Synthesis and Crystal Structures of Mixed Halophenylbismuthates(III)

P. Sharma a*, A. Cabrera a*, N. Rosas a, J. L. Arias a, A. Lemus a, M. Sharma b, S. HernaÂndez a, and J. L. Garcia a

Mexico D.F./Mexico, a Instituto de Quimica, UNAM and b Instituto de Biologia, UNAM

Received October 13th, 1999, revised November 17th, 1999.

Abstract. Synthesis and characterisation of mixed halophe-nylbismuthates(III) with a general formula Bu4N[PhBiX2Y]where X = Cl or Br; Y = Cl, Br or I; X ¹ Y are reported. Themolecular structures of Bu4N[PhBiCl2Br] (1) and Bu4N-[PhBiBr2I] (2) are determined by X-ray crystallography. Inmixed halophenylbismuthates, the anion exists as a dimer

with bismuth in a distorted square pyramidal coordination.In the dimer the two phenyl groups occupy anti position toeach other thereby minimising the repulsion.

Keywords: Bismuth complexes; Organobismuth halides; Ha-lobismuthates(III)

Synthese und Kristallstrukturen gemischt-halogenierter Phenylbismutate(III)

InhaltsuÈ bersicht. Es wird uÈ ber die Synthese und Charakteri-sierung gemischt-halogenierter Phenylbismutate(III) der all-gemeinen Formel Bu4N[PhBiX2Y] mit Y = Cl oder Br,Y = Cl, Br oder I, X ¹ Y berichtet. Die MolekuÈ lstrukturenvon Bu4N[PhBiCl2Br] (1) und Bu4N[PhBiBr2I] (2) wurden

roÈ ntgenographisch bestimmt. In den gemischt-halogeniertenPhenylbismutaten ist das Anion ein Dimeres mit Bismut inverzerrt quadratisch-pyramidaler Koordination. Im Dimerbesetzen die beiden Phenylgruppen trans-Positionen, wo-durch die Abstoûung minimiert wird.

Introduction

Mixed halophenylantimonates (III) and mixed halodi-phenylantimonates(III) are reported in literature [1±2]and their crystal structures are published later [3]. Si-milar to antimony, bismuth also forms halophenylbis-muthates(III) and halodiphenylbismuthates(III) show-ing the Lewis acid character of halophenylbismuthineand halodiphenylbismuthine, respectively [4±6]. Anumber of reports appeared in recent years on thehaloarylarsinates(III), antimonates(III) and bismutha-tes(III) to explore the structural differences arises dueto the presence of different pnictogen atom, halidesand the cation [7±10]. In view of that mixed halo-organobismuthates are unknown and the structuralchemistry of bismuth is an area of increasing interest,we thought it worthwhile to synthesise and to deter-mine their molecular structure.

Results and Discussion

All the four compounds are microcrystalline powders,sensitive to moisture to a varying extent. These com-pounds are soluble in acetonitrile, dichloromethane,toluene and are insoluble in carbon tetrachloride,ether and pentane. Bromochlorophenyl bismuthatesare colourless while chloroiodophenylbismuthates(III)are yellow and bromoiodophenylbismuthates(III) are

yellowish orange. All these compounds have sharpmelting points. The elemental analysis, m. p. importantIR and Raman bands are reported in Table 1.

IR spectra of these compounds in 4000±400 cm±1 re-gion resemble to some extent to their respective cat-ion, but in addition there are bands in the far-IR re-gion which are assignable to Bi±C, Bi±X and Bi±Yvibrations. The m(Bi±X) X = Cl, Br or I values are com-parable to those reported for related halobismuthates.The position and the number of bands expected forBi±X and Bi±Y vibrations in these compounds are af-fected by the interaction between these stretching vi-brations. In Raman spectrum of these complexesbands lower than 225 cm±1 can be assigned to Bi±Xand Bi±Y vibrations e. g. Bi±Cl (218 cm±1) and Bi±Br(167 cm±1) were assigned in Bu4N[PhBiCl2Br] while inBu4N[PhBiCl2I] Bi±Cl appears at 215 cm±1 and Bi±Iappears at 114 cm±1 [11±13].

