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Indexed by:期刊论文

Date of Publication:2013-04-01

Journal:CANADIAN JOURNAL OF CHEMISTRY-REVUE CANADIENNE DE CHIMIE

Included Journals:SCIE、EI、Scopus

Volume:91

Issue:4

Page Number:248-254

ISSN No.:0008-4042

Key Words:DFT/TDDFT; hydrogen bonding; excited state; spectral redshift; spectral blueshift; frontier molecular orbitals; absorption spectra

Abstract:The density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods were performed to investigate the electronic excited-state hydrogen bonding dynamics of the hydrogenbonded complex formed by BHC-nicotinamide (BHCN) and methanol (MeOH). The ground-state geometry optimizations, electronic transition energies, corresponding oscillation strengths of the low-lying electronically excited states, and the optimized S-1 excited-state geometry for the isolated BHCN and MeOH monomers, the hydrogen-bonded BHCN-MeOH dimers, and BHCN-2MeOH trimer complexes have been calculated by using the DFT and TDDFT methods, respectively. We have demonstrated that the intermolecular hydrogen bond C-10=O-14 center dot center dot center dot H-40-O-39-Me is weaker than C-16=O-17 center dot center dot center dot H-46-O-45-Me in the hydrogen-bonded dimers and trimer no matter whether in the ground state or the excited state. In addition, our results are consistent with the relationship between the electronic spectral shifts and excited-state hydrogen bonding dynamics: hydrogen bond strengthening can induce the relative electronic spectra redshift, whereas a blueshift will be induced. In addition, we focused our attention on the frontier molecular orbital and the results could reasonably explain the hydrogen bond strengthening or weakening mechanism.