Synthesis of novel platinum-silver and platinum-copper complexes with bridging alkynyl ligands

Resumen

The study of the reactivity of [Pt2M4(CCR)8] (MAg or cu; RPh or tBu) towards different neutral and anionic ligands is reported. This study reveals that reactions of the phenylacetylide derivatives [Pt2M4(CCPh)8] with anionic, X- (XCl or Br) or neutral donors (CNtBu or py) in a molar ratio 1:4 (m/donor ratio 1:1) yield the trinuclear anionic (NBu4)2[{Pt(CCPh)4 (MX)2] (MAg or Cu, X Cl or Br) or neutral [{Pt(CCPh04=sAGL)2] (LCNtBu or py) complexes, respectively. The crystal structure of (NBu4)2[{Pt(CCPh)4}(CuBr)2](4) shows that the anion is formed by a dianionic Pt(CCPh)4 fragment and two neutral CuBr units joined through bridging alkynyl ligands. All the alkynyl groups are σ bonded to Pt and η2-coordinated to a Cu atom which have an approximately trigonal-planar geometry. By contrast, similar reactions with [Pt2M4(CCtBu)8] (molar ratio M/donor 1:1) afford hexanuclear dianionic (NBu4)2[Pt2M4(CCtBu)8X2] or neutral [Pt2Ag4(CCtBu08Py2]. Only by treatment with a large exces of Br - (molar ratio M/Br- 1:2) are the trinuclear complexes (NBu4)2[{Pt(CCtBu4 (MBr)2] (MAg, Cu) obtained. Attempted preparations of analogous complexes with phosphines (L′PPh3 or PEt3) by reactions of [Pt2M4(CCR8] with L′ leads to displacement of alkynyl ligands from platinum and formation of neutral mononuclear complexes [trans-Pt(CCR)2L′2]. © 1995.