Binding affinity of p-PD-based schiff-bases towards human serum albumin; in-vitro and in-silico assessment

The Schiff-bases [N,N'-Bis(2-hydroxybenzylidene)-benzene-1,4-diamine (L-1), N,N'-Bis(5-bromo-2-hydroxybenzylidene)-benzene-1,4-diamine (L-2), N,N'-Bis(2-hydroxy-3-methoxy-benzylidene)-benzene-1,4-diamine (L-3), and N,N'-Bis(2-hydroxynaphthylidene)-benzene-1,4-diamine (L-4)) have been synthesised by the reaction of 1,4-phenylenediamine (p-PD) with the necessary aldehydes and characterised by UV-Vis, FT-IR, H-1 NMR, and mass spectroscopy. Their solubilities, at room temperature, were determined according to the USP and BP classification. Quantum chemical calculations of the compounds L-1 to L-4 have been carried out by DFT at the B3LYP/6-311++G(d,p) level; these show the results of the calculations to be in accordance with the experimental ones. A comparative analysis of the experimental and calculated vibrational frequencies was performed and significant bands were identified.