Spectroscopic and electrochemical study of biomimetic catecholase and phenoxazinone synthase activities of in situ complexes bearing pyrazolic ligands

In situ complexes, arising from six ligands based on pyrazol (L 1 -L 6 ): N,N-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)-4-fluoroaniline (L 1 ); 5-chloro-N-((3,5-dimethyl-1H-pyrazol-1-yl)methyl)pyridin-2-amine (L 2 ); N-((3,5-dimethyl-1H-pyrazol-1-yl)methyl)-N-phenylaniline (L 3 ); N-((1H-pyrazol-1-yl) methyl)-N-phenylbenzenamine (L 4 ); N,N-bis((1H-pyrazol-1-yl)methyl)-4-fluoroaniline (L 5 ); and N-((3,5-dimethyl-1H-pyrazol-1-yl)methyl)aniline (L 6 ), were reported and examined, in combination with different metallic salts, for their catecholase and phenoxazinone synthase activities at ambient conditions. We highlight the utility of spectroscopic and electrochemical methods, for studying the catalytic activity of biomimetic complexes and understanding the catalytic mechanism of substrate oxidation; the electrochemical oxidation of catechol has been successfully performed by cyclic voltammetry at room temperature and electrochemical cell with three electrodes. The role of metallic salt and the ligand structure of these complexes on their catecholase and phenoxazinone synthase activity have been examined. The metallic salt Cu(CH 3 COO) 2 appears a better candidate to produce the best model of the two studied enzymes in neutral mediums.