Catecholase biomimetic catalytic activity of copper(II) complexes with 2-methyl-3-amino-(3H)-quinazolin-4-one

Abstract

The oxidation of catechol by molecular oxygen in the presence of a catalytic amount of copper(II) complex with 2-methyl-3-amino-(3H)quinazoline-4-one (MAQ) and various anions (Cl ) , Br ) , ClO 4 ) , SCN ) , NO 3 ) and SO 4 -) was studied. The catecholase biomimetic catalytic activity of the copper(II) complexes has been determined spectrophotometrically by monitoring the oxidative transformation of catechol to the corresponding light absorbing o-quinone (Q). The rate of the catalytic oxidation reaction was investigated and correlated with the catalyst structure, time, concentration of catalyst and substrate and finally solvent effects. Addition of pyridine or Et 3 N showed a dramatic effect on the rate of oxidation reaction. Kinetic investigations demonstrate that the rate of oxidation reaction has a first order dependence with respect to the catalyst and catechol concentration and obeying Michaelis-Menten Kinetics. It was shown that the catalytic activity depends on the coordination environment of the catalyst created by the nature of counter anions bound to copper(II) ion in the complex molecule and follows the order:To further elucidate the catalytic activity of the complexes, their electrochemical properties were investigated and the catecholase mimetic activity has been correlated with the redox potential of the Cu 2+ /Cu + couple in the complexes.

Synthesis, superoxide dismutase, nuclease, and anticancer activities of copper(II) complexes incorporating bis(2-picolyl)amine with different counter anions

“…In this situation, complex 4 can behave as an oxidant (i.e., behaves as superoxide anion quencher) not as a catalyst. Such behavior was observed for analogous copper(II) complex during the catalytic oxidation of catechol [40]. Finally, for all the complexes, the cyclic voltammograms exhibit an additional cathodic peak almost at the same potential.…”

Triazole based copper(II) complexes: Synthesis, spectroscopic characterization, Density Function Theory study, and biomimicking of copper containing oxidase proteins

“…Also, if the copper complex containing counter‐anion is involved in the redox reaction, then the nature of the bound anion has exhibited an appreciable influence on the redox potential of the couple M n+ /M (n + 1)+ during the catalytic reaction. [ 18 ] However, the effect of the counter‐anion on stereochemistry, spectroscopy, structural, and catalytic properties of a wide range of copper complexes used as mimics of copper‐containing proteins have been studied. [ 17,18 ]…”

“…[ 18 ] However, the effect of the counter‐anion on stereochemistry, spectroscopy, structural, and catalytic properties of a wide range of copper complexes used as mimics of copper‐containing proteins have been studied. [ 17,18 ]…”

Transition metal complexes of 1,2‐dihydroquinazolinone derivative, an emerging class of analgesic and anti‐inflammatory agents

“…[11] Quinazoline-4(3H)-ones have also drawn the attention of coordination chemists, as they adopt various binding modes with transition and main group metal ions which have a positive effect on their activity. These bioactive molecules can act as monodentate or bidentate ligands, [12,13] and their coordination capacity can be further increased if aldehydes or ketones that contain additional functional group(s) in position(s) suitable for chelating are used for their preparation.…”