Тип публикации: статья из журнала
Год издания: 2016
Идентификатор DOI: 10.1039/c6ra21471a
Ключевые слова: Activation energy, Catalysis, Catalytic oxidation, Electronic states, Excited states, Oxidation, Peroxides, Potential energy, Quantum chemistry, Reaction intermediates, Aluminum derivatives, Catalytic decomposition, Catalytic reactions, Chemical excitation, Nucleophilic substitutions, Quantum chemical studies, Selective oxidation, Source of electrons, Aluminum
Аннотация: The quantum chemical study of the MeOOH/(MeO)(3)Al model system has been carried out in order to predict the mechanism of the catalytic decomposition of t-BuOOH under mild conditions for the t-BuOOH/(t-BuO)(3)Al system being a powerful synthetic tool for selective oxidation. To elucidate the chemical excitation of O-2 eliminated in the catalytic reaction and to predict the electronic state of O-2, the topology of the potential energy surface (PES), the structures of intermediates and transition states, the activation and reaction energies were obtained at the B3LYP/cc-pVTZ theory level. It was shown that the peroxide, (MeO)(2)AlOOMe, corresponding to the experimentally obtained (t-BuO)(2)AlOOBu-t, is formed in the first step of the reaction. After that, in the main pathway, the aluminum-containing peroxide reacts with the second MeOOH molecule through the nucleophilic substitution of the second methoxy group forming the MeOAl(OOMe)(2) diperoxide. The diperoxide rearranges to aluminum-containing ozonide MeOAlOOOMe. The ozonide isomerizes in the mononuclear-metal dioxygen intermediate (MeO)(3)Al.O-2. The latter decomposes through the adiabatic ((MeO)(3)Al + O-2(b(1)Sigma(+)(g))) and nonadiabatic ((MeO)(3)Al + O-2(X-3 Sigma(-)(g))) pathways, which corresponds to experimental data about the incomplete conversion of O-2 to O-2(X-1 Sigma(-)(g)). The generation of O-2(X-1 Sigma(-)(g) was revealed by the analysis of the energy diagram calculated with the CCSD(T), CCSDT(Q), and CASSCF methods. It was suggested that the eta(1)-(MeO)(3)Al . O-2 and, thus, (t-BuO)(3)Al.O-2 complexes are new sources of O-2(b(1)Sigma(+)(g)).
Журнал: RSC ADVANCES
Выпуск журнала: Vol. 6, Is. 98
Номера страниц: 95542-95555
ISSN журнала: 20462069
Место издания: CAMBRIDGE
Издатель: ROYAL SOC CHEMISTRY
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