Retention of configuration and optical activity in the aquation of the α and β [Co(trien)ClOH₂]²⁺ isomers

Abstract

Studies of the aquation reactions of the α and β [Co(trien)ClOH₂]²⁺ isomers are complicated by subsequent isomerization and racemization of the respective diaqua products, especially in the α system. Assuming the consecutive reactions involved are                    Λ-α-chloroaqua → Λ-α-diaqua → racemic-β-diaqua and                    Λ-β₁-chloroaqua → Λ-β-diaqua → racemic-β-diaqua the losses of optical activity calculated using the known rates of these individual steps agree reasonably with the measured losses of activity. The chloroaqua-diaqua equilibria lie substantially (c. 93 %) toward the diaqua products under all the reaction conditions studied. This is consistent with the proposal that each chloroaqua → diaqua reaction occurs with complete retention of configuration in the range 1 < [H⁺] < 10^-3M.