Synthesis, characterization and biological evaluation of nickel (ii) and zinc (ii) complexes from mixed ligand of n-phenyl and 4-methyl-nphenyl dithiocarbamate

Abstract

Dithiocarbamate compounds have received tremendous attention for their synthesis, characterization and biological activities. Two different dithiocarbamate ligands namely N-Phenyl dithiocarbamate and 4-Methyl-N-Phenyl dithiocarbamate were prepared separately by the reaction of aniline and para methyl aniline with carbon disulfide in the presence of concentrated ammonia. Transition metal mixed-ligand complexes of Nickel (II) and Zinc (II) have been synthesized using substitution method. The structures of synthesized ligands and metal complexes were elucidated by their elemental analysis, Magnetic susceptibility measurement , FT-IR, UV--Vis , 1 H and 13 C NMR and Atomic Absorption Spectroscopic data. The data from the elemental analysis suggest a good agreement between the calculated and the experimental values for the elements and the FT-IR studies revealed that each of the dithiocarbamate ligand acted as bidentate through sulfur atoms in synthesized complexes. The metal complexes were isolated in good yield and are thermally stable. The molar conductance measurements of the complexes indicated their non-electrolytic nature. On the basis of spectral studies and magnetic susceptibility measurements, a square planar geometry with dsp 2 hybridization has been assigned for Nickel (II) complex and tetrahedral for Zinc(II) complex with sp 3 hybridization. A comparative anti-microbial study test was performed using the disk diffusion method against on two gram positive bacteria (Staphylococcus aureus, Enterococcus faecalis,) and two gram negative bacteria (Escherichia coli and Salmonella typhi) and four fungi strains Aspergillus(spp) , Penicillium(spp) ,Fusarium(spp) and Trichoderma(spp). It was revealed that Zinc (II) complex has a much enhanced activity relative to synthesized ligands in all selected bacteria but Nickel (II) complex showed a reduced activity against Staphylococcus aureus. Moreover, in antifungal study Zinc (II) complex showed better zone of inhibition against Penicillium(spp) and Trichoderma(spp) relative to standard drug. Further tests are needed to evaluate anti microbial activities especially on Zinc complex against other (additional) microbial species to explore all possibilities to evaluate the potential of Zinc complex in the development of pharmaceutical drugs.