Molecular Modeling Investigation of Bonding, Spectroscopic, and Nonlinear Optical Properties of 2,5-Bis(4-chlorophenyl)-4,4,5-trifluoro-1,3-thiazole Derivatives

In this paper, we present a range of properties of novel fluorizoline analogues (4,5-difluorothiazoline, 4,4,5-trifluoro-2,5-diaryl-4,5-thiazoline, and 4,5,5-trifluoro-4,5-thiazoline). These compounds exhibit notable biological and pharmacological advantages. 4,5-Difluorothiazoline and 4,4,5-trifluoro-2,5-diaryl-4,5-thiazoline share the same S–C=N dipole orientation; however, they differ in the substituents at carbon 4 of the thiazoline ring, with one methyl and one fluorine in 4,5-difluorothiazoline and two fluorine atoms in 4,4,5-trifluoro-2,5-diaryl-4,5-thiazoline. The bonding nature, bond polarity index (BPI), quantum theory of atoms in molecules (QTAIM), non-covalent interaction (NCI), absorption, emission spectra, and nonlinear optical analysis were investigated. NCI analysis was performed to reveal weak interactions. The presence of the two fluorine atoms at position 4 in 4,4,5-trifluoro-2,5-diaryl-4,5-thiazoline plays a crucial role, significantly influencing the absorption spectra through shifts in the λabs value. Furthermore, the orientation of this dipole has a great influence on shifts in the λlum value (366.1 nm for 4,5,5-trifluoro-4,5-thiazoline). The calculated linear polarizability and static first-order hyperpolarizability indicate that these materials exhibit promising nonlinear optical behavior and could be used for nonlinear optical (NLO) devices.