Effect of phenanthroline substituents on the rate of oxygen uptake by copper(I) complexes

Abstract

The values of the rate constant for the oxidation reaction are reported for a series of substituted bis(phenanthroline)copper(I) complexes. The rate constant increases along the series: 2,9-diCH3 phen < 5-Cl phen < phen < 5-CH3 phen < 4,7-diC6H5 phen < 5,6-diCH3 phen. A correlation is developed between the experimental rate constants obtained and the acid dissociation constants for the ligands. The reaction fits a Hammett linear free energy relationship with ρ{variant} = -0.71. The rate determining step in each reaction is attributed to the electron transfer to the oxygen molecule, which is influenced principally by changes in electron density at the metal site. © 1976.