Reduction of Ru2(CH 3COO) 4+ and Co(C 2O 4) 33− by oxalatotitanuim(III) complexes in aqueous acidic solution

Abstract

Reductions of Ru 2(CH 3COO) 4 + and CO(C 2O 4) 3 3− by oxalato complexes of titanium(III) have been studied in LiCF 3SO 3 media of 1.0 mol dm −3 ionic strength. At 25°C and [H +] f = 0.150 mol dm −3, Ru 2(CH 3COO) 4 + and Co(C 2O 4) 3 3− are reduced by Ti(C 2O 4) 2 − with second-order rate constants of (4.17 ± 0.08) x 1O 3 and (3.20 ± 0.05) x 10 3 dm 3 mol −1 s −1, respectively. Both oxidants show no detectable reactivity towards Ti(C 2O 4) +. Both reactions are base-catalysed. The magnitude of the rate constant for reduction of Ru 2(CH 3COO) 4 + establishes an outer-sphere mechanism; the magnitude of the rate constant for Co(C 2O 4) 3 3− indicates a substitution-limited inner-sphere mechanism.