A Methoxylation‐Promoted CPET Reaction

Abstract

AbstractThe manuscript discloses a methoxylation reaction to an aromatic carbonyl function that carries out a CPET reaction oxidizing a transition metal ion. Spontaneous methoxylation of a redox non‐innocent fragment coordinated to a high spin cobalt(II) ion, promoted concerted proton electron transfer (CPET) reaction oxidizing cobalt(II) to cobalt(III) in air and subsequent demethoxylation induced reduction of cobalt(III) to cobalt(II) producing H2O2 are authenticated. The cobalt(III)/cobalt(II) electron transfer (ET) potential of the designed complex in CH2Cl2 is −0.27 V vs Fc+/Fc redox couple. However, in presence of MeOH the reduction potential decreases to −1.02 V due to CPET involving MeOH proton. In CH2Cl2/CHCl3 spontaneous demethoxylation occurs giving back the original complex and reactive methoxyl radical that reacts with O2 producing H2O2. Overall one molecule of MeOH produces one molecule of H2O2. To analyze the involvement of the proton, the rate constants of the CPET reactions in CH2Cl2‐MeOH (2 : 1) and CH2Cl2‐CD3OD (2 : 1) and the demethoxylation reaction in CHCl3 at 330 K were determined by time drive UV‐Vis spectroscopy.