Reactions of trans-hydridocyanoalkylplatinum(II) complexes with isocyanides. Preparation of novel platinum(II) compounds with adjacent Pt-H and Pt-C bonds

The hydridocyanopropyl complex of platinum(II) trans-[PtH(CH2CH2CH2CN)-(PPh3)2] reacts with an excess of isocyanide RNC (R = t-Bu or 2,6-Me2C6H3) to yield platinum(O) isocyanide complexes of the type [Pt(CNR)2(PPh3)2] through reductive elimination of 1-cyanopropane. In contrast the cyanomethyl complex trans-[PtH(CH2CN)(PPh3)2] reacts with RNC to give the novel platinum(II) complexes [PtH(CH2CN)(CNR)(PPh3)] (R = CH3; t-Bu; 2,6-Me2C6H3;p-MeOC6H4) by displacement of one phosphine ligand. Spectroscopic evidence shows these complexes to contain the cyanoalkyl group adjacent to the hydride and opposite to the phosphine. Heating of these complexes in the presence of equimolar amounts of PPh3 and RNC gives the corresponding platinum(O) species [Pt(CNR)2(PPh3)2].