C. Newton, D. G. Davis
Dec 1, 1975
Citations
0
Influential Citations
22
Citations
Journal
Journal of Magnetic Resonance
Abstract
Abstract The techniques of cyclic voltammetry, controlled-potential coulometry and ESR have been used to examine the mechanisms of the redox chemistry of vanadium(IV), chromium(III), molybdenum(V) and tungsten(V) tetraphenylporphyrins (TPP). Various nonaqueous aprotic solvents were used, especially N,N -dimethylacetamide (DMA) and dichloromethane. One-electron metal reductions were observed for all of the complexes except vanadium, as well as a one-electron oxidation of chromium(IV). Formation of π anions and π cations was detected resulting from the oxidation or reduction of the porphyrin ring. The heterogeneous rate constants for the various electrochemical reactions were determined. ESR studies revealed extrahyperfine interaction for the chromium and molybdenum complexes. The π anion radical of vanadium exhibited a relaxation mechanism by which the metal signal was broadened but the n radical signal was not.