Olefin and nitrile complexes of platinum.

The Introduction consists of a discussion of the way in which transition metals are bonded to olefins. The synthesis of chloro-olefin complexes of the type (PPh3)2Pt (olefin) are reported. These were prepared either by using the established methods of preparation starting from (PPh3)4Pt or hydrazine reduced cis-(PPh3)2PtC12, or by reaction of the olefins with (PPh3)2Pt (trans-stilbene) in ether solution, which proved to be a superior method of synthesising the olefin complexes. The conditions under which these chloro-olefin complexes isomerise to the vinyl ones, (PPh3)2Pt (chlorovinyl) C1, or in some cases break down to afford cis-(PPh3)2PtC12 are also reported. It is indicated from kinetic studies of the isomerisations of (PPh3)2Pt (C2C14) and (PPh3)2Pt (C2C13H) to the corresponding cis-vinyl complexes in various solvent systems, that the former probably proceeds via a process similar to SN1 (lim) solvolysis of t-butyl chloride, whilst the latter occurs more rapidly via a system of which the mechanism is probably intermediate between an SN1 and intramolecular type of process. The reactions of (PPh3)4Pt and (PPh3)2Pt (trans-stilbene) with chloromethyl cyanides, CF3CN and chloroacetone compounds are also reported. The complex (PPh3)2Pt (CF3CN) has been prepared as well as complexes containing NH and polymerised CF3CN fragments. The crystal structure of the complex (PPh3)2Pt (CF3CN)2NH is reported. Reactions with the chloro-ligands resulted in the formation of either cis-(PPh3)2PtC12 or complexes analogous to chlorovinyl ones. Infrared data of all novel complexes, n.m.r. data of many and some mass spectrum data are reported and discussed.