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Abstract

The oxidation and reduction of anhydrous metal (II) perchlorate complexes of iron, cobalt and nickel with 2,2'-bipyridyl, 4,4'-dimethylbipyridyl and 2,2',2"-terpyridyl in acetonitrile solutions has been studied by electrochemical methods.

Cyclic voltammetry at a stationary platinum electrode in a medium of 0.1M tetra-n-butylammonium perchlorate indicated that the metal (II) polypyridyl complexes were oxidised and reduced by reversible one electron processes. Confirmation of the one electron transfer processes was obtained using constant potential coulometry in which milligram quantities of the metal (II) complexes were electrolysed in acetonitrile solutions at potentials in the region of the peak potentials of the corresponding cyclic voltammograms.

The preliminary studies in voltammetry and coulometry were followed by preparative scale constant potential electrolyses; gram quantities of metal (II) polypyridyl complexes were oxidised and reduced to the corresponding metal (III) and metal(I) complexes respectively. Solid products were isolated in all the metal (III) preparations carried out; in the case of the preparation of metal (I) complexes, however, it was possible to isolate only the 2,2'-bipyridyl complexes of cobalt (I) and nickel (I). The magnetic susceptibilities of the solid products were determined at room temperature by the Gouy method and the effective magnetic moments of the metal ions calculated. Visible and near i.r. spectra in solution of the complete series of complexes were examined; where possible, band assignments have been made.

Values of the standard reduction potentials to the metal (III)/ metal (II) and metal (II)/metal (1) couples, obtained from the cyclic voltammetry data, are discussed in terms of crystal field effects.

Publication Type:	Thesis (Doctoral)
Subjects:	Q Science > QD Chemistry
Departments:	School of Science & Technology > School of Science & Technology Doctoral Theses Doctoral Theses

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