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Theoretical elaboration about the excited state dynamical behaviors for a novel fluorescent sensor
Author(s) -
Zhang Tianjie,
Zhang Qiaoli,
Lu Xuemei,
Jia Min,
Song Xiaoyan,
Yang Dapeng
Publication year - 2019
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.3931
Subject(s) - chemistry , time dependent density functional theory , excited state , enol , density functional theory , intramolecular force , hydrogen bond , fluorescence , molecular orbital , molecule , potential energy surface , computational chemistry , photochemistry , chemical physics , atomic physics , stereochemistry , quantum mechanics , physics , biochemistry , organic chemistry , catalysis
Using the density functional theory (DFT) and time‐dependent density functional theory (TDDFT) methods, we theoretically explore a novel fluorescent sensor molecule (abbreviated as “2”) ( Sensors Actuat B‐Chem . 2018, 263 , 585). Because of its symmetry, three stable structures can be located, ie, 2‐enol, 2‐SPT, and 2‐DPT forms in both S 0 and S 1 states. Via comparing the bond lengths and bond angles involved in the hydrogen bonding moieties, we find the dual intramolecular hydrogen bonds should be strengthened in the S 1 state. And based on infrared (IR) vibrational simulations, we further confirm the strengthening dual hydrogen bonds. Upon the photo‐excitation process, the charge redistribution via frontier molecular orbitals (MOs) reveals the tendency of excited state intramolecular proton transfer (ESIPT) reaction. In addition, the constructed S 0 ‐state and S 1 ‐state potential energy curves demonstrate that the excited state single proton transfer (ESSPT) should be the most supported one from 2‐enol to 2‐SPT form. In view of the S 1 ‐state stable 2‐SPT and 2‐DPT structures as well as the fluorescence peaks of them, we can further confirm the ESSPT mechanism for 2 chemosensor. This work not only clarifies the excited state behaviors of 2 system but also successfully explain the previous experimental phenomenon.