Polymer square planar metal chelates for science and industry

The topic of this review concentrates on those metal chelates where the metal atom is surrounded by a planar ligand: porphyrins, phthalocyanines, hemiporphyrazines (hexaazocyclanes), tetraaza(14)annulenes, bis(1,2-dioximes), and Schiff'base chelates (salens). The coordinative (through the metal atom) and covalent (through the ligand and metal atom) binding of the chelate in a polymer chain is described in detail. Binding of small molecules as oxygen and catalytic activity are the main promising properties. Then the covalent and coordinative incorporation of the chelate through the metal atom in the polymer chain is discussed. Electrical conductivity and thermal properties are further main interesting aspects of such polymers. Finally, this review deals with polymeric chelates with covalent introduction of the chelate through the ligand in the main chain. These polymeric chelates and their ligands show other interesting features, such as electrical conductivity, small molecule binding, catalytic and electrocatalytic properties.