Spectroscopic studies on copper(II) complexes derived from a substituted 2-acetylpyridine thiosemicarbazone

Summary Copper(II) complexes of general formula Cu(L4A)X] (where L4A is the deprotonated ligand, 1 H-hexahydroazepine-1-thiocarboxylic acid-2-1-(2-pyridinyl)ethylidene]hydrazide and X=Cl, Br, I, NCS, NO₃ and OAc) and Cu(HL4A)(L4A)]ClO₄ have been prepared and characterized by elemental analyses, magnetic susceptibility measurements, i.r. spectra, electronic spectra, conductivity measurements and e.s.r. spectra in the polycrystalline state and in chloroform solution. For all complexes, except the perchlorate salt, coordination occurs via imine nitrogen, pyridine nitrogen and thione sulphur. For the perchlorate salt, L4A is tridentate, while HL4A is monodentate via imine nitrogen. Electronic spectra suggest planar geometry for all the complexes. The calculated e.s.r parameters suggest coordination through sulphur in agreement with the i.r. results.