI][ICl2] and [CH3Ph2PCl][ICl2].

Each structure consists of an [R3PCl]+ cation (with a tetrahedral geometry around the

phosphorus atom), and a linear [ICl2]– anion. These two compounds are the first

[R3PCl][ICl2] structures to be crystallographically characterised.

The two step reactions of R3P compounds (R3P = Ph3P, (o-OCH3C6H4)3P, (p-FC6H4)3P, (o-

CH3C6H4)3P, (p-CH3C6H4)3P, (o-SCH3C6H4)3P) with Br2 followed by reaction with iodine

155

monobromide were pursued in order to attempt the synthesis of compounds of the

type [R3PBr][IBr2] but the resulting products gave the fully brominated products

[R3PBr][Br3], presumably as a consequence of the difficulty of stopping the first step of

the reaction at the [R3PBr]Br stage. The identity of the [R3PBr][Br3] products were

confirmed by single crystal X-ray diffraction and Raman Spectroscopy. The crystal

structure of [(o-CH3C6H4)3PBr][Br3] contains an [R3PBr]+ cation (with a tetrahedral

geometry around the phosphorus atom), and a linear [Br3]– anion. There are weak

Br···Br contacts between the cation and the anion leading to asymmetry in the [Br3]–

anion.

The direct reactions of methyltriphenyl phosphonium halides (X = Br, I) with the

halogenating agents Br2 and SO2Cl2 have been shown to produce [Ph3PCH3][X'X2]. The

crystal structure of [Ph3PCH3][ICl2] displays a [Ph3PCH3]+ cation with a tetrahedral

geometry, and a linear [ICl2]– anion. However, the crystal structure of the product of

the reaction of [Ph3PCH3]Br with Br2 contains two independent

methyltriphenylphosphonium cations, a bromide anion and a linear tribromide anion,

[Ph3PCH3]2[Br][Br3]. There is extensive C-H···Br hydrogen bonding in the solid state.

156

3.5. References

1. A. Michaelis, Justus Liebigs Ann. Chem., 1886, 233, 39. 2. S. M. Godfrey, D. G. Kelly, C. A. McAullife, A. G. Mackie, R. G. Pritchard and S. M.

Watson, J. Chem. Soc., Chem. Commun., 1991, 1163. 3. N. Bricklebank, S. M. Godfrey, C. A. McAuliffe, A. G. Mackie and R. G. Pritchard, J.

Chem. Soc., Chem. Commun., 1992, 355. 4. N. Bricklebank, S. M. Godfrey, C. A. McAuliffe, A. G. Mackie and R. G. Pritchard, J.

Chem. Soc., Chem. Commun., 1993, 2261. 5. S. M. Godfrey, C. A. McAuliffe, R. G. Pritchard, J. M. Sheffield and G. M. Thompson,

J. Chem. Soc., Dalton Trans., 1997, 4823. 6. A. G. Maki and R. Forneris, Spectrochimica Acta, 1967, 23A, 867. 7. J. Grebe, K. Harms, F. Weller and K. Dehnicke, Z. anorg. allg. Chem., 1995, 621,

1489. 8. R. Minkwitz and M. Berkei, Z. Naturforsch, 2001, 56 b, 39. 9. (a) F. B. Alhanash, N. A. Barnes, S. M. Godfrey, P. A. Hurst, A. Hutchinson, R. Z. Khan

and R. G. Pritchard, Dalton Trans., 2012, 41, 7708; (b) R. Z. Khan, PhD Thesis, University of Manchester (2011).

10. A. Okrut and C. Feldmann, Inorg. Chem., 2008, 47, 3084. 11. H. Vogt, S. I. Trojanov and V. B. Rybakov, Z. Naturforsch., B: Chem. Sci., 1993, 48,

258; H. Vogt and M. Meisel, Phosphorus, Sulfur Silicon Relat. Elem., 1996, 111, 95. 12. J. L. Dutton, R. Tabeshi, M. C. Jennings, A. J. Lough and P. J. Ragogna, Inorg. Chem.,

2007, 46, 8594. 13. N. A. Barnes, K. R. Flower, S. M. Godfrey, P. A. Hurst, R. Z. Khan and R. G. Pritchard,

CrystEngComm., 2010, 12, 4240. 14. N. A. Barnes, K. R. Flower, S. A. Fyyaz, S. M. Godfrey, A. T. McGown, P. J. Miles, R.

G. Pritchard and J. E. Warren, CrystEngComm., 2010, 12, 784. 15. S. G. W. Ginn, I. Haque and J. L. Wood, Spectrochimica Acta, 1968, 24A, 1531. 16. H. F. Askew, P. N. Gates and A. S. Muir, J. Raman Spectrosc., 1991, 22, 467. 17. S. M. Godfrey, C. A. McAuliffe, I. Mushtaq, R. G. Pritchard and J. M. Sheffield, J.

Chem. Soc., Dalton Trans., 1998, 3815. 18. L. D. Quin, A guide to Organophosphorus Chemistry, 2000, John Wiley & Sons.

157

Chapter 4. Synthesis and Characterisation of tertiary phosphine selenium tetrahalides

4.0. Tertiary phosphine selenium tetrahalides

4.1. Reactions of tertiary phosphines with selenium tetrahalides

4.2. Conclusion

4.3. References

158

4.0. Tertiary phosphine selenium tetrahalides

The reactions of group 16 tetrahalides SeX4 (X = Cl, Br) with the neutral phosphine

donors such as nBu3P and Ph3P and the reactions with N-heterocyclic carbenes have

been reported.[1] The reaction with neutral phosphine ligands is usually a redox

reaction where the Se(IV) centre is reduced to Se(II) and P(III) is oxidized to P(V),

resulting in compounds with the following formula: [R3PX][SeX3] (X = Cl, Br). The

reactions with different stoichiometric amounts of R3P with SeX4 have been reported

and were followed using 31P{1H} NMR spectroscopy.

The compounds [Ph3PCl][SeCl3], [nBu3PCl][SeCl3], [Ph3PBr][SeBr3] and

[nBu3PBr][SeBr3] were crystallographically characterised. The crystal structure of

[Ph3PCl][SeCl3] is shown in Fig. 4.0 which shows that the cation [Ph3PCl]+ has a

distorted tetrahedral geometry and the [SeCl3]- anions dimerizes to give [Se2Cl6]2- via

longer Se-Cl bridging bonds (2.817(2) Å and 2.712(1) Å) as is commonly found in these

types of anions.[2, 3]

Fig. 4.0. Solid state structure of [Ph3PCl][SeCl3], taken from ref [1].

159

4.1. Reactions of tertiary phosphines with selenium tetrahalides

This section concerns the syntheses of tertiary phosphine selenium tetrahalide

compounds, [R3PX][SeX3] by the reaction of tertiary phosphines with selenium

tetrahalides according to the following reaction:

where R3P = (o-tolyl)3P, (p-tolyl)3P, (o-OCH3C6H4)3P, (p-OCH3C6H4)3P,

(o-SCH3C6H4)3P, (p-FC6H4)3P, Me2PhP

and X = Cl, Br

The preparation of the [R3PX][SeX3] compounds was carried out by the direct

reaction of equimolar quantities of the tertiary phosphine with the selenium

tetrahalides, SeCl4 and SeBr4 respectively in diethyl ether under anhydrous and

anaerobic conditions. The resulting coloured products were filtered off under nitrogen

using Schlenk techniques and transferred to glass vials in a glove box. The products

were characterised by elemental analysis, 31P{1H} NMR and Raman Spectroscopy. The

elemental data for the prepared [R3PX][SeX3] compounds is shown in Table 4.0.

160

Table 4.0. Elemental analysis of [R3PX][SeX3] compounds

% P cal % P found

% X cal % X found (X = Cl,

Br)

% H cal % H found

% C cal % C found

Colour Compound

- - - - very pale

yellow

[(o-tolyl)3PCl][SeCl3], 17

-

- - - yellow [(p-tolyl)3PCl][SeCl3], 18

- - - - yellow [(p-OCH3C6H4)3PCl][SeCl3], 19

- - - - very pale

yellow

[(o-OCH3C6H4)3PCl][SeCl3], 20

4.99 5.29

22.84 20.12

3.41 3.49

40.59 42.34

yellow [(o-SCH3C6H4)3PCl][SeCl3], 21

5.77 6.00

26.42 21.97

2.25 2.06

40.24 41.04

pale yellow

[(p-FC6H4)3PCl][SeCl3], 22

- - - - dark grey

[Me2PhPCl][SeCl3], 23

- - - - dark yellow

[(o-tolyl)3PBr][SeBr3], 24

4.41 4.56

45.48 44.42

3.01 2.86

35.86 36.88

light brown

[(p-tolyl)3PBr][SeBr3], 25

- - - - light brown

[(p-OCH3C6H4)3PBr][SeBr3], 26

- - - - dark yellow

[(o-OCH3C6H4)3PBr][SeBr3], 27

3.88 4.20

40.02 39.54

2.65 2.64

31.55 32.86

brown [(o-SCH3C6H4)3PBr][SeBr3], 28

4.02 4.51

41.48 41.64

1.63 1.48

28.03 30.72

orange brown

[(p-FC6H4)3PBr][SeBr3], 29

- - - - orange [Me2PhPBr][SeBr3], 30

The elemental analysis figures for compounds 25 and 28 were in excellent agreement,

while 21 and 29 shows good agreement between calculated and observed figures. For

compounds, 17-20, 23, 24, 26, 27 and 30 agreement between calculated and observed

elemental analysis was not satisfactory.

161

Crystals suitable for X-ray diffraction were grown using dry dichloromethane/ diethyl

ether layered solutions of the compounds. Fortunately, the product of the reaction of

(p-OCH3C6H4)3P with SeCl4 resulted in crystals suitable for X-ray diffraction and its

molecular structure is shown in Fig. 4.1 and selected bond lengths and angles are given

in Table 4.1. The structure of the compound 19 consists of two [(p-OCH3C6H4)3PCl]+

cations and an [Se2Cl6]2– anion. However, the anion is non-symmetric and the two

[SeCl3]- units are not planar to each other. Comparison with previously reported

crystallographic data for [R3PCl][SeCl3] where R3 is Ph3, nBu3, the P-Cl bond lengths in

the [R3PCl]+ cations are 1.979(2) and 2.001(1) Å[1] which are consistent with the P-Cl

bond lengths in compound 19 (1.997(7) and 2.007(1) Å).

Some other examples of compounds which include [Se2Cl6]2- anions are

[Ph3PSH]2[Se2Cl6], [Se3N]2[Se2Cl6], [Ph4P]2[Se2Cl6] and [Me3SiN(H)PMe3][Se2Cl6], the

crystal structure of [Ph3PSH][Se2Cl6] shows that it a [Se2Cl6]2- dianion which is planar

(crystallographically centrosymmetric) with a square planar coordination on the Se

atoms, having terminal Se-Cl bond lengths of 2.288(2) and 2.238(2) Å while the

bridging Se-Cl bonds are slightly asymmetric (2.631(2) and 2.833(2) Å.

The asymmetric [Se2Cl6]2- dianion, observed for compound 19, is more similar

to that found in [Ph3PCl][SeCl3], which dimerizes through long Se···Cl contacts (2.817(2)

and 2.712(1) Å.[2, 3] The terminal Se-Cl bonds are 2.241(2) and 2.2900(18) Å and the

bridging Se-Cl are 2.6288(18) and 2.817(2) Å. The terminal bonds are shorter than the

bridging bonds which is consistent with compound 19, where the terminal Se-Cl bonds

are 2.269(6) and 2.316(5) Å, and the bridging Se-Cl bonds are 2.602(5) and 2.720(6) Å

respectively.

The p-anisyl groups on the cation engage in a number of short contacts,

including side-on hydrogen bond to the anion as shown in Fig. 4.2. There are also weak

Cl-Cl contacts between the anion and cation, although the Cl···Cl distances are quite

long, Cl(3)···Cl(8): 3.559(6) Å; Cl(6)···Cl(7): 3.289(7) Å.

162

Fig. 4.1. ORTEP representation of [(p-OCH3C6H4)3PCl][SeCl3], 19

Table 4.1. Selected bond lengths (Å) and angles (°) of [(p-OCH3C6H4)3PCl][SeCl3], 19


Se(1)-Cl(3) 2.269(6) Cl(2)-Se(1)-Cl(3) 91.31(18)

Se(1)-Cl(1) 2.316(5) Cl(1)-Se(1)-Cl(2) 173.0(2)

Se(1)-Cl(2) 2.602(5) Cl(1)-Se(1)-Cl(3) 94.34(19) Se(1)-Cl(4) 2.720(6) Cl(4)-Se(2)-Cl(5) 176.5(2)

Se(2)-Cl(4) 2.601(5) Cl(5)-Se(2)-Cl(6) 90.71(18)

Se(2)-Cl(5) 2.309(5) Cl(7)-P(1)-C(1) 106.2(6)

Se(2)-Cl(6) 2.256(6) Cl(7)-P(1)-C(8) 107.5(8) Se(2)-Cl(2) 2.778(6) Cl(7)-P(1)-C(15) 107.4(7)

P(1)-Cl(7) 2.001(7) Cl(8)-P(2)-C(29) 109.9(5)

P(2)-Cl(8) 1.997(7) Cl(8)-P(2)-C(22) 106.5(7)

Cl(6)-Cl(7) 3.289(7) Cl(8)-P(2)-C(36) 107.8(7) Cl(3)-Cl(8) 3.559(6)

163

Fig. 4.2. Crystal packing of [(p-OCH3C6H4)3PCl][SeCl3], 19 showing short contacts and

one-side hydrogen bonding between the anion and cation.

It was also possible to grow crystals from the product of the reaction of (o-SCH3C6H4)3P

with SeCl4, 21, its molecular structure is shown in Fig. 4.3 and bond lengths and angles

are given in Table 4.2. The structure of compound 21 and confirmed as

[(o-SCH3C6H4)3PCl][SeCl3] shows that the [SeCl3]- anion displays a monomeric T-shaped

structure, unlike the anion in compound 19 which is dimeric, with an interaction to one

of the sulfur atoms on the thioanisyl group of the cation as shown in Fig. 4.3. This Se···S

contact seems to prevent dimerisation of the anion. The selenium···sulfur distance is

3.069(4) Å which is within the sum of the relevant van der Waals radii, Se-S: 3.70 Å. [4]

Similar Se-S bond distances are reported in [Se{(EtO)2PS2)2}][5], in which there two

equal Se-S distances, d(Se-S) = 2.209(1) and 2.210(1) and two weak Se···S distances of

3.342(1) and 3.523(1) Å.

164

Fig. 4.3. ORTEP representation of [(o-SCH3C6H4)3PCl][SeCl3], 21

Table 4.2. Selected bond lengths (Å) and angles (°) of [(o-SCH3C6H4)3PCl][SeCl3], 21


Se(1)-Cl(2) 2.222(4) Cl(2)-Se(1)-Cl(3) 92.66(15)

Se(1)-Cl(3) 2.449(4) Cl(2)-Se(1)-Cl(4) 93.47(15) Se(1)-Cl(4) 2.401(4) Cl(3)-Se(1)-Cl(4) 172.78(15)

Cl(1)-P(1) 1.985(5) C(2)-S(1)-C(3) 102.2(7)

S(1)-C(2) 1.814(14) C(9)-S(2)-C(10) 101.9(7)

S(1)-C(3) 1.818(16) C(16)-S(3)-C(17) 101.8(6)

P(1)-Cl(1) 1.819(15) Cl(1)-P(1)-C(8) 106.1(5)

P(1)-C(8) 1.809(14) Cl(1)-P(1)-C(15) 104.7(5)

P(1)-C(15) 1.788(14) Cl(1)-P(1)-C(1) 111.7(5) Se(1)-S(1) 3.069(4)

Solid state FT Raman studies of compounds 17-30 in sealed glass tubes were

undertaken and recorded in the region ~ 3500-110 cm-1. It is not easy to assign the P-X

and Se-X stretches in these compounds as there is considerable overlapping of bands

especially at low frequencies. The Raman spectrum of [Ph3PCl]+Cl- shows a strong band

at 594 cm-1 which has been assigned as ν(P-Cl)[6], compounds 17-23 display peaks in

the region 550-610 cm-1 which may be due to ν(P-Cl). Although these systems are more

complex, so absolute assignment is not possible. For the bromo analogues, compounds

165

24-30, it is more difficult to assign individual modes since ν(P-Br) is ≈ 240 cm-1 in

[Ph3PBr]+Br- [7] and the Se-X stretching modes may also be at lower frequencies and are

likely to be of greater intensity and so may obscure ν(P-Br) modes. Compounds 24 and

30 gave no useful Raman data as they decomposed in the laser beam. Table 4.3 shows

selected Raman spectroscopic data for the [R3PX][SeX3] compounds. However, a

comparison with bromo- and chloro-selenates(II) compounds[8] was undertaken for

assignment of some ν(Se-X) stretches. It has been reported that the Raman spectra of

[Et4N][SeBr3][8] and [Ph4P][SeBr3][9] are similar to each other and that the structure of

[Ph4P][SeBr3] contains a dimeric [Se2Br6]2- anion similar to the [Se2Cl6]2- anion.

Table 4.3. Raman spectroscopic data for [R3PX][SeX3] compounds.

Compound ν(P-X) ν(Se-X terminal) ν(Se-X bridging) Assignment [Et4N][SeBr3](solid) consistent to [Se2Cl6]2- anion

- 222 189, 127 dimer

[SeBr3]- in MeCN - 258, 190, 159 monomer

[SeCl3]- in MeCN - 350, 268, 260 monomer

[(o-tolyl)3PCl][SeCl3], 17 604 227 163, 144 dimer

[(p-tolyl)3PCl][SeCl3], 18 570 346, 277 monomer [(p-OCH3C6H4)3PCl][SeCl3], 19 563 195a 187 dimer

[(o-OCH3C6H4)3PCl][SeCl3], 20 671a 195a 149 dimer

[(o-SCH3C6H4)3PCl][SeCl3], 21 585 351, 273, 257 monomer

[(p-FC6H4)3PCl][SeCl3], 22 570 351, 285, 230 monomer [Me2PhPCl][SeCl3], 23 551a 235a 139 dimer

[(p-tolyl)3PBr][SeBr3], 25 243 243b 193 dimer

[(p-OCH3C6H4)3PBr][SeBr3], 26 - 228 182, 163 dimer

[(o-OCH3C6H4)3PBr][SeBr3], 27 237a 165, 145 - [(o-SCH3C6H4)3PBr][SeBr3], 28 - 255, 229, 195 -

a. tentative assignment; b. It is not possible to uniquely assign this to ν(P-Br) or ν(Se-Br).

The 31P{1H} NMR spectra of 17-30 were recorded in CDCl3 and their peak

positions are listed in Table 4.4. Unfortunately, some of the materials were poorly

soluble, resulting in noisy spectra. It has been previously reported that the chemical

shift range for [R3PCl]+ is 60-80 ppm[10] and is dependent on the nature of the R group.

Thus, the 31P NMR data is consistent for compounds 17, 18, 19, 21 and 23 with the

formation of [R3PCl][SeX3] complexes. It has also been previously reported that the

chemical shift range for [R3PBr]+ is 40-60 ppm[11] which is consistent for compounds

24-30. The weak peaks (denoted by *) observed at ca. 40 ppm probably arise from

hydrolysis/decomposition in solution to give [R3POH]+ or [{R3PO}2H]+.

166

Table 4.4. 31P{1H} NMR chemical shifts of [R3PX][SeX3] compounds.

Compound 31P{1H} δ (ppm)

[(o-tolyl)3PCl][SeCl3], 17 64.4, 47.9, 43.5*

[(p-tolyl)3PCl][SeCl3], 18 66.0, 37.9* [(p-OCH3C6H4)3PCl][SeCl3], 19 64.3, 40.7*

[(o-OCH3C6H4)3PCl][SeCl3], 20 Insufficiently soluble

[(o-SCH3C6H4)3PCl][SeCl3], 21 56.9, 36.9*

[(p-FC6H4)3PCl][SeCl3], 22 31.9 [Me2PhPCl][SeCl3], 23 57.0, 79.9*

[(o-tolyl)3PBr][SeBr3], 24 54.9

[(p-tolyl)3PBr][SeBr3], 25 52.6

[(p-OCH3C6H4)3PBr][SeBr3], 26 49.9, 51.8*, 39.9* [(o-OCH3C6H4)3PBr][SeBr3], 27 32.7*, 48.3

[(o-SCH3C6H4)3PBr][SeBr3], 28 48.70

[(p-FC6H4)3PBr][SeBr3], 29 48.4

[Me2PhPBr][SeBr3], 30 67.6

4.2. Conclusion

The reactions of R3P (R3P = (o-tolyl)3P, (p-tolyl)3P, (o-OCH3C6H4)3P, (p-OCH3C6H4)3P,

(o-SCH3C6H4)3P, (p-FC6H4)3P and Me2PhP) with SeCl4 and SeBr4 have been shown to

undergo a redox reaction and generate compounds of the type [R3PX][SeX3] (X = Cl, Br)

based on elemental analysis and spectroscopic data. The crystal structures of two of

these compounds were obtained which confirmed the identity of the products.

