Synthesis and Structural Characterization, of Nickel(II) Complexs Supported by Aminodipyridylphosphine Oxide Ligand.The Catalytic Application to Thioacetalization of Aldehyde

Corey-Seebach Reaction Seebach, D.; Jones, N. R.; Corey, E. J. J. Org. Chem. 1968, 33, 300-105.

Acetalization and Thioacetalization of Carbonyl Compounds

The Earlier Catalyst for ThioacetalizationJ.W. Ralls, et. al., J. Am.Chem. Soc. 1949, 71, 3320-3325

HCl Catalyzed ThioacetalizationRobert Ramage, et. al., J. Chem. Soc., Perkin Trans. 1 1984, 71, 1547-1553.

Lewis Acid Catalyzed ThioacetalizationConventional Lewis Acids BF3-Et2OZnCl2AlCl3SiCl4LiOTfInCl3Nakata, T. et. al., Tetrahedron Lett. 1985, 26, 6461-6464.Evans, D. V. et. al., J. Am. Chem. Soc. 1977, 99, 5009-5017.Firouzabadi, H. et. al., Bull. Chem. Soc. Jpn. 2001, 74, 2401-2406.Transition Metal Lewis AcidsTiCl4WCl6CoCl2Sc(OTf)3MoCl5NiCl2Kumar, V. et. al., Tetrahedron Lett. 1983, 24, 1289-1292.Firouzabadi, H. et., al. Synlett 1998, 739-741.Goswami, S. et. al., Tetrahedron Lett. 2008, 49, 3092-3096.Lanthanide Metal Lewis AcidsLu(OTf)3 Nd(OTf)3Kanta, D. S. J. Chem. Res. Synop. 2004,230-231.Kanta, D. S. Synth. Commun. 2004, 34, 230-231.

BF3-Et2O Catalyzed ThioacetalizationOne use onlyPaulo J.S. Moran. J. Organomet. Chem. , 2000, 603, 220-224

MoCl5 or MoO2Cl2 Catalyzed ThioacetalizationS. Goswami, A. C. Maity . Tetrahedron Letters, 2008, 49, 30923096One use only

CoCl2 Catalyzed ThioacetalizationSurya Kanta De. Tetrahedron Letters, 2004, 45, 10351036

Nickel(II) Chloride Catalyzed Thioacetalization2.5 hour96 %A. T. Khan et al., Tetrahedron Lett. 2003, 44, 919922One use only10 mole % NiCl2

Motivation1.Traditional high valent metal halide Lewis acids are difficult to handle ex. MCln ,M=ZnWCoMo..2.Nickel is less expensive than other transition metal NiCl2 50g $ 29.2 WCl6 100g $ 152.5 PdCl2 25g $ 849 NIBr2 50g $ 72.2 W(CO)6 50g $ 1763.(DME)NiBr2 as preferable precursor not (DME)NiCl2 [HO(CH2)11N(H)P(O)(2-py)2]NiBr2 & [HO(CH2)11N(H)P(O)(2-py)2]NiCl2 4.Use HO(CH2)11N(H)P(O)(2-py)2 as chelate ligand [HO(CH2)11N(H)P(O)(2-py)2]NiBr2

Ni => small o => tetrahedral & square planar Pd & Pt => large o => square planar

Ligands => large , weak-field => tetrahedral Ligands => small, strong-field => square planar Comparison of M2+(d8 species)Square Planar vs. Tetrahedral Complexes

R. G. Hayter, F. S. Humiec. Inorg. Chem. 1965, 12, 1701-1706. The tetrahedral structure is increasingly favored in the orders PPh2RP(C2H5)3 < P(C2H5)2C6H5 < PC2H5(C6H5)2 < P(C6H5)3

X Cl < Br < I

Square Planar - Tetrahedral Isomerism of Nickel Halide Complexes of Ni(PPh2R)2X2

Preparation of Aminodipyridylphosphine Oxide Ligand75 %193 %2

Preparation of Nickel(II) Complex Catalyst76 %Paramagnetic32

Chemical Shift of Paramagnetic Compounds for NMRobserved =diamagnetic + hyperfine

diamagnetic = diamagnetic shift corresponds to the values for the free ligand.

hyperfine =contact + dipolarcontact = contact shifts are caused by spin delocalization of the unpaired electrons through chemical bonds (through bond)dipolar= dipolar shifts, between the paramagnetic center and the nucleus of interaction (through space)due to theparamagnetic center presenceMajorBroad signalJ. Phys. Chem. A, 2003, 107, 5821-5825

