Stereospecific transfer reactions of phenyl and ethynyl groups between platinum(II) atoms

Abstract

Treatment of cis-[PtPh2(CO)L], prepared from [PtClPh(CO)L](L = PMePh2; Cl trans to L) and HgPh2, with HgCl2 results in the specific replacement by Cl of the phenyl group trans to L. The same phenyl is replaced when cis-[PtPh2(CO)L] and cis-[PtCl2(13CO)L] react, forming [PtClPh(CO)L](Cl trans to L) and [PtClPh(13CO)L](Ph trans to L). By contrast, the ethynyl complex cis-[Pt(CCPh)2(CO)L] reacts with cis-[PtCl2(CO)L] to form only one product, [PtCl(CCPh)(CO)L] with Cl trans to L. The mixed bis(ethynyl) complex [Pt(CCMe)(CCPh)(CO)L](CCMe trans to CO) reacts with cis-[PtCl2(13CO)L′](L′= PMe2Ph) to produce mainly [PtCl(CCMe)(CO)L] and [PtCl(CCPh)(13CO)L′](both with Cl trans to phosphine) confirming that a chloride trans to CO is involved in this exchange. cis-[Pt(CCPh)2(13CO)L′] is also produced in this reaction, apparently via[Pt(CCMe)(CCPh)(CO)L] and [PtCl(CCPh)(13CO)L′]. The mechanisms of these reactions are discussed.