Organic Quasi-Liquid Schiff Bases from Biomolecules: Synthesis, Structure and Quantum Mechanical Studies

Phenylacetaldehyde, a naturally occurring plant-derived, occurs in vegetables and flowers during storage. We synthesized Schiff bases using phenylacetaldehyde and three natural biomolecules-adenine, cytosine, and l-leucine. We characterized them using various spectroscopic methods like FTIR, FT-NMR, UV-VIS, etc., followed by multiple theoretical tools. Detailed vibrational and electronic spectral explanations are reported using experimental and theoretically simulated spectra. The density functional theory analysis of molecules was optimized ground-state calculations using DFT/B3LYP method with 6-311G+ (2d, p) as a basis set, and this optimized structure undergoes electronic spectra were generated using energy calculations by TD-DFT/CAM-B3LYP method, 6-311G+ (2d, p) as a basis set with water as a solvent. Schiff base from cytosine was found to show excellent light-harvesting properties (86.51%). Analysis of wave function-based properties like electrostatic potential, ALIE, noncovalent interactions, etc., provide information about the reactivity and stability features. PASS and subsequent docking studies indicate that the first Schiff base shows DNA Lyase inhibition, and the other two show anti-eczematic properties.