[As8W48O184]40−, a new crown-shaped heteropolyanion: Electrochemistry and electrocatalytic properties towards reduction of nitrite

The electrochemical behavior of the new crown-shaped heteropolyanion [As8W48O184]40− was investigated. Compared to the analogous complex [P8W48O184]40−, [As8W48O184]40− displayed a close similar behavior. As previously reported for [P8W48O184]40−, [As8W48O184]40− is found to be stable in a large range of pH, roughly from 0 to 8 and found to be slightly more soluble than [P8W48O184]40−. Comparison between the cyclic voltammetry curves of the two complexes reveals that the potentials of the redox waves of [As8W48O184]40− are slightly shifted towards the positive values. Contrary to the high dependence of [P8W48O184]40− to buffer capacity of the supporting electrolyte, interestingly, [As8W48O184]40− displays less sensitivity. The numerous possibilities for chemical applications opened up by the electrochemistry of this new complex are exemplified here by the good linear relationship between the peak potentials of the redox waves as a function of pH and, by the electrocatalytic reduction of nitrite.