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Theoretical insight into the excited‐state behavior of a novel Compound 1: A TDDFT investigation
Author(s) -
Yang Dapeng,
Yang Guang,
Jia Min,
Song Xiaoyan,
Zhang Qiaoli
Publication year - 2018
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.3828
Subject(s) - time dependent density functional theory , chemistry , intramolecular force , density functional theory , excited state , enol , hydrogen bond , molecular orbital , computational chemistry , molecule , potential energy , proton , chemical physics , photochemistry , atomic physics , stereochemistry , quantum mechanics , organic chemistry , physics , catalysis
In the present work, using density functional theory and time‐dependent density functional theory methods, we investigated and presented the excited‐state intramolecular proton transfer (ESIPT) mechanisms of a novel Compound 1 theoretically. Analyses of electrostatic potential surfaces and reduced density gradient (RDG) versus sign(λ 2 )ρ, we confirm the existence of intramolecular hydrogen bond O1‐H2···N3 for Compound 1 in the S 0 state. Comparing the primary structural variations of Compound 1 involved in the intramolecular hydrogen bond, we find that O1‐H2···N3 should be strengthened in the S 1 state, which may facilitate the ESIPT process. Concomitantly, infrared (IR) vibrational spectra analyses further verify the stability of hydrogen bond. In addition, the role of charge transfer interaction has been addressed under the frontier molecular orbitals, which depicts the nature of electronical excited state and supports the ESIPT reaction. The theoretically scanned and optimized potential energy curves according to variational O1‐H2 coordinate demonstrate that the proton transfer process should occur spontaneously in the S 1 state. It further explains why the emission peak of Compound 1‐enol was not reported in previous experiment. This work not only presents the ESIPT mechanism of Compound 1 but also promotes the understanding of this kind of molecules for further applications in future.