synthesis and antimicrobial studies of 𝒐-anisidine-isatin derived schiff base and its metal complexes

This study focuses on the synthesis and characterization of a novel bidentate ligand and its metal complexes. with some metal ions, and the thus to demonstrate their biological activities were evaluated using some bacterial and fungal strains. the ligand was synthesized by reacting ortho-methoxy aniline (o-anisidine) with 1h-indole-2,3-dione (isatin) in absolute ethanol, achieving a yield of 85%. consequently, metal complexes were synthesized by reacting the synthesized ligand schiff base ligand with nickel(ii) chloride, copper(ii) chloride, palladium(ii) chloride, and silver(i) nitrate with yields ranging from 65% to 83%. the synthesized compounds were characterized using several spectroscopic techniques, such as, ft-ir, ¹h and ¹³c-nmr, lc-ms, and uv-visible spectroscopy. based on the results from the spectroscopic analysis indicated, proposed geometries for the complexes are an octahedral arrangement for the nickel complex and square planar for the other complexes. these compounds were screened for biological activity against two antibiotic-resistant strains of bacteria, which include gram-negative enterococcus faecalis and gram-positive acinetobacter baumannii, as well as a fungus called aspergillus niger. the results of the findings indicated that all compounds were active against the tested bacterial strains except for the copper complex which was inactive. the ligand and nickel complex showed the best inhibitory activities maintaining low optical densities (od) over a 4-hour period. furthermore, the study revealed that synthesized these compounds played a role in destroying pre-formed fungal hyphae, with the silver complex exhibiting the most pronounced effect, as evidenced by the lowest od readings against aspergillus niger after 72 hours.