Abstract
Novel hydrazones such as 1-(2,4-dinitrophenyl)-2-((3-methylthiophen-2-yl)methylene)hydrazine (L-1) and 1-(6-(2-(2,4-dinitrophenyl)hydrazono)ethyl)pyridine-2-yl)ethanone (L-2) have been synthesized and explored as colorimetric sensors. Systematic studies of ionophores (L-1 and L-2) with acetate ion in DMSO revealed that they involved in H-bonding and proton transfer with acetate ion. Due to these interactions change in visible region of spectrum was observed and colour of both the ionophores changed from yellow (L-1) and orange yellow (L-2) to magenta. Further ligand-acetae ion interactions were studied with the help of H-1 NMR titration in DMSO and found that binding is the combined function of hydrogen bonding, electrostatic interactions and structure of binding site. Antimicrobial activities of ionophores (L-1 and L-2) were examined and tested against fungi: Rhizoctonia solani and Bipolaris oryzae using agar well diffusion method. Both ligands L-1 and L-2 were found to be exhibit antifungal activity against these strains. Antibacterial activity of L-1 and L-2 was also studied against Gram positive bacteria: Staphylococcus aureus, Bacillus brevis and Gram negative bacteria: Escherichia coli, Pycnoclavella diminuta using disc diffusion method and it was cleared that ligands were not inhibiting the growth of these strains even at higher concentration of both the ligands. (C) 2014 Elsevier B.V. All rights reserved.