AMIDINATO-BRIDGED AND TRIAZENIDO-BRIDGED BINUCLEAR COMPLEXES OF PALLADIUM AND PLATINUM

The reaction of [M2Cl2(mu-Cl)(2)(PR3)(2)] (M=Pd or Pt; PR3=PEt3, PBu3, PMe2Ph, PMePh2) with lithium amidinate or sodium triazenide gave binu clear complexes containing amidinato- or triazenido-bridges, [M2Cl2(mu -ArNENAr)(2)(PR3)(2)] (E=CH, CMe or N). These complexes were character ized by elemental analysis and NMR (H-1, P-31 or Pt-195) data. The str uctures of two complexes, [(PdCl2)-Cl-2(mu-PhNC(Me)NPh)(2)(PMe2Ph)(2)] (10) and [Pt2Cl2(mu-PhNNNPh)(2)(PEt3)(2)] (11) were established by si ngle crystal X-ray structural analyses. The Pt-195 NMR data Show coupl ing between two metal centers in the cis triazenido-bridged complex. T he corresponding amidinate bridged complex does not show coupling. The role of the bridging ligand in mediating interaction between the meta l centers is probed through Extended Huckel Theory (EHT) calculations. It is suggested that M-M interactions are primarily affected by the b ridging ligands. (C) 1998 Elsevier Science Ltd. All rights reserved.