Polymer complexes:: supramolecular assemblies and structures of poly[N-(2'-pyridyl)propenamide] complexes

A number of new polymer complexes of palladium(II), platinum(II) and copper(II) containing homopolymer (N-(2'-pyridyl)propenamide; APH) and various anions (Cl-, Br-, I- or NO3_) have been synthesized and characterized by elemental analyses, magnetic susceptibility, electron paramagnetic resonance, IR and reflectance spectral measurements. The homopolymer shows three types of coordination behavior. In the mononuclear polymer complexes 1-6 and 9 it acts as a neutral bidentate ligand chelated through the pyridine-nitrogen and amide-oxygen atoms, whereas in the square-planar [Pd(APH)(2)X-2] (X = Cl, Br) unidentate APH is coordinated through the pyridine-nitrogen atom alone. Under alkaline conditions APH is deprotonated in the presence of palladium(II) to form [Pd(AP)(2)] (10), AP being an anionic bidentate ligand and chelating through the pyridine-nitrogen and amide-oxygen atoms. The poly-chelates are of 1: 1 and 1: 3 (metal: homopolymer) stoichiometry and exhibit six-coordination. The polymer complexes of stoichiometric [(APH)(2)CuX2] contain square planar (APH)(2) Cu2+ units and the anions X- are in the axial positions, giving distorted octahedral configurations. From the electron paramagnetic resonance and spectral data, the orbital reduction factors were calculated. Copyright (C) 2004 John Wiley Sons, Ltd.