Computational insights into solvent polarity associated excited state behaviour for 2-(1H-benzoimidazol-2-yl)−5-diethylamino-phenyl fluorophore

Abstract

Inspired by the mesmerising charm emanating from the precisely controlled attributes displayed by 2-(1H-benzoimidazol-2-yl)−5-diethylamino-phenyl (HDP) and its derivatives in the domains of photochemistry and photobiology, our present undertaking predominantly focuses on exploring the complexities of light-triggered excited state reactions for HDP fluorophore dissolved in solvents with diverse levels of polarity. Initially, we performed molecular structure optimisation at various stages of the proton transfer process and collected data on bond length, bond angle, and core-valence bifurcation (CVB) index for the molecular framework. Subsequently, infrared (IR) vibrational spectra were analysed to evaluate the reinforcement of hydrogen bonds in different solutions. Furthermore, the investigation of orbital transitions and potential energy curves has led to the conclusion that the ESIPT process of HDP molecules is most likely to occur in nonpolar ccl₄ solution, followed by chloroform solution; acetonitrile ranks last. In essence, the nonpolar aprotic solvents are more conducive to facilitating the ESIPT process. This research aims to contribute towards advancements in new luminescent materials and prove valuable in display technology and medical imaging fields while also promoting related technological development.

GRAPHICAL ABSTRACT

KEYWORDS:

• Intramolecular hydrogen bond; excited state intramolecular proton transfer; solvent polarity; potential energy curves

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Data are available on request from the corresponding author.

Additional information

Funding

This work was supported by the Liaoning Revitalization Talents Program [grant number XLYC2203155], the Support Program for Young and Middle-aged Scientific and Technological Innovation Talents of Shenyang City [grant number RC230960], the Major Incubation Program of Shenyang Normal University [grant number ZD202304], and Shenyang Normal University doctoral program [grant number BS202303]. The main part of this work was carried out at Bianshui Riverside Supercomputing Center (BRSC) of China.