Cyclic voltammetry study of a system of Ru(III)/Ru(II) chlorocarbonyl complexes

Electrochemical methods of determination of ruthenium most often use the oxidation-reduction reaction in hydrochloride solutions of its chloride complexes. However, it is well known that such solutions contain many different ionic forms of Ru(IV) and Ru(III), and therefore, the electrochemical determination is usually preceded by fairly delicate operations aimed at obtaining in solution only one ionic form with the required properties. This paper deals with a new system that is potentially suitable for determining ruthenium coulometrically and voltammetrically; the system includes chlorocarbonyl complexes of Ru(III)/Ru(II), which are considerably less subject to aquation, hydrolysis, and polymerization than the chloride complexes. In practice, ruthenium in the form of chlorocarbonyl complexes is present in solutions of technological processes utilizing formates and formic acid. Preliminary experiments have shown that in the course of a systematic analysis of materials containing Pt metals, a mixture of Ru(III) and Ru(II) chlorocarbonyls can easily be obtained by distilling RuO{sub 4} into an HCOOH + HCl mixture.