Theoretical study of stepwise hydrogenated closo-alane clusters Al13Hm- (m=1-12)

Charkin, O.P.; Klimenko, N.M.; Charkin, D.O.

Авторы: Charkin O.P., Klimenko N.M., Charkin D.O.
Журнал: Russian Journal of Inorganic Chemistry
Том: 51
Номер: 2
Год издания: 2006
Издательство: Maik Nauka/Interperiodica Publishing
Местоположение издательства: Russian Federation
Первая страница: 281
Последняя страница: 291
DOI: 10.1134/S0036023606020173
Аннотация: The structure, energy, and vibrational characteristics of different stepwise-hydrogenated closo-alane clusters Al13Hm- (m = 1-12) were calculated within the B3LYP approximation of the density functional theory using 6-31G* and 6-311+G* basis sets. For each of the m values, there is a set of several low-lying, closely spaced (within similar to 0.1-0.3 eV) isomers. In the first half of the series, inner isomers (with the centered cage Al@Al-12) are preferable; and in the second half, outer isomers (with the thirteenth Al atom located on the outside of the empty Al-12 icosahedron and coordinated to its face) are more favorable. In some of the outer isomers, the aluminum cage is severely distorted and loses its closo form. When a hydrogen atom is attached to paramagnetic radical anions (with odd m values), the most favorable site for attack is the Al* atom located opposite the Al-t-H bond and carrying most of the unpaired electron density. The resulting diamagnetic anions contain a maximum number of linear (or quasi-linear) HAlH-Al-c-AlHH or HAlH center dot center dot center dot AlHH fragments in the inner and outer isomers, respectively (the trans addition rule). The energy D-m (H) of successive addition of an H atom to the centered icosahedron Al-13(-) depends on m in a zigzag manner: the even bonds are always similar to 1 eV stronger than the odd bonds. This trend is interpreted in the framework of the molecular model of the valence states of the [Al-13] "superatom" with a variable valence increasing from 1 to 12 due to the unpairing of one to six electron pairs of the cage when the first, third, etc. odd H atoms are attached to it.
Добавил в систему: Чаркин Дмитрий Олегович

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Theoretical study of stepwise hydrogenated closo-alane clusters Al13Hm- (m=1-12)статья