Reagent-Regulated Oxidative O-Demethylation of a Ferrous Complex Stabilized by a Tetradentate N Ligand with a Methoxyphenyl Substituent: Reagent-Regulated Oxidative O-Demethylation of a Ferrous Complex Stabilized by a Tetradentate N Ligand with a Methoxyphenyl Substituent

A ferrous complex (FeLCl2)-L-II-Cl-OMe, 1, where L-OMe is 2-methoxy-N,N-bis(pyridin-2-ylmethyl) aniline, has been synthesized and studies on its structure, spectral properties, and reactivity have been carried out. The complex has rich spectral properties and shows a well-defined paramagnetic H-1 NMR spectrum with sharp and hyperfine shifted signals, which were assigned with the help of a combination of H-1-H-1 COSY and T1 and T2 relaxation time measurements. Though stable to air, complex 1 underwent oxidation in the presence of AgClO4, which resulted in the formation of a symmetric diferric oxo complex [((LFeCl)-Fe-OMe-Cl-III)(2)O](ClO4)(2), 2. However, on reaction with strong oxidants such as tBuOOH, complex 1 yielded a mixture of an unsymmetric diferric oxo complex (LFeClOFeCl3)-Fe-OMe-Cl-III-Cl-III, 3, and a mononuclear ferric complex (LO-FeCl2)-Cl-III, 4, with a modified phenoxide ligand LO-, which is formed as a result of the demethylation of L-OMe during oxidation. The factors affecting O-demethylation were studied and a possible mechanistic pathway involving a high-valent iron-oxo species is proposed.