Bu4N[PhBiBr2I] and Bu4N[PhBiCl2Br] were sub-jected to thermogravimetric analyses. The complexBu4N[PhBiBr2I] decomposes in two steps. In the firststep of decomposition (218.9 °C±279.0 °C) the weightloss corresponds to inter halogen BrI while in the sec-ond step of decomposition the organic component andthe halogen were lost simultaneously within the rangeof 279.0 °C±436.6 °C. The amount left after this de-composition corresponds to the percentage of bismuthnitride. Two step decomposition was also observed forBu4N[PhBiCl2Br] and the decomposition temperatureranges 191.1 °C±251.3 °C±455.9 °C. The amount leftcorresponds to percentage of bismuth nitride.

Z. Anorg. Allg. Chem. 2000, 626, 921±924 Ó WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000 0044±2313/00/626921±924 $ 17.50+.50/0 921

* Dr. Pankaj Sharma,Instituto de Quimica UNAM,Circuito Exterior Ciudad Universitaria,Mexico, 04510, D.F./Mexico

The FAB± mass spectra of these complexes showthe {Bu4N[PhBiX2Y]2}± ion peak is present showingthe dimeric nature of the anion. High resolution FABmass spectra each fragments were specified (Table 2).The main fragmentation pathway of dimeric[Bu4N]2[Ph2Bi2Br4I2] (2) has been investigated usingCollision Induced Dissociation (CID) technique. Thehighest peak observed (a) at m/z 1388 in FAB± massspectra is proposed for this process (scheme 1) thissuggests that the Bu4N+ ion was lost from the molecu-lar ion (m/z 1630). Other primary fragmentation ob-served in mass spectra of 2 are due to the loss ofPhBiBr2, [Bu4N][PhBiBr3], [Bu4N][PhBiBr2I] andPhBiBrI moeities. A secondary fragmentation of ions{[Bu4N][PhBiBr2I2]}1± and {[Bu4N][PhBiBr3I]}1± give[PhBiBrI2] and [PhBiBrI], respectively.

Molecular structure of 1 and 2 and the numberingsystems are shown in Figure 1 and Figure 2. Crystaldata, selected bond lengths and bond angles for 1 and2 are reported in Table 3 and 4, respectively. In theanion the geometry around bismuth is essentially

square pyramidal and the molecule exists as dimer.The Bi±Br bond length is 2.994(3) AÊ in anion 1 whileit is 2.874(0) AÊ in anion (2). These lengths are in therange of BiBr(bridging) and Bi±Br(terminal) as reported inliterature for similar type of compounds. The phenylgroup is at the axial position and the four halogen

P. Sharma, A. Cabrera, N. Rosas, J. L. Arias, A. Lemus, M. Sharma, S. HernaÂndez, J. L. Garcia

922 Z. Anorg. Allg. Chem. 2000, 626, 921±924

Table 1 M. p., elemental analysis data, selected IR and Raman bands

Compound m. p. °C FoundC

(Calc) % IR ( cm±1) Raman (cm±1)H N Bi

Bu4N[PhBiCl2Br] 185 39.47(39.69)

6.01(6.16)

2.02(2.10)

30.78(31.42)

222 (s), mBi±Cl

215 (m), mBi±Cl

167 (m) mBi±Br

212 (s) mBi±Cl

163 (m) mBi±Br

Bu4N[PhBiCl2I] 119 36.79(37.07)

5.42(5.75)

1.84(1.96)

29.17(29.35)

218 (s), mBi±Cl

215 (m), mBi±Cl

114 (br, m) mBi±I

210 (s) mBi±Cl

117 (s) mBi±Br

Bu4N[PhBiBr2Cl] 153 36.17(36.48)

5.47(5.66)

1.84(1.93)

28.30(28.87)

218 (m), mBi±Cl

165 (s), mBi±Br

154 (s) mBi±Br

202 (s) mBi±Cl

156 (m) mBi±Br

Bu4N[PhBiBr2I] 207 32.10(32.39)

5.01(5.03)

1.63(1.71)

25.04(25.64)

172 (s), mBi±Br

168 (s) mBi±Br

112 (m) mBi±I

158 (s) mBi±Br

115 (s) mBi±I

Table 2 Mass Spectral data for Mixedhalophenylbismuthates(III)

Bu4N[PhBiCl2Br]: Bu4N[Ph2Bl2Cl4Br2] 1116; Bu4N[PhBiCl2Br2] 759; Bu4N[PhBiCl3Br] 713; [PhBiClBr2] 481; [PhBiCl2Br] 436; [PhBiCl3] 392; [BiCl4]351; PhBi 286.

