Two hybrids based on Keggin polyoxometalates and dinuclear copper(II) complexes: syntheses, structures and electrocatalytic properties

Abstract

By introducing mixed-ligands en and ox, $$\hbox {Cu}^{2+}$$ and different polyoxotungstates as synthons, two new polyoxotungstate-based inorganic-organic hybrid compounds $$\{[\hbox {Cu}_{2}\hbox {(en)}_{2}\hbox {(ox)}]\hbox {[HPW}_{12}\hbox {O}_{40}]\}\cdot \hbox {(en)}_{2}\cdot \hbox {2H}_{2}\hbox {O}$$ (1) and $$\{[\hbox {Cu}_{2}\hbox {(en)}_{2}\hbox {(ox)}]$$ [ $$\hbox {H}_{3}\hbox {BW}_{12}\hbox {O}_{40}]\}\cdot \hbox {(en)}_{2}\cdot \hbox {2H}_{2}\hbox {O}$$ (2) (en = ethylenediamine and ox = oxalate), were obtained in identical hydrothermal conditions and further characterized by elemental analyses, IR spectroscopy and single-crystal X-ray diffraction. Structural analyses revealed that both compounds are isostructural, and show one-dimensional (1D) chain constructed by $$\hbox {[XW}_{12}\hbox {O}_{40}]^{\mathrm{n}-}$$ (X = P 1, B 2) Keggin-type polyoxoanions and $$[\hbox {Cu}_{2}\hbox {(en)}_{2}\hbox {(ox)}]^{2+}$$ dinuclear copper subunits. The electrochemical experiments indicated that 1-based carbon paste electrode possesses high catalytic efficiency and selectivity towards reduction of $$\hbox {H}_{2}\hbox {O}_{2}$$ , and thus 1 has potential to detect $$\hbox {H}_{2}\hbox {O}_{2}$$ . SYNOPSIS Two new hybrids based on polyoxoanions and dinuclear copper complexes have been synthesized and characterized. The results of electrocatalytic experiments indicate that the hybrid-based electrode possesses high catalytic efficiency and selectivity towards reduction of $$\hbox {H}_{2}\hbox {O}_{2}$$ .