Several copper compounds (CuCl, CuCl2, CuSO4, Cu(NO3)(2), Cu(OAc)(2), Cu(OCH3)(2), and Cu(OCH3)(Cl)) have been used as catalysts for the oxidation of 2-aminophenol with dioxygen at 60degreesC in DMF to 2-aminophenoxazine-3-one; a comparison of their activities was made through kinetic measurements. Stronger coordinating donor N-ligands (bpy, phen) accelerate the reaction rate remarkably and the amount of ligand influences the molecularity of the CuCl-catalyzed reaction. The overall second order rate equation was found at CuCl to phen ratio of 1:0 (k(2)/60degreesC = 11.3+/-0.5 x 10(2) mol(-3) l(3) s(-1)), while the reaction is zero order with respect to 2-aminophenol concentration at a CuCl to phen ratio of 1:2 (k(0)/60 degreesC = 13.9+/-0.7 x 10(-2) mol(-3) l(3) s(-1)). The kinetics of the CuCl(phen)-catalyzed reaction measured at 60degreesC resulted in a rate equation with first order dependence on copper, dioxygen and 2-aminophenol. The rate constant, activation enthalpy, and entropy at 333.16 K are as follows: k(obs) = 2.42+/-0.22 mol(-2) dm(6) s(-1), E-a = 25+/-1 kJmol(-1), DeltaH(double dagger) = 22+/-1 kJmol(-1) and DeltaS(double dagger) = -170+/-13 Jmol(-1) K-1. The catalytic systems investigated can be viewed as functional models of the enzyme phenoxazinone synthase. (C) 2004 Elsevier B.V. All rights reserved.