Spectral and structural studies of cobalt(II,III), nickel(II), and copper(II) complexes of dehydroacetic acid N4-dialkyl- and 3-azacyclothiosemicarbazones

Abstract

CoII,III, NiII, and CuII complexes of new dehydroacetic acid N4-substituted thiosemicarbazones have been studied. The substituted thiosemicarbazones, N4-dimethyl-(DA4DM), N4-diethyl-(DA4DE), 3-piperidyl-(DApip) and 3-hexamethyleneiminyl-(DAhexim), when reacted with the metal chlorides, produced two CoII complexes, [Co(DA4DE)Cl2] and [Co(DAhexim)2Cl2]; two CoIII complexes, [Co(DA4DM-H)2Cl] and [Co(DApip-H)(DApip-2H)]; a paramagnetic NiII complex, [Ni(DAhexim)(DAhexim-H)Cl]; three diamagnetic NiII complexes, [Ni(DA4DM-H)Cl], [Ni(DA4DE-H)Cl] and [Ni(DApip-H)Cl]; and four CuII complexes with the analogous stoichiometry of the latter three NiII complexes. These new thiosemicarbazones have been characterized by their melting points, as well as i.r., electronic and 1H-n.m.r. spectra. The metal complexes have been characterized by i.r. and electronic spectra, and when possible, n.m.r. and e.s.r. spectra, as well as elemental analyses, molar conductivities, and magnetic susceptibilities. The crystal and molecular structure of the four-coordinate CuII complex, [Cu(DAhexim-H)Cl] has been determined by single crystal X-ray diffraction and the anionic ligand coordinates via an oxygen of the dehydroacetic acid and the thiosemicarbazone moiety's imine nitrogen and thione sulfur.