Synthesis, structures, 119Sn Mössbauer spectroscopic studies and biological activity of some tin(IV) complexes containing pyridyl functionalised selenosemicarbazonato ligands

A series of tin(IV) complexes of the type [Sn(L)ClR2] (R: nBu, Me, Cl; L: anionic N,N,S or N,N,Se donor ligand) containing pyridyl functionalised thio- and selenosemicarbazonates was prepared and fully characterised by spectroscopic methods including 119Sn and 77Se NMR spectroscopy as well as 119Sn Mössbauer spectroscopy. In addition, the solid-state structures of several derivatives were determined by single crystal X-ray diffraction. The in vitro cytotoxicity of these compounds was evaluated in three different human tumour cell lines. The IC50 values are in the low nM range, the most active compound being a trichlorotin(IV) complex with a selenosemicarbazonato ligand.