Bimetallic systems. Part 5. Isonitrile–platinum(II)– or –palladium(II)–bis(diphenylphosphino)methane complexes including heterobimetallics with silver(I), gold(I), or rhodium(I)

Abstract

Treatment of cis-[PtCl2(dppm-PP′)] with ButNC gives [(ButNC)2Pt(µ-dppm)2Pt(CNBut)2]4+, isolated as the PF6– salt (dppm = Ph2PCH2PPh2). Treatment of [M(dppm-PP′)2]Cl2(M = Pt or Pd) with two equivalents of ButNC or MeNC gave fluxional, mononuclear isonitrile complexes of type [M(CNR)2(dppm-P)2]2+, isolated as their PF6– or BPh4– salts. The palladium salts readily lose the CNR ligands. The unidentate-dppm complexes of type [Pt(CNR)2(dppm-P)2]2+ react with AgPF6, HgCl2, or [Rh2Cl2(CO)4] to give heterobimetallic complexes with µ-dppm ligands, but these were not isolated in a pure state. However, the salts [M(dppm-PP′)2]Cl2(M = Pt or Pd) react with the compounds [AgCl(CNR)](R = Me, But, or p-tolyl) to give the heterobimetallic complexes [(RNC)-CIM(µ-dppm)2AgCl]+ in high yield. These were isolated as Cl–, BPh4–, or PF6– salts. The salt [Pt(CNBut)2(dppm-P)2]Cl2, prepared in situ from [Pt(dppm-PP′)2]Cl2 and ButNC, reacts with [{AgCl(PPh3)}4] or [AuCl(PPh3)] to give [(ButNC) ClPt(µ-dppm)2MCl]Cl (M = Ag or Au). Treatment of [Pt(dppm-PP′)2]Cl2 with [Au(CCPh)(CNBut)] gives [(ButNC)(PhCC)Pt(µ-dppm)2-AuCl]Cl. Treatment of [(ButNC)ClPt(µ-dppm)2AgCl]Cl with [Rh2Cl2(CO)4] gives the complex [(ButNC)ClPt(µ-dppm)2RhCl(CO)][RhCl2(CO)2] and silver chloride in a transmetallation reaction, I.r. and 1H-{31P}, 31P-{1H}, and 195Pt-{1H} n.m.r. data are given and discussed.