LAUSR

Abstract A new organic proton transfer compound, 2-aminothiazoliumbenzilate (2-ATB) was synthesized and single crystals of the compound were grown by solvent evaporation-solution growth method at ambient temperature. The compound was characterized by elemental analysis, UV–Vis NIR, FT-IR, 1 H and 13 C NMR spectroscopic analyses and single crystal X-ray diffraction (SXRD) structural study. Intermolecular and intramolecular N–H⋯O and O–H⋯O hydrogen bonding interactions stabilize the crystal network. The molecular structure was optimized at B3LYP/6-311G+(d,p) level using quantum chemical calculations. The natural bonding orbital (NBO) analysis was carried out to explore hyperconjugative interactions and intermolecular charge transfer. Hirshfeld surface analysis reveals that C⋯H, N⋯H and O⋯H interactions build hydrogen bond network in the molecular structure. The HOMO-LUMO energy gap value of 2-ATB is small enough for electron cloud transfer. The Z-scan technique was used to confirm 2-ATB as a third harmonic generating (THG) material for optical limiting device applications.