Influence of the macrocycle nature on the redox properties of vanadium porphyrinates in their reaction with an organic peroxide

Resumo

The redox properties of vanadium 5,15-bis(о-methoxyphenyl)-3,7,13,17-tetrabutyl-2,8,12,18-tetramethyl-5,10,15,20-tetraphenylporphyrinates in the reaction with an organic peroxide, specifically dicumyl peroxide, were studied. The kinetic parameters of the reaction were determined and its possible mechanism was suggested. The coordinating capacity of vanadium porphyrinates with respect to dicumyl peroxide and imidazole and the stability of the resulting molecular complexes were estimated. It was shown that the nature of the macrocyclic ligand and the surrounding of the coordination center affect the rate of redox transformations. The isolated structures of the reagents and oxidation intermediates were optimized and their geometric parameters were obtained by the quantum-chemical РМ3 method. The calculation results revealed a high degree of deformation of the intermediate molecule, leading to macrocycle destruction.