PHOSPHONATE YLIDE COMPLEXES OF PALLADIUM(II) AND PLATINUM(II): OXIDATIVE ADDITION AND REDUCTIVE ELIMINATION, THE CRYSTAL AND MOLECULAR STRUCTURES OF cis- AND trans-

Article abstract of DOI:10.1016/S0022-328X(00)99588-3

Phosphonate complexes M(PPh3)2(I)(CH2P(O)(OR)2) (M = Pd and Pt, R = Me, and Et) have been prepared by the oxidative addition of ICH2P(O)(OR)2 to M(PPh3)4.While the platinum product isomerized slowly from the cis- to the trans-isomer, the palladium compound decomposed in solution.Several compounds have been identified from the decomposition reaction: ICH2P(O)(OCH3)2, CH3P(O)(OCH3)2, I, OPPh3 and 2.In air, ICH2P(O)(OCH3)2 was the major product observed; however, in the absence of air, CH3P(O)(OCH3)2 was the major product.A study of the reaction pathway showed that the reductive elimination proceeded via phosphine dissociation.The structures of the trans- and cis-platinum compounds were determined by X-ray diffraction, and were refined to R_w = 0.036 (5382 observed reflections) and 0.027 (5274 observed reflections), respectively.The bond lengths of Pt-P, Pt-C and Pt-I trans to various ligands clearly demonstrate the order of the trans influence: phosphonate > phosphine > I.