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 l-isatin-4-ethyl-3-thiosemicarbazone (HIET) are reported. Elemental analyses, molar conductivities, magnetic and spectral (i. r., visible and 1H. 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(11) complexes on the basis of spectral and magnetic studies.