Co-ordination polymers

This paper is a review of the metal complex forming coordination polymers. A polymer-metal complex is composed of synthetic polymer and metal ions bou nd to the polymer ligand by a coordinate bond. A polymer ligand contains an choring sites like nitrogen, oxygen or sulphur obtained either by the polym erization of monomer possessing the coordinating site or by a chemical reac tion between a polymer and a low molecular weight compound having the coord inating ability. The polymer-metal complexes may be classified into differe nt groups according to the position occupied by the metal, which is decided by the method of preparation. The method include the complexation of polym eric ligand with various metal ions, cross-linked polymers with pendent, li gands forming either intramolecular and/or intermolecular chelating functio ns are highlighted in the first part. The various works on the coordination complexes has revealed that the heterogeneous systems possess more economi cal potentials and advantages over homogeneous systems. The co-ordination p olymers belong to the former case. The high molecular weight polymer-metal complexes work as storage houses for solar energy. Efficient chemical conve rsion in the storage of solar energy will be difficult with the homogeneous systems. The synthesis results in an organic polymer with inorganic functi ons. The metal atoms attached to the polymer backbone are bound to exhibit characteristic catalytic behaviour, which are distinctly different from the ir low molecular weight analogue. Many synthetic polymer-metal complexes, f ound to possess high catalytic efficiency, in addition to ion selectivity i n waste water treatment, recovery of trace metal ions, and hydrometallurgy are enlightened in the final part. (C) 2000 Elsevier Science Ltd. All right s reserved.