Spectroscopic, thermogravimetric and antibacterial studies for some bivalent metal complexes of oxalyl-, malonyl- and succinyl-bis(4-p-chlorophenylthiosemicarbazide)

Anodic oxidation of Co, Cu, Zn, and Sn metals in an anhydrous acetone solution of 1,1-oxalyl-, malonyl- or succinyl-bis(4-p-chlorophenylthiosemicarbazide) yields a new polynuclear complexes. The isolated complexes have the general composition [M2(L)(H2O)6], L = pClSuTS and M = Co(II), Cu(II) or Sn(II), [M2(L)(H2O)n]·nH2O where M = Cu(II), Co(II) or Sn(II), L = pClOxTS and n = 2 or 6, and [M2(L)(ac)2]·nH2O where M = Co(II) or Zn(II), L = pClOxTS or pClSuTS and n = 2. The thermogravimetry (TG) and derivative thermogravimetry (DTG) have been used to study the thermal decomposition of the investigated bisthiosemicarbazide ligands and their metal complexes. The kinetic thermodynamic parameters such as: E∗, ΔH∗, ΔS∗and ΔG∗ are calculated using Horowitz–Metzger (HM) and Coats–Redfern (CR) equations. The kinetic thermodynamic parameters such as: E∗, ΔH∗, ΔS∗and ΔG∗ are calculated from the DTG curves. The tested compounds show a reasonable activity against four strains of Gram-negative bacteria; Escherichia coli, Pseudomonas aeruginosa species and Gram-positive bacteria; Bacillus cereus and Staphylococcus aureus.