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8.
Density Functional and Molecular Orbital Studies on
the Activation of Donor-Acceptor Sub-systems, Charge Transfer and
Binding in the H3BNCH and H3BNCCH3
Complexes
Part-II Molecular Orbital Study
Jibanananda Jana
Department of Chemistry, Krishnagar Govt. College, Krishnagar,
Nadia, W.B., INDIA
E-mail:
jiban_jana@yahoo.co.in
ABSTRACT
In this study, the origin of
charge transfer and mechanism of bond formation are described along
with the amount of donation, back-donation and net charge transfer
in the formation of electron donor- acceptor (EDA) complexes of HCN
and CH3CN with BH3. The role of symmetry of the
interacting MO’s of the donors and acceptor is prominent and the
role of the MO next to frontier orbitals is nicely reflected when
frontier orbitals are found to be symmetrically barred during such
interaction. Local density functional parameters—fukui functions and
local softnesses are married to the MO theory for correlation of
efficiency of donation and back-donation and it is unambiguously
proved that s– is the more fundamental parameter than f– in
correlating the capability of donation of the donors. Heats of
formations and hence stabilities of the complexes are correlated in
terms of net charge transfer. Mulliken’s correlation related to the
stability of the electron donor-acceptor (EDA) complexes and
ionization potentials of the donors is nicely reflected here.
Key Words: Fukui functions,
Local softnesses, EDA complexes, HOMO-LUMO energy gap, configuration
interaction.
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