Immobilization of multifunctional Schiff base containing ruthenium complexes on MCM-41

Two solid catalysts in which a Schiff base containing ruthenium complex has been covalently anchored on MCM-41 have been prepared and characterized. The catalytic behavior of these materials in ring-closing metathesis (RCM), ring-opening metathesis polymerization (ROMP), Kharasch addition, atom transfer radical polymerization (ATRP) and vinylation reactions as well as the recycling characteristics in RCM reactions are presented to exemplify the effectiveness and the multifunctional character of these catalytic systems. For ROMP the influence of the polymerization solvent on the performance of the catalysts was checked. For the RCM reactions both reaction time and reaction temperature were varied in order to determine the influence of these parameters on the RCM activity of our catalysts. The activity of our catalytic systems in radical reactions such as ATRP and the Kharasch addition is promising. Our results demonstrate that the ATRP process of styrene proceeds in a controlled fashion allowing the synthesis of well-defined polymers. Furthermore, we were able to demonstrate that the Kharasch activity of our catalysts shows a pronounced temperature dependence. In addition to all this, we also postulated a mechanism that explains for the observed selectivities in the vinylation experiments. The host-guest interaction of these hybrid catalytic systems is studied by XRD, XRF, ICP/MS, BET, FT-Raman and solid state NMR analysis. (C) 2003 Elsevier Science B.V. All rights reserved.