Synthesis and Biological Activity of Three Novel Azo Dyes

The azo dyes that named, (E)-4-((2-nitrophenyl) diazenyl) benzene-1,3-diol (1), (E)-4- ((3-nitrophenyl) diazenyl) benzene-1,3-diol (2) and (E)-4-((4-nitrophenyl) diazenyl) benzene-1,3-diol (3) were synthesized and then characterized using IR, UV-visible spectrum. These results were compared with that obtained by ChemBio 3D Ultra - [Chem3D XML] Gaussian Interface and were seems to be identical. Then, the antimicrobial activity of each azo dye was carried out against two bacterial strains: Staphylococcus aureus NCTC 6571, and Escherichia coli ATCC 25922, and fungal strains of Candida albicans using Agar-well diffusion method. The results were showed that the three azo dyes were biologically active and the best reactivity was observed in (2). Though, the biological activity of (1) with NO2 group in ortho- position remained reasonable against Candida albicans. But, the effect of (1) was resisted by Staphylococcus aureus and Escherichia coli. However, the (2) and (3) with substituted NO2 group in meta- and para- positions respectively were showed better reactivity’s than (1) towered Candida albicans and Staphylococcus aureus. Further, the Gaussian interface properties and the conformational analysis of (1), (2) and (3) were intended. The results were indicated that the variations in the properties of each azo dye and their conformational energies of generated conformers can affect their biological activity afterward. Keywords: key words, Azo dyes, Staphylococcus aureus, Escherichia coli, Candida albicans, Agar-well diffusion method, Antimicrobial activit