SOLVENT-DEPENDENT ESTER ELIMINATION AND LIGAND-EXCHANGE REACTIONS BETWEEN TRIMETHYLSILYL ACETATE AND TIN(IV) TETRA-TERT-BUTOXIDE

The reaction between a prototypical metal alkoxide, Sn(O-t-Bu)4, and a metal carboxylate, Me3Si(OAc), has been studied by NMR spectroscopy in different solvents. These species were chosen as a result of the presence of their NMR-active isotopes. In nonpolar solvents such as toluene, ester elimination was observed with formation of (t-BuO)3Sn(OSiMe3) and (t-BuO)2Sn(OSiMe3)2. Experiments employing O-17-labeled Sn(O-17-t-Bu)4, show that the alkoxide group is transferred to the carbonyl ligand of the silyl acetate. In a coordinating solvent such as pyridine, the ligand exchange product, Sn(O-t-Bu)3(OAc)(py), is formed. This compound has also been characterized in the solid state by single-crystal X-ray diffraction. Crystal data: empirical formula C19H35NO5Sn, crystal system orthorhombic, space group Pnma; unit cell dimensions a = 12.638(4) angstrom, b = 11.305(5) angstrom, c = 16.858(9) angstrom; Z = 4. This compound is the first Sn(IV) alkoxide carboxylate that has been isolated and structurally characterized. The implications of this study for the use of ester elimination reactions in strategies to prepare metal oxide materials are discussed.