C-X AND C-H CLEAVAGE BY ELECTROCHEMICALLY GENERATED NONLINEAR [PTL2] COMPLEXES

The electrochemical reduction of [PtX2L2] (X = halide, L2 = bidentate diphosphine: Ph2PCH2CH2PPh2, dppe; Cy2PCH2CH2PCy2, dcpe; Cy2P{CH2}3PCy2, dcpp) has been used as a method of generating non-linear [PtL2] compounds whose reactivity with substrates Ar-X (X = Cl, Br, CN, H, C=CPh) has been examined. Generation of [PtL2] (L2 = dppe or dcpe) in the presence of excess Ph - X (X = Cl, Br) produces [PtXPhL2] efficiently. Similarly, generation of [PtL2] (L2 = dppe or dcpe) in the presence of PhC=CPh results in trapping to form [PtL2(PhC=CPh)]. Generation of [PtL2] (L2 = dppe or dcpe) in the presence of PhCN or PhH results in indiscriminate reactions that do not produce tractable products. In contrast, reduction of [PtCl2(dcpp)] in CH3CN/C6H6/Bu4NClO4 produces [PtHPh(dcpp)] with considerable selectivity via aromatic C-H activation by [Pt(dcpp)]. At room temperature the complex [PtHPh(dcpp)] undergoes exchange with C6D6 to generate [PtD(C6D5)(dcpp)].