Poly[[{μ3-dihydrogen [(pyridin-4-ylmethylimino)bis(methylene)]diphosphonato-κ5O:O′,N,O′′:N′}copper(II)] dihydrate]

Abstract

In the title polymer, {[Cu(C8H12N2O6P2)]·2H2O}n, the geometry of the five-coordinate CuII ion can best be described as slightly distorted square-pyramidal formed by one N and two O atoms of an N(CH2PO3H)2 group and one N atom from a pyridine ring. The elongated apex of the pyramid is occupied by one O atom from a third diphosphonate ligand. The interconnection of Cu2+ ions by the diphosphonate ligands results in the formation of a double-chain array along the b axis, in which the two sub-chains are interlocked by pairs of PO3 groups. The outside of each sub-chain is decorated by other PO3 groups. These double chains are further assembled into a three-dimensional supramolecular architecture via a large number of O—H...O hydrogen bonds between the phosphonate groups and lattice water molecules.