PLATINUM COMPLEXES BRIDGED BY (DIPHENYLPHOSPHINO)CYCLOPENTADIENYL LIGANDS - REACTIONS WITH TERT-BUTYL ISOCYANIDE OR PHOSPHORUS LIGANDS

The complexes [Pt2R2(mu-C5H4PPh2)2] (1) react with 2 equiv of CNBu(t) to form the face-to-face dimers [Pt2R2(CNBU(t))2(mu-eta1-C5H4PPh2)2] ( 2), in which the cyclopentadienyl rings of the bridging dppc ligands a re 1,2-substituted by Pt and P. Addition of further CNBu(t) produces c is- and trans-[PtR(CNBU(t))2(C5H4PPh2-P)] (3), in which the dppc ligan ds are coordinated through the P atom only. Reactions of [Pt2R2(mu-C6H 4PPh2)2] with phosphorus ligands proceed either to form complexes of t he type [PtR(PR3')2(CrH4PPh2-P) or (by reductive elimination of the ap propriate alkane) to produce the platinum(I) dimers [Pt2(PR3)2(mu-eta1 -C6H4PPh2)2], the course of the reaction being dependent on the nature of the ligand and the solvent. Platinum(I) species of the type [Pt2(P R3)2(mu-eta1-C5H4PPh2)2] may be prepared alternatively by displacement of carbon monoxide from [Pt2(CO)2(mu-eta1-C5H4PPh2)2]. The NMR spectr a of the platinum(1) compounds are discussed.