Self-assembled coordination complexes from various palladium(II) components and bidentate or polydentate ligands

Palladium(II) has four coordination sites and forms square planar complexes. Discrete self-assemblies are generated by the combination of a variety of palladium(II) components and ligands ranging from bi- to polydentate. The Pd(II) components used are generally of two varieties: cis-protected Pd(II) and unprotected Pd(II). Most common cis-protecting units (X-X) such as ethylenediamine, 2,2'-bipyridine and 1,3-bis(diphenylphosphino)propane and a few other related chelating systems have been exploited for the complexation reactions. The self-assemblies formed are generally represented as [{cis-Pd(X-X)} x(L) y](monoanion) 2x and [Pd m(L) n](monoanion) 2m when generated from the complexation of a suitable ligand (L) with cis-protected Pd(II) and simple Pd(II) units, respectively. When Pd(solvent) 2Cl 2 is complexed with ligands, the solvent molecules are replaced with the incoming ligands, leading to complexes in which the trans positions are occupied by the chloride anions. © 2012 Elsevier B.V.