Electronic structure and models of monooxygenase inductor receptor from a number of polychlorinated polycyclic compounds. 5. MNDO calculations of halogen derivatives of azoxybenzenes

Autor: Fokin, A. V., Bogachuk, E. B., Vorob'eva, N. P., Raevskii, N. I., Borisov, Yu. A., Kolomiets, A. F.
Zdroj: Russian Chemical Bulletin; January 1991, Vol. 40 Issue: 1 p86-89, 4p
Abstrakt: The MNDO method has been used to calculate the electronic and geometric structure of 3,3',4,4'-tetraehloroazoxybenzene (TCAOB), 3,3',4,4'-tetrachloro-6-hydroxyazobenzene (TCHAB), and 2,3,7,8-tetrachlorodibenzofuran (TCDF). The TCAOB exists in the gas phase in the form of two configurations, one nonplanar and one nearly planar. The latter is approximately 4 kcal/mole less stable than the first. The oxidation of 3,3',4,4'-tetrachloroazobenzene (TCAB) to TCAOB is endothermic only in the case of the acton of hydrogen peroxide, not molecular oxygen. The isomerization of TCAOB to TCHAB proceeds with a gain in energy (-62 kcal/mole); however, the reaction from the ground state of the TCAOB molecule is symmetry-forbidden and is possible only from an excited state of the TCAOB. The process of oxidation of TCAOB and TCHAB by molecular oxygen to form TCDF or 2,3,7,8-tetrachlorobenzo-p-dioxin is energy-favorable; this is important in judging the biological action of TCAOB.
Databáze: Supplemental Index
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