Quest for Organotin(IV) Cations Containing O,C,O-Chelating Ligands

A set of triorganotin(IV) compounds Ph2L1SnX and Ph2L2SnX (1−9) with O,C,O-chelating
ligands L1 and L2 (L1 = 2,6-(MeOCH2)2C6H3 and L2 = 2,6-(t-BuOCH2)2C6H3) containing
different electronegative substituents X (X = I, CF3COO, CF3SO3, PF6, and HgI3) was
prepared. These compounds have been characterized by elemental analysis, ESI-MS, and
1H, 13C, and 119Sn NMR spectroscopy. X-ray diffraction analysis showed that the decrease of
the nucleophilicity of X resulted in the formation of organotin cations stabilized by two strong
Sn−O intramolecular interactions. In this transformation the ligand geometry about the
tin atom changed from tetrahedral to trigonal bipyramidal with the OR groups in trans
arrangement. Solution NMR studies indicated that the coordination geometry of these
compounds is the same in the solid state and solution.