A Chloro-Bridged Linear Chain Imine-Copper(II) Complex and Its Application as an Enzyme-Free Amperometric Biosensor for Hydrogen Peroxide

Abstract

The synthesis, structural characterisation and magnetic properties of a new chloro-bridged linear chain imine-copper(II) compound are reported. The results indicate that uniform chains are formed by stacking of parallel pyramidal units formed from the copper centre coordinated to the imine ligands and bridged by chloride ions, with the uncoordinated perchlorate ions located between the layers to balance the charge. Magnetic measurements carried out on a powder sample at temperatures from 1.8 to 290 K and a field of 500 Oe, indicated an intramolecular magnetic coupling between the copper centres [J/k = (-12.3 +/- 0.2) K]. Moreover, an antiferromagnetic interaction can also be observed between the polynuclear arrays [J' z/k = -(10.4 +/- 1.7) K]. An analysis of the sample at high temperature indicated that the overall interaction would be antiferromagnetic (Theta(CW) = -14 K). Furthermore, this new inorganic-organic zigzag polymer was linked covalently to the poly (N-vinylimidazole) polymer, PVI, on a vitreous carbon electrode surface and used as a biomimetic material for the efficient analytical determination of hydrogen peroxide. Raman spectroscopy and electrochemical techniques were used to give a complete characterisation of the hybrid film obtained. The proposed enzyme-free biosensor for catalase-like activity exhibited good sensitivity (268 mA mol(-1) L cm(-2)) at -0.4V relative to the. SCE in a phosphate buffer solution (pH 7.0) and a wide linear range from 1 to 30 mmol L(-1) for hydrogen peroxide detection. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)