An Electrochemical Study of the Ruthenium(III) and ‐(IV) Hexachlorometallates in a Basic Room Temperature Chloroaluminate Molten Salt

Abstract

The ruthenium(IV) complex, , exhibits two successive voltammetric reduction waves with peak potentials of 0.34 and −1.09 V, respectively, in the 49.0/51.0 m/o aluminum chloride‐1‐methyl‐3‐ethylimidazolium chloride room temperature molten salt vs. the Al3+/Al couple in the 66.7/33.3 m/o melt at 40°C. The first wave corresponds to the reversible, uncomplicated reduction of to , and the second appears to arise from the multielectron reduction of the latter complex to produce more than one species. The formal potential of the redox system is 0.389 V, and the average Stokes‐Einstein products of and are respectively, in this melt. The reversible half‐wave potentials for a variety of 4d‐ and 5d‐hexachlorometallate redox couples that were measured in this molten salt exhibit the same orderly trends with increasing atomic number found in . This result was used in conjunction with the half‐wave potential of the couple to predict the potential of the redox system in the melt.