53277-00-2Relevant academic research and scientific papers
Versatile chelating behavior of benzil bis(thiosemicarbazone) in zinc, cadmium, and nickel complexes
Lopez-Torres, Elena,Mendiola, Ma. Antonia,Pastor, Cesar J.,Souto Perez, Beatriz
, p. 5222 - 5230 (2004)
Reactions of benzil bis(thiosemicarbazone), LH6, with M(NO 3)2·nH2O (M = Zn, Cd, and Ni), in the presence of LiOH·H2O, show the versatile behavior of this molecule. The structure of the ligand, with the thiosemicarbazone moieties on opposite sides of the carbon backbone, changes to form complexes by acting as a chelating molecule. Complexes of these metal ions with empirical formula [MLH4] were obtained, although they show different molecular structures depending on their coordinating preferences. The zinc complex is the first example of a crystalline coordination polymer in which a bis(thiosemicarbazone) acts as bridging ligand, through a nitrogen atom, giving a 1D polymeric structure. The coordination sphere is formed by the imine nitrogen and sulfur atoms, and the remaining position, in a square-based pyramid, is occupied by an amine group of another ligand. The cadmium derivative shows the same geometry around the metal ion but consists of a dinuclear structure with sulfur atoms acting as a bridge between the metal ions. However, in the nickel complex LH6 acts as a N2S2 ligand yielding a planar structure for the nickel atom. The ligand and its complexes have been characterized by X-ray crystallography, microanalysis, mass spectrometry, IR, 1H, and 13C NMR spectroscopies and for the cadmium complex by 113Cd NMR in solution and in the solid state.
Synthesis and characterisation of zinc, cadmium and mercury complexes of benzilbisthiosemicarbazone. Structure of cadmium derivative
López-Torres, Elena,Mendiola, Ma Antonia,Rodríguez-Procopio, Jesús,Sevilla, Ma Teresa,Colacio, Enrique,Ma Moreno, José,Sobrados, Isabel
, p. 130 - 138 (2008/10/08)
Complexes [MLH6(NO3)2] (M = Cd, Hg) (1 and 2), [MLH4] (M = Hg, Zn) (3 and 5) and [ZnLH5NO3] (4) have been synthesised by reaction of benzilbisthiosemicarbazone LH6 with cadmium, mercury and zinc nitrates in ethanol. The X-ray diffraction study of cadmium complex 1 shows that the azomethine nitrogen atoms, the sulfur atoms and the nitrate groups are bonded to the cadmium atom giving, the first time for this kind of ligands, a distorted octahedral geometry. Complexes have been characterised by elemental analyses and mass spectra as well as by IR, 1H, 13C and 113Cd NMR and 13C and 113Cd CP/MAS NMR spectroscopies. In all complexes LH6 acts as a tetradentate N2S2 ligand. The electrochemical behaviour of complexes, studied by cyclic voltammetry, shows metal centred and ligand reduction processes for all of them.
