KINETICS AND MECHANISM OF OXIDATION OF (AQUA-2-AMINOMETHYL-PYRIDINE)CHROMIUM(III) BY N-BROMOSUCCINIMIDE

The kinetics of oxidation of (aqua-2-aminomethylpyridine)Cr-III by N-b romosuccinimide (NBS) in aqueous solution to yield chromium(VI) has be en studied spectrophotometrically over the 25-40 degrees C range. The reaction rate is first order with respect to both [NBS] and [Cr-III], and increases with increasing pH between 7.6 and 8.6. The thermodynami c activation parameters were calculated. The experimental rate law is consistent with a mechanism in which the deprotonated [Cr(L)(2)(OH)](2 +) was considered to be the most reactive form compared to its conjuga te acid. It is assumed that electron transfer takes place via an inner -sphere mechanism.