Interestingly, in [(p-OCH3C6H4)3PCl][SeCl3] the [SeCl3]– moiety was found to dimerize via

Se···Cl interactions, to give a [Se2Cl6]2- dianion, whilst in [(o-SCH3C6H4)3PCl][SeCl3] the

[SeCl3]- anion was found to interact preferentially with the sulfur atom on the cation,

and no secondary Se···Cl interactions were observed.

167

4.3. References

1. J. L. Dutton, R. Tabeshi, M. C. Jennings, A. J. Lough and P. J. Ragogna, Inorg. Chem., 2007, 46, 8594.

2. S. Hague, V. Janickis and K. Maroy, Acta Chem. Scand., 1998, 52, 435. 3. C. J. Carmalt, N. C. Norman and L. J. Farrugia, Polyhedron, 1995, 14, 1405. 4. A. Bondi, J. Phys. Chem., 1964, 68, 441. 5. L. S. Refaat, K. Maartmann-Moe and S. Husebye, Acta Chem. Scand., 1984, A 34,

303. 6. M. A. H. A. Al-Juboori and P. N. Gates, J. Raman Spectrosc., 1995, 26, 101. 7. M. A. H. A. Al-Juboori, P. N. Gates and A. S. Muir, J. Chem. Soc., Dalton Trans., 1994,

1441. 8. J. B. Milne, Polyhedron, 1987, 6, 849. 9. B. Krebs and A. Schaffer, Z. Naturforsch. 1984, 39b, 1633. 10. S. M. Godfrey, C. A. McAuliffe, R. G. Pritchard, J. M. Sheffield and G. M. Thompson,

J. Chem. Soc., Dalton Trans., 1997, 4823. 11. S. M. Godfrey, C. A. McAuliffe, I. Mushtaq, R. G. Pritchard and J. M. Sheffield, J.

Chem. Soc., Dalton Trans., 1998, 3815.

168

Chapter 5. Synthesis and Characterisation of Phosphine selenides

5.0. Phosphine selenides


5.2. Reactions of tris-p fluorophenylphosphine selenides with group 15 halides

5.3. Reactions of aryl phosphine selenides (Ph3PSe, (o-tolyl)3PSe, (p-tolyl)3PSe) and

mixed aryl ((o-tolyl)2PhP and (o-tolyl)Ph2P) with group 15 halides

5.4. Reactions of alkyl/aryl phosphine selenides with group 15 halides

5.5. Reactions of diphosphine diselenides with group 15 halides

5.6. Conclusion

5.7. References

169

5.0. Synthesis and characterisation of phosphine selenides

The coordination chemistry of tertiary phosphine sulfides and selenides is important

because of their interesting bonding properties and novel structures, as well as their

applications in extractive metallurgy and catalysis.[1, 2] Only a few reports concerning

the structural chemistry of phosphine selenide complexes have appeared, which may

be due to the poor solubility of the complexes. The work on phosphine selenide

reactions with metal salts has been extended so as to further explore the structural

chemistry of metal-selenium interactions and their importance in metal-organic

vapour deposition.[3] A limited number of studies have previously been reported on

the reactions of phosphine selenides with group 15 trihalides.[4, 5, 6]


This section is concerned with the syntheses of a number of tertiary and bidentate

phosphine selenides and their characterization by elemental analysis, multinuclear

NMR and Raman spectroscopy.

The syntheses of the tertiary, mixed aryl, mixed aryl/alkyl phosphine selenides,

[{R3PSe}n](n = 1 or 2) was carried out by refluxing the tertiary phosphines with

selenium powder at 90°C for 24 hrs, followed by filtration. The filtrate was then

evaporated using a rotary evaporator. The phosphine selenides were synthesized in

1:1 ratios for (p-tolyl)3P, (p-FC6H4)3, (o-tolyl)2PhP, (o-tolyl)Ph2P, (CH3)2PhP, Ph2CH3P and

1:2 ratios for bis(diphenylphosphino)methane(dppm), 1,2-bis(diphenylphosphino)

ethane(dppe), 1,6-(diphenylphosphino)hexane(dpph), cis-1,2-bis(diphenylphosphino)

ethylene and trans-1,2-bis(diphenylphosphino)ethylene respectively.

The syntheses were performed according to the following reactions:

where R3P = (p-tolyl)3P, (p-FC6H4)3P, (o-tolyl)2PhP, (o-tolyl)Ph2P, (CH3)2PhP and Ph2CH3P.

170

where R4P2 = Ph2PCH2PPh2 (dppm), Ph2P(CH2)2PPh2 (dppe), Ph2P(CH2)6PPh2 (dpph), cis-

Ph2PCH=CHPPh2 and trans-Ph2PCH=CHPPh2.

The reactions were performed in either 1:1 or 1:2 ratios, depending on the number of

phosphorus atoms (as shown in the previous reactions). The resulting phosphine

selenides were characterised by elemental analysis, multinuclear NMR and Raman

spectroscopy. The 31P{1H} NMR data of the starting phosphines and their selenides is

shown in Table 5.0.

Table 5.0. 31P{1H} NMR chemical shifts of the starting phosphines and their selenides,

as well as their coupling constants 1J(PSe).

Compound 31P{1H} δ (ppm)

Starting phosphine

31P{1H} δ (ppm)

Phosphine selenide

Coupling constants 1J(SeP)/Hz

Ph3PSe, 31 -5.5 35.2 729 (o-tolyl)3P=Se, 32 -29.4 28.2 704

(p-tolyl)3P=Se, 33 -7.8 33.7 718

(p-FC6H4)3P=Se, 34 -9.2 32.3 742

(o-tolyl)2PhP=Se, 35 -20.8 29.1 713

(o-tolyl)Ph2P=Se, 36 -13.3 31.9 724

(CH3)2PhP=Se, 37 -45.6 16.0 703

Ph2CH3P=Se, 38 -26.8 23.3 718

Ph2P(Se)CH2P(Se)Ph2 (dppmSe2), 39 -21.3 25.0 745 Ph2P(Se)(CH2)2P(Se)Ph2 (dppeSe2), 40 -11.6 35.9 735

Ph2P(Se)(CH2)6P(Se)Ph2 (dpphSe2), 41 -16.2 34.1 720

Mixed trans/cis-Ph2P(Se)CH=CHP(Se)Ph2, 42 -23.2 28.5, 22.6* 753, 737

trans-Ph2P(Se)CH=CHP(Se)Ph2, 43 -7.6 28.6 753 The compounds Ph3PSe & (o-tolyl)3P=Se have been previously synthesized.

The 31P{1H} NMR spectroscopic data of complexes 31-43 recorded in CDCl3 (Table 5.0)

shows that the resonances of the starting phosphines are all replaced by signals at

higher frequencies which suggests the formation of the desired phosphine selenides.

Fig. 5.0 shows this shift in the 31P{1H} NMR spectra, using (CH3)2PhP=Se as an example.

Fig. 5(a) shows the starting phosphine δP = -45.6 ppm, whilst 5(b) shows the shift upon

171

formation of (CH3)2PhP=Se, to δP = 16.0 ppm with 1J(SeP) = 703 Hz. Fig. 5(c) shows the

77Se{1H} NMR spectrum (7.6 % abundance) of the same phosphine selenide,

(CH3)2PhP=Se, which exhibits a doublet at δSe = -287.2 ppm, with a coupling constant of

1J(SeP) = 703 Hz. The 31P{1H} NMR spectra of these phosphine selenides showed SeP

coupling constant values which range from 703 to 753 Hz.

(a) (b)

(c)

Fig. 5 (a) 31P{1H} NMR spectrum of (CH3)2PhP (b) 31P{1H} NMR spectrum of

(CH3)2PhP=Se and (c) 77Se{1H} NMR spectrum of (CH3)2PhP=Se in CDCl3.

However, the 31P{1H} NMR spectra of biphosphine selenides are more complex than

the monophosphine selenides. The 31P{1H} NMR spectrum of

172

[Ph2P(Se)(CH2)2P(Se)Ph2](dppeSe2), 40 is rather complicated since a number of

isotopomers are possible. The central peak arises from Ph2P(Se)(CH2)2P(Se) molecules

which contain either no spin active 77Se nuclei (85.5 % of all molecules), or two 77Se

nuclei (0.5 % of molecules), making both phosphorus centres equivalent. In the latter

case coupling will also be observed to the two spin-active selenium nuclei to give low

intensity satellites. However, in the remaining 14 % of molecules when only one spin-

active77Se nucleus is present there are two different environments for the phosphorus

nuclei, so P-P coupling will be observed. So, as shown in Fig. 5.1, two doublet

phosphorus signals are observed, with 3J(PP) = 64.8 Hz. One with a coupling constant

of 1J(PSe) = 735 Hz for phosphorus and the other with 4J(PSe) = 6.4 Hz.

Fig. 5.1. 31P{1H} NMR spectrum of [Ph2P(Se)(CH2)2P(Se)Ph2](dppeSe2), 40 in CDCl3.

The 31P{1H} NMR spectrum of 42 shows two phosphorus signals with different

selenium coupling constants. One of the signals corresponds to 43, the other

presumably being the desired cis isomer. It was not possible to separate these two

isomers, and this is referred to a mixed system subsequently.

173

Table 5.1 shows the elemental analysis data of the phosphine selenides which confirms

that there is good agreement between the calculated and observed elemental analysis

figures for compounds, 33, 34, 35, 36, 39, 40, 41, 42 whilst that for 43 is reasonable.

Due to small insufficient amounts of the known compounds 37 and 38 no elemental

analysis data was obtained. Almost all the phosphine selenides synthesized were solids

except for 37 and 38 which were viscous liquids.

Table 5.1. The elemental analysis data of phosphine selenides and diselenides.

Compound Colour % C cal % C found

% H cal % H found

% P cal % Pfound

[(p-tolyl)3P=Se], 33 white 65.78 65.99

5.52 5.36

8.09

8.11

[(p-FC6H4)3P=Se], 34 white 54.68

54.92

3.06

2.74

7.84

7.94

[(o-tolyl)2PhP=Se], 35 pink 65.03

65.00 5.19 5.21

8.39

8.31

[(o-tolyl)Ph2P=Se], 36 yellowish white

64.21

65.14

4.83 4.95

8.72

8.77

[(CH3)2PhP=Se], 37 viscous yellow liquid

Not performed

[Ph2CH3P=Se], 38 viscous yellow liquid

Not performed

[Ph2P(Se)CH2P(Se)Ph2](dppmSe2), 39 off white 55.35

55.47

4.09

3.92

11.43

11.32

[Ph2P(Se)(CH2)2P(Se)Ph2](dppeSe2), 40

pink 56.11

58.13

4.35

4.49

11.14

10.46

[Ph2P(Se)(CH2)6P(Se)Ph2] (dpphSe2), 41

dark pink 58.81

59.01

5.27

5.31

10.12

9.90

[Ph2P(Se)CH=CHP(Se)Ph2],a 42 pale yellow

56.31 56.39

4.00 3.81

11.18

11.21

[trans-Ph2P(Se)CH=CHP(Se)Ph2], 43 beige 56.31

59.32

4.00

4.22

11.18 10.18

a-mixed trans/cis isomer

5.2. Reactions of tris-p fluorophenylphosphine selenides with group 15 halides

This section concerns the reactions of a tertiary phosphine selenide (tris-p-

fluorophenylphosphine selenide) with group 15 halides in 1:1 ratio which have been

synthesized as shown in the following reaction

174

MX3 (M = Bi, Sb and As; X = Cl, Br).

The preparation of the [MX3(Se=PR3)] compounds was by the direct reaction of

equimolar quantities of the tertiary phosphine selenide (tris-p-fluorophenylphosphine

selenide) with bismuth halides, antimony halides and arsenic halides in diethyl ether

under anhydrous and anaerobic conditions. The compounds were isolated by

concentration of the solvent and precipitation on addition of anhydrous pentane

except for [SbBr3{Se=P(p-FC6H4)3}] which was insoluble in diethylether and filtered off

under nitrogen using Schlenk techniques and transferred to glass vials in a glove box.

However, the reactions of bismuth, antimony and arsenic iodides with (p-FC6H4)3P=Se

were unsuccessful and resulted in isolation of the starting triiodides.

The compounds were characterised by elemental analysis, multinuclear

spectroscopy, Raman spectroscopy and single crystal X-ray diffraction where crystals

were obtained. Table 5.2 shows the elemental analysis data of [MX3{Se=(p-FC6H4)3}]

compounds.

Table 5.2. The elemental analysis data for [MX3{Se=(p-FC6H4)3}] compounds


% H cal % H found

% X cal % X found (X= Cl, Br)

% P cal % Pfound

[BiCl3{Se=P(p-FC6H4)3}], 44 pale yellow

30.41 30.40

1.70

1.05

14.97

14.99

4.36

4.17

[BiBr3{Se=P(p-FC6H4)3}], 45 yellow 25.60

25.82

1.43

1.03

28.41

28.72

3.67

3.66

[SbCl3{Se=P(p-FC6H4)3}], 46 white 34.66

35.19

1.94

1.57

17.07

17.28

4.97

3.28

[SbBr3{Se=P(p-FC6H4)3}], 47 yellow 28.55

29.44

1.60

1.44

31.69

31.45

4.09

3.30

[AsCl3{Se=P(p-FC6H4)3}], 48 white 37.48

38.02

2.10

1.86

18.46

18.06

5.37

6.42

[AsBr3{Se=P(p-FC6H4)3}], 49 white 30.44

29.67

1.70

1.11

33.78

33.54

4.36

4.38

175

The elemental data for compounds 44, 45, 46, 47, 48 and 49 show good agreement

between calculated and observed elemental analysis data.

The NMR spectroscopic data of compounds 44-49 are summarised in Table 5.3 which

shows the 31P{1H}, 77Se{1H} chemical shifts and the coupling constants of the

corresponding p-fluorophenylphosphine selenide compounds. The 31P{1H} chemical

shifts of compounds 44-49 are observed between 29.9 and 32.3 ppm. Compounds 47-

49 displayed the same chemical shift as starting Se=P(p-FC6H4)3, 34, 32.3 ppm which is

close to that previously reported for Se=P(p-FC6H4)3, 33.6 ppm.[7]

The 77Se{1H} NMR spectra were only obtained for 48 and 49 due to their high solubility

in CDCl3. The 77Se{1H} chemical shifts (-248.3 ppm for 48 and -249.4 ppm for 49) and

1J(SeP) coupling constant of 740 Hz are similar to those observed for Se=P(p-FC6H4)3,

34, -251.4 ppm and 1J(SeP) of 742 Hz and to the previous literature reports for Se=P(p-

FC6H4)3, -246.1 ppm and 1J(SeP) of 741 Hz.[7]

Table 5.3. NMR Spectroscopic data of p-fluorophenyl phosphine selenide compounds

Compound 31P{1H} δ ppm 77Se{1H} δ ppm 1J(SeP) Hz

[BiCl3{Se=P(p-FC6H4)3}], 44 30.8 - -

[BiBr3{Se=P(p-FC6H4)3}], 45 29.9 - -

[SbCl3{Se=P(p-FC6H4)3}], 46 30.8 - -

[SbBr3{Se=P(p-FC6H4)3}], 47 32.3 - -

[AsCl3{Se=P(p-FC6H4)3}], 48 32.3 -248.3 740

[AsBr3{Se=P(p-FC6H4)3}], 49 32.3 -249.4 740

Crystals suitable for X-ray diffraction were grown using dry dichloromethane/diethyl

ether layered solutions of compounds 44, 45 and 46, whereas crystals of 49 were

formed by layering of a dry dichloromethane solution with pentane. The structures of

the four compounds were isomorphous, and the asymmetric units consist of a

pyramidal MX3 molecule interacting weakly with a Se=P(p-FC6H4)3 molecule. The

molecular structures of compounds 44 and 45 are shown in Figs. 5.2 and 5.3, with

selected bond lengths and angles being given in Tables 5.4 and 5.5. The M···Se (M is Bi,

Sb and As) interactions in compounds 44, 45, and also of 46 and 49, are significantly

176

longer than the sum of the appropriate covalent radii, (Bi & Se: 2.67-2.68 Å, Sb & Se:

2.56-2.59 Å and As & Se: 2.37-2.39 Å), which have been previously re-determined by

Alvarez and co-workers,[8] and Pyykkö and co-workers.[9] The M···Se interactions are

longer than these covalent radii, but are shorter than the sum of the van der Waals

radii (3.97 Å for Bi and Se, 3.96 Å for Sb and Se, 3.75 Å for As and Se).[10] Since no

phosphine selenide complexes of bismuth(III) are known, a comparison for Bi···Se

interactions was made with related selenoether compounds. The Bi···Se interactions in

compounds 44 and 45 are 3.3464(12) Å and 3.3691(13) Å, significantly longer than in

corresponding selenoether complexes such as [BiCl3{o-C6H4(SeMe)2]where the Bi-Se

bond lengths are between 2.952(2) and 3.156(4) Å.[11-13]

Fig. 5.2. ORTEP representation of [BiCI3{Se=P(p-FC6H4)3}], 44

Table 5.4. Selected bond lengths (Å) and angles (°) of [BiCI3{Se=P(p-FC6H4)3}], 44


Bi(1)-Cl(1) 2.495(3) Cl(1)-Bi(1)-Cl(1ii) 94.38(11)

Se(1)-P(1) 2.182(3) Cl(1)-Bi(1)···Se(1) 86.68(8)

Se(1)···Bi(1) 3.3464(12) Cl(1ii)-Bi(1)···Se(1) 106.73(8) P(1)-C(1) 1.808(13) Cl(1iii)-Bi(1)···Se(1) 158.75(8)

C(4)-F(1) 1.394(14) P(1)-Se(1)···Bi(1) 113.75(9)

Se(1)-P(1)-C(1) 110.7(4)

C(1)-P(1)-C(1) 108.2(6)

177

Fig. 5.3. ORTEP representation of [BiBr3{Se=P(p-FC6H4)3}], 45

Table 5.5. Selected bond lengths (Å) and angles (°) of [BiBr3{Se=P(p-FC6H4)3}], 45

Bond Length (Å) Angle Angle (°) Bi(1)-Br(1) 2.6401(14) Br(1)-Bi(1)-Br(1ii): 94.40(4)

Se(1)-P(1) 2.189(3) Br(1)-Bi(1)···Se(1): 85.92(4)

Se(1)···Bi(1) 3.3691(13) Br(1ii)-Bi(1)···Se(1) 106.50(4)

P(1)-C(1) 1.814(12) Br(1iii)-Bi(1)···Se(1) 159.03(4)

C(4)-F(1) 1.353(13) P(1)-Se(1)···Bi(1) 114.52(9)

Se(1)-P(1)-C(1) 111.6(4)

C(1)-P(1)-C(1) 107.2(5)

The molecular structure of compound [SbCl3{Se=P(p-FC6H4)3}], 46 is shown in Fig. 5.4

with the selected bond lengths and angles given in Table 5.6.

178

Fig. 5.4. ORTEP representation of [SbCI3{Se=P(p-FC6H4)3}], 46

Table 5.6. Selected bond lengths (Å) and angles (°) of [SbCI3{Se=P(p-FC6H4)3}], 46

Bond Length (Å) Angle Angle (°) Sb(1)-Cl(1) 2.388(3) Cl(1)-Sb(1)-Cl(1ii) 94.19(11) Se(1)-P(1) 2.152(3) Cl(1)-Sb(1)···Se(1) 85.61(8)

Se(1)···Sb(1) 3.3640(15) Cl(1i)-Sb(1)···Se(1) 160.31(9)

P(1)-C(1) 1.801(15) Cl(1iii)-Sb(1)···Se(1) 105.47(8)

C(4)-F(1) 1.366(16) P(1)-Se(1)···Sb(1) 115.54(10)

Se(1)-P(1)-C(1) 110.3(5)

C(1)-P(1)-C(1) 108.6(7)

The Sb···Se interaction in compound 46 can be compared with the only other reported

antimony phosphine selenide, [Sb2I6(SePPh3)2] where the Sb-Se bond length is 2.861(2)

Å.[4, 5] This is significantly shorter than in 46, where the Sb-Se distance is 3.3640(15) Å,

(which is within the sum of the van der Waals radii 3.96 Å for Sb and Se).[10] The P-Se

bonds of 44, P-Se: 2.182(3) Å, 45, P-Se: 2.189(3) and 46, P-Se: 2.158(3) Å are

lengthened compared to those found in the structure of Se=P(p-FC6H4)3, which has two

independent molecules with P=Se bond lengths of 2.1100(13) Å and 2.1115(12) Å but

similar to the two independent molecules in the structure of (p-FC6H4)3PSeI2[7] where

the P-Se bonds lie between 2.1659(18) and 2.1673(18) Å.

