STRUCTURAL STABILITY AND SUBSTITUENT EFFECTS ON THE PHOTOPHYSICAL PROPERTIES OF THIOANISOLE EXPLORED BY EXCITED-STATE DYNAMIC SIMULATIONS

Abstract

The photophysical properties of thioanisole (SCH3) and its derivatives as a representative system for investigating aryl sulfides were explored by TD-DFT using the B3LYP functional. Thioanisole appears in a variety of chemical applications due to its structural and reactive properties such as in dyes, drugs, and materials. Our investigations focus on the structural, photophysical, and dynamic properties influenced by substituents (F and Cl) on absorption and emission spectra. The electronic transition mainly corresponds to S0→S2 (π→σ*) with excitation energies of 5.11 eV and 5.02 eV for SCH3F and SCH3Cl, respectively. The dynamic simulations on the first-excited state provide additional insights that complement those obtained from static calculations. The fluorescence spectrum of SCH3F typically shows a blue shift, while the fluorescence spectrum of SCH3Cl displays a red shift compared to SCH3. These findings indicate that the inductive effect plays a crucial role in structural stability, particularly influencing internal conversion during the dynamics, which may lead to a reduced fluorescence intensity.