A Highly Active and Reusable Heterogeneous Ruthenium Catalyst for Olefin Metathesis

Abstract

Abstract:The synthesis and characterization of Ru complexes of the type [L 2 X 2 Ru ¼ CHR] (L ¼ PPh 3 , PCy 3 , N-heterocyclic carbenes or their derivates; X ¼ Cl) grafted on mesoporous SBA-15 material are described. In this heterogeneous catalyst the Ru complexes are anchored in the pore channels of mesoporous silica material SBA-15 to prevent the decomposition of the catalytic species. Compared with formal organic-supported heterogeneous catalysts, this heterogeneous catalyst shows relatively high catalytic activity in olefin metathesis reactions and can be used several times without any decrease in catalytic activities.

Strategies to Immobilize Well‐Defined Olefin Metathesis Catalysts: Supported Homogeneous Catalysis vs. Surface Organometallic Chemistry

“…[42] 6) Reaction of a modified Grubbs II catalyst having a pending trimethoxy group on the side chain of the NHC ligand with the surface of a SBA-15 (9c). [43] These catalysts have been mainly used in RCM and related reactions. In all cases, good catalytic performances are obtained, the catalysts can be recycled, and the Ru-contamination is lowered.…”

An Efficient and Recyclable Catalyst for N‐Alkylation of Amines and β‐Alkylation of Secondary Alcohols with Primary Alcohols: SBA‐15 Supported N‐Heterocyclic Carbene Iridium Complex

“…In the FT‐IR spectrum of 1 (see Supporting Information, Figure S1), the characteristic bands of SBA‐15 around 1085 and 462 cm −1 for ν(SiO) and δ(SiO) are maintained and the band around 937 cm −1 assigned to SiOH stretching of silanols on the surface almost disappears 12. These indicate that the Ir complex is tethered onto SBA‐15 surface, which is further confirmed by solid state NMR spectra.…”

SBA-15 as a Support for Effective Olefin Metathesis Catalysts

“…The S BET areas (m 2 /g), void volumes (cm 3 /g), and pore diameter (nm) were 829, 1.18, and 6.6 for the parent SBA-15, 585, 0.98, and 6.5 for 4.4/SBA-15, and 591, 0.97, and 6.5 for 4.5/SBA-15. Similarly, 4.1 immobilization on SBA-15 using an N-heterocyclic carbene (NHC ) linker (Table 1, entry 7) led to a decrease in S BET from 734 to 233 m 2 /g and in pore size from 7.4 to 5.2 nm, thus highlighting that the mesoporous character was preserved [48]. The preservation of the SBA-15 structure in the corresponding hybrid catalysts was also clearly shown by TEM [47,48].…”