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Theoretical study on a chemosensor for fluoride anion‐based on a urea derivative
Author(s) -
Liu Wenfang,
Wang Bingqiang,
Zhang Caiyun,
Yin Xiaofen,
Zhang Jian
Publication year - 2013
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.24527
Subject(s) - deprotonation , chemistry , hydrogen bond , intramolecular force , fluoride , ion , density functional theory , intermolecular force , transition state , inorganic chemistry , photochemistry , crystallography , computational chemistry , molecule , stereochemistry , organic chemistry , catalysis
The sensing mechanism of the N‐Phenyl‐N′‐(3‐quinolinyl)urea (PQU) chemosensor for fluoride anion has been investigated by density functional theory/time‐dependent density function theory. The double intermolecular hydrogen bonds are formed between the three anions (X − F − , AcO − , Cl − ) and the urea fragment of PQU. In the S 0 states, the H b X − hydrogen bonds are slightly stronger than the H a X − hydrogen bonds and the fluoride‐induced deprotonation occurs at the NH b position rather than at the NH a position. Consequently, the absorption peaks, including an intramolecular charge transfer transition and a ππ* transition, are significantly red‐shifted. Thermodynamic calculations confirm that the deprotonation in the ground state is favorable in energy only when excess fluoride anion exists. Along with the S 0 → S 1 transition, the H a X − hydrogen bonds strengthen and the H b X − hydrogen bonds weaken. However, the emission spectra of [PQU‐H b ] − , instead of [PQU‐H a ] − , are observed upon addition of fluoride anion. © 2013 Wiley Periodicals, Inc.