Platinum phosphido complexes by sodium promoted reaction of cis-PtCl2(PHCy2)2. Synthesis and crystal structure of [trans-Pt(PCy2H)2(PCy2)Cl], a rare example of terminal phosphido platinum(II) complex

cis‐PtCl2(PHCy2)2 (1) reacts at 0 °C in toluene with sodium metal to give the dinuclear PtI complexes cis‐[(PHCy2)(H)Pt(μ‐PCy2)]2 (2) and [(PHCy2)(Cl)Pt(μ‐PCy2)Pt(PHCy2)2](Pt−Pt) (3). On standing in solution, complex 3 isomerizes to trans‐[(PHCy2)(Cl)Pt(μ‐PCy2)2Pt(PHCy2)(H)] (4). When treated with sodium at room temperature, complex 3 transforms into [Pt(μ‐PCy2)(PHCy2)]2(Pt−Pt) (5). The sodium reduction of 1 carried out at room temperature leads to the direct formation of the phosphido bridged dinuclear complex [Pt(μ‐PCy2)(PHCy2)]2(Pt−Pt) (5) along with the mononuclear platinum(II) complex [trans‐Pt(PCy2H)2(PCy2)Cl] (6). Complex 6, which has also been obtained by reaction of 1 with LiPCy2, unambiguously shows by single‐crystal X‐ray diffraction the presence of a pyramidal terminal phosphido ligand.