Synthesis and characterization of three new organotin complexes containing piperazine as a bidentate ligand

The reaction of dichlorostannanes R₂SnCl₂ (R=Me 1, Buⁿ 2) with piperazine ligand in molar ratio 1:2, in dry methylene dichloride, in an inert atmosphere leads to the synthesis of R₂Sn(C₄H₉N₂)₂(R=Me 1, Buⁿ 2). In a similar manner, The reaction between Ph₂SnCl₂ and piperazine in dry ethanol in molar ratio 1:1 produces Ph₂Sn(C₄H₈N₂)]₂ (3). The yields of these new products were excellent and they have been fully characterized by FT-IR, UV–Vis, multinuclear (¹H, ¹³C, ¹¹⁹Sn) NMR spectroscopy and mass spectrometry, as well as elemental analysis. The spectroscopic results indicate that the piperazine ligand is coordinated to tin atom of organotin moieties, through the nitrogen atoms. Furthermore, the ligand behaves as a bidentate fashion in (1) and (2) and gives 1:2 substitution products, while in the complex (3) the two six-membered rings bind in bidentate-chelate forms between the two Sn atoms.