Structure and Biological Activity of Trichlorophenyl-Thiosemicarbazone and its Complexes with Some Transition Metal Cations

Abstract

The complexes of 4-(2,4,6-trichlorophenyl)-3-thiosemicarbazide (HL¹) with transition metal cations VO(II), Co(II), Ni(II), Cu(II), Pd(II), and Pt(II) are prepared and characterized using elemental and thermal analyses, UV-visible spectrophotometry, FTIR, mass, and NMR spectroscopy, X-ray diffraction, and molar conductance and magnetic susceptibility measurements. The results show that the prepared chelates have the following chemical formulae and structures: [(VO)₂(L¹)(SO₄)(C₂H₅O)·H₂O] (square based pyramidal structure), [Co₂(HL¹)Cl₃C₂H₅OH]·Cl (square planar structure), [Ni(HL¹)Cl₂]·3H₂O (square planar structure), [Cu(L¹)₂(H₂O)₂] (octahedral structure), [Pd(HL¹)Cl₂]·H₂O (weakly distorted square planar structure), and [Pt(HL¹)Cl₂]·1/2H₂O (square planar structure). Generally, the complexes exhibit a high thermal stability, however, the Pd(II) and Pt(II) complexes are more stable than the other complexes. The ligand (HL¹), and its complexes are screened for their biological activity. Some of the complexes are found more biologically active than the parent ligand.