Bu4N[PhBiCl2I]: Bu4N[Ph2Bi2Cl4I2] 1210; Bu4N[PhBiCl2I2] 853; Bu4N[PhBiCl3I] 761 [PhBiClI2] 575; [PhBiCl2I] 484; [PhBiCl3] 392; [BiCl4] 351; PhBi286.

Bu4N[PhBiBr2Cl]: Bu4N[Ph2Bi2Br4Cl2] 1205; Bu4N[PhBiBr2Cl2] 759; Bu4N[PhBiBr3Cl] 802 [PhBiBr2Cl] 481; [PhBiBrCl2] 436; [BiBr4] 529; [PhBiBr3]525; PhBi 286.

Bu4N[PhBiBr2I]: Bu4N[Ph2Bi2Br4I2] 1388; Bu4N[PhBiBr2I2] 942; Bu4N[PhBiBr3I] 894 [PhBiBrI2] 620; [PhBiBr2I] 573; [BiBr4] 529; [PhBiBr3] 525; PhBi286.

Fig. 1 Molecular Structure of [PhBiCl2Br]± anion

Fig. 2 Molecular Structure of [PhBiBr2I]± anion

Synthesis and Crystal Structures of Mixed Halophenylbismuthates(III)

atoms form the basal plane of the square pyramid foranion 1. The structure of anion 1 is refined with par-tial occupation factor 0.5 for Br and 0.5 for Cl. Theseatoms were refined isotropically. In the anion 2 thetwo iodine atoms and two bromine atoms form the ba-sal plane of square pyramid. In all the reported[PhSbX3]±, [PhSbX2Y]± and [PhBiX3]± dimeric anionsthe phenyl groups occupy the anti position [3, 4, 10]though in a very recent report in the crystal structureof dimeric [PhSbI3]± anion the two phenyl groups oc-cupy a cis position [7]. In mixed halophenylbismutha-tes(III) reported here, in the dimer the two phenylgroups occupy anti position to each other therebyminimising the repulsion. The tetrahedral cation hasno interaction with the anion. The cation has angles inthe 104.2° to 112.3° range in complex (1) and a meanC±N distance of 1.53AÊ . There are no unusual featureassociated with phenyl group. The four atoms of bis-muth, two bromine and iodine in Bu4N[PhBiBr2I] andbismuth, two bromine and chlorine in Bu4N-[PhBiCl2Br] respectively, are in the same plane, whichis different than that noticed in [Bi2Ph2I6]2±.

In [PhBiBr2I] dimeric anion iodine atoms formthe bridges between two Bi atoms. The averageBi±I(bridging) distance is 3.156(0) AÊ which is ~ 0.12AÊ

shorter than the Bi±I(bridging) distance reported in lit-erature. In [Bi2Ph2I6]2± anion Bi±I(bridging) is3.289(2) AÊ while in [Bi2I9]3± this distance is 3.249(5)AÊ .It is also worth commenting that in the case of iodo-bromo-bismuthate the bridging halides are almostequidistant from the central metal (~ 0.04AÊ ) while inthe case of bromo-, chloro- iodo- antimonates and ar-sinates, the bridging halides are not equidistant fromthe central metal (~ 0.28AÊ ) which may be due to thebigger size and higher electropositivity of the bismuthatom resulting in a more stronger interaction.

