ChemInform Abstract: Bromine Oxidation of a Nickel(II) Bis(oxime-imine) Complex. Evidence for a Single-Step Outer-Sphere Two-Electron Transfer?
Abstract
Kinetics and mechanism of the two-electron oxidation of (Ia) by Br2 are investigated in bromide ion medium between pH 3.1 and 7.6 at 25 °C. In the presence of excess of Br2 or Ni(II), oxidation is monophasic leading to the initial product (Ib), a formal Ni(IV) species, which undergoes subsequent reactions to an unknown product or the Ni(III) complex (Ic), depending on the reaction conditions.
ChemInform Abstract
Kinetics and mechanism of the two-electron oxidation of (Ia) by Br2 are investigated in bromide ion medium between pH 3.1 and 7.6 at 25 °C. In the presence of excess of Br2 or Ni(II), oxidation is monophasic leading to the initial product (Ib), a formal Ni(IV) species, which undergoes subsequent reactions to an unknown product or the Ni(III) complex (Ic), depending on the reaction conditions. Rate constants for the reaction of (Ia) and its monoprotonated form are given. The existence of the intermediate (Ib) leads to the implication that a single-step two-electron transfer may be involved in the mechanism.
