Cyclic voltammetric study of the catalytic behavior of nickel(I) salen electrogenerated at a glassy carbon electrode in an ionic liquid (1-butyl-3methylimidazolium tetrafluoroborate, BMIM+BF4-)

Cyclic voltammetry has been employed to examine the electrochemistry of nickel(II) salen at a glassy carbon electrode in an ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate, BMIM+BF4-). Residual water in the ionic liquid can be eliminated by introduction of activated molecular sieves into the electrochemical cell. Nickel(II) salen exhibits a one-electron, quasi-reversible reduction to nickel(I) salen, and the latter species serves as a catalyst for the cleavage of carbon¯halogen bonds in iodoethane and 1,1,2-trichlorotrifluoroethane (Freon® 113). In BMIM+BF4- the diffusion coefficient for nickel(II) salen at room temperature has been determined to be 1.8×10-8 cm2 s-1, which is more than 500 times smaller than that (1.0×10-5 cm2 s-1) in a typical organic solvent¯electrolyte system such as dimethylformamide (DMF) containing 0.10 M tetramethylammonium tetrafluoroborate.