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Indexed by:期刊论文

Date of Publication:2013-06-01

Journal:JOURNAL OF CLUSTER SCIENCE

Included Journals:SCIE

Volume:24

Issue:2,SI

Page Number:459-470

ISSN No.:1040-7278

Key Words:Hydrogen bonding; Dihydrogen bonding; Electronically excited state; Vibrational modes; Red-shift; Blue-shift

Abstract:In this work, the intermolecular dihydrogen and hydrogen bonding interactions in electronically excited states of a 2-pyridone (2PY)-borane-trimethylamine (BTMA) cluster have been theoretically studied using time-dependent density functional theory method. Our computational results show that the S-1 state of 2PY-BTMA cluster is a locally excited state, in which only 2PY moiety is electronically excited. The theoretical infrared (IR) spectra of the 2PY-BTMA cluster demonstrate that the N-H stretching vibrational mode is slightly blue-shifted upon the electronic excitation. Moreover, the computed IR spectrum of the 2PY-BTMA cluster exhibits no carbonyl character due to the extension of the C=O bond length in the S-1 state. However, the N-H bond is shortened slightly upon photoexcitation. At the same time, the H center dot center dot center dot H and H center dot center dot center dot O distances are obviously lengthened in the S-1 sate by comparison with those in ground state. In addition, the electron density of the carbonyl oxygen is diminished due to the electronic excitation. Consequently, the proton acceptor ability of carbonyl oxygen is decreased in the electronic excited state. As a result, it is demonstrated that the intermolecular dihydrogen and hydrogen bonds are significantly weakened in the electronically excited state.