179

The arrangement of primary and secondary bonds around M (Bi, Sb, As) can be related

to the structures of the parent halides, where the pyramidal MX3 molecules with three

primary M-X bonds extend their coordination sphere through additional secondary

interactions to halide atoms from neighbouring MX3 molecules.[14]

Commonly, there are either five or six secondary M…X interactions in the structures of

MCl3 or MBr3 (M = Bi, Sb, As) which result in overall coordination numbers of [5 + 3]

(bicapped trigonal prismatic geometry) as seen for SbCl3,[15] β-SbBr3,[16] BiCl3[17] and α-

BiBr3[18] or [5 + 4] (tricapped trigonal prismatic geometry) as seen for AsCl3,[19] AsBr3,[20]

and α-SbBr3.[21] The polymeric β-BiBr3 form is an exception which has an AlCl3-type

structure with six long Bi-Br bonds of intermediate distance between primary and

secondary bonds.[18] The arrangement of three primary Sb-Cl bonds and three

secondary Sb-Se contacts is similar to that observed for the antimony seleno complex

[SbCl3(mbts)(μ-mbts)2SbCl3(mbts)][22] (mbts = N-methylbenzothiazole-2-selone) which

is shown in Fig. 5.5 giving a distorted octahedral geometry at Sb atom.

Fig. 5.5. ORTEP representation of [SbCl3(mbts)(μ-mbts)2SbCl3(mbts)], taken from

ref [22].

180

The three primary M-X bond lengths within compound 44 and 46 are equal (Bi-Cl:

2.494(3) Å x 3 and Sb-Cl: 2.387(3) Å x 3 respectively) as well as their X-M-X angles (Cl-

Bi-Cl: 94.29(13)° and Cl-Sb-Cl: 94.17(11)° unlike the M-X bonds in most structures of

the parent halides which are unequal except for SbCl3[15] (which has two equal Sb-Cl

bond lengths) and polymeric β-BiBr3[18] (which has six bonds distances intermediate

between primary and secondary bond lengths).

The molecular structure of compound 49 is shown in Fig. 5.6 with selected bond

lengths and angles given in Table 5.7.

Fig. 5.6. ORTEP representation of [AsBr3{Se=P(p-FC6H4)3}], 49.

Table 5.7. Selected bond lengths (Å) and angles (°) of [AsBr3{Se=P(p-FC6H4)3}], 49.


As(1)-Br(1) 2.379(3) Br(1)-As(1)-Br(1ii) 96.54(9)

Se(1)-P(1) 2.155(5) Br(1)-As(1)…Se(1) 106.13(8) Se(1)…As(1) 3.372(2) Br(1ii)-As(1)…Se(1) 84.72(7)

P(1)-C(1) 1.806(15) Br(1iv)-As(1)…Se(1) 157.02(9)

C(4)-F(1) 1.37(2) P(1)-Se(1)…As(1) 113.90(15)

Se(1)-P(1)-C(1) 112.4(5) C(1)-P(1)-C(1) 106.4(7)

181

The MX3 units in each of the structures of the four compounds, 44, 45, 46 and 49 all

have three primary M-X bonds of equal length and each MX3 unit further interacts with

three Se=P(p-FC6H4)3 groups resulting in an overall distorted octahedral [3 + 3]

arrangement around M, as shown in Fig. 5.7. However, each of the Se=P(p-FC6H4)3

groups further form bridges to three MX3 units, resulting in a distorted M4Se4 (M = Bi,

Sb, As) cuboid as shown in Fig. 5.8 where four opposing corners of the cuboid are

occupied by the M atom of MX3 pyramid and the other four by the selenium atom of

phosphine selenides.

Fig. 5.7. Octahedral coordination [3 + 3] environment in [AsBr3{Se=P(p-FC6H4)3}], 49,

showing primary AsBr3 fragment with three Se=P(p-FC6H4)3 molecules.

182

Fig. 5.8. Generation of the As4Se4 cuboid motif in the structure of

[AsBr3{Se=P(p-FC6H4)3}], 49.

Examples of complexes having cuboid-like motifs include the bismuth thioether,

[Bi4Cl12(MeSCH2CH2CH2SMe)4]n.nH2O[23] which contains a Bi4Cl4 cuboid with very

unequal Bi-Cl bonds, and the [Et4N]4[Sb4Cl16][24] anion containing a Sb4Cl4 cuboid.

The crystal packing of [AsBr3{Se=P(p-FC6H4)3}], 49, shows that the formation of the

cuboid results in F···F and F···H contacts between the p-fluorophenyl groups as shown

in Fig. 5.9.

183

Fig. 5.9. Crystal packing of [AsBr3{Se=P(p-FC6H4)3}], 49, showing the As···Se, F···F and

F···H interactions in the extended structure of the co-crystal.

The solid state FT Raman studies of compounds 44-49 in sealed glass tubes were

undertaken and recorded in the region ~ 3500-110 cm-1. It can be suggested that the

M-X symmetric and asymmetric stretching bands will occur below 500 cm-1.

There is a significant shift in the position of ν(M-X) bands for compounds 44-49 to

those of the starting MX3 (M = Bi, Sb, As; X = Cl, Br) in most cases, as shown in Table

5.8 where the most intense bands are the ν1 symmetric M-X stretch and the ν3

degenerate mode of the parent trihalides, MX3. Compounds 44-49 also exhibit these

intense bands which can be compared with parent trihalides MX3.

184

Table 5.8. Comparison of Raman data of M-X stretches of p-fluorophenyl phosphines

selenide compounds to parent trihalides MX3

Compound Raman M-X stretches (cm-1)

Raman M-X stretches in MX3 (cm-1)

ν1 ν3

[BiCl3{Se=P(p-FC6H4)3}], 44 298, 274 282 263-252

[BiBr3{Se=P(p-FC6H4)3}], 45 199, 187 189 180

[SbCl3{Se=P(p-FC6H4)3}], 46 327, 307 340 318-312

[SbBr3{Se=P(p-FC6H4)3}], 47 222, 214 243 238-230 [AsCl3{Se=P(p-FC6H4)3}], 48 364, 337 416 393

[AsBr3{Se=P(p-FC6H4)3}], 49 253 281 277-254

There is a slight shift to higher wavenumbers of the ν(M-X) bands in compounds 44

[ν(Bi-Cl) at 298 and 274 cm-1] and 45 [ν(Bi-Br) at 199 and 187 cm-1] as compared to ν1

and ν3 in BiCl3[25] ν(Bi-Cl) at 282 and 263-252 cm-1 and BiBr3

[26] ν(Bi-Br) at 189 and 180

cm-1 respectively. However, for the antimony analogues, 46 and 47, there is a shift to

lower wavenumbers, compounds 46 [ν(Sb-Cl) at 327 and 307 cm-1] and 47 [ν(Sb-Br) at

222 and 214 cm-1] compared to ν(Sb-Cl) of 340 and 318-312 cm-1 in SbCl3[27] and

ν(Sb-Br) of 243 and 238-230 cm-1 in SbBr3[28] respectively. The arsenic compounds 48

and 49 follow a similar trend as the antimony compounds 46 and 47, where there is a

shift to lower wavenumbers in the position of the ν(M-X) bands. Compound 48 showed

[ν(As-Cl) at 364 and 337 cm-1] as compared to ν(As-Cl) at 416 and 393 cm-1 in AsCl3,[29]

whilst compound 49 showed only one intense band at [ν(As-Br) at 253 cm-1 as

compared to ν(As-Br) at 281 and 277-254 cm-1 in AsBr3.[25]

5.3. Reactions of aryl phosphine selenides (Ph3PSe, (o-tolyl)3PSe, (p-tolyl)3PSe) and

mixed aryl ((o-tolyl)2PhP and (o-tolyl)Ph2P) with group 15 halides

This section is concerned with the direct reaction of aryl and mixed aryl phosphine

selenides with main-group halides in diethyl ether as shown in the following reaction:

where R3P = Ph3P, (o-tolyl)3P, (p-tolyl)3P, (o-tolyl)2PhP and (o-tolyl)Ph2P;

M = Bi, Sb and As and X = Cl, Br and I.

185

The preparation of these compounds was carried out by reacting two equivalents of

the aryl and mixed aryl phosphine selenides with bismuth halides, antimony halides

and arsenic halides respectively in diethyl ether under anhydrous and anaerobic

conditions. The reactions of triphenylphosphine selenide with group 15 halides will be

discussed first followed by o- and p- tolyl phosphine selenides, then the mixed

substituted aryl systems (o-tolyl)2PhP and (o-tolyl)Ph2P respectively.

The compounds [BiBr3{Se=PPh3}2], [SbCl3{Se=PPh3}2], [SbBr3{Se=PPh3}2],

[AsI3{Se=PPh3}2] were isolated by concentration of the solvent (anhydrous

dichloromethane) whilst for compound [BiCl3{Se=PPh3}2] the solvent used was

anhydrous diethyl ether. All products were precipitated on addition of anhydrous

pentane, and filtered off under nitrogen using Schlenk techniques and transferred to

glass vials in a glove box.

[BiCI3{Se=PPh3}] was insoluble in anhydrous pentane, whilst [Bil3{Se=PPh3}] was

insoluble in diethylether and [SbI3{Se=PPh3}] was insoluble in dichloromethane,

therefore all were directly filtered off under nitrogen using Schlenk techniques and

transferred to glass vials in a glove box. However, the reactions of arsenic chloride and

bromide with Ph3PSe were unsuccessful, resulting only in the isolation of the starting

phosphine selenide, Ph3PSe. The resulting products were characterised by elemental

analysis, multinuclear NMR spectroscopy, Raman spectroscopy and single crystal X-ray

diffraction if possible. The elemental analysis data is summarised in Table 5.9.

Compounds 50, 52 and 54 show good agreement between calculated and

observed figures while 51 and 55 show reasonable agreement and 57 shows a high

phosphorus content. Compounds 53 and 56 gave unsatisfactory elemental results.

Interestingly, even though the reactions were carried out in a 2:1 ratio of phosphine to

MX3 in some cases 1:1 ratio products were obtained.

186

Table 5.9. Elemental data for [MX3{Se=PPh3}] and [MX3{Se=PPh3}2]


% H cal % H found

% X cal % X found

(X= Cl, Br or I)

% P cal % Pfound

[BiCl3{Se=PPh3}2], 50 yellow 43.31

44.20

3.03

2.74

10.66

9.86

6.21

6.43

[BiCI3{Se=PPh3}], 51 yellow 32.91 33.75

2.30

1.96

16.20

13.83

4.72

4.82

[BiBr3{Se=PPh3}2], 52 yellow 38.20

37.70

2.67

2.55

21.20

21.85

5.48 5.28

[Bil3{Se=PPh3}], 53 v. dark grey

- - - -

[SbCl3{Se=PPh3}2], 54 white 47.46

46.62

3.32

3.15

11.69

12.23

6.81

6.28

[SbBr3{Se=PPh3}2], 55 off-white 41.40

40.33

2.90

2.66

22.97

25.43

5.94

5.28

[SbI3{Se=PPh3}], 56 orange - - - -

[AsI3{Se=PPh3}2], 57 orange 37.97

39.07

2.66

2.72

33.46

31.83

5.44

8.65

Crystals suitable for X-ray diffraction were grown from an anhydrous

dichloromethane/diethyl ether layered solution of compounds 50 and 55, so it was

possible to obtain crystal data, and their molecular structures are shown in Figs. 5.10 &

5.11, with selected bond lengths and angles given in Tables 5.10 & 5.11. Compound 50

adopts a dimeric structure with chloride bridges between the two bismuth atoms, both

of which are in an approximately octahedral configuration with a Bi(1)-Cl(1)-Bi(1-2)

bridge where the angle is 97.06 (6)°. The bridging distances [Bi(1)-Cl(1): 2.8717(19) Å

and Bi(1)-Cl(1-2): 2.8770(19) Å] are almost symmetric, and are longer than the terminal

bonds, Bi(1)-Cl(2): 2.5911(19) Å and Bi(1)-Cl(3): 2.5682(19) Å.

The bridging and terminal Bi-Cl distances in compound 50 are similar to those

found in [BiCl3{MeSe(CH2)3SeMe}][12] where the bridging Bi-Cl distances are 2.826(4)

and 2.884(4) Å, and the terminal Bi-Cl distances of 2.554(4) and 2.566(4) Å

respectively. However, one of the Bi-Se bonds in compound 50, Bi(1)-Se(1): 3.0559(8) Å

is consistent with one of the Bi-Se bond distances in BiCl3{MeSe(CH2)3SeMe}] where

the Bi-Se distances are 2.988(2) and 3.036(2) Å respectively, whilst the other, Bi(1)-

Se(2) is significantly shorter, at 2.8429(8) Å.

187

Fig. 5.10. ORTEP representation of [BiCl3{Se=PPh3}2], 50

Table 5.10. Selected bond lengths (Å) and angles (°) of [BiCl3{Se=PPh3}2], 50


Bi(1)-Se(1) 3.0559(8) Se(1)-Bi(1)-Se(2) 159.97(2)

Bi(1)-Se(2) 2.8429(8) Se(1)-Bi(1)-Cl(1) 87.29(4)

Bi(1)-Cl(1) 2.8717(19) Se(1)-Bi(1)-Cl(2) 93.35(4) Bi(1)-Cl(2) 2.5911(19) Se(1)-Bi(1)-Cl(3) 103.89(5)

Bi(1)-Cl(3) 2.5682(19) Se(1)-Bi(1)-Cl(1-2) 82.24(4)

Bi(1)-Cl(1-2) 2.8770(19) Se(2)-Bi(1)-Cl(1) 72.70(4)

Se(1)-P(1) 2.142(2) Se(2)-Bi(1)-Cl(2) 86.84(4) Se(2)-P(2) 2.158(2) Se(2)-Bi(1)-Cl(3) 95.96(5)

Se(2)-Bi(1)-Cl(1-2) 95.84(4) Cl(1)-Bi(1)-Cl(2) 92.60(6) Cl(1)-Bi(1)-Cl(3) 164.83(6) Cl(1)-Bi(1)-Cl(1-2) 82.98(5) C(12)-Bi(1)-Cl(3) 96.87(6) Cl(1-2)-Bi(1)-Cl(2) 173.88(6) Cl(1-2)-Bi(1)-Cl(3) 88.35(6) Bi(1)-Se(1)-P(1) 113.13(6) Bi(1)-Se(2)-P(2) 111.01(6) Bi(1)-Cl(1)-Bi(1-2) 97.02(6)

188

The structure of compound 55 is a 1:1 [SbBr3{Se=PPh3}] compound which forms a

dimer via the dimerization of two "see-saw" monomeric units of [SbBr3{Se=PPh3}] via

bridging Sb-Br bonds. This results in an overall square- pyramidal geometry at the

antimony atom. The bridging Sb-Br bonds are asymmetric, Sb(1)-Br(2): 2.6568(16) and

Sb(1)-Br(2i): 3.4724(16) Å. The apical Sb-Br bond is the shortest with d(Sb-Br)=

2.5173(15) Å. However the elemental analysis of compound 55 shows that the bulk

material is a 2:1 product, therefore the crystal obtained may be a minor by-product,

which is not representative of the bulk powder.

Fig. 5.11. ORTEP representation of [SbBr3{Se=PPh3}], 55

Table 5.11. Selected bond lengths (Å) and angles (°) of [SbBr3{Se=PPh3}], 55


Sb(1)-Se(1) 2.9756(15) Br(1)-Sb(1)-Br(2) 90.15(5)

Sb(1)-Br(1) 2.5173(15) Br(1)-Sb(1)-Br(3) 95.84(5)

Sb(1)-Br(2) 2.6568(16) Br(2)-Sb(1)-Br(3) 94.45(5) Sb(1)-Br(3) 2.5422(16) Br(1)-Sb(1)-Se(1) 77.97(4)

Se(1)-P(1) 2.151(3) Br(2)-Sb(1)-Se(1) 167.43(5)

Sb(1)-Br(2i) 3.4724(16) Br(3)-Sb(1)-Se(1) 90.89(5)

Sb(1)-Se(1)-P(1) 105.19(9)

The Sb-Se bond in compound 55, Sb(1)-Se(1): 2.9756(15) Å is longer than in previously

reported [SbI3{SePPh3}][4] where the Sb-Se is 2.861(2) Å.

189

Attempts were made to record the 31P{1H} NMR and 77Se{1H} NMR spectra of 50-57 in

CDCl3. In most cases, as shown in Table 5.12 the 31P chemical shifts of the products are

shifted to slightly lower frequencies than the starting phosphine selenide, [Ph3PSe]: δP

= 35.2 ppm [1J(PSe) = 729 Hz] which is similar to that found in previous studies[30],

Ph3PSe δP = 35.3 ppm, 1J(PSe) = 728 Hz. The magnitude of the coupling constants

1J(PSe) for compounds 50, 1J(PSe) = 672 Hz, 54, 1J(PSe) = 701 Hz and 55, 1J(PSe) = 701

Hz are lower than that of the starting phosphine selenide, Ph3PSe, 1J(PSe): 728 Hz. Due

to the poor solubility for many of the compounds, it was not possible to obtain 77Se{1H}

NMR spectra for any of the compounds other than 54 and 55, where the shifts were

observed at -200.3 and -205 ppm.

Table 5.12. NMR Spectroscopic data for [MX3{Se=PPh3}] and [MX3{Se=PPh3}2]

Compound 31P{1H} δ ppm 77Se{1H} δ ppm 1J(PSe) Hz

[BiCl3{Se=PPh3}2], 50 33.8 - 672

[BiCI3{Se=PPh3}], 51 33.8 - -

[BiBr3{Se=PPh3}2], 52 33.8 - -

[Bil3{Se=PPh3}], 53 35.5 - -

[SbCl3{Se=PPh3}2], 54 34.8 -200.3 701

[SbBr3{Se=PPh3}2], 55 35.0 -205 701

[SbI3{Se=PPh3}], 56 33.2 - -

[AsI3{Se=PPh3}2], 57 35.1 - -

The reactions of o- and p-tolyl phosphine selenides (which are selenides of more

electron donating ligands) with group 15 halides have been undertaken in a similar

manner to the triphenylphosphine selenide compounds, as shown at the beginning of

this section. All reactions were carried out under anhydrous and anaerobic conditions.

The reaction of (o-tolyl)3PSe with BiI3 was unsuccessful and yielded only the starting

bismuth iodide, and both the reactions of (p-tolyl)3PSe with AsCl3 and AsBr3 led to

isolation of the starting phosphine selenide, (p-tolyl)3PSe. The compounds

[AsCl3{Se=P(o-tolyl)3}], [AsBr3{Se=P(o-tolyl)3}2] and [AsI3{Se=P(o-tolyl)3}2] were isolated

by concentration of the solvent, anhydrous diethyl ether, and precipitation by addition

of anhydrous pentane followed by filtering under nitrogen using Schlenk techniques

190

and storage in glass vials in a glove box. However, the compound [BiCI3{Se=P(p-

tolyl)3}2] was isolated by concentration of diethyl ether to dryness and transferred to

glass vials in a glove box. The compounds were characterised by elemental analysis,

multinuclear NMR spectroscopy, Raman spectroscopy and single crystal X-ray

diffraction, if crystals were obtained. Table 5.13 shows the elemental analysis data for

[MX3{Se=P(o-tolyl)3}], [MX3{Se=P(o-tolyl)3}2], [MX3{Se=P(p-tolyl)3}] and [MX3{Se=P(p-

tolyl)3}2] compounds.

Table 5.13. Elemental analysis data for [MX3{Se=P(o-tolyl)3}], [MX3{Se=P(o-tolyl)3}2],

[MX3{Se=P(p-tolyl)3}] and [MX3{Se=P(p-tolyl)3}2] compounds.


