Synthesis and characterisation of cobalt(III), nickel(II), copper(I) and silver(I) complexes of silylated pyridine-2-thione

The electrochemical oxidation of anodic metal (cobalt, nickel, copper and silver) in acetonitrile solutions of the appropriate heterocyclic thione, RMe(2)SipySH (3-Bu(t)Me(2)SipySH, 3-ThexMe(2)SipySH, 6-ThexMe(2)SipySH) gave complexes of general formula [M(RMe(2)SipyS)] (M=Cu, Ag) and [M(RMe(2)SipyS)(n)] (when M=Co, n=3; M=Ni, n=2). When the oxidation was repeated in the presence of 2,2'-bipyridine (bipy), the mixed complexes [M(RMe(2)SipyS)(2)(bipy)] were obtained only in the case of M=Ni. The reaction between copper complexes, [M(RMe(2)SipyS)], and 1,2-bis(diphenylphosphino)ethane (dppe) and bis(diphenylphosphino)methane (dppm) in acetonitrile yielded [Cu-2(RMe(2)SipyS)(2)(dppe)(3)] and [Cu-2(RMe(2)SipyS)(2)(dppm)(2)]. The molecular structures of [Cu-6(3-Bu(t)Me(2)SipyS)(6)], 1, [Cu-6(6-ThexMe(2)SipyS)(6)], 2, and [3-Bu(t)Me(2)SipyS-Spy-3-(BuSiMe2)-Si-t], 3, were determined by X-ray diffraction. Compounds 1 and 2 are hexanuclear with the six copper atoms arranged in a distorted octahedral geometry and each copper atom in a distorted trigonal planar [CuS2N] environment, each ligand adopting the N,S-bidentate S-bridging mode. The electronic, vibrational and H-1 and C-13 NMR spectra of the complexes are discussed and related to the structure.