Dimerization thiosemicarbazones

Copper(II) complexes of 2,6-lutidylphenylketone thiosemicarbazone, 38, have been prepared from copper(II) chloride and copper(II) bromide [186]. Similar to 2-pyridyl thiosemicarbazones, 38-H coordinates via the ring nitrogen, the azomethine nitrogen and the thiol sulfur based on infrared spectral assignments. Magnetic susceptibilities and electron spin resonance spectra indicate dimeric complexes and both are formulated as [Cu(38-H)A]2 with bridging sulfur atoms. The electronic spectra of both halide complexes show band maxima at 14500-14200 cm with shoulders at 12100 cm S which is consistent with a square pyramidal stereochemistry for a dimeric copper(II) center. 

Lutidylphenylketone thiosemicarbazone, 38, and nickel(II) chloride, bromide, or iodide yield [Ni(38-H)2]A2 with NNS coordination based on infrared spectra [187]. All three complexes are electrolytes and the cations are dimeric with sulfur atoms acting as bridges interdimer interactions via sulfur are present. The electronic spectra suggest a nickel(Il) stereochemistry other than tetrahedral or octahedral for these paramagnetic complexes. 

Formylthiophene thiosemicarbazone, 26, forms nickelfll) complexes of stoichiometry of [Ni(26)2]A2, [Ni(26)A2], Ni(26-H)A, and [Ni(26-H)2] where A = Cl, Br, I, NCS etc. [211]. Except when A = NCS in the first two types of complexes, the rest are diamagnetic and planar. The thiosemicarbazone moiety bonds NS, but there is no indication whether the Ni(26-H)A complexes are dimeric, or the thiophene sulfur completes the coordination sphere, which is less likely. 

IR spectra were consistent with the structure shown for (92), where X = F, Cl, R = Me, Et.549 The IR spectra of square-planar-coordinated dimers LPtCl2PtL, where L = range of thiosemicarbazone ligands, show that L is 7V,.S -bidentate.550 IR data for Pt(II) complexes of bioactive thiosemicarbazones derived from 4-amino-antipyrine show that they are coordinated as N,N,S-donors.551... 

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