Synthesis, spectroscopic, thermal and antimicrobial investigations of new mono and binuclear Cu(II), Co(II), Ni(II), and Zn(II) thiosemicarbazide complexes

Abstract

The thiosemicarbazone (TSC) derivative chelate was synthesized by condensation of 2-hydroxybenzaldehyde with substituted thiosemicarbazide. Eight mono and binuclear transition metal(II) complexes of TSC derivative have been prepared in 1:1 and 2:1 (M:TSC) ratios. Elemental analysis, molar conductivity, magnetic measurements, thermogravimetric, UV–Vis., FTIR, 1H NMR, and mass spectra have been used to identify those complexes. The 1:1 complexes have the general formula [M(TSC)(NH3) x(Cl)y(H2O)z]. nH2O, where M = Ni, Cu and Zn, x = 3, 3 and 1; y = 1; n = 2, 2 and 3 respectively, while Co(II) complex has formula [Co(TSC)(NH3)2(Cl)(H2O)]·6H2O. The binuclear 2:1 complexes have the general formulas [Co2(TSC)(NH3)2(Cl)2(H2O)4]·2H2O, [Ni2(TSC)(NH3)4(Cl)2(H2O)2]·4H2O, [Cu2(TSC)(NH3)4(Cl)2(H2O)2]·2H2O, and [Zn2(TSC)(NH3)2(Cl)2] 2H2O respectively. The mononuclear and binuclear complexes are found to have distorted octahedral stereochemistry in which one of the central metal ions is bonded to TSC chelate through phenolate oxygen atom and azomethine nitrogen atom, while in case of binuclear complexes the other central metal ions is coordinated toward TSC chelate via two oxygen atoms of carboxylate group that associated from the hydrolyses of the terminal cyano group. The TSC ligand and its complexes have been studied for their possible biological activity including antibacterial and antifungal activity.