title: Tethered ansa-bridged titanium complexes immobilized on 3-mercaptopropyl-functionalized silica gel and their application for the hydrosilylation of imines.
abstract: Four tethered titanocene complexes were covalently immobilized onto 3-mercaptopropyl-functionalized silica gel. We have investigated the influence of the length of the tether and of the ansa-bridge on the activity in the heterogeneous hydrosilylation of the cyclic imine 2-phenylpyrroline, taken as an illustrative example. Possible metal leaching during the reaction was investigated using ICP/OES, recycling studies and the three-phase test. The novel immobilized catalysts exhibit an activity similar to their homogeneous analogues in the tested hydrosilylation reactions with a TOF of ~20 h(-1). Furthermore, our results indicate that metal leaching is negligible under the applied reaction conditions.
authors.affiliation: Institute for Process and Particle Engineering, Graz University of Technology, Inffeldgasse 21A/II, A-8010 Graz, Austria.
authors.forename: Heidrun
authors.initials: H
authors.lastname: Gruber-Woelfler
authors.forename: Georg J
authors.initials: GJ
authors.lastname: Lichtenegger
authors.forename: Christoph
authors.initials: C
authors.lastname: Neubauer
authors.forename: Eleonora
authors.initials: E
authors.lastname: Polo
authors.forename: Johannes G
authors.initials: JG
authors.lastname: Khinast