Hybrid Organic-Inorganic Materials for Heterogeneous Catalysis: Development of supported Ti and Pd-Catalysts

We present the development of novel catalytic systems for the heterogeneous synthesis of pharmaceutical intermediates employing supported titanocenes and palladium complexes. In the first step we synthesized tethered ethylenebis(indenyl)-titanocenes, which include ligands of different length and functionality. The synthesis and optimization of the new catalysts were accompanied with molecular modeling approaches using Density Functional Theory methods in order to investigate (a) the relationship between function and structure of the catalysts [1] and (b) possible transition states of the catalytic active compounds [2]. The tethered titanocenes were covalently immobilized on various solid supports including H-terminated Si-wafers [3] and particles as well as on functionalized silica gel particles. The activity of the heterogeneous catalysts was tested for the hydrosilylation of imines. In a further step the evolved immobilization methods were used for the development of heterogeneous Palladium-complexes. These catalytic systems were implemented in continuous flow setups and were used for the production of substituted biaryls via heterogeneous Suzuki-Miyaura reactions.