Microvoltammetric and spectroelectrochemical studies of (TPP)Co oxidation/reduction in toluene and benzene solutions

Abstract

Abstract The microvoltammetry and spectroelectrochemistry of (TPP)Co (where TPP is the dianion of tetraphenylporphyrin) are reported in toluene and benzene solutions, and provide the first examples of spectroelectrochemistry in these two low dielectric constant solvents. (TPP)Co undergoes four reversible oxidation‐reduction reactions in toluene or benzene. The reductions involve one‐electron transfers and occur at E 1/2 = −0.86 and −2.03 V vs. SCE in both solvents. The oxidations involve the successive reversible abstraction of two electrons and one electron from the initial (TPP)Co species and occur at E 1/2 = 1.00 and 1.27 V vs. SCE in both solvents. Each electrode reaction was spectrally and electrochemically characterized in toluene and benzene, and the data in these two solvents are compared to data obtained in CH 2 Cl 2 where (TPP)Co redox reaçtions have been extensively characterized in detail. Special emphasis is placed on comparing the thin‐layer spectra of [(TPP)Co 1 ] in toluene and benzene with that in other solvents commonly used for nonaqueous electrochemical studies.