Electronic structure of anionic σ complexes of m-dinitrobenzene and its derivatives.

Autor: Kaminskii, A.
Zdroj: Theoretical & Experimental Chemistry; Jan1989, Vol. 25 Issue 1, p23-29, 7p
Abstrakt: It has been established as a result of calculations of the electronic structure of products of the addition of nucleophilic agents (H and CH) to m-dinitrobenzene and its derivatives by the CNDO/S method that the negative charge of these anions is delocalized over the π system of the cyclohexadiene ring (∿50%) and the nitro groups (15-20% each), of which the nitro group in the para position (to the sp-hybridized carbon atom) is more negatively charged. A certain fraction of the charge of the anion is distributed according to an induction mechanism to the hydrogen atoms and the geminal substituents. The data on the bond orders and the distribution of charges attest to the quinoidal structure of the carbon ring in the a complexes. The results of the calculations make it possible to predict the direction of the reactions of the anionic σ complexes with electrophilic and nucleophilic reagents. The calculated values of the total energies of the σ complexes correctly reflect their relative stability. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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