Square planarTetrahedral

IR of [HO(CH2)11N(H)P(O)(2-py)2]NiBr2

EPR of HO(CH2)11N(H)P(O)(2-py)2]NiBr2 g=2g = 2.18

SUQID of HO(CH2)11N(H)P(O)(2-py)2]NiBr2 = m / Hm = ( / W) Meff = (3k / N2)1/2(mT)1/2 = 2.828(mT)1/2m , H (10000 guess), m , W, Meff, T , K , N6.02 x 1023slope = 1/(mT) = 0.936mT = 1/0.936 eff = 2.828 (mT)1/2 eff = 2.92

HO(CH2)11N(H)P(O)(2-py)2]NiBr2Tetrahedraleff = 2.92The Organometallic Chemistry of The Transition Metals. 2005

FAB-MS of HO(CH2)11N(H)P(O)(2-py)2]NiBr2 HO(CH2)11N(H)P(O)(2-py)2]NiBr+ = 528 m+/Z

Nickel Lewis Acids Complex Catalyzed Thioacetalization Thiol ==

Entry Time Yield (%) Paper Reported cat. (NiCl2) Time Yield (%)1 1.5 hr922.75 hr9622 min>998 min96410 min9945 min9065 hr9220 hr82

Entry Time Yield (%)

2 2 min>99340 min90410 min9952 hr90

Entry Time Yield (%)

6 5 hr92715 hr8083 hr92

Entry Time Yield (%)

10 2 hr911160 min95124.5 hr871360 min92

Entry Time Yield (%)

14 60 min/4.5 hr79 / 7060 min94

Entry Time Yield (%) Paper Reported cat. (NiCl2) Time Yield (%)15 2.5 hr892.5 hr94165 min>9930 min931830 min941.15 hr892018 hr93

Entry Time Yield (%)

16 5 min>99172.5 hr911830 min94194.5 hr92

Entry Time Yield (%)

20 18 hr932118 hr61226.5 hr82

Entry Time Yield (%)

24 2 hr912530 min91265.5 hr792750 min97

Entry Time Yield (%)

28 30 min/5.5 hr75/8230 min93

EntryRThiol 40oC25oC Time Yield (%) Time Yield(%)29 10 min881.5 hr (1)923015 min 872.5 hr (15)89311.5 hr865 hr (6)92323 hr9018 hr (20)93

Comparison of Catalytic Activity Amoung Various Different Catalyst

EntryCat.Time Yield (%)APaper ( NiCl2 anhydrous)30 min93 BNONE24 hour96 CHO(CH2)11N(H)P(O)(2-py)2190 hour34 D(DME)NiCl25 min90 E[HO(CH2)11N(H)P(O)(2-py)2]NiCl2 35 min93 F(DME)NiBr25 min 95 G[HO(CH2)11N(H)P(O)(2-py)2]NiBr2 5 min >99

Proposed Mechanism(3)

Recyclable Nickel(II) Complex Catalyst for Thioacetalization of Aldehyde1H NMR Solvent= CDCl3 (0.01478M 4-Iodoanisole)

Recycling NO.ReactionTimeYield 1 5 min94 %25 min99 %35 min99 %45 min99 %55 min99 %6.5 min99%7.5 min99 %8.5 min99 %

Near Future Work for Nickel(II) ComplexImmobilization onto AuNPs surfacesCat.

Conclusions1.We have successfully synthesized an air- and water-stable and efficient catalyst { [HO(CH2)11NHPOpy2]NiBr2 }.

2. We use 1H NMR FT-IREPRSQUID and FAB-MS for structural characterization of Nickel(II) complex, we have proved the compound demonstrated that it is a paramagnetic tetrahedral compound, and we will proceed detection of Elemental Analysis (EA).

3.In Ni-catalyst series, the Nickel(II) complex only can be reused for catalytic of thioacetalization of aldehyde many times without any loss of reactivity.

Chemoselectivities in Acetalization, and ThioacetalizationJ. Phys. Chem. A 2006, 110, 2181-2187

(DME)NiCl2 5g 3549(DME)NiBr2 5g 4060 $ 77.3CoCl5 100g $ 75MoCl5 100g $ 130 MoO2Cl2 10g $ 120

EPR of [Ni(CTH)DTBSQ]PF6at B = 3.2 Teslag = 2 g1 = 5.8g1 = 2.4g1 = 1.7Inorganic Chemistry, 1988, 27, 2831-2836Zero-field spectra and Kramers degeneracy (Kramers doublet)