Bioinspired copper corrole and porphyrin catalysts for oxidation and hydrocarboxylation of alkanes

The development of novel bioinspired catalytic systems that are efficient in the mild oxidative transformation of alkanes remains an attractive research direction in the area of molecular catalysis. In the current study, three copper corrole/porphyrin complexes were synthesized, characterized, and evaluated as homogeneous catalysts in the oxidative transformation of cycloalkanes under mild conditions. New copper complexes of 5,10,15-tris(pentafluorophenyl)corrole and 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin derivatives bearing a hydroxyethoxy unit were obtained via the controlled nucleophilic substitution of para fluorine atom with ethylene glycol. The model catalytic processes include: (i) the oxidation of cycloalkanes with H2O2 into a mixture of cyclic ketones and alcohols, and (ii) the hydrocarboxylation of cycloalkanes in the CO/S2O82−/H2O system to generate cycloalkanecarboxylic acids as main products. Both model reactions occur under mild conditions (50−60 °C). Selectivity features, substrate and oxidant scope, and the effects of various reaction parameters were studied and discussed. The best catalysts were the copper corrole derivatives, the performance of which is slightly influenced by the presence of the ethylene glycol moiety. In particular, the copper(III) complex of 5,10,15-tris(pentafluorophenyl)corrole is an efficient catalyst for the mild oxidation and carboxylation of cycloalkanes. This work widens the types of Cu-based corrole/porphyrin derivatives that can be used as bioinspired catalytic systems.