The Kinetics and Mechanisms of Substitution Reactions of Trans-[Co(en)2CNCl]+ in Binary Mixed Solvent

The kinetics and mechanisms of the substitution reactions of trans-[Co(en)2CNCl]+ with unidentate anions,  , CN¯, I¯,  , Br¯ and SCN¯ in 60% v/v DMF-H2O binary solvent at 40.0±0.2 °C were studied spectrophotometrically. An Id mechanism was assigned for the replacement of chlorine by , CN¯ and I¯, an Ia one for the entry of  and SCN¯, and a D mechanism for Br¯ entry. Comparing the interchange rate constants, ki, values has led to the following trend of reactivity of the anions toward the given substrate:   The replacement of chlorine by the anions proceeded with a complete retention of configuration.