Electrochemical Reductions Of Ni(2+), Cu(2+) And Zn(2+) Complexes Of Azinyl Methyl Ketoximes On Mercury

Electroreductions of Ni(2+), Cu(2+) and Zn(2+) complexes of azinyl (pyridin-2-yl, pyridazin-3-yl, pyrimidin-2-yl, pyrimidin-4-yl, pyrazinyl) methyl ketoximes on mercury electrode were studied using de polarography. Three different types of complex behavior on the mercury electrode were observed: In the Ni(2+) complexes, the hydroxyimino group of the ligand is reduced, whereas in the Cu(2+) complexes, the reduction proceeds on the metal ion. With Zn(2+) complex of methyl pyridin-2-yl ketoxime, only reduction waves of the uncoordinated ligand and metal were observed due to a rapid decomplexation pre-equilibrium. The structure of [Zn(methyl pyridin-2-yl ketoxime)(2)(NO(3))(2)], isolated from water-ethanolic solution, was determined by X-ray diffraction. The distorted octahedral coordination sphere around the zinc atom, made up of two pyridine and two oxime nitrogen atoms and two nitrate oxygen atoms, was verified.