چکیده
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UMP2/aug-cc-pVTZ calculations are carried
out to investigate the geometry, interaction energy and
bonding properties of single-electron triel bond (SETB)
interactions in binary X 3 ZCH 3 complexes, where Z = B,
Al and X = H, F, Cl, Br, CN, NC, OH and CH 3 . The
estimated binding distances are found to be in the range of
2.129–3.321 and 2.358–2.555 A
˚
for X 3 BCH 3 and X 3
AlCH 3 complexes, respectively, which are much smaller
than the sum of the van der Waals radii of corresponding
interacting atoms. The strength of SETBs strongly depends
upon the nature of the Z and X substituents. For a given Z
atom, the presence of electron-withdrawing groups such as
F or CN in ZX 3 molecule tends to increase the absolute
value of interaction energy, while a reverse trend is seen
for the electron-donating groups (OH and CH 3 ). According
to quantum theory of atoms in molecule, all strong SETB
interactions indicate a partially covalent character. The
analysis of the intermolecular orbital interactions in the
title complexes also indicates that the amount of charge
transfer from the single-electron occupied p orbital of
radical methyl to the empty p orbital of Z atom increases in
the order CN [ NC [ H [ CH 3 [ F [ Cl [ Br [ OH.
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