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-oxaly1-, malonyl- or succinyl-bis(4-p-chlorophenylthiosemicarbazide) yields a new polynuclear complexes. The isolated complexes have the general composition [M-2(L)(H2O)(6)], L = pCISuTS and M = Co(II), Cu(II) or Sn(II), [M-2(L)(H2O)(n)]center dot nH(2)O where M = Cu(II), Co(II) or Sn(II), L = pCIOxTS and n = 2 or 6, and [M-2(L)(ac)(2)]center dot nH(2)O where M = Co(II) or Zn(II), L = pCIOxTS or pCISuTS 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., Delta H*, Delta S* and Delta G* are calculated using Horowitz-Metzger (HM) and Coats-Redfern (CR) equations. The kinetic thermodynamic parameters such as: E*, Delta H*, Delta S* and Delta G* 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. (C) 2011 Elsevier B.V. All rights reserved.