Synthesis, structural and molecular characterization of 2,2-diphenyl-2H,3H,5H,6H,7H-imidazo[2,1-b][1,3]thiazin-3-one

Abstract

The thiohydantoin scaffold is of substantial importance and it is commonly used in drug discovery. Herein, a novel thiohydantoin-based compound, namely 2,2-diphenyl-2H,3H,5H,6H, 7H-imidazo[2,1-b][1,3]thiazin-3-one (PIT) was synthesized and its crystal structure was determined by single-crystal X-ray diffraction (XRD) studies. Hirshfeld surface analysis and quantum chemical calculations were performed using density functional theory (DFT) at the B3LYP/6-311++G (d,p) level. Hirshfeld surface analysis (dnorm surface and two-dimensional fingerprint plots) revealed the nature of intermolecular interactions. The most important contributions for the crystal packing are from H⋯H (49.4%), H⋯C/C⋯H (26.6%), H⋯S/S⋯H (9.1%) and H⋯O/O⋯H (7.1%) interactions. The optimized structural parameters calculated using DFT correlated well with those determined by the XRD method. The molecular reactivity of the synthesized compound was further explored using HOMO-LUMO, molecular electrostatic potential (MEP), Mulliken atomic charges (MAC), natural atomic charges (NAC) and condensed descriptors (Fukui functions and the dual descriptor). Natural bond orbital (NBO) analysis was carried out to elucidate the intramolecular, hybridization and delocalization of electron density within the studied molecule.