% H cal % H found

% X cal % X found (X= Cl, Br

or I)

% P cal % Pfound

[BiCl3{Se=P(o-tolyl)3}], 58 white 36.08

35.43

3.03

2.93

15.23

15.19

4.43

4.30

[BiBr3(Se=P(o-tolyl)3)], 59 yellow 30.30

30.44

2.54

2.45

28.82

29.01

3.72

3.67

[SbCl3{Se=P(o-tolyl)3}], 60 white 41.23

41.20

3.46

3.40

17.40

17.10

5.07

10.08

[SbBr3{Se=P(o-tolyl)3}], 61 v. pale yellow

33.85

33.89

2.84

2.78

32.20

32.46

4.16

4.15

[SbI3{Se=P(o-tolyl)3}], 62 dark yellow

28.46

28.18

2.39

2.53

42.99

43.22

3.50

App. 3

[AsCl3{Se=P(o-tolyl)3}], 63 white 44.65

44.90

3.75

3.40

18.85

20.36

5.49

5.40

[AsBr3{Se=P(o-tolyl)3}2], 64 pale yellow

46.63

44.31

3.92

3.92

22.18

24.87

5.73

5.41

[AsI3{Se=P(o-tolyl)3}2], 65 orange 41.25

40.94

3.46

3.49

31.16

30.79

5.07

4.77

[BiCI3{Se=P(p-tolyl)3}2], 66 yellow 46.60

45.83

3.91

3.87

9.83

9.93

5.73

5.71

[BiBr3{Se=P(p-tolyl)3}], 67 dark yellow

30.30

30.93

2.54

2.62

28.82

27.99

3.72

3.69

[BiI3{Se=P(p-tolyl)3}], 68 red brick

25.90

25.25

2.18

2.00

39.14

39.79

3.18

3.03

[SbCl3{Se=P(p-tolyl)3}], 69 white - - - -

[SbBr3{Se=P(p-tolyl)3}], 70 v. pale yellow

33.85

33.82

2.84

2.98

32.20

32.80

4.16

3.17

[SbI3{Se=P(p-tolyl)3}], 71 orange 28.46

27.91 2.39

2.18 42.99

42.71 3.50

3.38 [AsI3{Se=P(p-tolyl)3}], 72 orange 30.05

31.60

2.52

2.82

45.39

38.19

3.69

3.83

191

The calculated and observed values for almost all compounds are in good agreement

from the elemental analysis data, except for compound 60 which gave high % P and

compound 69 which was unsatisfactory. Interestingly, again, almost all products gave a

1:1 ratio product even though the reactions were carried out in a 2:1 ratio.

Crystals suitable for X-ray diffraction were grown from a dry dichloromethane/diethyl

ether layered solution of a number of the compounds. It was possible to obtain X-ray

crystal data for compounds, 60, 63, 66 and 67. Compound 60 which gave a 1:1

compound with a dimeric structure and bridging Sb-Cl bonds. The molecular structure

is shown in Fig. 5.12 and selected bond lengths and angles are given in Table 5.14. The

structure consists of two [SbCl3{SeP(o-tolyl)3}] monomers of "see-saw" geometry which

dimerize via halogen bridges resulting in an overall square-pyramidal geometry at

antimony. Interestingly, the vacant sixth coordination site appears to be blocked by

the tolyl ring.

Fig. 5.12. ORTEP representation of [SbCI3{Se=P(o-tolyl)3}], 60

Table 5.14. Selected bond lengths (Å) and angles (°) of [SbCI3{Se=P(o-tolyl)3}], 60


Sb(1)-Se(1) 2.8985(18) Se(1)-Sb(1)-Cl(1) 167.26(11)

Sb(1)-Cl(1) 2.571(4) Se(1)-Sb(1)-Cl(2) 81.91(10) Sb(1)-Cl(2) 2.360(4) Se(1)-Sb(1)-Cl(3) 93.92(10)

Sb(1)-Cl(3) 2.411(3) Sb(1)-Se(1)-P(1) 96.53(12)

Se(1)-P(1) 2.170(4)

Sb(1)-Cl(1_3) 3.101(5)

192

The shortest Sb-Cl bond is to the apical chlorine atom Cl(2) which lies outside the

square-plane. The bridging Sb-Cl bonds are asymmetric with Sb(1)-Cl(1) of 2.571(4) Å

and Sb(1)-Cl(1_3) of 3.101(5) Å.

The crystals obtained from compound 63 yielded a 1:1 product where its

structure shows two independent molecules within the asymmetric unit, each of see-

saw geometry around the arsenic centre. The molecular structure is shown in Fig. 5.13.

The As-Se bonds are very weak; As(3)-Se(2): 3.0411(9) Å in molecule A and As(4)-Se(1):

2.8997(9) Å in molecule B which suggests that AsCl3 is a weaker Lewis acid towards

phosphine selenides than SbCl3. There is also a considerable difference in the As-Se

bonds between the two molecules.

Molecule A Molecule B

Fig. 5.13. ORTEP representation of [AsCI3{Se=P(o-tolyl)3}], 63

The interaction of the two independent molecules A and B is shown in Fig. 5.14.

Molecule B (left hand side in the Fig. 5.14) dimerises in a similar way to the antimony

compound 60, whereas molecule A (on the right hand side of the picture) features

monomeric “see-saw” units linked by a very weak As···Cl contact of 3.590 Å (this is only

193

just inside the sum of the van der Waals radii of arsenic and chlorine, which is 3.60 Å).

In fact there is a shorter Cl···Cl contact of 3.346 Å between chlorine atoms of molecule

A and B. So it is appropriate to describe molecule A as monomeric.

Fig. 5.14. Interaction of molecules A and B in [AsCI3{Se=P(o-tolyl)3}], 63

Molecule B dimerizes in a similar way to the previous antimony complex 60, which is

shown in Fig. 5.15 and selected bond lengths and angles are given in Table 5.14. The

terminal As-Cl bonds are similar to those in the structure of AsCl3[19] where the As-Cl

bonds are 2.162 to 2.171 Å. Again, the shortest As-Cl bond is to the apical chlorine,

Cl(4). The two bridging As-Cl bonds, 2.3184(17) Å and 3.3288(18) Å are very

asymmetric suggesting that the secondary interactions resulting in dimerization are

much weaker for arsenic than antimony. Molecule B is thus a weakly interacting dimer.

194

Fig. 5.15. ORTEP representation of dimer B of [AsCI3{Se=P(o-tolyl)3}], 63

Table 5.15. Selected bond lengths (Å) and angles (°) of dimer B of

[AsCI3{Se=P(o-tolyl)3}], 63


Se(2)-P(2) 2.1581(17) Cl(4)-As(2)-Cl(6) 96.26(6)

As(2)-Cl(6) 2.2084(16) Cl(5)-As(2)-Cl(6) 93.35(6) As(2)-Cl(5) 2.3184(17) Cl(4)-As(2)-Cl(5) 93.43(7)

As(4)-Cl(4) 2.1905(18)

As(2)-Se(2) 2.8997(9)

As(2)_Cl(5_2) 3.3288(18)

The other molecule, A, is rather different, its molecular structure is shown in Fig. 5.16

and selected bond lengths and angles are given in Table 5.16; the monomeric units

interact weakly as there is a much weaker As···Cl contact of 3.5896(17) Å and this is

from the apical As···Cl of the square pyramid. The square pyramid is thus more

distorted and this molecule might be best interpreted as a pair of four-coordinate

monomers with very weak As-Cl links.

195

Fig. 5.16. ORTEP representation of dimer A of [AsCI3{Se=P(o-tolyl)3}], 63

Table 5.16. Selected bond lengths (Å) and angles (°) of dimer A of

[AsCI3{Se=P(o-tolyl)3}], 63


As(1)-Cl(2) 2.2550(19) Cl(2)-As(1)-Cl(3) 94.56(8) As(1)-Cl(3) 2.182(2) Cl(1)-As(1)-Cl(3) 98.76(7)

As(1)-Cl(1) 2.1843(17) Cl(1)-As(1)-Cl(2) 92.56(7)

Se(1)-P(1) 2.1419(17)

Se(1)-As(1) 3.0411(9) As(1)-Cl(3_2) 3.5896(17)

Compound 66 [BiCI3{Se=P(p-tolyl)3}] was also characterised crystallographically and

was also found to be a dimer. Its molecular structure is shown in Fig. 5.17 and selected

bond lengths and angles are given in Table 5.17. The X-ray structure of compound 66

shows that it is a 1:1 product having a dimeric structure which is isostructural with the

SbI3/Ph3PSe complex reported by Haase et al[4]. The compound is formed from the

dimerization of two [BiCl3L] units, resulting in the bismuth having an overall square

pyramidal geometry. The vacant sixth coordination site is probably occupied by the

196

lone pair but blocked by one of the aryl rings. The Bi-Cl terminal bonds are comparable

in length to those in BiCl3,[13] but the bridging Bi-Cl bonds are considerably longer.

Fig. 5.17. ORTEP representation of [BiCI3{Se=P(p-tolyl)3}], 66

Table 5.17. Selected bond lengths (Å) and angles (°) of [BiCI3{Se=P(p-tolyl)3}], 66


Bi(1)-Se(1) 2.9202(7) Se(1)-Bi(1)-Cl(1) 172.41(4)


Bi(1)-Cl(3) 2.5127(18) Cl(1)-Bi(1)-Cl(2) 97.89(7)

Se(1)-P(1) 2.166(2) Cl(1)-Bi(1)-Cl(3) 90.36(5)

Bi(1)-Cl(1_3) 2.9866(18) Cl(2)-Bi(1)-Cl(3) 92.52(7) Bi(1)-Se(1)-P(1) 96.31(5)

The asymmetry between the two bridging Bi-Cl bonds is much less than in the

antimony complex 60, the Bi-Cl bond lengths being 2.7708(17) and 2.9866(18) Å. This

suggests that the secondary bonding is more important for the heavier bismuth than

for antimony and arsenic. Interestingly, the elemental analysis of compound 66 fits to

be a 2:1 product, therefore the crystal obtained may be a minor by-product, which is

not representative of the bulk powder.

197

Crystals obtained for compound 67 showed the complex to be a 1:1 product that was

isostructural with 66; its molecular structure is shown in Fig. 5.18 and bond lengths

and angles are given in Table 5.18. Compound 67 forms a dimeric structure which can

be described as two edge-sharing square pyramids. The asymmetry between the two

bridging Bi-X halide bonds is much less in complex 67 (2.9680(18) and 3.0868(18) Å)

than in 66 (2.5127(18) and 2.9866(18) Å) respectively.

Fig. 5.18. ORTEP representation of [BiBr3{Se=P(p-tolyl)3}], 67

Table 5.18. Selected bond lengths (Å) and angles (°) of [BiBr3{Se=P(p-tolyl)3}], 67


Bi(1)-Br(1) 2.6735(18) Br(1)-Bi(1)-Br(2) 89.40(5) Bi(1)-Br(2) 2.9680(18) Br(1)-Bi(1)-Br(3) 93.34(6)

Bi(1)-Br(3) 2.634(2) Br(1)-Bi(1)-Se(1) 96.72(5)

Bi(1)-Se(1) 2.8922(19) Br(1)-Bi(1)-Br(2_3) 170.66(6)

Bi(1)-Br(2_3) 3.0868(18) Br(2)-Bi(1)-Se(1) 169.62(6)

Se(1)-P(1) 2.181(6) Br(2)-Bi(1)-Br(2_3) 82.46(5)

Bi(1)-Se(1)-P(1) 96.83(13)

The 31P{1H} and 77Se{1H} NMR spectra of compounds 58-72 were recorded in CDCl3 and

the 31P{1H}, 77Se{1H} chemical shifts and coupling constants of these compounds are

shown in Table 5.19. There was no significant change in the 31P NMR chemical shift of

the o-tolyl substituted phosphine selenide compounds 59, 61, 64 and 65, which display

resonances very similar to those of the starting o-tolylphosphine selenide, Se=P(o-

198

tolyl)3, δP: 28.2 ppm. Both compounds 62 and 63 have the same chemical shift, δP: 29.2

ppm which is slightly shifted to higher resonances to δP: 28.2 ppm compared to the

starting o-tolylphosphine selenide, Se=P(o-tolyl)3. There was no useful spectroscopic

data obtained for compounds 58 and 60 because of their poor solubility in CDCl3

resulting in noisy spectra.

Table 5.19. Spectroscopic data for [MX3{Se=P(o-tolyl)3}], [MX3{Se=P(o-tolyl)3}2],

[MX3{Se=P(p-tolyl)3}] and [MX3{Se=P(p-tolyl)3}2].

Compound 31P{1H} δ ppm 77Se{1H} δ ppm

1J(PSe) Hz

[BiCl3{Se=P(o-tolyl)3}], 58 insufficiently soluble - -

[BiBr3(Se=P(o-tolyl)3)], 59 28.2 - -

[SbCl3{Se=P(o-tolyl)3}], 60 insufficiently soluble - -

[SbBr3{Se=P(o-tolyl)3}], 61 28.5 - 662

[SbI3{Se=P(o-tolyl)3}], 62 29.2 - -

[AsCl3{Se=P(o-tolyl)3}], 63 29.2 - 703

[AsBr3{Se=P(o-tolyl)3}2], 64 28.1 - 700

[AsI3{Se=P(o-tolyl)3}2], 65 28.1 -

[BiCI3{Se=P(p-tolyl)3}2], 66 32.5 - 671

[BiBr3{Se=P(p-tolyl)3}], 67 31.3 - -

[BiI3{Se=P(p-tolyl)3}], 68 33.7 - -

[SbCl3{Se=P(p-tolyl)3}, 69 32.9 -142.3 670

[SbBr3{Se=P(p-tolyl)3}], 70 33.3 -122.8 658

[SbI3{Se=P(p-tolyl)3}], 71 34.4 - -

[AsI3{Se=P(p-tolyl)3}], 72 33.7 - -

The magnitude of the coupling constants of compounds 61, (1J(PSe): 662 Hz), 63,

(1J(PSe): 703 Hz) and 64 (1J(PSe): 700 Hz) are slightly lower than the starting phosphine

selenide, (o-tolyl)3P=Se, with (1J(PSe): 704 Hz), this value is consistent with previously

reported values for (o-tolyl)3P=Se, (1J(PSe): 706 Hz).[31] The NMR spectroscopic data for

the p-tolyl substituted phosphine selenides compounds 66-72 were also obtained. The

chemical shifts, δP, obtained for compounds 68 and 72 were the same as the starting

p-tolylphosphine selenide, δP: 33.7 ppm, while compounds 66, 67, 69 and 70 displayed

slightly lower chemical shifts δP: 32.5, 31.3, 32.9 and 33.3 ppm respectively, except for

71 (δP: 34.4 ppm) which was shifted to a slightly higher frequency.

It was possible to obtain coupling constants for only three SeP(p-tolyl)3

compounds due to poor solubility of the compounds in CDCl3. The compounds 66,

(1J(PSe): 671 Hz), 69, (1J(PSe): 670 Hz) and 70, (1J(PSe): 658 Hz) exhibited coupling

199

constants values lower than that for the starting (p-tolyl)3P=Se, (1J(PSe): 718 Hz), this

value agreeing with the previously reported value for (p-tolyl)3P=Se, (1J(PSe): 720

Hz).[31] A decrease in the chemical shifts and coupling constants in the o-tolyl

phosphine selenide compounds as well as the p-tolylphosphine selenide compounds

relative to the starting o- and p-tolyl phosphine selenides is observed.

The reactions of mixed aryl phosphine selenides [(o-tolyl)2PhP and (o-

tolyl)Ph2P)] with group 15 halides were also investigated. The syntheses of these mixed

aryl phosphine selenides was performed in a similar manner as previously described at

the beginning of section 5.3. All the reactions were carried out under anhydrous and

anaerobic conditions. The coloured products were filtered off under nitrogen using

Schlenk techniques and transferred to glass vials in a glove box. Unfortunately, the

reactions of SbCl3, AsCl3 and AsBr3 with (o-tolyl)2PhPSe were unsuccessful and resulted

in the isolation of the starting mixed aryl phosphine selenide, (o-tolyl)2PhPSe.

Interestingly, almost all products exhibited a 1:1 ratio products even though the

reactions were carried out in a 2:1 ratio.

The reactions of the diphenyl-o-tolylphosphine selenide with antimony(III)

trihalides have been studied, and with antimony(III) chloride and bromide(III) the

products obtained exhibited a 2:1 stoichiometry. [SbCl3{Se=PPh2(o-tolyl)}2] and

[SbBr3{Se=PPh2(o-tolyl)}2] were isolated by concentration of the solvent, anhydrous

diethyl ether and were precipitated on addition of anhydrous pentane, and filtered off


However, [SbI3{Se=PPh2(o-tolyl)}] was isolated by concentration of diethyl ether to

dryness.

The compounds were characterised by elemental analysis, multinuclear NMR

spectroscopy, Raman spectroscopy and single crystal X-ray diffraction if crystals were

obtained. Table 5.20 shows the elemental analysis data for [MX3{Se=PPh(o-tolyl)2}]

(M = As, Sb, Bi; X = halide) and [SbX3{Se=PPh2(o-tolyl)}2].

200

Table 5.20. Elemental analysis data for [MX3{Se=PPh(o-tolyl)2}] and [SbX3{Se=PPh2(o-

tolyl)}2].


% H cal % H found


or I)

% P cal % Pfound

[BiCl3{Se=PPh(o-tolyl)2}], 73 yellowish white

35.07

34.45

2.80

2.56

15.54 15.13

4.53

4.46

[BiBr3{Se=PPh(o-tolyl)2}], 74 yellow 29.35 30.44

2.34

2.18

29.31

28.91

3.79

3.82

[BiI3{Se=PPh(o-tolyl)2}], 75 dark brown

- - - -

[SbBr3{Se=PPh(o-tolyl)2}], 76 dusty white

32.85

32.67

2.62

2.62

32.81

32.92

4.24

4.32

[SbI3{Se=PPh(o-tolyl)2}], 77 orange 27.54

26.01 2.20 1.85

43.68

45.08 3.55

3.41 [AsI3{Se=PPh(o-tolyl)2}], 78 dark

yellow - - - -

[SbCl3{Se=PPh2(o-tolyl)}2], 79 off-white 48.60

47.64

3.65 3.38

11.34

12.05

6.60

6.40

[SbBr3{Se=PPh2(o-tolyl)}2], 80 pale yellow

42.55

41.87

3.20

2.57

22.37

23.13

5.78

5.65

[SbI3{Se=PPh2(o-tolyl)}], 81 red brown

- - - -

Compounds 73, 74, 76 and 77 showed that the reactions resulted in the

formation of 1:1 products, and the calculated figures are consistent with the observed

values, as determined from the elemental analysis data, while compounds 79 and 80

resulted in 2:1 products. However, compounds 75, 78 and 81 showed less satisfactory

agreement between calculated and observed values.

Fortunately, crystals suitable for X-ray diffraction were grown from a dry

dichloromethane/diethyl ether layered solution of compound 80, its molecular

structure is shown in Fig. 5.19 and bond lengths and angles are given in Table 5.21.

201

Fig. 5.19. ORTEP representation of [SbBr3{Se=PPh2(o-tolyl)}].CH2Cl2, 80

Table 5.21. Selected bond lengths (Å) and angles (°) of [SbBr3{Se=PPh2(o-tolyl)}].

CH2Cl2, 80


Sb(1)-Br(1) 2.7033(12) Br(1)-Sb(1)-Br(2) 89.40(4) Sb(1)-Br(2) 2.5203(14) Br(1)-Sb(1)-Br(3) 90.54(4)

Sb(1)-Br(3) 2.5685(13) Br(1)-Sb(1)-Se(1) 168.98(4)

Sb(1)-Se(1) 2.9466(12) Br(2)-Sb(1)-Br(3) 94.34(5)

Sb(1)-Br(1i) 3.2161(13) Br(2)-Sb(1)-Se(1) 79.67(4) Se(1)-P(1) 2.151(3) Br(3)-Sb(1)-Se(1) 91.65(4)

Sb(1)-Se(1)-P(1) 95.97(8)

The structure of compound 80 showed that it is also a 1:1 product (with a molecule of

CH2Cl2 solvent crystallized) and is a dimer. Compound 80 dimerises in a similar manner

as in previous work involving Ar3PSe and group 15 halides. The monomeric unit again

has a see-saw geometry which dimerises via bridging bromides. This dimerisation

results in an overall square pyramidal geometry at antimony with highly asymmetric

bridging, Sb(1)-Br(1): 2.7033(12) and Sb(1)-Br(1i): 3.2161(13) Å. The aryl ring of the o-

tolyl group is located over the vacant coordination site on the antimony atom.

However, the elemental analysis of compound 80 shows that the bulk material is a 2:1

product. The crystal packing of compound 80 shows that there are weak interactions

between Br(2)-Br(2): 3.3230(18) Å of the dimers as shown in Fig. 5.20.

202

Fig. 5.20. Crystal packing of [SbBr3{Se=PPh2(o-tolyl)}].CH2Cl2, 80 showing the weak

Br···Br interactions between dimers.

The 31P{1H} NMR spectra (in CDCl3 solution) of compounds 73-81 were obtained and

the 31P{1H} chemical shifts and some coupling constants are listed in Table 5.22.

