Oligo- and polymeric PdII and PtII using pyridyl carboxylate spacers for topology control

Abstract

An array of PdII and PtII supramolecular assemblies have been constructed using pyridyl carboxylates as spacers and phosphines [(C5H4PPh2)2Fe (dppf) and PPh 3)] as supporting ligands. Different molecular topologies such as squares, triangles, rectangles, and polymers can be controlled by the spatial and directional character of the spacer. A change of the denticity of the phosphine does not affect the topological outcome. Significant differences, however, are observed for the congeneric analogues, with PdII showing a more pronounced tendency toward coordination polymer formation and its attached carboxyl a higher affinity toward Ag+. The ability of these assemblies to capture cations, such as Na+ in [Pt3Na(3- NC5H4CO2)3(OTf)3(PPh 3)6]+ through hydrogen bonding or Ag + in [PdAg(2-NC5H4CO2)(OTf) 2(dppf)] through dative bonding, is described and compared. All of the complexes are structurally characterized by single-crystal X-ray crystallography. © 2008 American Chemical Society.