SYNTHESIS, SPECTRAL CHARACTERIZATION, THERMAL AND BIOLOGICAL STUDIES OF CU(II), CO(II), TH(IV) AND ZR(IV) COMPLEXES WITH SYMMETRIC THIOCARBOHYDRAZONE LIGAND

Abstract

The thiocarbohydrazone Schiff base ligand (LH2) was synthesized by the condensation of thiocarbohydrazide and 1-(5- bromo-2-hydroxyphenyl)ethanone. Such Schiff base ligand with heteroatoms such as nitrogen, oxygen and sulphur as donor atoms have unique tendency to conjugate with metal ion for the formation of metal complexes. By knowing this fact, a series of Cu(II), Co(II), Th(IV), and Zr(IV) metal complexes were synthesized from (H2L) Schiff base ligand and characterized by using spectroscopic techniques. IR spectra reveal that co-ordination of the ligand with metal ion resulting into mononuclear complexes. The ligand mainly coordinates through the hydroxyl oxygen and azomethine nitrogen to give five membered rings in some cases. Molar conductance values of synthesized metal complexes in DMF indicate the nonelectrolytic nature of the complexes. From the observed magnetic moment and electronic spectral data, probable structures for the complexes have been proposed. The thermal behavior of ligand and metal complexes shows the presence of lattice and the co-ordinate water around their co-ordination sphere. The synthesized Schiff base ligand and its complexes were also tested for their antimicrobial activity against E. Coli, S. aureus, S. epidermis, and K. pneumoniae.