SYNTHESIS AND SPECTROSCOPIC STUDIES OF NEW METAL-COMPLEXES OF THIOSEMICARBAZONES DERIVED FROM 4-ETHYL-3-THIOSEMICARBAZIDE AND BIACETYLMONOXIME, CHROMONE-3-CARBOXALDEHYDE OR ISATIN

Synthesis and characterization of Ni(II), Pd(II), Cu(II) and Cd(II) complexes of 1-biacetylmonxime-4-ethyl-3-thiosemicarbazone (HBMET), 1-chromone-3-carboxaldehyde-4-ethyl-3-thiosemicarbazone (HCET) or 1-isatin-4-ethyl-3-thiosemicarbazone (HIET) are reported. Elemental analyses, molar conductivities, magnetic and spectral (i.r., visible and H-1.n.m.r) measurements have been used to characterize the complexes. IR spectral data show that HCET and HIET act as bidentate ligands coordinating via C=S and C=N groups while HBMET behaves as a bidentate ligand coordinating via OH(oxime) and C=N groups. Different stereochemistries are proposed for the Ni(II), Pd(II) and Cu(II) complexes on the basis of spectral and magnetic studies.