Mononuclear copper (II) complexes catalyzed oxidation of TMPD and O-phenylenediamine and oxygen insertion in the O-phenylenediamine/ Ph3P/ Copper (II) catalyst.

Abstract

The catalytic activities of bis(acetato) bis (imidazole) copper (II) and bis(valproato) bis(imidazole) copper (II) complexes for the oxidation of TMPD (N,N,N',N'-tetramethyl-P-phenylenediamine) in air were followed spectrophotometrically by monitoring the increase in the TMPD* absorbance in methanol at 565nm as a function of time [1]. For both complexes, the method of initial rates showed a first-order dependence on the catalyst and TMPD concentrations. These complexes were found to be an effective catalysts for the oxidative cyclization of 0-phenylenediamine (OPD) to 2,3- diaminophenazine (DAP). The catalytic activities were followed spectrophotometrically by monitoring the increase in the DAP absorbance in methanol at 428nm as a function of time. When copper (II) complexes were added to a methanolic solution containing OPD and Ph,P in a mole ratio of 1:4 under the atmospheric air, DAP were not obtained but instead Ph,P = 0 was produced. The production of Ph,P = 0 was monitored by following the increase in the P = 0 IR frequency at 1195 cm-I. The relevance of these copper (II) complexes to the biological functions of copper proteins and enzymes are discussed [2].