Synthesis, Spectral, Thermal and Quantum Mechanical Studies on 2-Amino-4-Picolinium 2-Hydroxybenzoate Crystal

An organic polymorphic crystal of 2-amino-4-picolinium 2-hydroxy-benzoate (APHB) was synthesized by solvent evaporation solution growth technique at room temperature using methanol as solvent. Single crystal X-ray diffraction study revealed that the title salt belongs to monoclinic crystal system with centrosymmetric P21/c space group. The thermal characteristics of synthesized crystal were analyzed by TG-DTA study. The chemical construction has been proved by 1H and 13C NMR spectral techniques. The presence of various functional groups was examined by FTIR spectrum. The UV-vis-NIR spectrum was carried out to decide the optical transmittance window and lower cut-off wave length of the crystal. Theoretical calculations were performed using density functional theory (DFT) method to derive the optimized geometry, HOMO-LUMO energy gap and Mulliken charge analysis.