Sensing mechanism of fluorogenic urea with fluoride in solvent media: A new fluorescence quenching mechanism

Yong Xia; Mengyao Li; Aixiang Xu; Zhe Zhang; Aokui Sun; Sha Ding; Yuejun Liu

doi:10.1016/j.saa.2020.118992

Sensing mechanism of fluorogenic urea with fluoride in solvent media: A new fluorescence quenching mechanism

Spectrochim Acta A Mol Biomol Spectrosc. 2021 Feb 5:246:118992. doi: 10.1016/j.saa.2020.118992. Epub 2020 Sep 28.

Authors

Yong Xia¹, Mengyao Li², Aixiang Xu³, Zhe Zhang³, Aokui Sun², Sha Ding⁴, Yuejun Liu²

Affiliations

¹ Hunan Key Laboratory of Biomass Fiber Functional Materials, School of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007, China; College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China. Electronic address: [email protected].
² Hunan Key Laboratory of Biomass Fiber Functional Materials, School of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007, China.
³ School of Civil Engineering, Hunan University of Technology, Zhuzhou 412007, China.
⁴ Hunan Key Laboratory of Biomass Fiber Functional Materials, School of Packaging and Materials Engineering, Hunan University of Technology, Zhuzhou 412007, China; School of Civil Engineering, Hunan University of Technology, Zhuzhou 412007, China. Electronic address: [email protected].

PMID: 33038861
DOI: 10.1016/j.saa.2020.118992

Abstract

The interaction of 1-Phenyl-3-(pyren-1-yl) urea (LH) and fluoride anion (F^-) with a unique ON¹-OFF-ON² fluorescent response has been investigated by the density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations. The hydrogen-bonding dynamics and photophysical properties of the complex LH-F, as well as its isolated receptor LH and anion form L-H₁, have been studied in detail. We demonstrate that the intermolecular hydrogen bond (N-H…F) of the complex LH-F is greatly enhanced in the electronically excited state. The nonradiative deactivation via electron transfer and internal conversion rather than excited-state intramolecular proton transfer (ESIPT) can be facilitated by the excited state hydrogen bond strengthening. The results have been cross-validated by molecular structure, electronic spectra, frontier molecular orbitals, and infrared spectra as well as hydrogen bond binding energy. These results indicate that the current calculations completely reproduce the experimental results and provide compelling evidence for the sensing mechanism of LH for F^-.

Keywords: Fluoride anion; Fluorogenic urea; Hydrogen bond; Sensing mechanism; TDDFT.