Spectroscopy and solvatochromism studies along with antioxidant and antibacterial activities investigation of azo–azomethine compounds 2-(2-hydroxyphenylimino)methyl)-4-phenyldiazenyl)phenol

•Azo-azomethine dyes.•The enol-imine and hydrazone tautomerism.•The solvatochromism is dependent on the substitution, solvent, pH, temperature and dipole moment.•The compounds exhibited antioxidant and antibacterial activities.

The azo–azomethine compounds 2-(2-hydroxyphenylimino)methyl)-4-phenyldiazenyl)phenol (2a–d) were prepared from the reaction of 2-aminophenol with 2-hydroxy-5-(aryldiazenyl)benzaldehyde (1a–d). The structures of all compounds were then characterized by elemental analysis, mass, infrared, UV–vis, 1H and 13C NMR spectroscopy. The electronic absorption spectra indicated enol–keto tautomeric and positive solvatochromism in compounds (2a–d), which is dependent on the substitution, nature of solvent, pH and environment temperature. The compounds (2a–d) were also evaluated for antibiotic activities by disc diffusion method. Compounds 2a and 2b exhibited antibacterial activities against Staphylococcus aureus and Bacillus cereus, but 2c and 2d were found to have no remarkable antibacterial activity. All the compounds (2a–d) also showed antioxidant activity as determined by 1,1-diphenyl-2-picryl-hydrazyl (DPPH) method.

Graphical abstractThe azo-azomethine dye 2-(2-hydroxyphenylimino)methyl)-4-phenyldiazenyl) phenol was prepared. This compound shows positive solvatochromism that dependent to the substitution, solvent, pH and temperature of solution. Antibacterial and antioxidant activities of this compound were studied.Figure optionsDownload full-size imageDownload as PowerPoint slide