The invention relates to a method for synthesizing silasesquioxane metal complexes, to new silasesquioxane metal complexes and to their use.
The synthesis of silasesquioxane metal complexes by the reaction of trisilanol, which is substituted by cyclohexyl groups, with a metal compound, is known (Polyhedron, 1995, vol. 14, No. 22, pages 3239-3253).
The synthesis of a trisilanol, containing cyclohexyl groups, is very time consuming. This trisilanol is, however, readily soluble, so that the reaction to the desired metal complexes is readily possible.
A trisilanol, which is substituted by cyclopentyl groups, can be synthesized in a much shorter time. However, the trisilanol is not very soluble, so that the synthesis of the corresponding metal complexes has not previously been described.
The previously known methods for the synthesis of the metal complexes are very time consuming and require large amounts of solvents, which must be worked up once again.
The use of titanium containing metal complexes as catalysts for the synthesis of epoxide compounds by the oxidation of unsaturated hydrocarbons is also known. For example, the WO 97/24344 discloses a method for the oxidation of olefinically unsaturated hydrocarbons, for which titanium silasesquioxane catalysts are used. However, this method is limited to organic hydroperoxides as oxidizing agents and can be carried out only in anhydrous organic solvents. The titanium atoms in the titanium silasesquixoane catalysts used are tetrahedrally coordinated four fold.