Electrochemical Studies of Zinc Tetraphenylporphin

The reduction of zinc (II) tetraphenylporphin (ZnTPP) in dimethylformamide (DMF) was investigated. The products of electron transfer and associated chemical reactions were studied by polarography, cyclic voltammetry, thin‐layer controlled potential coulometry and spectroscopy, and epr. Reduction proceeds initially as a series of two reversible one‐electron steps. After the second and subsequent steps, however, proton abstraction from the solvent medium occurs which, in turn, determines the reaction path. Characteristics of the porphyrin ring reactions are studied and compared with those of porphyrin free bases.