Theoretical exploring effects of solvent polarity and atomic electronegativity on excited state behaviour for BY4TP fluorophore

Abstract

As widely acknowledged, the realm of novel organic molecules boasting extraordinary attributes pertaining to excited-state intramolecular proton transfer (ESIPT) has emerged as a captivating subject matter. In this context, our primary focus lies in delving into the excited-state behaviour exhibited by 2-benzoxazol-2-yl-4-triethylsilanylethynyl-phenol (BY4TP), an alluring derivative derived from 2-(2-hydroxyphenyl)benzoxazole (HBO). Relying on the examination of four distinct aprotic solvents with varying degrees of polarities, we can unequivocally affirm that solvent polarity exerts a profound influence on the intricate interplay of hydrogen bonding interactions, charge redistribution and reorganisation, as well as associated ESIPT phenomena by light. Through meticulous comparison and precise measurement of reaction barriers across diverse solvent environments, our groundbreaking findings indicate that lowly polar solvents serve as efficacious facilitators for promoting the occurrence of the ESIPT reaction in BY4TP fluorophore. By considering atomic-electronegativity-regulated hydrogen bonding effects and excited state behaviours for BY4TP-S and BY4TP-Se, we also present low atomic electronegativity with Se substation promotes ESIPT reaction. We ardently anticipate that this study will provide invaluable insights into the behaviour exhibited by BY4TP upon excitation and under the influence of solvent polarity and atomic electronegativity, while simultaneously paving new avenues for future research endeavours and applications encompassing novel HBO derivatives.