Mechanistic implications of the active species involved in the oxidation of hydrocarbons by iron complexes of pyrazine-2-carboxylic acid.

The reactivity towards H2O2 of the complexes [Fe(pca)2(py)2]·py (1) and Na2{[Fe(pca3)]2O}·2H2O·CH3CN (2) (where pca− is pyrazine-2-carboxylate) and their catalytic activity in the oxidation of hydrocarbons is reported. Addition of H2O2 to 1 results in the formation of a dinuclear Fe(iii)–(µ-O)–Fe(iii) species characterized spectroscopically and by cyclic voltammetry. By contrast, treatment of 2 with H2O2 results in the formation of mononuclear iron(ii) complexes, [Fe(pca)2(solvent)2]. The experimental results indicate that the catalytic activity of the starting complexes 1 and 2 is strongly dependent on the species formed in solution. [ABSTRACT FROM AUTHOR]