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

• Published in: Polyhedron 2004-10, Vol.23 (16), p.2541-2547
• Main Authors: Salunke-Gawali, S., Rane, S.Y., Puranik, V.G., Guyard-Duhayon, C., Varret, F.
• Format: Article
• Language: English
• Subjects: 2-Hydroxy-1; 4-Naphthoquinone; Amine oxidase; Antiferromagnetic coupling; Copper complexes; EPR; H-bonding; Lawsone; Quinones
• ISSN: 0277-5387
• DOI: 10.1016/j.poly.2004.08.022

Three types of intermolecular H-bondings between H 2O and ONQ molecules result in a supramolecular 3D structure of complex 1, [Cu(II)(ONQ) 2(H 2O) 2] n . The magnetostructural correlation is explained by magnetic chains with antiferromagnetic exchange ( J = −3.26 cm −1) between Cu(II)ions in 1 via non-covalent H-bondings together with interchain exchange ( zJ′ = 0.01 cm −1) using the Bonner and Fisher model. Supramolecular [Cu(II)(ONQ) 2(H 2O) 2] n ( 1) a complex of the 2-hydroxy-1,4-naphthoquinone ligand (2HNQ), has been synthesized using CuCl 2 · 2H 2O. 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) Å 3 at 295 K to 427.9(6) Å 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 1 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.