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

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. 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 other compounds could be isolated: the organostannoxane [Sn2Ph4ClO(OH)]2, or [SnPh2(C15H10N3S)Cl], was formed by the loss of one thiosemicarbazone arm with a subsequent cyclisation.