Tin Oxometallates from the Hydrolysis of SnMe22+ in the Presence of 2,6-Lutidine-α2,3-diol and Different Anions

The reaction of the dimethyltin(IV) cation with 2,6-lutidine-α2,3-diol (Lut, 2-hydroxymethyl-3-hydroxy-6-methylpyridine) has been investigated in ethanol/water mixtures (80:20 v/v) containing Cl– and NO3–, NO3– and OAc– or Cl– and OAc– ions in various molar ratios. From these reactions, several tin oxometallates were isolated and characterized by IR, Raman, 1H NMR, 13C NMR and 119Sn NMR spectroscopy as well as ESI-MS. The crystal structures of the compounds [Lut+H]Cl·H2O, [(SnMe2)4O2(Lut-H)2Cl2] (1), [SnMe2(Lut-H)Cl] (2), [(SnMe2)3O(Lut-H)2Cl]Cl (3), [(SnMe2)3O(Lut-H)2Cl2]·H2O (4·H2O) and [(SnMe2)4O2(Lut-H)2(NO3)2] (5) were determined by X-ray diffractometry. The structure of 2 contains dimeric [SnMe2(Lut-H)Cl]2 units based on a central Sn2O2 fragment, the Lut ligand is monodeprotonated, and both the tin atoms are hexacoordinate. The other metallates are all tri- or tetranuclear and show the dimethyltin(IV) unit in several penta- or hexacoordinate environments. The C–OH group of the Lut-H fragment, the Cl atoms, the O atoms of the nitrate group and the water molecules (for 4·H2O) are involved in hydrogen bonds, which modulate the interactions between the units and the packing in the crystal. The NMR and ESI-MS spectra show the existence of complex equilibria in solution.