Synthesis, characterization and X-ray crystallographic structural study of copper(II) and nickel(II) complexes of the 2-quinoline carboxaldehyde Schiff base of S-methyldithiocarbazate (Hqaldsme)

Complexes of general formulae, [Cu(qaldsme)(X)(CH3OH)(n)] and [Ni(qaldsme)(2)] (.) 0.5CH(3)CN (qaldsme = anionic form of the 2-quinoline carboxaldehyde Schiff base of S-methyldithiocarbazate; X = NCS-, I-, NO3-; n = 0 or 1) have been synthesized and characterized by magnetic and spectroscopic techniques. X-ray crystal structure determination of [Cu(qaldsme)(ONO2)(CH3OH)] (1), [Cu(qaldsme)(NCS)](2) (2) and [Ni(qaldsme)(2)] (.) 0.5CH(3)CN (4) shows that the nitrato-complex of copper (1) is monomeric and five-coordinate and the thiocyanato-complex (2) has a novel thiolate sulfur-bridged dimeric structure in which each of the copper(II) ions adopts a five-coordinate, approximately square-pyramidal geometry, with a CuN3S2 coordination kernel. The nickel(II) complex (3) has a distorted octahedral geometry with meridional dispositions of the two uninegatively charged tridentate NNS ligands. In all these complexes, the Schiff bases are coordinated in their iminothiolate forms via the quinoline nitrogen atom, the azomethine nitrogen atom and the thiolate sulfur atom. (c) 2006 Elsevier Ltd. All rights reserved.