Compounds 73, 74 and 78 (δP: 28.2, 28.4 and 28.4 ppm) exhibit chemical shifts slightly

shifted from the free phosphine selenide, [(o-tolyl)2PhP=Se] δP: 29.1 ppm; this shift is

also observed for compound 75, whilst compounds 76 and 77 display chemical shifts at

slightly higher resonances. The coupling constants for 75, 1J(PSe): 711 Hz and 76,

1J(PSe): 671 Hz were obtained and also show a decrease compared to the starting

phosphine selenide, [(o-tolyl)2PhP=Se], 1J(PSe): 713 Hz. There are no major shifts for

compounds 79-81 when comparing with starting diphenyl-o-tolyl phosphine selenide,

[(o-tolyl)Ph2P=Se], δP: 31.9 ppm, 1J(PSe): 724 Hz which is similar to that previously

reported for [(o-tolyl)Ph2P=Se],[32] δP: 32.6 ppm, 1J(PSe): 730 Hz.

203

Table 5.22. 31P NMR Spectroscopic data of mixed aryl phosphine selenides

Compound 31P{1H} δ ppm 1J(PSe) Hz

[BiCl3{Se=PPh(o-tolyl)2}], 73 28.2 -

[BiBr3{Se=PPh(o-tolyl)2}], 74 28.4 -

[BiI3{Se=PPh(o-tolyl)2}], 75 29.1 711

[SbBr3{Se=PPh(o-tolyl)2}], 76 29.6 671

[SbI3{Se=PPh(o-tolyl)2}], 77 29.7 -

[AsI3{Se=PPh(o-tolyl)2}], 78 28.4 -

[SbCl3{Se=PPh2(o-tolyl)}2], 79 31.8 706

[SbBr3{Se=PPh2(o-tolyl)}2], 80 32.0 -

[SbI3{Se=PPh2(o-tolyl)}], 81 31.4 -

5.4. Reactions of alkyl/aryl phosphine selenides with group 15 halides

Further investigations were made with mixed alkyl/aryl phosphine selenides in a

similar manner as previously discussed in section 5.3. The reactions of the alkyl/aryl

phosphine selenides were performed according to the following reaction

where R3P = (CH3)2PhP and CH3Ph2P

M = Bi, Sb and As

X = Cl, Br and I.

All the starting phosphine selenides discussed earlier in section 5.3 were solids,

whereas the phosphine selenides in this section are viscous liquids. The reactions were

all carried out under anaerobic and anhydrous conditions.

The coloured products were filtered off under nitrogen using Schlenk

techniques and transferred to glass vials in a glove box. The compounds were

characterised by elemental analysis, multinuclear NMR spectroscopy, Raman

spectroscopy and single crystal X-ray diffraction if crystals were obtained.

204

The reactions of (CH3)2PhPSe with AsCl3 and AsBr3 were unsuccessful, as were the

reactions of CH3Ph2PSe with SbCl3, AsCl3, AsBr3 and AsI3, the latter gave unreacted AsI3.

All the compounds 82-93 analyse as 1:1 products as shown in Table 5.23, except for 88,

where its elemental analysis data is not as expected, it seems that the product is

mainly unreacted AsI3.

Table 5.23. Elemental analysis data for [MX3{Se=PPh(CH3)2}] and [MX 3{Se=PPh2CH3}].


% H cal % H found

% X cal % X found (X = Cl, Br

or I)

% P cal % Pfound

[BiCl3{Se=PPh(CH3)2}], 82 dark brown

18.03 18.48

2.08 1.88

19.98 18.91

5.82 5.86

[BiBr3{Se=PPh(CH3)2}], 83 yellow 14.42 14.45

1.67 1.50

36.01 36.47

4.65 4.69

[BiI3{Se=PPh(CH3)2}], 84 red brown

11.90 11.84

1.37 0.76

47.19 47.63

3.84 3.55

[SbCl3{Se=PPh(CH3)2}], 85 cream 21.57 21.88

2.49 1.60

23.89 23.67

6.96 6.66

[SbBr3{Se=PPh(CH3)2}], 86 yellow 16.60 17.07

1.92 1.09

41.44 41.30

5.35 4.92

[SbI3{Se=PPh(CH3)2}], 87 yellow 13.34 13.35

1.54 1.33

52.91 53.55

4.31 4.12

[AsI3{Se=PPh(CH3)2}], 88 brick red 14.27 5.86

1.65 0.41

56.60 73.85

4.60 1.65

[BiCl3{Se=PPh2CH3}], 89 greenish brown

26.25 25.54

2.20 2.48

17.89 17.74

5.21 4.92

[BiBr3{Se=PPh2CH3}], 90 yellow 21.44 21.39

1.80 1.83

32.94 34.11

4.26 4.30

[BiI3{Se=PPh2CH3}], 91 red brick 17.96 16.42

1.51 1.30

43.82 43.26

3.57 3.42

[SbBr3{Se=PPh2CH3}], 92 pale yellow

24.36 24.53

2.05 2.05

37.43 37.41

4.84 4.75

[SbI3{Se=PPh2CH3}], 93 dark yellow

19.96 18.96

1.68 1.39

48.72 48.50

3.96 3.77

The elemental analyses for compounds 82-87 and 89-93 show excellent agreement

between calculated and observed figures.

Fortunately, crystals suitable for single crystal X-ray diffraction were grown from a dry

dichloromethane/diethyl ether layered solution of compounds 86 and 89. The

molecular structure of compound 86 is shown in Fig. 5.21 and bond lengths and angles

205

are given in Table 5.24. Compound 86 is a 1:1 product with distorted square pyramidal

geometry at antimony with bridging phosphine selenides between two antimony

atoms. The Sb-Br bonds, Sb(1)-Br(1): 2.561(3) Å, Sb(1)-Br(2): 2.618(3) Å and Sb(1)-

Br(3): 2.616(2) Å are of similar length and the dimerisation occurs via bridging

phosphine selenides rather than bridging halides, with Sb(1)-Se(1): 3.106(2) Å and

Sb(1)-Se(1i): 3.130(3) Å.

Fig. 5.21. ORTEP representation of [SbBr3{Se=PPh(CH3)2}], 86

Table 5.24. Selected bond lengths (Å) and angles (°) of [SbBr3{Se=PPh(CH3)2}], 86


Sb(1)-Br(1) 2.561(3) Br(2)-Sb(1)-Br(3) 90.06(9)

Sb(1)-Br(2) 2.618(3) Br(1)-Sb(1)-Br(2) 91.72(9) Sb(1)-Br(3) 2.616(2) Br(1)-Sb(1)- Br(3) 96.71(9)

Sb(1)-Se(1) 3.106(2)

Sb(1)-Se(1i) 3.130(3)

Se(1)-P(6) 2.167(8)

Fig. 5.22 shows the crystal packing of compound, 86 which shows the formation of a

polymeric chain formation via bridging of the phosphine selenide ligands instead of

bridging halides.

206

Fig. 5.22. Crystal packing of [SbBr3{Se=PPh(CH3)2}], 86

The molecular structure of compound 89 is shown in Fig. 5.23 and bond lengths and

angles are given in Table 5.25. The structure of compound 89 is a Bi4Cl16 cluster with a

centre of inversion which consists initially of a dimer containing two different bismuth

atoms, which further dimerises resulting in the formation of a tetramer

[Bi4Cl12{Se=PPh2Me}4]. Each bismuth atom has octahedral geometry with a Cl5Se

coordination sphere. Bi(1) has one Bi(1)-Se(1) bond: 2.814(3) Å, one terminal bond,

Bi(1)-Cl(3): 2.508(8) Å and four bridging bonds, Bi(1)-Cl(1): 3.022(7) Å, Bi(1)-Cl(2):

2.699(8) Å, Bi(1)-Cl(4i): 2.733(9) Å and Bi(1)-Cl1i): 2.957(8) Å while the other bismuth

atom, Bi(2) has one Bi(2)-Se(2): 2.710(6) Å, two terminal bonds, Bi(2)-Cl(5): 2.507(10) Å

and Bi(2)-Cl(6): 2.519(10) Å and three bridging bonds, Bi(2)-Cl(2): 2.972(8) Å, Bi(2)-

Cl(1): 2.968(8) Å and Bi(2)-Cl(4): 2.893(9) Å.

207

Fig. 5.23. ORTEP representation of tetramer of [BiCl3{Se=PPh2CH3}], 89, hydrogen

atoms omitted for clarity.

Table 5.25. Selected bond lengths (Å) and angles (°) of tetramer of [BiCl3{Se=PPh2CH3}],

89


Bi(1)-Se(1) 2.814(3) Se(1)-Bi(1)-Cl(1) 88.02(17)


Bi(1)-Cl(3) 2.508(8) Cl(1)-Bi(1)-Cl(2) 84.1(2)

Bi(2)-Se(2) 2.710(6) Cl(1)-Bi(1)-Cl(3) 174.0(3)

Bi(2)-Cl(1) 2.968(8) Cl(2)-Bi(1)-Cl(3) 92.2(3) Bi(2)-Cl(2) 2.972(8) Se(2)-Bi(2)-Cl(1) 96.0(2)

Bi(2)-Cl(4) 2.893(9) Se(2)-Bi(2)-Cl(2) 71.8(2)

Bi(2)-Cl(5) 2.507(10) Se(2)-Bi(2)-Cl(4) 164.6(2)

Bi(2)-Cl(6) 2.519(10) Se(2)-Bi(2)-Cl(5) 103.3(3) Se(1)-P(1) 2.182(11) Se(2)-Bi(2)-Cl(6) 85.4(3)

Se(2)-P(2) 2.164(10) Cl(1)-Bi(2)-Cl(2) 80.5(2)

Cl(1)-Bi(2)-Cl(4) 82.5(2)

Cl(1)-Bi(2)-Cl(5) 96.4(3)

208

The Bi-Se bonds in compound 89 are 3.0559(18) and 2.8429(8) Å. These are

considerably longer than those in compound 50, [{BiCl3(SePPh3)2}], where the Bi-Se

bonds are 2.814(3) and 2.710(6) Å. In contrast, the Bi-Cl bonds in compound 89 are

much shorter than in compound 50. For example, the terminal Bi-Cl bonds in

compound 89 are 2.507(10) to 2.519(10) Å, whilst in compound 50 they range

between 2.5682(19) and 2.5911(19) Å. The crystal packing of the tetramer,

[Bi4Cl12{Se=PPh2Me}4] is shown in Fig. 5.24, along the c-axis which shows regions

occupied by bismuth and chlorine atoms and regions of the interaction of the phenyl

rings.

Fig. 5.24. Crystal packing of the tetramer [Bi4Cl12{Se=PPh2(CH3}4], 89 along the

crystallographic c-axis.

Attempts were made to record the 31P{1H} NMR spectra of compounds 82-93 in CDCl3.

Their chemical shifts, δP are shown in Table 5.26, but it was not possible to obtain

209

77Se{1H} NMR spectra (and thus their coupling constant values), due to the poor

solubility of almost all the compounds 82-93. It was only possible to obtain 77Se{1H}

data for compound 92, which was the most soluble compound. Compound 92

displayed a chemical shift, δP: 24.3 ppm, δSe: -158.4 ppm and 1J(PSe): 668 Hz. There is

a slight increase in the chemical shift, δP and a decrease in the coupling constant as

compared to the starting alkyl aryl phosphine selenide, {(CH3)2PhP=Se}, δP: 23.3 ppm,

1J(PSe): 718 Hz. From Table 5.26, it can be seen that the compounds 82 (δP: 16.3 ppm),

85 (δP: 17.3 ppm) and 86 (δP: 17.1 ppm) exhibit chemical shifts δP, slightly higher than

the starting alkyl/aryl phosphine selenide, ((CH3)2PhP=Se) especially the antimony

analogues whereas 84, 87 and 88 display similar chemical shifts to (CH3)2PhP=Se.

Table. 5.26. Spectroscopic data for [MX3{Se=PPh(CH3)2}] and [MX 3{Se=PPh2CH3}].

Compound 31P{1H} δ ppm

[BiCl3{Se=PPh(CH3)2}], 82 16.3

[BiBr3{Se=PPh(CH3)2}], 83 - [BiI3{Se=PPh(CH3)2}], 84 15.9

[SbCl3{Se=PPh(CH3)2}], 85 17.3

[SbBr3{Se=PPh(CH3)2}], 86 17.1

[SbI3{Se=PPh(CH3)2}], 87 16.0

[AsI3{Se=PPh(CH3)2}], 88 15.9

[BiCl3{Se=PPh2CH3}], 89 23.1

[BiBr3{Se=PPh2CH3}], 90 -

[BiI3{Se=PPh2CH3}], 91 23.1

[SbBr3{Se=PPh2CH3}], 92 24.3

[SbI3{Se=PPh2CH3}], 93 24.0

Compounds 89 and 91 (δP: 23.1 ppm) displayed the same chemical shifts, δP, which are

similar to the starting phosphine selenide, {CH3Ph2P=Se} (δP: 23.3 ppm) while 92 (δP:

24.3 ppm) and 93 (δP: 24.0 ppm) showed slightly higher chemical shifts as previous

observed for the diphenylmethyl phosphine selenide compounds.

5.5. Reactions of diphosphine diselenides with group 15 halides

One of the common class of ligands in organometallic and coordination chemistry are

bidentate phosphorus ligands. A limited number of studies have been reported

concerning bidentate phosphine ligands with group 15 halides, complexes such as

210

BiCl3.dppm (where dppm is Ph2PCH2PPh2) have been studied but the complex obtained

from this reaction was in its oxidized form, i. e. [BiCl3{Ph2P(O)CH2P(O)Ph2}]2.[33]

This section concerns the reactions of a series of diphosphine diselenides with

group 15 halides which include bis(diphenylphosphino)methane diselenide(dppmSe2),

1,2-bis(diphenylphosphino)ethane diselenide(dppeSe2), 1,6-(diphenylphosphino)

hexane diselenide(dpphSe2), cis-1,2-bis(diphenylphosphino)ethylene diselenide and

trans-1,2-bis(diphenylphosphino)ethylene diselenide. These have all been synthesized

according to the following reaction

where L: Ph2PCH2PPh2(dppm), Ph2P(CH2)2PPh2(dppe), Ph2P(CH2)6PPh2(dpph),

cis-Ph2PCH=CHPPh2 and trans-Ph2PCH=CHPPh2.

M: Bi, Sb and As and X: Cl, Br and I.

The reactions were performed under anaerobic and anhydrous conditions. The

coloured products were filtered off under nitrogen using Schlenk techniques and

transferred to glass vials in a glove box. The compounds were characterised by

elemental analysis, multinuclear NMR spectroscopy, Raman spectroscopy and single

crystal X-ray diffraction when crystals were obtained. The elemental analysis data of

the compounds is shown in Table 5.27.

211

Table 5.27. Elemental analysis data for [MX3{Ph2P(Se)CH2P(Se)Ph2}]


% H cal % H found


or I)

% P cal % Pfound

[BiCl3{Ph2P(Se)CH2P(Se)Ph2}], 94 pale yellow

34.99

34.80

2.59

2.41

12.41

12.65

7.23

7.25

[BiBr3{Ph2P(Se)CH2P(Se)Ph2}], 95 dark yellow

30.28

31.08

2.24

2.12

24.20

24.12

6.25 6.25

[BiI3{Ph2P(Se)CH2P(Se)Ph2}], 96 orange 26.51

26.11

1.96 1.66

33.64

34.57

5.47

5.71

[SbCl3{Ph2P(Se)CH2P(Se)Ph2}], 97 white 38.95

39.34

2.88

2.69

13.81

13.98

8.04

7.04

[SbBr3{Ph2P(Se)CH2P(Se)Ph2}], 98 pale yellow

33.20

33.56

2.45

2.25

26.53

26.52

6.86

6.39

[SbI3{Ph2P(Se)CH2P(Se)Ph2}], 99 pale orange

28.72

28.76

2.12

2.06

36.45

36.25

5.93

5.70

[AsCl3{Ph2P(Se)CH2P(Se)Ph2}], 100 pale pink

41.48

41.86

3.07

2.86

14.70

14.53

8.56

8.81

[AsBr3{Ph2P(Se)CH2P(Se)Ph2}2], 101 v. pale yellow

42.90

41.61

3.17

2.65

17.14

19.05

8.86

8.68

[AsI3{Ph2P(Se)CH2P(Se)Ph2}], 102 dark yellow

30.07

30.33

2.22

1.80

38.16

38.59

8.56

8.81

With the exception of compound, 101, where its elemental analysis suggests the

formation of a 2:1 product, all the other compounds 94-100 and 102 analysed as 1:1

products and the calculated figures were in excellent agreement with the observed

figures.


dichloromethane/diethyl ether layered solution of compound 98, its molecular is

shown in Fig. 5.25 and bond lengths and angles are listed in Table 5.28. This is the one

of the first structures of a group 15 trihalide with a bidentate phosphine selenide. The

monomeric unit has the expected saw-horse geometry with only one selenium atom of

the dppmSe2 ligand strongly bound, Sb(1)-Se(1): 2.8670(18) Å, whilst the other

selenium atom weakly interacts with the antimony centre, Sb(1)-Se(2): 3.2033(18) Å.

This differing strength of interaction is reflected in the P=Se bonds as well, as

P(1)-Se(1) is 2.169(4) Å, whilst P(2)-Se(2) is significantly shorter at 2.132(4) Å. The

compound dimerises in the same way as [SbX3{Se=PAr3}] complexes via bridging

bromine atoms with very asymmetric bridges Sb(1)-Br(1): 2.7981(18) Å and

212

Sb(1)-Br(1i): 3.1434(19) Å. The overall geometry is square pyramidal at the antimony

with the weaker Sb···Se interaction to the sixth vacant coordination site.

Fig. 5.25. ORTEP representation of [SbBr3{Ph2P(Se)CH2P(Se)Ph2}], 98

Table 5.28. Selected bond lengths (Å) and angles (°) of [SbBr3{Ph2P(Se)CH2P(Se)Ph2}],

98


Sb(1)-Br(1) 2.7981(18) Br(1)-Sb(1)-Br(2) 86.89(6)

Sb(1)-Br(2) 2.5772(19) Br(1)-Sb(1)-Br(3) 90.94(6) Sb(1)-Br(3) 2.5938(19) Br(1)-Sb(1)-Se(1) 160.44(6)

Sb(1)-Se(1) 2.8670(18) Br(2)-Sb(1)-Br(3) 91.24(6)

Sb(1)-Se(2) 3.2033(18) Br(2)-Sb(1)-Se(1) 77.22(5)

Se(1)-P(1) 2.169(4) Br(3)-Sb(1)-Se(1) 100.63(6) Se(2)-P(2) 2.132(4)

Sb(1)-Br(1i) 3.1434(19)

Attempts were made to record the 31P{1H} NMR spectra of compounds 94-102 in

CDCl3. Their chemical shifts, δP are shown in Table 5.29, but it was not possible to

obtain 77Se{1H} NMR spectra for the compounds with the exception of compound 101,

δSe: -238 ppm; 1J(PSe): 743 Hz. Also the 1J(PSe) coupling constant values could not be

213

resolved in most cases due to the poor signal to noise ratio arising from poor solubility

of the compounds.

Table 5.29. Spectroscopic data for [MX3{Ph2P(Se)CH2P(Se)Ph2}]

Compound 31P{1H} δ ppm 1J (PSe) Hz

[BiCl3{Ph2P(Se)CH2P(Se)Ph2}], 94 insufficiently soluble

-

[BiBr3{Ph2P(Se)CH2P(Se)Ph2}], 95 insufficiently soluble

-

[BiI3{Ph2P(Se)CH2P(Se)Ph2}], 96 25.1 -

[SbCl3{Ph2P(Se)CH2P(Se)Ph2}], 97 insufficiently soluble

-

[SbBr3{Ph2P(Se)CH2P(Se)Ph2}], 98 25.1 -

[SbI3{Ph2P(Se)CH2P(Se)Ph2}], 99 24.8 -

[AsCl3{Ph2P(Se)CH2P(Se)Ph2}], 100 25.0 743

[AsBr3{Ph2P(Se)CH2P(Se)Ph2}2], 101 25.0 743

[AsI3{Ph2P(Se)CH2P(Se)Ph2}], 102 24.9 737

The chemical shifts δP assigned for compounds 96, δP: 25.1 ppm, 98-102, δP: 25.1, 24.8,

25.0, 25.0 and 24.9 ppm respectively are similar to the starting diphosphine diselenide,

{Ph2P(Se)CH2P(Se)Ph2}, dppmSe2, δP: 25.0 ppm; 1J(PSe): 745 Hz. It was possible to

obtain coupling constants for only three compounds 100, 101 and 102, and their

values are 1J(PSe): 743 and 737 Hz respectively. Compounds 100 and 101 have the

same 1J(PSe) values and are similar to the starting diphosphine diselenide

{Ph2P(Se)CH2P(Se)Ph2}, dppmSe2.

The reactions of 1,2-bis(diphenylphosphino)ethanediselenide (dppeSe2) with

group 15 halides were carried out in a similar manner as those with dppmSe2. The

reactions were performed under anaerobic and anhydrous conditions. The coloured

products were filtered off under nitrogen using Schlenk techniques and transferred to

glass vials in a glove box. The compounds were characterised by elemental analysis,

multinuclear NMR spectroscopy, Raman spectroscopy and single X-ray diffraction if

crystals were obtained. The elemental analysis data of the compounds is shown in

Table 5.30.

