Amidinato- and triazenido-bridged binuclear complexes of palladium and platinum

Abstract

The reaction of [M 2Cl 2( μ-Cl) 2(PR 3) 2] (M=Pd or Pt; PR 3=PEt 3, PBu 3, PMe 2Ph, PMePh 2) with lithium amidinate or sodium triazenide gave binuclear complexes containing amidinato- or triazenido-bridges, [M 2Cl 2( μ-ArNENAr) 2(PR 3) 2] (E=CH, CMe or N). These complexes were characterized by elemental analysis and NMR ( 1H, 31P or 19;Pt) data. The structures of two complexes, [Pd 2Cl 2{ μ-PhNC(Me)NPh} 2(PMe 2Ph) 2] (10) and [Pt 2Cl 2( μ-PhNNNPh) 2(PEt 3) 2] (11) were established by single crystal X-ray structural analyses. The 19;Pt NMR data show coupling between two metal centers in the cis triazenido-bridged complex. The corresponding amidinate bridged complex does not show coupling. The role of the bridging ligand in mediating interaction between the metal centers is probed through Extended Huckel Theory (EHT) calculations. It is suggested that M–M interactions are primarily affected by the bridging ligands.