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J. Geserick, U. Schubert:
"Cluster-Modified Porous Silica: A Novel Quasi Water-Free Route Towards Thin Films And Powders";
Poster: 14. Österreichische Chemietage, Johannes Kepler Universität, Linz; 26.09.2011 - 29.09.2011; in: "14. Österreichische Chemietage - Program", (2011), Paper-Nr. PO-79, 1 S.

The concept of clusters within a porous matrix is well-known. Even magnetic clusters had been incorporated into the channels of mesoporous materials with ordered pore structure by impregnation method. However, the control over the cluster-cluster distance and the cluster distribution within the matrix was not achieved with this method.
Using a new quasi water-free sol-gel route, based on the evaporation-induced selfassembly (EISA), thin films and powders with high loadings of potential cluster ligands can be achieved. Therefore, tetraethoxysilane was co-condensed with SiCl4 and bissilylated organosilanes that contain potential ligand groups in the presence of Pluronic F127 as template from pure ethanolic solution. Due to the absence of water there is only a low condensation rate; i.e. the water-free sol is stable at room temperature even for months. Not until the EISA process is performed in ambient atmosphere, the air moisture provides the water that is necessary for the hydrolysis and condensation reactions, which eventually lead to the final network. The obtained materials offer well-defined pore systems and good distribution of the organic sites even for high loadings up to 20% (based on total silicon content).
That means, the clusters were not only intercalated into the matrix, but actually bonded by these ligand groups. This allows a higher control over the target characteristics (cluster-cluster distance and distribution within the matrix).