Synthesis, spectroscopic characterization, biological activity, and conducting properties of functionalized Ni(II) dithiocarbamate complexes with solvent extraction studies of the ligands

A series of new nickel(II) dithiocarbamate complexes of general formula [M L₂], (where L=benzyl(4-fluorobenzyl)carbamodithioate (L1), benzyl(4-cyanobenzyl)carbamodithioate (L2), ethyl(4-methylbenzyl)carbamodithioate (L3), (4-methoxybenzyl) (naphthalen-1-ylmethyl)carbamodithioate (L4) and ethyl(4-methoxybenzyl)carbamodithioate (L5)) have been synthesized, and characterized via elemental analysis, FT-IR, electronic spectra, ¹H NMR, ¹³C NMR, Mass spectrometry and Thermogravimetric analysis (TGA). The continuous variation method (Job's method) was used to determine the stoichiometry of the complexes. TGA was used to analyze the thermal decomposition behavior of metal complexes in nitrogen atmosphere. As a result of the thermal decomposition process, all of the complexes produced NiS as the final product. X-ray Diffraction (XRD), Energy dispersive X-ray analysis (EDAX), and Transmission electron microscopy (TEM) studies confirm the formation of NiS nanomaterial. Crystalline size of NiS was obtained between 19.97 to 21.35nm range by applying the Scherrer equation using XRD. Solid-state electrical conductivities reveal that all the complexes behave as a semiconductor at room temperature. All the synthesized dithiocarbamate ligands and complexes were screened against five human bacterial pathogens (Escherichia coli, Staphylococcus aureus, Salmonella typhi, Aeromonas hydrophila, and Shigella boydii) by disc diffusion method. Solvent extraction studies show that the ligand has strong extractability towards metal ions in a basic medium (pH=10).