Single crystal structure of nitro terminated Azo Schiff base: DNA binding, antioxidant, enzyme inhibitory and photo-isomerization investigation

Abstract

Novel azo schiff base compound, namely, 2‑hydroxy-5-[(E)-phenyldiazenyl] benzaldehyde (AzNP) was synthesized by reacting 2‑hydroxy-5-[(E)-phenyldiazenyl]benzaldehyde and 4-(4-nitrophenoxy)benzenamine under inert conditions. The synthesized compound AzNP was characterized by Fourier transform (FT-IR), Nuclear magnetic resonance (NMR) and Ultraviolet-visible (UV–vis) spectroscopy. The solid state structure was elucidated by single-crystal X-ray crystallography. The compound was crystallized in the Monoclinic system with P 1 21/c1 space group, having a = 6.4859(3 Å, b = 15.6673(7) Å, c = 19.7908(9) Å, β = 90.945(2), and Z = 4, showing only one intermolecular C21-H21...N2 interaction, with donor and acceptor distance of 3.5774(16) Å, responsible for the elegant 3D network of the structure. DFT calculations were performed for structure-property relationship information of AzNP. In order to comprehend the selectivity behavior of the compound, binding interaction with CT-DNA was examined using standard optical spectroscopy. The observed hypochromism in the binding studies indicated that ligand substantially interact via the groove binding mode (Kb =9.91×103 mol−1dm3) with the DNA. Further assessment of binding mode of AzNP with DNA was made through hydrodynamic measurement and molecular docking analysis which confirmed the major groove binding mode of the ligand. Additionally, the DPPH (2,2-diphenyl-1-picrylhydrazyl), the ferric reducing power, and the α-amylase inhibition assays were used to evaluate the biological significance. Analysis of Cis-Trans conformational changes was also done to investigate photoisomerization properties of synthesized compound AzNP.