The first neutral Sn(II) complex derived from a pentadentate thiosemicarbazone ligand

The electrochemical oxidation of a tin plate in the presence of an acetonitrile suspension of the ligand bis-(4-N-methylthiosemicarbazone)-2,6-diacetylpyridine, H4DAPTsz-Me, yields the complex Sn(H2DAPTsz-Me)(H2O)2 (1). Recrystallisation of 1 in a methanol/acetone solution leads us to isolate yellow crystals of [Sn(H2DAPTsz-Me)(CH3OH)2] · CH3OH (2), structurally characterised. To the best of our knowledge, 2 is the first neutral Sn(II) complex derived from a pentadentate thiosemicarbazone Schiff base ligand. This complex shows a distorted pentagonal bipyramidal geometry for Sn(II), being the metal surrounded by the N3S2 donor set of the bideprotonated ligand [H2DAPTsz-Me]2−. This compound self-assembles into a 3D network through intermolecular hydrogen bonds.