On the chemical properties of the transient complexes L_mM~(n+1)-OOR Part I. The case of (2,3,9,10-tetramethyl-1,4,8,11-tetraazacyclotetradeca-1,3,8,10-tetraene)(H_2O)Co~III-OOCH_3~(2+)

摘要

The transient complex (2, 3, 9, 10-tetramethyl-1, 4, 8, 11-tetraazacyclotetradeca-1, 3, 8, 10-tetraene)(H_2O)Co~III-OOCH_3~(2+), (time)(H_2O)Co~III-O_2CH_3~(2+), was prepared via the reaction of Co~II(tim)(H_2O)_2~(2+) with methylperoxyl radicals, applying radiation chemistry techniques. The transient complex decomposes mainly via a‘Fenton-like’reaction with excess Co~II(tim)(H_2O)_2~(2+), k = 16+-1 M~(-1) s~(-1). The transient complex reacts with the CH_3O_2~. radicals, k = (1.4+-0.3)×10~9 M~(-1) s~(-1) to form Co~II(tim)(H_2O)_2~(2+) 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.