Novel α-N-heterocyclic thiosemicarbazone complexes: synthesis, characterization, and antimicrobial of properties investigation

In this paper, eight novel α-N-heterocyclic thiosemicarbazone complexes were synthesized in search of new biologically active compounds, and characterized via organic elemental analysis, nuclear magnetic resonance spectroscopy, infrared spectra, thermogravimetric analysis, ultraviolet-visible spectroscopy, molar conductance and magnetic susceptibility measurements. The in vitro antimicrobial activity of these complexes was examined against ten disease-causing pathogens: Gram-positive bacteria ( Micrococcus luteus ATCC9341, Staphylococcus epidermidis ATCC12228, Bacillus cereus RSKK863) and Gram-negative bacteria ( Pseudomonas aeroginosa ATCC27853, Klebsiella pneumonia ATCC27853, Enterobacter aerogenes ATCC51342, Salmonella typhi H NCTC9018394, Shigella dysenteria NCTC2966, Proteus vulgaris RSKK96026) and yeast ( Candida albicans Y-1200-NIH). The results revealed that the α-N-heterocyclic thiosemicarbazone compounds showed potent activity. It was observed that all thiosemicarbazone complexes were more susceptible to Gram-negative strains based on the presence of an electron-withdrawing substituent (-Br/-Cl/-F). It was determined that thiosemicarbazone Cu 2+ complexes showed stronger antifungal effects. In this paper, eight novel α-N-heterocyclic thiosemicarbazone complexes were synthesized in search of new biologically active compounds, and characterized via 1 H-NMR, IR, TGA, UV-Vis, molar conductance and magnetic susceptibility measurements.