Six-co-ordinate tris(bidentate ligand) tin(IV) complexes

Abstract

New six-co-ordinate tris(bidentate ligand) complexes of tin(IV) with O,O′ ligands have been prepared and characterised by ¹H and ¹¹⁹Sn NMR spectroscopy, elemental analysis and mass spectrometry. The ¹¹⁹Sn NMR spectra of the symmetrical complexes reveal the interaction of the three ligands with the tin nuclei. Long range ⁴J(Sn–H) and ⁵J(Sn–H) coupling is observed. Comparison with the corresponding silicon complexes shows a linear relationship between the chemical shifts of the ¹¹⁹Sn and ²⁹Si nuclei. Tin-119 NMR spectroscopy indicates that the tin(IV) complexes are six-co-ordinate species, except for the Sn(trop)₃X (Htrop = tropolone, X = Cl, Br or I) complexes which are seven-co-ordinate. Mixed mono- and di-basic bidentate ligand complexes form neutral six-co-ordinate complexes.