214

Table 5.30. Elemental analysis data for [MX3{Ph2P(Se)CH2CH2P(Se)Ph2}]


% H cal % H found

% X cal % X found (X = Cl, Br or I)

% P cal % Pfound

[BiCl3{Ph2P(Se)(CH2)2P(Se)Ph2}], 103 yellow 35.80 35.43

2.78 2.42

12.21 12.34

7.11 6.95

[BiBr3{Ph2P(Se)(CH2)2P(Se)Ph2}], 104 dark yellow

31.05 30.85

2.41 1.94

23.91 25.05

6.18 5.83

[Bil3{Ph2P(Se)(CH2)2P(Se)Ph2}], 105 dark orange

27.23 27.35

2.11 1.94

33.23 33.62

5.41 5.26

[SbCl3{Ph2P(Se)(CH2)2P(Se)Ph2}], 106 white 39.79 38.54

3.08 2.71

13.56 14.94

7.90 6.52

[SbBr3{Ph2P(Se)(CH2)2P(Se)Ph2}], 107 pale yellow

- - - -

[SbI3{Ph2P(Se)(CH2)2P(Se)Ph2}], 108 turmeric - - - -

[AsCl3{Ph2P(Se)(CH2)2P(Se)Ph2}], 109 white - - - -

[AsBr3{Ph2P(Se)(CH2)2P(Se)Ph2}], 110 pale yellow

35.83 35.91

2.78 2.18

27.53 27.92

7.11 7.01

[AsI3{Ph2P(Se)(CH2)2P(Se)Ph2}], 111 dark yellow

30.84 30.64

2.39 2.02

37.63 37.85

6.12 5.89

The elemental analysis of compounds 103-106, 110, 111 showed good agreement

between the observed values and figures calculated on the basis of 1:1 products,

however, for the compounds 107, 108 and 109, their elemental analysis data shows

unsatisfactory agreement between calculated and observed figures.

Attempts were made to record the 31P{1H} and 77Se{1H} NMR spectra of compounds

103-111 in CDCl3. The 31P{1H} NMR data is more complicated in case of diphosphine

diselenides. Their chemical shifts, δP, δSe and J(PSe) are shown in Table 5.31. It was

possible to obtain 77Se{1H} NMR data for three compounds only, the arsenic analogues,

109-111, which were more soluble in CDCl3 than the rest of the compounds; this

solubility effect was also observed in the previous arsenic analogues of dppmSe2.

215

Table 5.31. Spectroscopic data for [MX3{Ph2P(Se)CH2CH2P(Se)Ph2}]


77Se{1H} δ ppm

J/ Hz

[BiCl3{Ph2P(Se)CH2CH2P(Se)Ph2}], 103 insufficiently soluble

- -

[BiBr3{Ph2P(Se)CH2CH2P(Se)Ph2}], 104 35.9 - -

[Bil3{Ph2P(Se)CH2CH2P(Se)Ph2}], 105 35.9 - -

[SbCl3{Ph2P(Se)CH2CH2P(Se)Ph2}], 106 36.0 - -

[SbBr3{Ph2P(Se)CH2CH2P(Se)Ph2}], 107 35.9 - -

[SbI3{Ph2P(Se)CH2CH2P(Se)Ph2}], 108 35.2 - -

[AsCl3{Ph2P(Se)CH2CH2P(Se)Ph2}], 109

35.9 -349.4 734 64.1

6.6

[AsBr3{Ph2P(Se)CH2CH2P(Se)Ph2}], 110

35.9 -349.1 734

64.6

6.5

[AsI3{Ph2P(Se)CH2CH2P(Se)Ph2}], 111

35.9 -341.5 732

64.8

6.4

The 31P{1H} NMR spectrum of arsenic analogues, 109, 110 and 111 are

complicated and similar to the spectrum of the starting diphosphine diselenide,

dppeSe2, 40, showing a singlet for molecules containing no 77Se nuclei and two

different environments for the phosphorus atoms arising from molecules possessing

one active 77Se nucleus. The coupling constants are as shown in Fig. 5.26 with 1J(PSe) =

732 Hz and 3J(PP) = 64.8 Hz for phosphorus (a) and 3J(PP) = 64.8 Hz and 4J(PSe) = 6.4 Hz

for phosphorus (b) respectively. It was also possible to obtain the 77Se{1H} NMR

spectrum of compound 111, which shows a doublet of doublets but these doublets

are not well resolved, the coupling constants are 1J(PSe) = 732 Hz and 4J(PSe) = 6.4 Hz.

216

Fig. 5.26. 31P{1H} NMR spectrum of [AsI3{Ph2P(Se)CH2CH2P(Se)Ph2}] 111 in CDCl3


dichloromethane/diethyl ether layered solution of compound 106. Its molecular

structure is shown in Fig. 5.27 and selected bond lengths and angles are given in Table

5.32. Compound 106 exhibits a square-based pyramidal geometry at antimony with

two Se donor atoms and three chlorine atoms and the apical Sb(1)-Cl(1): 2.3897(16) Å

being the shortest of the three Sb-Cl bonds. The Sb-Cl bonds can be compared with the

parent halide SbCl3[15] where two of the Sb-Cl bond distances are equal, Sb-Cl: 2.340(2)

Å and the third bond is 2.368(1) Å.

In compound 106, two of the Sb-Cl bonds are quite similar to each other Sb(1)-

Cl(2): 2.4238(16) and Sb(1)-Cl(3): 2.4309(17) Å but are slightly longer than in the parent

halide SbCl3. The Sb-Se bonds in compound 106, Sb(1)-Se(1): 3.1460(7) and Sb(1)-Se(2):

3.1977(9) Å are similar to the Sb-Se interactions observed in the seleno complex of

217

SbCl3 [SbCl3(mbts)(μ-mbts)2SbCl3(mbts)][22] which range from 3.1395(8) to 3.2208(8) Å

around one of the antimony atoms.

Fig. 5.27. ORTEP representation of [SbCl3{Ph2P(Se)CH2CH2P(Se)Ph2}]n.0.5CH2Cl2, 106,

CH2Cl2 molecule omitted for clarity.

Table 5.32. Selected bond lengths (Å) and angles (°) of

[SbCl3{Ph2P(Se)CH2CH2P(Se)Ph2}]n.0.5CH2Cl2, 106


Sb(1)-Se(1) 3.1460(7) Cl(2)-Sb(1)-Cl(3) 93.41(6) Sb(1)-Se(2) 3.1977(9) Cl(1)-Sb(1)-Cl(2) 90.36(5)

Sb(1)-Cl(2) 2.4238(16) Cl(1)-Sb(1)-Cl(3) 93.63(6)

Sb(1)-Cl(3) 2.4309(17)

Sb(1)-Cl(1) 2.3897(16) Se(1)-P(1) 2.1482(17)

Se(2)-P(2) 2.1298(17)

The Se donors are cis to one another and the diphosphine diselenide bridges to form a

chain which is shown in Fig. 5.28.

218

Fig. 5.28. Polymeric chain of [SbCl3{Ph2P(Se)CH2CH2P(Se)Ph2}]n.0.5CH2Cl2, 106

The chemistry of the diphosphine diselenides has been extended by increasing the

CH2 chain in {Ph2P(Se)(CH2)nP(Se)Ph2} to 6, i.e. 1,6-(diphenylphosphino)hexane

diselenide. This has then been reacted with group 15 halides in the same fashion as

dppmSe2 and dppeSe2 as described at the beginning of section 5.5, and all the

reactions were performed under anaerobic and anhydrous conditions.

The coloured products were filtered off under nitrogen using Schlenk

techniques and transferred to glass vials in a glove box. The compounds were

characterised by elemental analysis, multinuclear NMR spectroscopy, Raman

spectroscopy and single crystal X-ray diffraction (if crystals were obtained). The

reactions of chlorides and bromides of both antimony and arsenic with 1,6-(diphenyl

phosphino)hexane diselenide were unsuccessful and gave the starting diphosphine

diselenide, {Ph2P(Se)(CH2)6P(Se)Ph2}. The elemental analysis data of the compounds

112-116 is shown in Table 5.33.

Interestingly, even though the reactions were performed in a 1:1 ratio,

compound 116 analysed as 2:1 adduct from elemental analysis data. The calculated

and observed figures were in excellent agreement for compound 114, and

unsatisfactory for compound 112, 113 and 115.

219

Table 5.33. Elemental analysis data of [MX3{Ph2P(Se)(CH2)6P(Se)Ph2}]


% H cal % H found

% X cal

% X found (X = Cl, Br or I)

% P cal % Pfound

[BiCl3{Ph2P(Se)(CH2)6P(Se)Ph2}2],

112

yellow - - - -

[BiBr3{Ph2P(Se)(CH2)6P(Se)Ph2}2],

113

dark

yellow

- - - -

[BiI3{Ph2P(Se)(CH2)6P(Se)Ph2}],

114

grey 29.95

29.26

2.68

2.58

31.68

31.67

5.15

5.21

[SbI3{Ph2P(Se)(CH2)6P(Se)Ph2}],

115

orange - - - -

[AsI3{Ph2P(Se)(CH2)6P(Se)Ph2}2],

116

turmeric 42.86

43.72

3.84

3.69

22.66

20.99

7.38

7.56

The 31P{1H} and 77Se{1H} NMR spectra of compounds 112-116 in CDCl3 have been

recorded. The spectroscopic data is shown in Table 5.34.

Table 5.34. Spectroscopic data for [MX3{Ph2P(Se)(CH2)6P(Se)Ph2}]

Compound 31P{1H} δ ppm 77Se{1H} δ ppm J(PSe) Hz

[BiCl3{Ph2P(Se)(CH2)6P(Se)Ph2}2], 112 34.0 insufficiently soluble

718

[BiBr3{Ph2P(Se)(CH2)6P(Se)Ph2}2], 113

33.9 insufficiently soluble

704

[BiI3{Ph2P(Se)(CH2)6P(Se)Ph2}], 114

33.9 insufficiently soluble

720

[SbI3{Ph2P(Se)(CH2)6P(Se)Ph2}], 115 34.1 insufficiently soluble

710

[AsI3{Ph2P(Se)(CH2)6P(Se)Ph2}2], 116 34.0 -335 720

The 31P{1H} chemical shifts of the compounds 112-116 are similar to that of the starting

diphosphine diselenide, {Ph2P(Se)(CH2)6P(Se)Ph2}, δP: 34.1 ppm. It was possible to

obtain 77Se{1H} NMR data and coupling constant only for compound 116 which has a

77Se{1H} chemical shift δSe: -335, J(PSe): 720 Hz, both of which are also similar to the

starting diphosphine diselenide, {Ph2P(Se)(CH2)6P(Se)Ph2}, δSe: -345, J(PSe): 720 Hz.

220

Finally, the reactions between cis and trans-1,2-bis(diphenylphosphino)ethylene

diselenide, {Ph2P(Se)CH=CHP(Se)Ph2}, with group 15 halides have also been studied.

The reactions were undertaken in a similar way as previously described according to

the reaction outlined at the beginning of section 5.5. All the reactions were performed

under anaerobic and anhydrous conditions. The coloured products were filtered off


The compounds were characterised by elemental analysis, multinuclear NMR

spectroscopy, Raman spectroscopy and single crystal X-ray diffraction if crystals were

obtained.

The elemental analysis data is shown in Table 5.35. The reactions of

antimony(III) chloride with cis- and trans-1,2-bis(diphenylphosphino)ethylene

diselenide resulted in 2:1 products as well as arsenic(III) bromide with cis-1,2-

bis(diphenylphosphino)ethylene diselenide which also gave a 2:1 product even though

all the reactions were carried out in a 1:1 ratio. The compounds 117, 120, 121, 122,

124, 126, 129 and 130 show good agreement between calculated and observed

figures, however, for compounds 118, 119, 123, 125, 127, 128, 131 and 133 were

unsatisfactory.

221

Table 5.35. Elemental analysis data for [MX3{cis-Ph2P(Se)CH=CHP(Se)Ph2}] and

[MX3{trans-Ph2P(Se)CH=CHP(Se)Ph2}].


% H cal % H found

% X cal % X found (X= Cl, Br or I)

% P cal % Pfound

[BiCI3{cis-Ph2P(Se)CH=CHP(Se)Ph2}], 117 dark brown

35.89 36.13

2.55 2.38

12.23 11.36

7.13 6.77

[BiBr3{cis-Ph2P(Se)CH=CHP(Se)Ph2}], 118 pale green

- - - -

[BiI3{cis-Ph2P(Se)CH=CHP(Se)Ph2}], 119 orange red

- - - -

[SbCI3{cis-Ph2P(Se)CH=CHP(Se)Ph2}2], 120 pale yellow

46.70 47.73

3.32

3.05 7.96

7.36

9.27

8.84

[SbBr3{cis-Ph2P(Se)CH=CHP(Se)Ph2}], 121 pale yellow

34.08 34.34

2.42

2.11

26.18

26.04

6.77

6.58

[SbI3{cis-Ph2P(Se)CH=CHP(Se)Ph2}], 122 yellow 29.53 29.08

2.10

1.86

36.04

36.04

5.86

4.55

[AsCl3{cis-Ph2P(Se)CH=CHP(Se)Ph2}], 123 dark pink

- - - -

[AsBr3{cis-Ph2P(Se)CH=CHP(Se)Ph2}2], 124 pale yellow

44.55 43.87

1.58

2.71

17.12

17.33

8.85

8.82

[AsI3{cis-Ph2P(Se)CH=CHP(Se)Ph2}], 125 orange - - - -

[BiCl3{trans-Ph2P(Se)CH=CHP(Se)Ph2}], 126 yellow 35.89 34.98

2.55

1.87

12.23

12.27

7.13

6.96

[BiBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}], 127 yellow - - - -

[BiI3{trans-Ph2P(Se)CH=CHP(Se)Ph2}], 128 orange brown

- - - -

[SbCl3{trans-Ph2P(Se)CH=CHP(Se)Ph2}2], 129 greyish white

46.70 45.86

3.32

2.84

7.96 8.55

9.27

8.56

[SbBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}], 130 yellow 34.08 34.31

2.42 1.99

26.18

25.54

6.77

5.67

[SbI3{trans-Ph2P(Se)CH=CHP(Se)Ph2}], 131 yellow - - - -

[AsCl3{trans-Ph2P(Se)CH=CHP(Se)Ph2}], 132 pink 42.43 39.64

3.02

2.20

14.46

16.75

8.42

8.14

[AsBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}], 133 v. pale yellow

- - - -

[AsI3{trans-Ph2P(Se)CH=CHP(Se)Ph2}], 134 dark yellow

30.90

29.52

2.20

1.85

37.71

40.18

6.14

5.67

222

Attempts were made to record the 31P{1H} NMR spectra of compounds 117-134 in

CDCl3. Their chemical shifts, δP are listed in Table 5.33., it was not possible to obtain

77Se{1H} NMR spectra for all the compounds due to their poor solubility, with the

exception of both cis- and trans-Ph2P(Se)CH=CHP(Se)Ph2 compounds of the arsenic

chlorides and bromides, i.e. compounds 123, 124, 132 and 133.

Table 5.36. Spectroscopic data for [MX3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}] and

[MX3{trans-Ph2P(Se)CH=CHP(Se)Ph2}].


77Se{1H} δ ppm

J/Hz (P)

J/Hz (Se)

[BiCI3{Ph2P(Se)CH=CHP(Se)Ph2}],a 117 28.6, 39.0* - - -

[BiBr3{Ph2P(Se)CH=CHP(Se)Ph2}],a118 28.6, 39.1* - - -

[BiI3{Ph2P(Se)CH=CHP(Se)Ph2}],a 119 28.6 - - -

[SbCI3{Ph2P(Se)CH=CHP(Se)Ph2}2],a 120 28.6, 21.2* - - -

[SbBr3{Ph2P(Se)CH=CHP(Se)Ph2}],a 121 28.6, 19.6* - - -

[SbI3{Ph2P(Se)CH=CHP(Se)Ph2}],a 122 28.6 - - -

[AsCl3{Ph2P(Se)CH=CHP(Se)Ph2}],a 123 28.5, 22.4* -322.8 752 61.1

6.1

752

6.3

[AsBr3{Ph2P(Se)CH=CHP(Se)Ph2}2],a 124 28.7, 39.3* -325 753 60

6.0

753 5.8

[AsI3{Ph2P(Se)CH=CHP(Se)Ph2}],a 125 28.4 - - -

[BiCl3{trans-Ph2P(Se)CH=CHP(Se)Ph2}], 126 insufficiently soluble

- - -

[BiBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}], 127 28.6 - - -

[BiI3{trans-Ph2P(Se)CH=CHP(Se)Ph2}], 128 28.6 - - -

[SbCl3{trans-Ph2P(Se)CH=CHP(Se)Ph2}], 129 28.6 - - -

[SbBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}], 130 28.7 - - -

[SbI3{trans-Ph2P(Se)CH=CHP(Se)Ph2}], 131 28.6 - - -

[AsCl3{trans-Ph2P(Se)CH=CHP(Se)Ph2}], 132 28.7 -319 753

60.5

6

753

6

[AsBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}], 133 28.8 -323.7

753

61 6.1

753

6

[AsI3{trans-Ph2P(Se)CH=CHP(Se)Ph2}], 134 28.4 - - -

a-mixed cis/trans isomer

223

The 31P{1H} NMR spectra of the these four compounds is also complicated. The 31P{1H}

NMR spectrum of the starting phosphine diselenide, mixed {trans/cis-

Ph2P(Se)CH=CHP(Se)Ph2}, 42 shown in Fig. 5.29 is similar to the 31P{1H} NMR spectrum

of dppeSe2, 40 which shows that the phosphorus has different environments when one

spin-active selenium nucleus is present. The coupling constants are as shown in Fig.

5.29 with 1J(PSe) = 753 Hz and 3J(PP) = 60.0 Hz and 4J(PSe) = 6.0 Hz.

Fig. 5.29. 31P{1H} NMR spectrum of {trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}, 42 in CDCl3.

There is also an additional peak which resonates at δP 22.6 which is the cis isomer and

may suggest that the compound 42 is actually a mixed trans/cis as is clear from the

31P{1H} NMR spectrum which shows the same pattern as the trans with the weak peak

in addition. The 77Se{1H} NMR spectrum of the starting phosphine diselenide, mixed

{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}, 42, is a doublet of a doublets with coupling

constants 1J(PSe) = 753 Hz and 4J(PSe) = 5.8 Hz, it also shows a weak doublet with

coupling constant J(PSe) = 737.7 Hz which is suggested to be the cis isomer. However,

the 31P{1H} and 77Se{1H} NMR spectra of compounds 123 and 124, (the arsenic

analogues) are similar to the spectra of the starting phosphine diselenide, mixed

224

{trans/cis- Ph2P(Se)CH=CHP(Se)Ph2}, 42. It can be seen from Fig. 5.30 that compound

123 has a similar 31P{1H} NMR spectrum as 42, with coupling constants, 1J(PSe) = 752

Hz, 3J(PP) = 61.1 Hz and 4J(PSe) = 6.1 Hz in the 31P{1H} NMR spectrum whilst the

77Se{1H} NMR spectrum shows a doublet of doublets with 1J(PSe) =752 Hz and 4J(PSe) =

6.3 Hz. There is another weak peak in the 31P{1H} NMR spectrum at δP 22.4 ppm which

is the cis isomer.

Fig. 5.30. 31P{1H} NMR spectrum of [AsCl3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}], 123 in

CDCl3.

Compound 124, also displays similar chemical shifts and coupling constants to previous

compound 123 as shown in Fig. 5.31. The 31P{1H} NMR spectrum Fig. 5.31 shows the

coupling constants of 1J(PSe) = 753 Hz, 3J(PP) = 60 Hz and 4J(PSe) = 6.0 Hz, whereas the

77Se{1H} NMR spectrum shows a doublet of doublets with 1J(PSe) = 753 Hz and 4J(PSe) =

5.8 Hz. There is also another weak peak in the 31P{1H} NMR spectrum at δP 39.3 ppm

which is suggested to be the phosphine oxide peak.

225

Fig. 5.31 31P{1H} NMR spectrum of [AsBr3{trans/cis-Ph2P(Se)CH=CHP(Se)Ph2}2], 124 in

CDCl3.

It has been observed that the 31P{1H} and 77Se{1H} NMR spectra of the starting

phosphine diselenide, {trans-Ph2P(Se)CH=CHP(Se)Ph2}, 43, is analogous to mixed

{trans/cis- Ph2P(Se)CH=CHP(Se)Ph2}, 42 as shown in Fig. 5.32. The coupling constants

are 1J(PSe): 753 Hz, 3J(PP) = 60.6 Hz and 4J(PSe) = 6.0 Hz whereas the 77Se{1H} NMR

spectrum shows a doublet of doublets with 1J(PSe) = 753 Hz and 4J(PSe) = 6.0 Hz. In a

number of compounds, the 31P{1H} spectra shows that these compounds dissociate in

solution.

