David G. Calatayud - Unexpected differences in the reactivity between MPh2Cl2 (M = Pb or Sn) and benzil bis(thiosemicarbazone). X-ray crystal structure of benzil bis(thiosemicarbazonate)lead(II)

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      Publication Details (including relevant citation   information):

      Lopez-Torres, E, Calatayud, D G, Pastor, C J, Mendiola, M A   Polyhedron 2008 27 (12)   2507-2512

      Abstract: The differences in the reactivity of   diphenyllead and diphenyltin dichloride with benzil   bis(thiosemicarbazone) LH6 are explored. The reaction of PbPh2Cl2   afforded the complex [Pb(LH4)] 1, containing the ligand doubly   deprotonated and without the phenyl groups bonded to the metal.   The reaction with SnPh2Cl2 in the absence of solvent yielded the   complex [Sn(LH4)Cl2] 2. The lead(II) complex, also obtained by   the reaction with lead(II) nitrate, was formed by a   redistribution of the organolead derivative followed by a   reductive elimination reaction, while the tin one was formed by a   dephenylation process. Reactions in solution of the organotin   derivative are complicated and depending on the working   conditions different compounds could be isolated: the   organostannoxane [Sn2Ph4ClO(OH)]2, which was confirmed by X-ray   crystallography, or a complex containing a triazine-3-thione   ligand, formed by the loss of one of the thiosemicarbazone arms   with subsequent cyclisation. The compounds were characterized by   IR, mass spectrometry, 1H, 13C and 119Sn NMR spectroscopy in   solution and in the solid state. The structure of [Pb(LH4)] has   been studied by X-ray diffraction and the ligand acts as a N2S2   planar bideprotonated ligand, with the lead(II) ion localized   1.3858 Å over this plane.

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