(615a) Rigid Tripods for Pharmaceutical Applications

Homogeneous organometallic catalysts, despite their high activity and selectivity, are rarely used in industrial processes. The reasons lie in the nature of these molecules: In contrast to heterogeneous (insoluble) catalysts, the homogeneous complexes are in the same phase as the educts / products. The separation and recovery of catalysts, as well as a continuous process control need a big effort. The immobilization (heterogenization) of organometallic compounds to solid carriers is an excellent opportunity to overcome the disadvantages of homogeneous catalysts and get the advantages. Target of this work was synthesing new rigid-linkers to immobilize on silicon substrate and finding the right way to functionalize the ?fourth leg? for further reaction to the catalyst. The tripod is a molecule with expanded tetrahedral symmetry (figure) that bears three functionalities for the immobilization of the molecule onto a surface and a fourth functional group for further derivatization. The rigidity stems and the conjugated molecules (double bonds) are interesting features which make these compounds very useful. The attachment of different catalysts at distinct locations is made possible using surface patterning methods via the UV-induced hydrosilylation. Examples of new tripods are illustrated below.