226

Fig. 5.32. 31P{1H} NMR of {trans-Ph2P(Se)CH=CHP(Se)Ph2}, 43 in CDCl3.


dichloromethane/diethyl ether layered solution of compound 130. The molecular

structure is shown in Fig. 5.33 and selected bond lengths and angles are listed in Table

5.37. The Sb-Br bond lengths in compound 130, Sb(1)-Br(2): 2.548(2), Sb(1)-Br(3):

2.580(2) and Sb(1)-Br(1): 2.5922(19) Å show a lengthening compared with the parent

halide SbBr3 (which has two forms, α-SbBr3[21] and β-SbBr3

[16]) where the Sb-Br bond

distances are Sb-Br1: 2.46(3), Sb-Br2: 2.50(4) and Sb-Br3: 2.54(3) Å for the α-SbBr3

while in β-SbBr3, Sb-Br1: 2.46(15) Å and other two equal Sb-Br bonds with bond

distances of Sb-Br2 = Sb-Br3: 2.51(16) Å. However, the Sb-Br bonds in compound 86

are slightly longer than in compound 130 with Sb(1)-Br(1): 2.561(3) Å and the other

two almost equal, Sb(1)-Br(2): 2.618(3) and Sb(1)-Br(3): 2.616(2) Å. The Sb-Se bonds

are weakly bonded with Sb-Se bond distances between 3.237(2) to 3.4185(19) Å. The

complex shows that the antimony is in a square pyramidal geometry although the sixth

coordination site is involved in the polymeric network. The selenium donors are cis- to

227

one another, the phosphine selenide then bridges between antimony atoms to

propagate the chain polymer.

Fig. 5.33. ORTEP representation of [SbBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}]n, 130.

Table 5.37. Selected bond lengths (Å) and angles (°) of [SbBr3{trans-

Ph2P(Se)CH=CHP(Se)Ph2}]n, 130.


Sb(1)-Br(3) 2.580(2) Br(1)-Sb(1)-Br(3) 95.47(6)

Sb(1)-Br(1) 2.5922(19) Br(2)-Sb(1)-Br(3) 93.81(6)

Sb(1)-Br(2) 2.548(2) Br(1)-Sb(1)-Br(2) 91.70(6) Se(1)-P(1) 2.116(4)

Se(2)-P(2) 2.155(5)

Sb(1)-Se(2) 3.4185(19)

Sb(1)-Se(1) 3.237(2)

The repeat unit propagates into a polymer both by dimerisation between two

antimony atoms via bridging diphosphine diselenide ligands, and also by the

diphosphine diselenide acting as a bridging ligand as shown in Fig. 5.34 which is also

observed in polymerization of compound 106 where the polymeric chain is also

formed through the bridging diphosphine diselenide ligands.

228

Fig. 5.34. Polymeric chain of [SbBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}]n, 130.

A useful comparison could be made for compounds 55, 80 and 98 to visualize the

asymmetry of Sb-Se and Sb-Br bonds with different ligands which is shown in Table

5.38.

Table 5.38. Geometric parameters of Sb-Se and Sb-Br bonds found in

crystallographically characterised complexes of different phosphine selenide ligands

with SbBr3.

Compound Sb-Se (Å) Sb-Br apical (Å)

Sb-Br terminal (Å)

Sb-Br bridging (Å)

Asymmetry of the

bridge (Å)

[SbBr3{Se=PPh3}], 55 2.9756(15) 2.5173(15) 2.5422(16)

2.6568(16) 3.4276(16)

0.77

[SbBr3{Se=PPh2(o-tolyl)}], 80 2.9466(12) 2.5203(14) 2.5685(13) 2.7033(12) 3.2161(13)

0.51

[SbBr3{Ph2P(Se)CH2P(Se)Ph2}], 98

2.8670(18) 3.2033(18)

2.5772(19)

2.5938(19) 2.7981(18) 3.1434(19)

0.34

It can be concluded from the Table 5.38 that the Sb-Br bridges are asymmetric in all

three of the SbBr3 compounds, although the asymmetry is lowest in the compound

with the bidentate ligand, dppmSe2 (0.34 Å). This contrasts with a higher asymmetry of

0.51 Å for [SbBr3{Se=PPh2(o-tolyl)}], and 0.77 Å for [SbBr3{Se=PPh3}]. It therefore

appears that the degree of secondary Sb-Br bonding may be related to the basicity of

the R groups on the R3PSe or dppmSe2 groups. The basicity of the R groups is expected

to decrease in the order dppmSe2 > Ph2(o-tolyl)PSe > Ph3PSe, which is also the order in

229

which secondary bonding decreases, with a resulting increase in the asymmetry of the

Sb-Br bridges.

5.6. Interpretation of Raman spectroscopic data of some phosphine selenides and

phosphine diselenides

The solid state FT Raman spectroscopic studies of the compounds in sealed glass tubes

were undertaken and recorded in the region ~ 3500 – 110 cm-1. It is anticipated that

the M-X stretching bands will be observed below 400 cm-1. It is not easy to assign the

different bridging and terminal M-X stretches (where M = Bi, Sb and As; X = Cl, Br and I)

in such compounds. The suggested assignments for the compounds are made by

comparison of other reported studies. The values of the M-X stretches in bold are the

more intense as shown in Tables 5.39, 5.41 and 5.42 for the chloro, bromo and iodo

compounds respectively.

The Raman spectra of bismuth compounds such as [NH3(CH2)5NH3]BiCl5][34]

have been previously reported and showed that characteristic bands below 300 cm-1

are for the anions, which have (BiCl52-)n units and are composed of BiCl6

3- chains of

octahedra sharing two corners[35] which have bridging and terminal Bi-Cl bonds. The

Raman spectrum of [NH3(CH2)5NH3][BiCl5][34] showed a broad medium-strength band

at 280 cm-1 which was assigned as the terminal Bi-Cl stretch and another broad, weak

band at 245 cm-1 was assigned to the Bi-Cl bridging stretch. In a similar manner, the

Raman spectrum of [NH3(CH2)4NH3]BiCl5.H2O[36] displays a strong band at 270 cm-1

which was attributed to be the terminal Bi-Cl stretch and the medium broad band at

228 cm-1 was assigned as the bridging Bi-Cl stretch.

On the other hand, the compound [C12H12N]2BiCl5][37] showed similar bridging

and terminal bands, with two bands, a strong band at 244 cm-1 and a weak one at 197

cm-1 where both were assigned as bridging Bi-Cl stretches whereas the terminal Bi-Cl

exhibited a very strong band at 285 cm-1. In the Raman spectrum of

[(C5H10NH2)2BiCl5][35], the terminal and bridging Bi-Cl stretching vibrations are at 276

cm-1 (very strong) and 233 cm-1 (medium) respectively. The tentative assignments of

Bi-Cl stretches in compounds 50, 51, 58, 66, 73, 103, 117 and 126 are shown in Table

5.39, and fall in the range 283-234 cm-1. Intense stretches were assigned as Bi-Cl

stretches (terminal and bridging Bi-Cl were indicated in Table 5.36 where possible) by

230

comparison with previously reported bismuth chloride compounds [34-37] discussed

earlier in this section. The terminal Bi-Cl stretches of the previously structures in the

literature are at higher frequencies, between (285-275 cm-1) than the bridging modes,

245-233 cm-1. The attempts to assign Bi-Cl stretches in compounds 103, 117 and 126

were undertaken by comparison with Bi-Cl stretches in the parent BiCl3[25]

as shown in

Table 5.40.

Table 5.39. Selected Raman stretches for phosphine selenide and phosphine

diselenides of BiCl3, SbCl3 and AsCl3 compounds.

Key: t : terminal M-Cl stretch and b: bridging M-Cl stretch.

Compound Raman stretches below 400 cm-1 (most intense peaks in bold typeface.)

[BiCl3{Se=PPh3}2], 50 262 ν(Bi-Cl)t, 247, 197, 170, 150.

[BiCI3{Se=PPh3}], 51 283 ν(Bi-Cl)t , 268 ν(Bi-Cl)t, 250, 180. [BiCl3{Se=P(o-tolyl)3}], 58 324, 266, 236, 196, 147.

[BiCI3{Se=P(p-tolyl)3}2], 66 300, 283, 234 ν(Bi-Cl)b.

[BiCl3{Se=PPh(o-tolyl)2}], 73 324, 266, 236, 193, 141.

[BiCl3{Ph2P(Se)(CH2)2P(Se)Ph2}], 103 281 ν(Bi-Cl)t , 262 ν(Bi-Cl)t, 252, 239 ν(Bi-Cl)b.

[BiCI3{cis-Ph2P(Se)CH=CHP(Se)Ph2}], 117 298, 270 ν(Bi-Cl), 252 ν(Bi-Cl), 197, 181, 169.

[BiCl3{trans-Ph2P(Se)CH=CHP(Se)Ph2}], 126 272 ν(Bi-Cl), 253 ν(Bi-Cl), 196, 187. [SbCl3{Se=PPh3}2], 54 337 ν(Sb-Cl)t, 268, 250, 199, 149.

[SbCl3{Se=P(o-tolyl)3}], 60 349 ν(Sb-Cl)t, 306 , 236, 217, 162.

[SbCl3{Se=P(p-tolyl)3}, 69 338 ν(Sb-Cl)t, 320, 264, 233, 220, 151, 135.

[SbCl3{Ph2P(Se)(CH2)2P(Se)Ph2}], 106 336 ν(Sb-Cl)t, 314 ν(Sb-Cl)t, 290, 258, 207, 168, 147, 127.

[SbCI3{cis-Ph2P(Se)CH=CHP(Se)Ph2}2], 120 351, 331, 296, 264, 183.

[SbCl3{trans-Ph2P(Se)CH=CHP(Se)Ph2}2], 129 348 ν(Sb-Cl)t, 333, 262, 196, 182, 136.

[AsCl3{Se=P(o-tolyl)3}], 63 388 ν(As-Cl)t, 365, 302, 268, 240, 187, 164.

[AsCl3{Ph2P(Se)(CH2)2P(Se)Ph2}], 109 372, 349, 323, 256, 211, 184, 171, 152, 125.

[AsCl3{cis-Ph2P(Se)CH=CHP(Se)Ph2}], 123 384 ν(As-Cl)t, 353, 324, 252, 198, 186, 154.

[AsCl3{trans-Ph2P(Se)CH=CHP(Se)Ph2}], 132 382 ν(As-Cl)t, 354, 325, 254, 199, 185, 154, 123.

231

The Sb-Cl stretches of the antimony chloride compounds, 54, 60, 69, 106, 120

and 129 displayed bands between 349-314 cm-1. The tentative assignments were made

for selected intense bands obtained (as shown in Table 5.39) as terminal ν(Sb-Cl)

vibration stretches in comparison with previously reported studies on methyl

ammonium chloroantimonates(III),[38] where the Sb-Cl terminal stretches are in the

range 328-312 cm-1 and the bridging Sb-Cl stretches are 282-275 cm-1 respectively.

For compounds 106 and 129, the Sb-Cl stretches ν(Sb-Cl) = 336 and 314 cm-1 for

compound 106; ν(Sb-Cl) = 348 cm-1 for 129 were assigned tentatively on comparison

with the parent halide, SbCl3[27]

which displayed bands at 340 cm-1 and 318 -312 cm-1

for Sb-Cl vibration stretches respectively as shown in Table 5.40. The Raman bands for

the arsenic chloride compounds 63, 123 and 132 displayed bands between 388-382

cm-1 which are suggested to be As-Cl stretches based on comparing these bands with

the parent arsenic chloride AsCl3[29]

shown in Table 5.40 where the As-Cl stretches are

416 and 393 cm-1.

The Raman spectra of selected bromo- bismuth, antimony and arsenic

compounds was also examined, as shown in Table 5.41. Some intense vibration

stretches of compounds, 67, 74, 90, 104, 118 and 127 between 198-179 cm-1 were

suggested to be Bi-Br as assigned on comparison with the parent BiBr3[26], which

displayed Bi-Br stretches at 189 and 180 cm-1 as shown in Table 5.40. The Raman

spectrum of compound 67 is shown in Fig. 5.35.

Furthermore, the bromo-antimony compounds 55, 70, 76, 80, 92, 107, 121 and

130 displayed bands at 238–197 cm-1 which are suggested to be Sb-Br stretches in

agreement with previously reported data for bromoantimonates(III)[39] where the

terminal stretches of Sb-Br are between 215-148 cm-1 and the Sb-Br bridging were at

123-122 cm-1 respectively. The parent SbBr3[28] showed bands at 243 and 238-230 cm-1

presented in Table 5.40 which were assigned as the Sb-Br stretches. The Raman

spectra of compound 70 and 130 are shown in Figs. 5.36 and 5.37.

232

Table 5.40. Raman stretches ν (M-X) reported for parent MX3 halides

Parent MX3 ν (M-Cl) cm-1 ν (M-Br) cm-1

BiX3 282; 263-252 189; 180 SbX3 340; 318-312 243; 238-230

AsX3 416; 393 281; 277-254

The Raman spectra of two arsenic compounds 64 and 110 showed bands at 277-255

cm-1 which may be assigned as As-Br stretches by comparison with the parent AsBr3[25]

where the As-Br stretches were at 281 and 277-254 cm-1 as shown in Table 5.40.

Table 5.41. Selected Raman stretches for phosphine selenide and phosphine diselenide

of BiBr3, SbBr3 and AsBr3 compounds.

Key: t : terminal M-Br stretch.

Compound Raman ν (M-X) stretches below 400 cm-1 (most intense peaks in bold typeface.)

[BiBr3{Se=PPh3}2], 52 247, 232, 218, 196, 174, 161, 144. [BiBr3(Se=P(o-tolyl)3)], 59 236, 217, 178.

[BiBr3{Se=P(p-tolyl)3}], 67 235, 191 ν(Bi-Br)t.

[BiBr3{Se=PPh(o-tolyl)2}], 74 242, 198 ν(Bi-Br)t.

[BiBr3{Se=PPh2CH3}], 90 272, 248, 219, 185 ν(Bi-Br)t, 160. [BiBr3{Ph2P(Se)CH2P(Se)Ph2}], 95 378, 278, 254, 219, 168.

[BiBr3{Ph2P(Se)(CH2)2P(Se)Ph2}], 104 252, 191 ν(Bi-Br)t, 175, 148.

[BiBr3{Ph2P(Se)(CH2)6P(Se)Ph2}2], 113 220, 191, 168, 155, 120.

[BiBr3{cis-Ph2P(Se)CH=CHP(Se)Ph2}], 118 190 ν(Bi-Br)t, 179 ν(Bi-Br)t, 155. [BiBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}], 127 254, 193 ν(Bi-Br)t, 174, 156.

[SbBr3{Se=PPh3}2], 55 269, 251, 236 ν(Sb-Br)t, 221 ν(Sb-Br)t, 195, 167.

[SbBr3{Se=P(o-tolyl)3}], 61 242, 203.

[SbBr3{Se=P(p-tolyl)3}], 70 318, 234 ν(Sb-Br)t, 178. [SbBr3{Se=PPh(o-tolyl)2}], 76 397, 237 ν(Sb-Br)t, 211 ν(Sb-Br)t.

[SbBr3{Se=PPh2(o-tolyl)}2], 80 250, 234 ν(Sb-Br)t, 224, 211, 163.

[SbBr3{Se=PPh2CH3}], 92 258, 238 ν(Sb-Br)t, 213 ν(Sb-Br)t, 171, 150, 126.

[SbBr3{Ph2P(Se)(CH2)2P(Se)Ph2}], 107 254, 222 ν(Sb-Br)t, 212 ν(Sb-Br)t, 201.

[SbBr3{cis-Ph2P(Se)CH=CHP(Se)Ph2}], 121 211 ν(Sb-Br)t, 194.

[SbBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}], 130 213 ν(Sb-Br)t, 197 ν(Sb-Br)t. [AsBr3{Se=P(o-tolyl)3}2], 64 277 ν(As-Br)t, 254, 237, 205, 169.

[AsBr3{Ph2P(Se)(CH2)2P(Se)Ph2}], 110 255 ν(As-Br)t, 232, 168, 127.

233

Fig. 5.35. Raman spectrum of [BiBr3{Se=P(p-tolyl)3}], 67

Fig. 5.36. Raman spectrum of [SbBr3{Se=P(p-tolyl)3}], 70

234

Fig. 5.37. Raman spectrum of [SbBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}], 130

The Raman spectra of the corresponding selected iodo-compounds of bismuth and

antimony is shown in Table 5.42 where some selected bands have been tentatively

assigned on comparison with compounds previously reported.[39, 40] Compounds 53,

68, 91, 96, 105 and 114 displayed bands between 148-115 cm-1 which may be assigned

as Bi-I stretches on comparison with [C6H4(NH3)2]2Bi2I10.4H2O[40] where the Bi-I terminal

stretches are 140-130 cm-1 for symmetric and antisymmetric stretches respectively.

However, the bands at 117-82 cm-1 were assigned to be the bridging Bi-I stretches.

Compounds 62, 71, 93 and 122 exhibited bands between 170-160 cm-1 and these are

suggested to be Sb-I stretches. The Raman spectra of previously reported

iodoantimonates(III) compounds,[39] showed that Sb-I stretches between 181-134 cm-1

which were assigned as terminal modes, while the bridging Sb-I stretches were

between 129-100 cm-1. When comparing the previous reports with Raman data for the

compounds 62, ν(Sb-I) = 168 cm-1, 71, ν(Sb-I) = 160 cm-1, 93, ν(Sb-I) = 170 cm-1 and 122

ν(Sb-I) = 168cm-1, it can be concluded that Sb-I are within range as expected. The

Raman spectrum of compound 71 is shown in Fig. 5.38.

235

Table 5.42. Selected Raman stretches for phosphine selenide and phosphine diselenide

of BiI3 and SbI3 compounds.

Key: t : terminal M-I stretch

Compound Raman ν(M-X) stretches below 400 cm-1 (most intense peaks in bold typeface.)

[Bil3{Se=PPh3}], 53 281, 272, 245, 233, 220, 199.

[BiI3{Se=P(p-tolyl)3}], 68 323, 236, 225, 150, 136 ν(Bi-I)t, 115. [BiI3{Se=PPh2CH3}], 91 254, 145 ν(Bi-I)t, 117.

[BiI3{Ph2P(Se)CH2P(Se)Ph2}], 96 379, 278, 244, 218, 133 ν(Bi-I)t.

[Bil3{Ph2P(Se)(CH2)2P(Se)Ph2}], 105 253, 153, 138 ν(Bi-I)t, 115 ν(Bi-I).

[BiI3{Ph2P(Se)(CH2)6P(Se)Ph2}], 114 258, 249, 232, 157, 148 ν(Bi-I), 141 ν(Bi-I)t, 133 ν(Bi-I)t, 118 ν(Bi-I).

[SbI3{Se=P(o-tolyl)3}], 62 230, 184, 168 ν(Sb-I). [SbI3{Se=P(p-tolyl)3}], 71 322, 224, 180, 160 ν(Sb-I).

[SbI3{Se=PPh(o-tolyl)2}], 77 327, 188, 179, 158, 148, 130.

[SbI3{Se=PPh2CH3}], 93 251, 222, 170 ν(Sb-I). [SbI3{cis-Ph2P(Se)CH=CHP(Se)Ph2}], 122 262, 227, 214, 183, 168 ν(Sb-I).

Fig. 5.38. Raman spectrum of [SbI3{Se=P(p-tolyl)3}], 71

236

5.7. Conclusion

A series of reactions of tertiary phosphine selenides R3PSe (R3P = (p-FC6H4)3P, Ph3P,

(o-tolyl)3P, (p-tolyl)3P, (o-tolyl)2PhP, (o-tolyl)Ph2P, (CH3)2PhP, CH3Ph2P) with group 15

halides MX3 have been undertaken. Most of the products formed were 1:1

[MX3(SePR3)] species. Four crystal structures were obtained for compounds of the

(p-FC6H4)3PSe donor, [BiCl3{Se=P(p-FC6H4)3}], [BiBr3{Se=P(p-FC6H4)3}], [SbCl3{Se=P(p-

FC6H4)3}] and {Se=P(p-FC6H4)3}]. In each case the M···Se interaction is weak, and these

compounds are best described as co-crystals. However, M···Se interactions link to form

highly unusual, distorted M4Se4 cuboid structures. Most of the other compounds

formed, such as [BiCl3{Se=PPh3}2], [SbBr3{Se=PPh3}], [SbCl3{Se=P(o-tolyl)3}],

BiCl3{Se=P(p-tolyl)3}], BiBr3{Se=P(p-tolyl)3}], [SbBr3{Se=PPh2(o-tolyl)}] exist in the solid-

state as dimers linked by M-X bridges. The asymmetry of the M-X bridges is dependent

on the nature of M and X. Usually, the aryl rings are located over the vacant

coordination site occupied by the lone pair on the square pyramidal As, Sb or Bi atom.

