Bimetallic systems. Part 10. Synthesis of complexes of type [(RCC)Pt(µ-dppm)2Pt(CCR)](dppm = Ph2PCH2PPh2, R = Ph or p-tolyl) and their corresponding ‘A frames’[(RCC)Pt(µ-dppm)2(µ-H)Pt(CCR)]Cl or [(RCC)Pt(µ-dppm)2(µ-X)Pt(CCR)] with X = CS2 or MeOOCCCCOOMe

Abstract

Treatment of trans-[Pt(CCR)₂(dppm-P)₂](dppm = Ph₂PCH₂PPh₂, R = Ph or p-tolyl) with trans-[PtH (Cl)(PPh₃)₂] gives hydride-bridged binuclear salts of type [(RCC)Pt(µ-dppm)₂(µ-H)Pt-(CCR)]Cl in good (86–97%) yield. These complexes are fluxional at +21 °C but when cooled to –56 °C the ¹H n.m.r. spectrum corresponds to a static structure with pseudo-axial and pseudo-equatorial methylene hydrogen resonances. Deprotonation of these salts with sodium isopropoxide gives the binuclear complexes, [(RCC) Pt(µ-dppm)₂Pt(CCR)], with platinum–platinum bonds. These react with CS₂ or with MeOOCCCCOOMe, ‘X’, to give ‘A frames,’[(RCC) Pt(µ-dppm)₂-(µ-X)Pt(CCR)], which were fully characterized. Treatment of [(PhCC)Pt(µ-dppm)₂Pt(CCPh)] with SO₂ probably gave the ‘A frame’[(PhCC)Pt(µ-dppm)₂(µ-SO₂)Pt(CCPh)] which was not isolated but was characterized in solution by ³¹P-{¹H}n.m.r. spectroscopy. N.m.r. and i.r. data are given.