Catalytic applications of recyclable silica immobilized NHC–ruthenium complexes

A monosilylated Hoveyda–Grubbs ruthenium alkylidene has been prepared and grafted through the NHC ligand to a mesostructured silica, in refluxing toluene or at room temperature, giving two new organic–inorganic hybrid silica materials M2 and M3, respectively. While M3 exhibited good performances in several metathesis reactions, M2 showed good selectivity in the hydrosilylation of terminal alkynes, where the β-(Z)-vinylsilane was obtained as major product. Recycling of the supported catalysts without significant decrease in activity and selectivity was proven for at least three cycles in both transformations.