Three dimensional hydrogen-bonding network in a copper complex of 2-hydroxy-1,4-naphthoquinone: structural, spectroscopic and magnetic properties

Supramolecular [Cu(II)(ONQ)(2)(H2O)(2)](n) (1) a complex of the 2-hydroxy-1,4-naphthoquinone ligand (2HNQ), has been synthesized using CuCl2 . 2H(2)O. ONQ is the deprotonated oxidized form of the ligand (viz. 2-oxido-1,4-naphthoquinone). The complex has been characterised by X-ray crystallography, variable temperature magnetic susceptibility measurements (SQUID), EPR and CV studies. The crystal structure of 1 has been solved at 295 and 161 K. The cell volume decreases from 435.3(6) Angstrom(3) at 295 K to 427.9(6) Angstrom(3) at 161 K. The monomeric units of 1 are linked by three types of intermolecular hydrogen bondings through coordinated ONQ ligands and water molecules, which results in a supramolecular three dimensional hydrogen bonding network. The magnetic susceptibility data of I were best fitted with the Bonner Fisher equation with the coupling parameter J = -3.2 cm(-1), indicating a weak antiferromagnetic interaction along the chain. (C) 2004 Elsevier Ltd. All rights reserved.