However, the crystal structure of [AsCl3{Se=P(o-tolyl)3}] contains two independent

molecules within the asymmetric unit. One of these molecules forms a weakly

interacting dimer, while the other molecule is best described as monomeric.

Different types of structures are found in mixed alkyl/aryl phosphine selenide

compounds. The crystal structure of the reaction of BiCl3 with Se=PPh2CH3 gave a

tetrameric compound, [Bi4Cl16{SePPh2CH3}4], with octahedral bismuth centres. In

contrast the 1:1 [SbBr3{Se=PPh(CH3)2}] compound formed a polymeric chain structure,

linked via bridging phosphine selenides. But, in solution according to 31P{1H} NMR

spectra, a number of compounds dissociate.

Furthermore, reactions of bidentate phosphine diselenides R4P2Se

(R4P2 = Ph2PCH2PPh2 (dppm), Ph2P(CH2)2PPh2 (dppe), Ph2P(CH2)6PPh2 (dpph), cis-

Ph2PCH=CHPPh2 and trans-Ph2PCH=CHPPh2) with MX3 were investigated. The

compounds [SbBr3{Ph2P(Se)CH2P(Se)Ph2}], [SbCl3{Ph2P(Se)CH2CH2P(Se)Ph2}] and

[SbBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}]n exhibited polymeric structures where the

antimony atoms are linked via bridging phosphine diselenides.

237

5.8. References

1. T. S. Lobana, Prog. Inorg. Chem. 1989, 37, 495. 2. T.S. Lobana, The chemistry of organophosphorus compounds (ed.) F R Hartley

(Chichester: John Wiley and Sons), 1990, vol. 2, p. 409. 3. S. A. Mbogo, W. R. McWhinnie and T. S. Lobana, J. Organomet. Chem. 1990, 384,

115 and references cited therein. 4. D. Haase, R. Lotz and S. Pohl, Z. Kryst., 1989, 186, 111. 5. S. Pohl, W. Saak, R. Lotz and D. Haase, Z. Naturforsch., Teil B, 1990, 45, 1355. 6. G. R. Willey, J. R. Barras, M. D. Rudd and M. G. B. Drew, J. Chem. Soc., Dalton Trans.,

1994, 3025. 7. N. A. Barnes, S. M. Godfrey, R. T. A. Halton, R. Z. Khan, S. L. Jackson and R. G.

Pritchard, Polyhedron, 2007, 26, 4294. 8. B. Cordero, V. Gómez, A. E. Platero-Prats, M. Revés, J. Echeverría, E. Cremades, F.

Barragán and S. Alvarez, Dalton Trans., 2008, 2832. 9. P. Pyykkö and M. Atsumi, Chem. Eur. J., 2009, 15, 186; P. Pyykkö and M. Atsumi,

Chem. Eur. J., 2009, 15, 12770. 10. M. Mantina, A. C. Chamberlin, R. Valero, C. J. Cramer and D. G. Truhlar, J. Phys.

Chem. A, 2009, 113, 5806. 11. W. Levason, S. Maheshwari, R. Ratnani, G. Reid, M. Webster and W. Zhang, Inorg.

Chem., 2010, 49, 9036. 12. A. J. Barton, A. R. J. Genge, W. Levason and G. Reid, J. Chem. Soc., Dalton Trans., 2000, 859. 13. A. J. Barton, A. R. J. Genge, W. Levason and G. Reid, J. Chem. Soc., Dalton Trans.,

2000, 2163. 14. J. Galy and R. Enjalbert, J. Solid state Chem., 1982, 44, 1. 15. A. Lipka, Acta Crystallogr., Sect. B: Struct. Crystallogr. Cryst. Chem., 1979, 35, 3020. 16. D. W. Cushen and R. Hulme, J. Chem. Soc., 1962, 2218. 17. S. C. Nyburg, G. A. Ozin and J. T. Szymański, Acta Crystallogr., Sect. B: Struct.

Crystallogr. Cryst. Chem., 1971, 27, 2298. 18. H. von Benda, Z. Kristallogr., 1980, 151, 271. 19. J. Galy, R. Enjalbert, P. Lecante and A. Burian, Inorg. Chem., 2002, 41, 693. 20. J. Trotter, Z. Kristallogr., 1965, 122, 230. 21. D. W. Cushen and R. Hulme, J. Chem. Soc., 1964, 4162. 22. N. A. Barnes, S. M. Godfrey, R. G. Pritchard and S. Ratcliffe, Polyhedron, 2010, 29,

1822. 23. A. R. J. Genge, W. Levason and G. Reid, Chem. Commun., 1998, 2159. 24. U. Ensinger, W. Schwarz and A. Schmidt, Z. Naturforsch. Teil B, 1982, 37, 1584; J.

Zaleki, Ferroelectrics, 1997, 192, 71. 25. A. Kondyurin, N. Byelousova, S. Byelousova and A. Kozulin, J. Raman Spectrosc.,

1993, 24, 825. 26. K. Ichikawa and K. Fukushi, J. Raman Spectrosc., 1986, 17, 139. 27. K. W. Fung, G. M. Begun and G. Mamantov, Inorg. Chem., 1973, 12, 53. 28. J. C. Evans, J. Mol. Spectrosc., 1960, 4, 435. 29. T. M. Klapötke, Main Group Met. Chem., 1997, 2, 81. 30. J. A. Davies, S. Dutremez and A. A. Pinkerton, Inorg. Chem., 1991, 30, 2380. 31. J. Malito, E. C. Alyea, Phosphorus, Sulfur and Silicon, Relat. Elem. 1990, 54, 95. 32. D. W. Allen and I. W. Nowell, J. Chem. Soc., Dalton Trans., 1985, 2505. 33. G. R. Willey, M. D. Rudd, C. J. Samuel and M. G. B. Drew, J. Chem. Soc., Dalton

238

Trans., 1995, 759. 34. H. Jeghnou, A. Ouasri, A. Rhandour, M. C. Dhamelincourt, P. Dhamelincourt, A.

Mazzah and P. Roussel, J. Raman Spectrosc., 2005, 36, 1023. 35. B. Bednarska-Bolek, J. Zaleski, G. Bator, R. Jakubas, J. Phys. Chem. Solids, 2000, 61,

1249. 36. A. Rhandour, A. Ouasri, P. Roussel, A. Mazzah, J. Mol. Struct. 2011, 990, 95. 37. H. Khili, N. Chaari, M. Fliyou, A. Koumina, S. Chaabouni, Polyhedron, 2012, 36, 30. 38. V. Varma, R. Bhattacharjee, H. N. Vasan and C. N. R. Rao, Spectrochimica Acta,

1992, 48A, 1631. 39. P. W. Jagoddzinski and J. Laane, J. Raman Spectrosc., 1980, 9, 22. 40. C. Hrizi, A. Samet, Y. Abid, S. Chaabouni, M. Fliyou and A. Koumina, J. Mol. Struct.

2011, 992, 96.

239

6. Appendix

X-ray crystal data

240

6.1. Crystal data for [(p–FC6H4)3PCl][ICl2], 2

Formula C18 H12 Cl3 F3 I1 P1

Formula Weight 549.50

Crystal System Monoclinic

Space group P21/c, (No. 14)

a, b, c [Å] 8.5921(2), 11.8885(3), 19.1712(6)

alpha, beta, gamma [] 90, 93.9770(10), 90

V [Å3] 1953.57(9)

Z 4

D(calc) [g/cm3] 1.868

Mu(MoKa) [mm-1] 2.159

F(000) 1064

Crystal Size [mm] 0.08 x 0.08 x 0.20

Data Collection

Temperature (K) 100

Radiation [Å] MoKa, 0.71073

Theta Min-Max [] 3.1, 26.0

Tot., Uniq. Data, R(int) 24422, 3826, 0.081

Observed data [I > 2.0 sigma(I)] 2638

Refinement

Nref, Npar 3826, 235

R, wR2, S 0.0817, 0.2397, 1.12

Max. and Av. Shift/Error 0.00, 0.00

Min. and Max. Resd. Dens. [e Å-3] -1.63, 3.44

241

6.2. Crystal data for [CH3Ph2PCl][ICl2], 7

Formula C13 H13 Cl3 I1 P1


Crystal System Triclinic

Space group P-1, (No. 2)

a, b, c [Å] 8.4735(3), 8.8727(3), 11.2753(3)

alpha, beta, gamma [] 73.993(2), 83.651(2), 78.8580(10)

V [Å3] 798.01(5)

Z 2

D(calc) [g/cm3] 1.804

Mu(MoKa) [mm-1] 2.589

F(000) 420


Data Collection

Temperature (K) 100

Radiation [Å] (MoKa), 0.71073




Refinement


R, wR2, S 0.0560, 0.1510, 1.16


Min. and Max. Resd. Dens. [e Å3] -1.70, 2.84

242

6.3. Crystal data for [(o-tolyl)3PBr][Br3], 11

Formula C21 H21 Br4 P1


Crystal System Orthorhombic

Space group P212121, (No. 19)

a, b, c [Å] 10.1330(3), 13.4817(5), 16.1088(6)

V [Å3] 2200.63(13)

Z 4

D(calc) [g/cm3] 1.883

Mu(MoKa) [mm-1] 7.391

F(000) 1208


Data Collection

Temperature (K) 100





Refinement


R, wR2, S 0.0625, 0.1422, 1.07


Flack 0.05(2)


243

6.4. Crystal data for [Ph3PCH3][ICl2], 15

Formula C19 H18 Cl2 I1 P1



Space group P21/n, (No. 14)

a, b, c [Å] 10.7810(3), 14.9120(3), 12.2850(4)

alpha, beta, gamma [] 90, 100.2870(10), 90

V [Å3] 1936.82(10)

Z 4

D(calc) [g/cm3] 1.629

Mu(MoKa) [mm-1] 2.009

F(000) 936


Data Collection

Temperature (K) 100





Refinement


R, wR2, S 0.0826, 0.2460, 1.12



244

6.5. Crystal data for [Ph3PCH3]2[Br3]Br, 16

Formula C38 H36 Br4 P2




a, b, c [Å] 11.3772(2), 14.8675(2), 21.2248(4)

alpha, beta, gamma [] 90, 92.0420(10), 90

V [Å3] 3587.91(10)

Z 4

D(calc) [g/cm3] 1.618

Mu(MoKa) [mm-1] 4.602

F(000) 1736


Data Collection

Temperature (K) 100





Refinement


R, wR2, S 0.0468, 0.1237, 1.03



245

6.6. Crystal data for [(p-OCH3C6H4)3PCl][SeCl3], 19

Formula C42 H42 O6 Cl8 P2 Se2



Space group Pbca, (No. 61)

a, b, c [Å] 13.6818(4), 19.2298(8), 36.1691(18)

V [Å3] 9516.0(7)

Z 8

D(calc) [g/cm3] 1.600

Mu(MoKa) [mm-1] 2.116

F(000) 4608


Data Collection

Temperature (K) 100





Refinement


R, wR2, S 0.0754, 0.2051, 1.17



246

6.7. Crystal data for [(o-SCH3C6H4)3PCl][SeCl3], 21

Formula C21 H21 Cl4 P1 S3 Se1




a, b, c [Å] 9.7377(13), 26.655(2), 9.6400(11)

alpha, beta, gamma [] 90, 94.179(4), 90

V [Å3] 2495.5(5)

Z 4

D(calc) [g/cm3] 1.654

Mu(MoKa) [mm-1] 2.257

F(000) 1248


Data Collection

Temperature (K) 100





Refinement


R, wR2, S 0.0828, 0.2188, 1.17



247

6.8. Crystal data for [AsBr3{SeP(p-FC6H4)3}], 49

Formula C18 H12 As1 Br3 F3 P1 Se1


Crystal System Cubic

Space group I23 (No. 197)

a, b, c [Å] 16.2032(18), 16.2032(18), 16.2032(18)

V [Å3] 4254.1(14)

Z 8

D(calc) [g/cm3] 2.217

Mu(MoKa) [mm-1] 9.047

F(000) 2672


Data Collection

Temperature (K) 100





Refinement

Nref, Npar 1011, 83

R, wR2, S 0.0631, 0.1600, 1.08


Flack 0.03(7)


248

6.9. Crystal data for [SbCl3{SeP(p-FC6H4)3}], 46

Formula C18 H12 Sb1 Cl3 F3 P1 Se1




a, b, c [Å] 16.1817(5), 16.1817(5), 16.1817(5)

V [Å3] 4237.1(2)

Z 8

D(calc) [g/cm3] 1.954

Mu(MoKa) [mm-1] 3.501

F(000) 2384


Data Collection

Temperature (K) 100





Refinement

Nref, Npar 902, 83

R, wR2, S 0.0611, 0.1633, 1.17


Flack 0.33(6)


249

6.10. Crystal data for [BiCl3{SeP(p-FC6H4)3}], 44

Formula C18 H12 Bi1 Cl3 F3 P1 Se1




a, b, c [Å] 16.1402(9), 16.1402(9), 16.1402(9)

V [Å3] 4204.6(4)

Z 8

D(calc) [g/cm3] 2.245

Mu(MoKa) [mm-1] 10.602

F(000) 2640


Data Collection

Temperature (K) 100





Refinement

Nref, Npar 1593, 82

R, wR2, S 0.0571, 0.1525, 1.03


Flack 0.01(2)


250

6.11. Crystal data for [BiBr3{SeP(p-FC6H4)3}], 45

Formula C18 H12 Bi1 Br3 F3 P1 Se1




a, b, c [Å] 16.3328(8), 16.3328(8), 16.3328(8)

V [Å3] 4356.9(6)

Z 8

D(calc) [g/cm3] 2.573

Mu(MoKa) [mm-1] 15.367

F(000) 3072


Data Collection

Temperature (K) 100





Refinement

Nref, Npar 1491, 83

R, wR2, S 0.0454, 0.1062, 1.06


Flack 0.06(2)


251

6.12. Crystal data for [BiCl3{SePPh3}2], 50

Formula C72 H60 Bi2 Cl6 P4 Se4




a, b, c [Å] 10.9711(3), 12.3216(3), 13.7459(4)

alpha, beta, gamma [] 92.7790(10), 104.8810(10), 93.438(2)

V [Å3] 1788.70(8)

Z 1

D(calc) [g/cm3] 1.853

Mu(MoKa) [mm-1] 7.302

F(000) 956


Data Collection

Temperature (K) 100





Refinement

Nref, Npar 36240, 397

R, wR2, S 0.0509, 0.1314, 1.02



252

6.13. Crystal data for [SbBr3{SePPh3}], 55

Formula C18 H15 Br3 P1 Sb1 Se1




a, b, c [Å] 9.7529(4), 13.5936(7), 18.0674(9)

alpha, beta, gamma [] 90, 98.220(2), 90

V [Å3] 2127.64(18)

Z 4

D(calc) [g/cm3] 2.194

Mu(MoKa) [mm-1] 8.715

F(000) 1312


Data Collection

Temperature (K) 100





Refinement


R, wR2, S 0.0637, 0.1602, 1.04



253

6.14. Crystal data for [AsCl3{SeP(o-tolyl)3}], 63

Formula C21 H21 As1 Cl3 P1 Se1




a, b, c [Å] 12.2842(2), 13.9380(2), 15.3025(3)

alpha, beta, gamma [] 66.090(1), 68.551(1), 86.715(1)

V [Å3] 2216.56(7)

Z 4

D(calc) [g/cm3] 1.692

Mu(MoKa) [mm-1] 3.614

F(000) 1120


Data Collection

Temperature (K) 293





Refinement


R, wR2, S 0.0556, 0.1560, 1.05



254

6.15. Crystal data for [SbCl3{SeP(o-tolyl)3}], 60

Formula C21 H21 Sb1 Cl3 P1 Se1




a, b, c [Å] 8.2186(3), 14.8166(6), 19.1200(9)

alpha, beta, gamma [] 90, 101.315(2), 90

V [Å3] 2283.02(17)

Z 4

D(calc) [g/cm3] 1.779

Mu(MoKa) [mm-1] 3.229

F(000) 1192


Data Collection

Temperature (K) 100





Refinement


R, wR2, S 0.0853, 0.2375, 1.27



255

6.16. Crystal Data for [BiCl3{SeP(p-tolyl)3}], 66





a, b, c [Å] 10.6617(2), 19.7861(5), 11.8743(3)

alpha, beta, gamma [] 90, 110.8640(10), 90

V [Å3] 2340.67(10)

Z 2

D(calc) [g/cm3] 1.983

Mu(MoKa) [mm-1] 9.503

F(000) 1320


Data Collection

Temperature (K) 100





Refinement


R, wR2, S 0.0440, 0.1168, 1.05



256

6.17. Crystal Data for [BiBr3{SeP(p-tolyl)3}], 67





a, b, c [Å] 10.6031(4), 20.0983(8), 11.9979(6)

alpha, beta, gamma [] 90, 110.494(2), 90

V [Å3] 2394.98(18)

Z 4

D(calc) [g/cm3] 2.307

Mu(MoKa) [mm-1] 13.958

F(000) 1536


Data Collection

Temperature (K) 293





Refinement


R, wR2, S 0.0662, 0.1769, 1.18



257

6.18. Crystal Data for [SbBr3{SePPh2(o-tolyl)}].CH2Cl2, 80

Formula C20 H19 Br3 Cl2 P1 Sb1 Se1




a, b, c [Å] 9.0523(4), 14.5182(5), 19.9793(10)

alpha, beta, gamma [] 90, 103.031(2), 90

V [Å3] 2558.12(19)

Z 4

D(calc) [g/cm3] 2.082

Mu(MoKa) [mm-1] 7.465

F(000) 1512


Data Collection

Temperature (K) 100





Refinement


R, wR2, S 0.0628, 0.1937, 1.03



258

6.19. Crystal Data for [SbBr3{SePPh(CH3)2}], 86





a, b, c [Å] 7.2926(7), 15.231(2), 13.1649(13)

alpha, beta, gamma [] 90, 96.208(7), 90

V [Å3] 1453.7(3)

Z 4

D(calc) [g/cm3] 2.644

Mu(MoKa) [mm-1] 12.723

F(000) 1056


Data Collection

Temperature (K) 100





Refinement


R, wR2, S 0.0918, 0.2083, 1.06



259

6.20. Crystal data for [BiCl3{SePPh2CH3}], 89

Formula C52 H52 Bi4 O1 P4 Se3



Space group Pbca, (No. 61)

a, b, c [Å] 15.4648(18), 17.5631(11), 25.495(3)

V [Å3] 6924.7(12)

Z 4

D(calc) [g/cm3] 2.225

Mu(MoKa) [mm-1] 12.302

F(000) 4288


Data Collection

Temperature (K) 100





Refinement


R, wR2, S 0.1050, 0.2214, 1.14



260

6.21. Crystal Data for [SbBr3{Ph2P(Se)CH2P(Se)Ph2}], 98





a, b, c [Å] 13.8686(15), 11.2395(13), 17.997(2)

alpha, beta, gamma [] 90, 91.601(6), 90

V [Å3] 2804.2(5)

Z 4

D(calc) [g/cm3] 2.141

Mu(MoKa) [mm-1] 7.982

F(000) 1704


Data Collection

Temperature (K) 100





Refinement


R, wR2, S 0.0722, 0.1935, 1.01



261

6.22. Crystal data for [SbCl3{Ph2P(Se)(CH2)2P(Se)Ph2}].0.5CH2Cl2, 106

Formula C26.5 H25 Cl4 P2 Sb1 Se2




a, b, c [Å] 10.5487(2), 12.1415(4), 13.9130(4)

alpha, beta, gamma [] 110.163(1), 93.410(1), 113.954(1)

V [Å3] 1486.78(7)

Z 2

D(calc) [g/cm3] 1.847

Mu(MoKa) [mm-1] 3.860

F(000) 802


Data Collection

Temperature (K) 100





Refinement


R, wR2, S 0.0485, 0.1414, 1.05



262

6.23. Crystal data for [SbBr3{trans-Ph2P(Se)CH=CHP(Se)Ph2}], 130





a, b, c [Å] 10.3780(4), 12.3471(6), 13.9098(9)

alpha, beta, gamma [] 110.511(2), 93.577(2), 111.990(2)

V [Å3] 1508.99(14)

Z 1

D(calc) [g/cm3] 2.124

Mu(MoKa) [mm-1] 7.510

F(000) 914


Data Collection

Temperature (K) 100





Refinement


R, wR2, S 0.0901, 0.2874, 1.04



reactions of tertiary phosphines with group 15

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