Synthesis, structural analysis, spectroscopic characterization and second order hyperpolarizability of 2-amino-4-methylpyridiniium-4-hydroxybenzolate crystal

Organic nonlinear optical (NLO) single crystals of 2-amino-4-methylpyridinium-4-hydroxybenzolate (2A4MP4HB) were grown by slow solvent evaporation (SSE) method. The title compound belongs to centrosymmetric space group P2_1/c in a monoclinic crystal system which was successfully studied by X-ray diffraction (XRD) study. Molecular geometry and vibration spectral (FTIR, RAMAN & NMR) analysis were carried out experimentally and theoretically by using density functional theory (DFT) at 6311++G(d,p) level of theory. Molecular geometry, HOMO–LUMO energy gap and molecular electrostatic potential (MEP) surface were derived by using DFT methods. The thermal characteristics of as-grown crystal were analyzed by using thermogravimetry (TG) and differential thermal analysis (DTA). The second order hyperpolarizability of 2A4MP4HB crystal was analyzed theoretically and the results are reported in this paper.