Experimental Part

IR spectra were recorded in KBr on Nicolet-Magna 750spectrometer Raman spectra were obtained on Perkin Elmer2000, FT Raman spectrometer. FAB± Mass spectra were re-corded on a Jeol SX102 Double focussing mass spectrometerwith reverse geometry using a 6 kV Xenon beam (10 mA);m-nitrobenzyl alcohol was used as matrix for recording themass spectra. The CID spectra were recorded with the sameinstrument using the constant B/E linked scan technique.The helium pressure in the fast field free region collision cellwas adjusted until the main beam signal was reduced to 50percent. Thermogravimetric studies of Bu4N[PhBiBr2I] andBu4N[PhBiCl2Br] were carried out on General V 4.1 C Du-pont 2100 series recording thermobalance in the nitrogen at-mosphere. The heating rate was 10 °C/min and the tempera-ture range of study was from room temperature to 500 °C.

PhBiCl2 and PhBiBr2 were prepared by interaction of 1 : 2molar mixtures of Ph3Bi and BiCl3 or BiBr3 respectively[14]. Other chemicals used were commercially available. Allthe solvents were dried before use.

Bu4N[PhBiX2Y]

These compounds were prepared by cocrystallization of 1 : 1mixtures of Bu4NY and PhBiX2 from anhydrous methanolwhere X ¹ Y. For the preparation of each compound, the tworeactants were dissolved separately in anhydrous methanol,then they were mixed together, under nitrogen atmosphere,and stirred. The reaction took place immediately leading tothe formation of a precipitate. The reaction was completedwithin 30 min. The product was filtered, washed with a littleamount of methanol, followed by cold toluene. It was thendried in vacuum. The crystals of Bu4N[PhBiCl2Br] (1) wereobtained by solvent diffusion from CH2Cl2 (5 ml)-ethanol(10 ml) mixtures at ±5 °C over a period of two days while thecrystals of Bu4N[PhBiBr2I] (2) were obtained from slow eva-poration of its dichloromethane solution. Bu4[PhBiBr2I] (2)crystallises with a CH2Cl2 as a solvent of crystallisation.

Z. Anorg. Allg. Chem. 2000, 626, 921±924 923

Table 3 Selected Bond Lengths/AÊ and Angles/° for 1.

Bi(1)±Cl(1) 2.687(8) Bi(1)±Br(1 a) 3.031(4)N(1)±C(13) 1.46(3) Bi(1)±C(17) 2.261(1)Bi(1)±Br(2) 2.700(5) Bi(1)±Cl(2) 3.020(7)Bi(1)±Br(1) 2.957(3) Bi(1)±Cl(2 a) 2.861(7)Cl(2)±Bi(1 a) 2.861(7) N(1)±C(13) 1.523(1)N(1)±C(1) 1.516(1) C(17)±Bi(1)±Cl(3) 91.6(3)C(17)±Bi(1)±Cl(1) 93.0(3) Cl(3)±Bi(1)±Cl(1) 87.3(2)C(17)±Bi(1)±Br(2) 89.3(3) Cl(1)±Bi(1)±Br(1) 174.8(2)C(17)±Bi(1)±Cl(2) 83.8(3) Cl(2)±Bi(1)±Br(1 a) 83.2(1)Br(1)±Bi(1)±Br(2) 177.8(1) Cl(3)±Bi(1)±Br(1) 88.78(9)Cl(2 a)±Bi(1)±Cl(2) 84.6(2) Br(2)±Bi(1)±Br(1 a) 91.1(1)

Table 4 Selected Bond Lengths/AÊ and Angles/° for 2.

Bi(1)±C(17) 2.29(2) Bi(1)±Br(1) 2.867(2)Bi(1)±Brl(3) 2.882(2) Bi(1)±I(17) 3.135(2)Bi(1)±I(1 a) 3.173(2) N(1)±C(13) 1.49(2)N(1)±C(5) 1.47(2) N(1)±C(1) 1.54(2)C(17)±Bi(1)±Br(1) 92.3(4) C(17)±Bi(1)±Br(3) 91.6(4)Br(1)±Bi(1)±Br(3) 94.15(6) C(17)±BI(1)±I(1) 90.0(4)Br(1)±Bi(1)±I(1) 172.73(6) Br(3)±Bi(1)±I(1) 92.69(6)C(17)±Bi(1)±I(1a) 90.6(4) Br(1)±Bi(1)±I(1 a) 87.87(5)

