Release Time:2019-03-09  Hits:

Indexed by: Journal Article

Date of Publication: 2011-01-01

Journal: JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY

Included Journals: SCIE

Volume: 217

Issue: 1

Page Number: 219-223

ISSN: 1010-6030

Key Words: Excited state; Hydrogen bonding; Proton transfer; Infrared spectra

Abstract: In this work, both the intermolecular and intramolecular hydrogen bonding of 3-aminophthalimide (3AP) dimer complex in the electronically excited state have been investigated theoretically using the time-dependent density functional theory (TDDFT) method. The calculated infrared spectrum of the hydrogen-bonded 3AP dimer complex for the S(1) state shows that the C=O and H-N bonds involved in the intramolecular hydrogen bond C(3)=O(5)center dot center dot center dot H(8)-N(6) and intermolecular hydrogen bond C(1)=O(4)center dot center dot center dot H(7')-N(2') which are markedly red-shifted compared with those predicted for the ground state. The calculated length of the two hydrogen bonds C(3)=O(5)center dot center dot center dot H(8)-N(6) and C(1)=O(4)center dot center dot center dot H(7')-N(2'), are significantly shorter in S(1) state than in the ground state. However, the bond lengths of the intramolecular hydrogen bond C(3')=O(5)center dot center dot center dot H(8')-N(6'), and intermolecular hydrogen bond C(1)=O(4)center dot center dot center dot H(7')-N(2') nearly unchanged upon electronic excitation to the S(1) state. Thus, the intramolecular hydrogen bond C(3)=O(5)center dot center dot center dot H(8)-N(6) and intermolecular hydrogen bond C(1)=O(4)center dot center dot center dot H(7')-N(2') of the hydrogen-bonded 3AP dimer complex are stronger in the electronically excited state than in the ground state. Moreover, it has been demonstrated that the excited-state proton transfer reaction is facilitated by the electronic excited-state hydrogen bond strengthening. (C) 2010 Elsevier B.V. All rights reserved.