Investigation of spectroscopic and some electronic properties of (3-aminomethylpyridine)-salicylidene Schiff base by DFT method

This study explores the structural, spectroscopic, and electronic properties of the (3-aminomethylpyridine)-salicylidene Schiff base molecule using Density Functional Theory (DFT) at the B3LYP/6-311G++(d,p) level. Theoretical predictions for molecular geometry, bond lengths, vibrational modes, and electronic properties show strong agreement with experimental data, particularly in modeling complex structures involving heteroatomic bonds. Vibrational analysis identifies FT-IR spectral peaks for key functional groups, with theoretical frequencies closely matching experimental values. NMR analysis provides detailed chemical shift data, aligning with experimental findings while highlighting substituent and electronic effects. HOMO-LUMO analysis reveals a large energy gap (4.9353 eV), indicating high stability and moderate reactivity. Electronic descriptors, including ionization potential and chemical hardness, confirm resistance to electron loss and moderate electrophilic nature. Nonlinear optical (NLO) properties, assessed through polarizability and hyperpolarizability, indicate enhanced optical responses compared to reference materials like urea. The molecular electrostatic potential (MEP) map highlights reactive sites, with oxygen and nitrogen as electrophilic centers and hydrogen atoms as nucleophilic sites. These findings validate DFT methods for characterizing Schiff base molecules and emphasize their potential in optoelectronics, nonlinear optics, and biochemistry, bridging theoretical and experimental insights while paving the way for future applications.