Synthesis, characterization, solvatochromic, antioxidant and antibacterial activities investigation of 2,2′-((1E,1′E)-((1,2,5-oxadiazole-3,4-diyL)bis(azanylylidene))bis(methanylylidene))bis(4-(phenyldiazenyl)phenol)

The azo-azomethine dyes 2-[(4-amino-1,2,5-oxadiazol-3-ylimino)methyl)-4-(phenyl diazenyl]phenol (2a-h) have been synthesized from the condensation reaction of 3,4-diamino -1,2,5-oxadiazole with 2-hydroxy-5-[(E)-(aryldiazenyl)]benzaldehyde(1a-h) in methanol. The structures of dyes have been characterized by elemental analysis, mass, 1R, UV-Vis, H-1 and C-13 NMR spectroscopy. UV Vis absorption spectra indicated enol keto tautomeric and positive solvatochromism in compounds 2a-h which is dependent on the substitution, solvent, pH and environment temperature. The synthesized compounds were investigated for their in vitro antioxidant activity by 1,1-dipheny1-2-picrylhydrazyl (DPPH) assay. Compounds substituted with electron donating groups, such as, alkyl and methoxy groups showed moderate to mild antioxidant activity. The in-vitro antibacterial activity of all compounds was determined by disc diffusion method. The tested compounds showed varying degree of inhibition against B. cereus and S. aureus strains. However, E.coli and K pneumonia were not sensitive to any of the tested samples.