Electrochemical Study of Vicinal Dibromide Dehalogenation Catalyzed by Cobaloximes

Abstract

The electrochemical dehalogenation of trans −1,2-dibromocyclohexane will be studied using a family of cobaloximes by the cyclic voltammetry. The cobaloximes used are: Co(dmgH) 2 Cl(py), Co(mpgH) 2 Cl(py), Co(dpgH) 2 Cl(py), Co(chgH) 2 Cl(py), Co(dmgH) 2 Cl(PPh 3 ), Co(mpgH) 2 Cl(PPh 3 ) and Co(dpgH) 2 Cl(PPh 3 ) (where dmgH is dimethylglyoximato, mpgH is methylphenylglyoximato, dpgH is diphenylglyoximato, chgH is 1,2-cyclohexanedione dioxime, PPh 3 is triphenylphosphine and py is pyridine). The dehalogenation kinetics were studied by monitoring the current increases zone near to the Co(II/I) half wave potential as the concentration of the trans −1,2-dibromocyclohexane in the electrochemical cell is increased. The rate constants of the dehalogenation processes were estimated using the foot-of-the-wave analysis (FOWA), finding higher constant values when the potential of the Co(II/I) pair is shifted to more negative values.