A new tetradentate Schiff base of N, N’-bis (3, 5 - diiodosalicylidene)-1,2-phenylenediamine: Spectral aspects, Hirshfield surfaces, DFT computations and molecular docking

Abstract

We reported a new tetradentate Schiff base, 6,6′-(1,2-phenylenebis(azan-1-yl-1-ylidene)bis(methan-1-yl-1-ylidene)bis(2,4-diiodophenol) (PMDP) and its binding with the bovine serum albumin which was comprehensively investigated with the aid of UV–Vis, fluorescence spectroscopy and molecular docking. The molecular structure of the ligand was optimized by DFT/B3LYP/LANL2DZ levels of theory were found in good agreement with the experimental data. Based on the optimized structure, the theoretical frequency and electronic absorption spectrum of the compound were computed to elucidate the vibrational and electronic transition assignments. 1H and 13C NMR was computed using SCF-GIAO method to assess the chemical structure. Natural bond orbital (NBO), molecular electrostatic potential (MEP), Mulliken atomic charge and HOMO-LUMO energies were calculated using the same level of theory. Fukui functions and global reactivity parameters were also performed. Hirshfield surface analysis exactly revealed each significant interaction and the influence of contacts involving hydrogen such as I···H, H···H, C···H on their molecular properties. The combination of BSA and Schiff base induced conformational changes in the microenvironment around the fluorophores of BSA were studied using synchronous and three dimensional fluorescence measurements. Molecular docking studies supported the interactions involved and its minimum binding energy conformer to be revealed.