Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5398615 | Journal of Luminescence | 2016 | 5 Pages |
Abstract
Time-dependent density functional theory (TD-DFT) method at B3LYP/6-31G(d,p) theoretical level was employed to investigate the excited-state intramolecular proton transfer (ESIPT) reaction of 6-amino-2-(2â²-hydroxyphenyl)benzoxazole in dichloromethane and methanol solvents. Upon photo-excitation, the intramolecular hydrogen bond between the hydroxyl and neighboring N atom is significantly strengthened, which provides a driving force in facilitates the ESIPT reaction. The calculated steady-state absorption and fluorescence spectra agree well with the experimental results. Especially, after the photo-excitation from HOMO (Ï) to LUMO (Ï*), the rearrangement of electronic density distribution of frontier molecular orbitals (MOs) is a very important positive factor for the ESIPT process. The potential energy curves confirm that, after photo-excitation, the EXIPT reaction occurs with the H atom of the hydroxyl group remove to the neighboring N atom. By contrast, the potential barrier of the 6A-HBO-MeOH complex in the S1 state falls ca. 3.57Â kcal/mol, lower than the isolated 6A-HBO. It is likely that the ESIPT reaction occurs more easily for the 6A HBO-MeOH complex due to the influence of the intermolecular hydrogen bonding.
Keywords
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Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Chaozheng Li, Chi Ma, Donglin Li, Yufang Liu,