Synthesis, Characterization and Biological Activity of Novel Metal Complexes Derived from Cyclohexylthiosemicarbazide

In recent years, thiosmicarpazide compounds and its complexes have attracted the interest of researchers due to their many applications. Three new complexes [LMnCl2(H2O)] (C1), [LCoCl2(H2O)] (C2), and [LNiCl2(H2O)] (C3) with the ligand N1-cyclohexyl-N2-(dietheylcarbamoyl) hydrazine-1,2-bis(carbothioamide) (L) were carried out by mixing the metal chloride and ligand in a 1:1 mole ratio using methanol as the medium. Complex formation between the metal (II) moiety and the ligand occurred through the O, S, and N donor atoms. The ligand and its complexes were characterized by elemental analysis, FT-IR, and NMR (1H and 13C) spectroscopy. Accordingly, the complexes were proposed to have octahedral geometry. The ligand and its complexes were screened for their antimicrobial activities against some Gram-positive and Gram-negative bacteria. The studies demonstrated that complexation can increase the antimicrobial activity, compared with the free ligand. The results indicated that the ligand behaves as coordinate in tridentate to give an octahedral around the Mn II, Co II, and Ni II ions.