ESTER ELIMINATION - A GENERAL SOLVENT DEPENDENT NON-HYDROLYTIC ROUTE TO METAL AND MIXED-METAL OXIDES

Molecular routes to metal oxides has become an area of intense scienti fic interest due to the technological relevance of these materials. Mo lecular routes are proving important as a result of the possibility to control the physical and chemical properties of the final materials. We have chosen to study non-hydrolytic methods, namely eater eliminati on reactions between two prototypical molecular precursors metal alkox ides, M(OR)(n), and metal carboxylates, M(O(2)CR)(n), to synthesize me tal oxides: M(OR)(n) + M'(O(2)CR')(n) --> MM'(O)(x)(OR)(n-x)(O(2)CR')( n-x) + xRO(2)CR' MM'(O)(x)(OR)(n-x)(O(2)CR')(n-x) --> MM'(O)(n) + n - xRO(2)CR This method allows for the synthesis of pure metal oxides by complete elimination of the organic supporting ligands with concomitan t formation of M-O-M' bridges. Furthermore, incomplete ester eliminati on can lead to isolation of molecular clusters as intermediates which can also be used as building blocks for the formation of metal oxides with controlled microstructure. Here we report a series of reactions b etween Sn and Si alkoxides and carboxylates designed to gain further i nsight into the factors governing ester elimination reactions. By choo sing compounds with varying coordination environments and steric acces sibility we have devised a set of criteria which should allow for succ essful ester elimination between metal alkoxide and carboxylate compou nds. Furthermore we have also shown the ability of ester elimination d erived molecular clusters with specific microstructure to be used in t he synthesis of bulk materials retaining the structural attributes of the precursor cluster.