Abstract:

The process of electron transfer (ET) from benzenitrile radical anion to carbon dioxide is studied by the quantum chemical semiempirical AM1 and ab initio methods on 3-21G and parlization 6-21G* levels. The results showed that the donor-to-acceptor distance in the precursor is 0.2728 nm for AM 1, 0.2479 nm for UHF/3-21G and 0.2769 nm for UHF/6-31G*. In such a short distance, the HOMO in donor and LUMO in acceptor will approach and overlap considerably, which correspondes to a nonneghgrble interaction between the donor and the acceptor. It showed that this ET reaction is not a simple out-sphere but rather an inner-sphere process, the violation of Marcus theory for this reaction can therefore be explained reasonabley. The binding energy of the Precursor is calculated to be 0. 19 eV for AM1 and 0.26 eV for ab initio 6-31G* level.

Key words: Inner-sphere electron transfer, AMl, Ab initio method