Nickel(III) complexes with cyclic and noncyclic tetramines

A voltammetric study was made of the redox properties of Ni(II) complexes with poly-aza ligands and it was found that complexes with the open chain tetramine undergo a reversible 1-electron oxidn. on Pt in MeCN. The simplicity and reversible nature of the oxidn. was confirmed by the usual electrochem. tests and the stoichiometry of the electron transfer was coulometrically confirmed. Exhaustive electrolysis produces an intense green color which is typical for Ni macrocyclic MeCN complexes. The UV spectrum was that expected for a [Ni(tetramine)(MeCN)2]3+ chromophore.