Novel mixed-metal-alkynyl complexes stabilised by di-imine ligands:: synthesis, characterisation and electrochemistry of [(tBu2bipy)Pt(CCR)2M(SCN)] (R = C6H4MR, SiMe3; M = Cu, Ag)

Reaction of (4,4'-bis-tert-butyl-2,2'-dipyridyl) platinum bis-alkynyl [('Bu(2)bipy)Pt(C=CR)(2)] (R = C6H4Me 1a, SiMe3 1b) with Group 11 metal thiocyanate salts (M = Cu, Ag) affords 1:1 mixed-metal complexes [('Bu(2)bipy)Pt(C=CR)(2)M(SCN)] (M = Cu, R = C6H4Me 2a, SiMe3 2b; M = Ag, R = C6H4Me 3a, SiMe3 3b). X-ray analyses of the complexes 2a and 3b show that the group 11 metal is bonded in an eta(2) fashion to two carbon-carbon triple bonds so that the co-ordination geometry is trigonal planar. The Pr atom geometry in both complexes is square planar. An electrochemical study of the copper complexes 2a and 2b reveals one fully reversible one electron reduction that is consistent with the first reduction of the co-ordinated bipyridyl ligand. There is also an irreversible one electron oxidation that corresponds to the Cu-I to Cu-II transition. (C) 1999 Elsevier Science S.A. All rights reserved.