An experimental and theoretical study of solvent hydrogen-bond-donating capacity effects on ultrafast intramolecular charge transfer of LD 490

Hui Li; Hang Yin; Xiaochun Liu; Ying Shi; Mingxing Jin; Dajun Ding

doi:10.1016/j.saa.2017.05.027

An experimental and theoretical study of solvent hydrogen-bond-donating capacity effects on ultrafast intramolecular charge transfer of LD 490

Spectrochim Acta A Mol Biomol Spectrosc. 2017 Sep 5:184:270-276. doi: 10.1016/j.saa.2017.05.027. Epub 2017 May 15.

Authors

Hui Li¹, Hang Yin¹, Xiaochun Liu¹, Ying Shi², Mingxing Jin¹, Dajun Ding¹

Affiliations

¹ Institute of Atomic and Molecular Physics, Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy, Jilin University, Changchun 130012, China.
² Institute of Atomic and Molecular Physics, Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy, Jilin University, Changchun 130012, China. Electronic address: shi_ying@jlu.edu.cn.

PMID: 28525861
DOI: 10.1016/j.saa.2017.05.027

Abstract

The excited-state intramolecular charge transfer (ICT) of LD 490 were investigated in different hydrogen-bond-donating solvents (α scale) on the basis of the Kamlet-Taft solvatochromic parameters (π*, α, β). The femtosecond transient absorption spectra and the kinetics decay rate reveal that with an increase of solvent's α capacity, the long-lived picosecond process, which is attributed to the ICT, becomes much faster. Combining with time-dependent density functional theory (TDDFT) calculations, we demonstrate that the enhancement of α acidity substantially increases the electronegativity of the carbonyl oxygen in LD 490, which strengthen excited-state intermolecular hydrogen bonding interactions and consequently facilitate the ICT process.

Keywords: Femtosecond transient absorption spectra; Intermolecular hydrogen bonding; Intramolecular charge transfer; TDDFT.