THE PREPARATION AND CHARACTERIZATION OF SOME COPPER(II) COMPLEXES OF THE 6-METHYL-2-FORMYLPYRIDINE THIOSEMICARBAZONE AND THE X-RAY CRYSTAL-STRUCTURE OF THE HLORO(6-METHYL-2-FORMYLPYRIDINETHIOSEMICABAZONATO) COPPER(II) COMPLEX

Copper(II) complexes of general empirical formulae, [Cu(NNS)X]. xH(2)O (NNS = uninegatively charged tridentate ligand formed by condensation of 6-methylpyridine-2-aldehyde with thiosemicarbazide; X = Cl, Br, NO 3, and CH3COO; x = 0, 1) and [Cu(NNS)(2)]. 0.5H(2)O have been prepared and characterized by conductance, magnetic, electronic and infrared s pectroscopic measurements. Magnetic and spectral data support a square -planar structure for [Cu(NNS)X] (X = Cl, Br, NO3, CH3COO) and a disto rted octahedral structure for [Cu(NNS)(2)]. 0.5H(2)O. The crystal and molecular structure of [Cu(NSS)Cl] has been determined by X-ray diffra ction. This complex has a distorted square-planar geometry with the co pper(II) ion lying in an approximate plane of four coordinating atoms, three of which come from the 6-methylpyridine-2-carboxaldehyde thiose micarbazone and the fourth coordination site is occupied by the chlori de ligand. The thiosemicarbazone is present as the thiolate form and i s coordinated to the copper(II) ion via the pyridine nitrogen atom, th e azomethine nitrogen atom and the mercaptide sulfur atom. Copyright ( C) 1996 Elsevier Science Ltd.