On the chemical properties of the transient complexes L(m)M(n+1) - OOR Part I. The case of (2,3,9,10-tetramethyl-1,4,8,11-tetraazacyclotetradeca-1,3,8,10-tetraene)(H₂O )Co(III)- OOCH₃²⁺

The transient complex (2,3,9,10-tetramethyl-1,4,8,11-tetraazacyclotetradeca-1,3,8,10-tetraene)(H₂O )Co(111)-OOCH₃²⁺, (tim)(H₂O)Co(III)-O₂CH₃²⁺, was prepared via the reaction of Co(11)(tim)(H₂O)₂²⁺ with methylperoxyl radicals, applying radiation chemistry techniques. The transient complex decomposes mainly via a 'Fenton-like' reaction with excess Co(II)(tim)(H₂O)₂²⁺, k= 16 ± 1 M^-1 s^-1. The transient complex reacts with the CH₃O₂ radicals, k=(1.4 ± 0.3) x 10⁹ M^-1 s^-1 to form Co(11)(tim)(H₂O)₂²⁺ and formaldehyde. This reaction is surprisingly fast and if this rate is typical for analogous reactions these reactions have to be considered in a variety of radical induced oxidation processes. The plausible role of analogous reactions in oxidation processes by peroxides and dioxygen, which are catalyzed by cobalt complexes, is discussed. (C) 2000 Elsevier Science S.A.