Hydrolysis and Condensation of Tin (IV) Alkoxide Compounds: The Control of Structural Evolution.
Annual rept. Apr 93-Jun 94,
NEW MEXICO UNIV ALBUQUERQUE DEPT OF CHEMISTRY
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We are investigating the mechanism of ester elimination reactions between metal alkoxide compounds and metal carboxylate compounds as a method to form metal-oxo clusters in a controlled fashion. We anticipate that the fundamental insight gained will result in a better understanding of methods to control the evolution of microstructure in metal oxide ceramics. Two parts of our preliminary experiments are reported here. Part 1 describes a series of proton 1H NMR magnetization transfer experiments utilized to measure the kinetic parameters of alcohol interchange between the homoleptic metal alkoxide, SnO-t-Bu4, and t-butanol, its parent alcohol. These data suggest that the metal center, even in sterically encumbered metal alkoxide compounds such as SnO-t-Bu4, are sufficiently coordinately and electronically unsaturated to react with bulky alcohols. These observations must be taken into account when conducting sol-gel type hydrolysis and condensation reactions. In part 2, the alkoxide SnO-t-Bu4 and carboxylate Me3SiOAc are used in a detailed study of the ester elimination process. We report time dependent 170 NMR spectra of the ester elimination reaction of the two from which a plausible associative transition state can be described. Microstructure, Porosity, Tin oxide.
- Physical Chemistry
- Inorganic Chemistry
- Organic Chemistry
- Atomic and Molecular Physics and Spectroscopy