ELECTROCHEMICAL AND SPECTROSCOPIC PROPERTIES OF MANGANESE TETRA(4-NN'N''-TRIMETHYLANILINIUM)PORPHYRIN

A BETTELHEIM, D OZER, R PARASH

Research output: Contribution to journalArticlepeer-review

Abstract

The electrochemistry of themanganese(m)/manganese(II) tetra(4-NN’N”-trimethylanilinium)-porphyrin couple (abbreviated as MnlI1/MnlITMAP) has been investigated in aqueous solutions in the entire pH range by means of cyclic voltammetry and thin-layer coulometry. The spectroscopic characteristics of the oxidized and reduced porphyrin in the 350-700 nm range have been studied using a gold optical transparent electrode. A displacement reaction of Mn2+from MnIITMAP by hydrogen ions was identified at pH < 3.6. The effect of adsorption of MnTMAP on the electrode process is described. The absorbed reactant is reduced at a potential close to that of the dissolved porphyrin; Ei is -0.375 V, independent of the pH of the solution. The catalytic aspects of MnI’ITMAP for the reduction of molecular oxygen to hydrogen peroxide are also presented in terms of cyclic voltammetry. The overpotential is reduced by ca. 300 mV. The role of an oxygen adduct formed between molecular oxygen and the metal atom of the macrocycle is postulated to explain the difference between the redox potential for the Mn”‘/MnlITMAP couple and the potential at which the catalytic reduction of oxygen occurs.
Original languageEnglish GB
Pages (from-to)1555-1564
JournalPhysical Chemistry Chemical Physics
Volume79
StatePublished - 1983

Fingerprint

Dive into the research topics of 'ELECTROCHEMICAL AND SPECTROSCOPIC PROPERTIES OF MANGANESE TETRA(4-NN'N''-TRIMETHYLANILINIUM)PORPHYRIN'. Together they form a unique fingerprint.

Cite this