Table 5 Crystal data

1 2

Formula Bu4N[PhBiCl2Br] Bu4N[PhBiBr2I]M 679.35 837.79Crystal system monoclinic monoclinicSpace group P21/c P21/ca/AÊ 9.786(2) 9.971(1)b/AÊ 20.968(2) 17.517(2)c/AÊ 14.307(4) 18.892(2)b/° 109.76(2) 103.52(2)V/AÊ 3 2762.8(1) 3208.3(6)Z 4 4Dc/gcm±3 1.633 1.734l(MoKa)/mm±1 8.029 8.959F(000) 1328 1594Crystal size/mm 0.44 ´ 0.16 ´ 0.08 0.36 ´ 0.22 ´ 0.162h 4.5 to 50.0° 4.5 to 50.0°Reflection observed 507 5874Unique reflection 4810 5546Rint 0.0493 0.0390R[I > 2r(I)] 0.0441 0.0734Method of solution Full matrix least square

on F2Full matrix least squareon F2

Rx 0.0925 0.2019Max/min Dq/eAÊ ±3 0.911/±0.953 2.056/±1.962S [goodness-of-fit] 0.775 0.912

Crystal X-ray structure determination: Data were collectedon a Siemens P4/Pc diffractometer at 293 °K using mono-chromated Mo-Ka radiation (k = 0.07107). The system usedfor calculations was Siemens SHELXTL PLUS (PC Version)and structure determination by direct methods and refine-ment by a full matrix least squares procedure. Atomic coor-dinates, equivalent isotropic and anisotropic displacementcoefficients have been deposited with the Cambridge Crys-tallographic Data Center (CCDC 141265, CCDC 141266).Copies may be obtained free of charge on application toCCDC, 12 Union Road, Cambridge CB2 1E2, UK.

References

[1] J. R. Ugal, P. Sharma, N. K. Jha, Indian J. Chem. Sect. A1993, 32 A, 71.

[2] J. R. Ugal, P. Sharma, N. K. Jha, Synth. React. Inorg.Metal Org. Chem. 1995, 25, 769.

[3] P. Sharma, N. Rosas, R. Shankar, S. Hernandez, A. Tos-cano, A. Cabrera, Main Group Met. Chem. 1996, 19, 21.

[4] W. Clegg, R. J. Errington, G. A. Fisher, R. J. Flynn,N. C. Norman, J. Chem. Soc., Dalton Trans. 1993, 637.

[5] W. Clegg, R. J. Errington, G. A. Fisher, D. C. Hockless,N. C. Norman, A.G . Orpen, S. E. Stratford, J. Chem.Soc., Dalton Trans. 1992, 1967.

[6] S. Patai, in : The Chemistry of Organic As, Sb and BiCompounds, K. C. H. Lange and T. M. KlapoÈ tke (eds),John Wiley, N.Y. 1994, p. 315.

[7] H. J. Breunig, M. Denker, E. Lork, Z. Anorg. Allg.Chem. 1999, 625, 117.

[8] S. Grewe, T. HaÈusler, M. Mannel, M. Robenbeck, W. S.Sheldrick, Z. Anorg. Allg. Chem. 1998, 624, 613.

[9] H. Preut, F. Huber, G. Alonzo, Acta Crystallogr. 1987,C 43, 46.

[10] M. Hall, D. B. Sowerby, J. Organomet. Chem. 1988, 347,59.

[11] M. Ali, W. R. Mcwhinie, A. R. West, T. A. Hamor, J.Chem. Soc., Dalton Trans. 1990, 899.

[12] T. Allman, R. G. Goel, H. S. Prasad, J. Organomet.Chem. 1979, 166, 365.

[13] S. Faleschini, P. Zanella, L. Doretti, G. Faraglia, J. Orga-nomet. Chem. 1972, 44, 317.

[14] M. Nunn, D. B. Sowerby, D. M. Weslock, J. Organomet.Chem. 1988, 251, C45.

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