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

By introducing mixed-ligands en and ox, ${\text{Cu}}^{2+}$ and different polyoxotungstates as synthons, two new polyoxotungstate-based inorganic-organic hybrid compounds $\left\{\right[{\text{Cu}}_2{\text{(en)}}_2\text{(ox)}\left]{\text{[HPW}}_{12}{\text{O}}_{40}\right]\}\cdot {\text{(en)}}_2\cdot {\text{2H}}_2\text{O}$ (1) and $\left\{\right[{\text{Cu}}_2{\text{(en)}}_2\text{(ox)}]$ [${\text{H}}_3{\text{BW}}_{12}{\text{O}}_{40}\left]\right\}\cdot {\text{(en)}}_2\cdot {\text{2H}}_2\text{O}$ (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 ${\text{[XW}}_{12}{\text{O}}_{40}{]}^{n-}$ (X = P 1, B 2) Keggin-type polyoxoanions and $[{\text{Cu}}_2{\text{(en)}}_2\text{(ox)}{]}^{2+}$ dinuclear copper subunits. The electrochemical experiments indicated that 1-based carbon paste electrode possesses high catalytic efficiency and selectivity towards reduction of ${\text{H}}_2{\text{O}}_2$, and thus 1 has potential to detect ${\text{H}}_2{\text{O}}_2$.

Graphical Abstract

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 ${\text{H}}_2{\text{O}}_2$. .