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 Bu^tNC gives [(Bu^tNC)₂Pt(µ-dppm)₂Pt(CNBu^t)₂]⁴⁺, isolated as the PF₆^– salt (dppm = Ph₂PCH₂PPh₂). Treatment of [M(dppm-PP′)₂]Cl₂(M = Pt or Pd) with two equivalents of Bu^tNC 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, Bu^t, 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(CNBu^t)₂(dppm-P)₂]Cl₂, prepared in situ from [Pt(dppm-PP′)₂]Cl₂ and Bu^tNC, reacts with [{AgCl(PPh₃)}₄] or [AuCl(PPh₃)] to give [(Bu^tNC) ClPt(µ-dppm)₂MCl]Cl (M = Ag or Au). Treatment of [Pt(dppm-PP′)₂]Cl₂ with [Au(CCPh)(CNBu^t)] gives [(Bu^tNC)(PhCC)Pt(µ-dppm)₂-AuCl]Cl. Treatment of [(Bu^tNC)ClPt(µ-dppm)₂AgCl]Cl with [Rh₂Cl₂(CO)₄] gives the complex [(Bu^tNC)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.