Specific anion effects in the copper(II)-catalysed racemization reaction of the Λ-bis(oxalato)(l,10-phenanthroline)chromate(III) anion

Abstract

The kinetics of racemization of Λ-bis(oxalato)(1,10-phenanthroline)chromate(III) anion in solutions of Cu^II salts, at an ionic strength of 2, fit the expression, rate = (k₁+k₂[Cu^II_F])[complex] where [Cu^II_F] is the concentration of 'free' copper(II) ions in solution as calculated from ion pair formation constants for copper(II) salts. Results in solutions of both constant and nonconstant ionic strength confirm that the ionic environment of the solvent water is a determining factor in the magnitude of the catalytic effect. Thus a divalent sulfate medium is more effective than any of the monovalent perchlorate, nitrate or chloride salts.