Novel mixed-metal-alkynyl complexes stabilised by di-imine ligands: synthesis, characterisation and electrochemistry of [((t)Bu(2)bipy)Pt(C CR)(2)M(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 thiocyan ate 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, SiMe 3 3b). X-ray analyses of the complexes 2a and 3b show that the group 11 met al 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 bot h complexes is square planar. An electrochemical study of the copper comple xes 2a and 2b reveals one fully reversible one electron reduction that is c onsistent with the first reduction of the co-ordinated bipyridyl ligand. Th ere 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 reserve d.