Investigation on crystalline structure, optical, thermal, mechanical properties and Hirshfeld surface analysis of hippuric acid single crystal

Hippuric acid (N-benzoyl-glycine), a naturally occurring organic compound which crystallizes in non-centrosymmetric orthorhombic space group P2 1 2 1 2 1 . Single crystals of hippuric acid were grown at room temperature by using slow evaporation solution technique (SEST) using a mixed solvent of methanol and acetone having a methanol to acetone ratio of 1:1. Properties of hippuric acid single crystal were analyzed using various characterization methods. Crystal structure and crystal parameters of single crystal were characterized using powder X-ray diffraction (PXRD) technique. UV-Vis spectroscopy revealed that the optical bandgap of the material is 4.1 eV and it has a stable transmittance of ~ 30% in visible range. Photoluminescence studies showed an emission at 308 nm (4.02 eV) which is close to bandgap. Vickers microhardness studies revealed Meyer’s index = 2.49, with load independent microhardness of 43.84 × 10 6 kg/m 2 (Hays-Kendall law) and 50.37 × 10 6 kg/m 2 (PSR Model). TG/DTA analysis found out a melting point of 196.7 °C and thermal stability up to 212 °C. Hirshfeld surface analysis, fingerprint plots, and energy framework calculations revealed the dominant hydrogen-bonding and van der Waals interactions responsible for stabilizing the crystal packing.