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Theoretical insights into excited‐state process for the novel 2,3‐bis[(4‐diethylamino‐2‐hydroxybenzylidene)amino]but‐2‐enedinitrile system
Author(s) -
Xu Lei,
Zhang Tianjie,
Yang Dapeng,
Zhang Qiaoli
Publication year - 2020
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.201900202
Subject(s) - chemistry , intramolecular force , hydrogen bond , excited state , density functional theory , photoexcitation , molecule , photochemistry , proton , computational chemistry , potential energy surface , chemical physics , atomic physics , stereochemistry , organic chemistry , physics , quantum mechanics
In this present work, we clarify the excited‐state intramolecular proton transfer (ESIPT) mechanism for 2,3‐bis[(4‐diethylamino‐2‐hydroxybenzylidene)amino]but‐2‐enedinitrile (BDABE) system. We present the fact that excited‐state single proton transfer can occur along with one hydrogen bond, even though BDABE form consists of two intramolecular hydrogen bonds. Based on the density functional theory and time‐dependent density functional theory methods, we theoretically investigate and elaborate the excited‐state intramolecular dual hydrogen‐bonding interactions. By simulating the electrostatic potential surface, we verify the formation of dual intramolecular hydrogen bonds for BDABE molecule in the S 0 state. Furthermore, comparing the primary bond lengths and bond angles as well as the infrared vibrational spectra, we find that the double hydrogen bonds should be strengthened in the S 1 state. When it comes to photoexcitation process, we discover the charge redistribution around hydrogen bonding moieties. The increased electronic density around proton acceptor plays the important roles in strengthening hydrogen bonds and in facilitating ESIPT reaction. In view of the possible ESIPT reaction paths (i.e., stepwise and synchronization double proton transfer) for BDABE molecule, we explored the S 0 ‐state and S 1 ‐state potential energy curves. This work explains experimental results and further clarifies the excited‐state behaviors for BDABE system.