Electroreductions of bis- and tris-2,2'-bipyridine complexes of chromium(III)

• Published in: Journal of electroanalytical chemistry and interfacial electrochemistry 1967-01, Vol.13 (4), p.400-410
• Main Authors: Tucker, Beverly V., Fitzgerald, J.M., Hargis, L.G., Rogers, L.B.
• Format: Article
• Language: English
• ISSN: 0022-0728
• DOI: 10.1016/0022-0728(67)80042-1

Dichlorobis(2,2'-bipyridine)chromium.(III) chloride and tris (2,2'-bipyridine). chromium(III) perchlorate have been investigated using polarography and controlled. potential coulometry. In aqueous medium, neither complex underwent three simple one-electron reductions to the corresponding chromium(o) complex; reductions were complicated, and changes occurring on oxidation allowed 2,2'-bipyridine to be extracted from either complex. In one instance, reduction was complicated by a disproportionation reaction. Results indicated that, after reduction of either chromium(III) complex to the chromium(o) complex, the product of an oxidation by cerium(IV) or air was a bis(2,2'-bipyridine) chromium(III) complex from which one mole of 2,2'-bipyridine could be extracted. However, the polarographic and coulometric behaviour of the chromium(III) products from the two treatments differed considerably.