Synthesis, structural characterization, DNA binding and antioxidant studies of 4,4′-Nitrophenoxyaniline derived azo dyes

Abstract

Evaluation of DNA sensing and antioxidant potential has always been an open field of interest for pharmacists and other researchers. This paper presents a study on the synthesis, DNA sensing, and free radical scavenging potential of a series of new azo dyes derived from 4,4-nitrophenoxyaniline. The dyes were synthesized by classical diazotization-coupling method involving phenol, naphthol, and resorcinol as coupling component. Structural characterization of the synthesized dyes was done by Fourier transform infrared (FT-IR), Nuclear magnetic resonance (NMR), Ultraviolet–visible (UV/VIS) spectroscopy and single crystal XRD techniques. X-ray diffractions results revealed that dye 1a, 2 b, and 3c crystallized in the monoclinic system with P21/c, P21/n, and P21/c space groups respectively. Furthermore, for the dye 2 b, the single crystal X-ray data revealed a shorter NN bond length confirming predomination of hydrazo-keto form as compared to 1a and 3c dyes. The mode of interaction of these dyes with Salmon Sperm (SS) DNA was investigated using UV/VIS spectroscopy, viscosity, and molecular docking techniques. These results showed that synthesized dyes bind to the SS-DNA in a mixed binding mode with the dominant partial intercalative mode. Furthermore, the antioxidant potential of these dyes was also evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and H2O2 antioxidant assays.