A Covalently Immobilized Triphenylphosphine Rhodium Complex: Synthesis, Characterization, and Application in Catalytic Olefin Hydrogenation

Abstract

A trimethoxysilane functionalized triphenylphosphine was coordinated to rhodium(I) and the resulting rhodium complex was covalently bound to a mesoporous SBA‐15 support. The catalytic activity of this hybrid material was studied for the hydrogenation of 2‐cyclohexen‐1‐one and compared with the corresponding homogeneous catalyst. According to the 31P‐MAS NMR data, the catalytically active species was stable against oxidation; no structural change could be detected after exposing it to air for more than two months. Transmission electron microscopy (TEM) measurements on the used catalyst confirmed that the rhodium species was also stable against reduction to the metal because the formation of rhodium nanoparticles during the catalysis could be excluded. The kinetic curves of the recycled system confirmed that this hybrid catalyst shows excellent activity, selectivity, stability, and reusability, and is truly heterogeneous in the hydrogenation reaction.

Heterogenized Wilkinson‐Type Catalyst for Transfer Hydrogenation of Carbonyl Compounds

“…Previously, Wilkinson-type catalysts have been immobilized for the hydrogenation of olefins with molecular hydrogen. [11][12][13][14] Their syntheses and extensive solid-state NMR characterization have been recently reviewed by Blümel. [15] So far, there are no reports on hydrogen transfer reactions with immobilized rhodium complexes.…”

Rückgewinnung von Zinn aus ehemaligen Bergbauhalden

“…Grafting only the ligand would yield statistically distributed phosphine molecules on the surface, all of which might not be in an ideal position to coordinate to the rhodium(I) center in the given manner. In 2010, we synthesized a structurally closely related system covalently supported on SBA‐15, which could completely be characterized spectroscopically 27…”

“…In the IR spectrum of 9@Fe 2 O 3 (Figure 8), a band at 1980 cm −1 can be assigned to the CO stretching vibration of the carbonyl ligand coordinated to the rhodium center 27. This band is only shifted by a few cm −1 towards higher energy compared to the data of the rhodium precursor 9 .…”

“…In 2010, we published a study on the synthesis and the catalytic activity of a structurally closely related system in which we grafted a Rh(CO)Cl complex coordinated by two functionalized triphenylphosphine ligands, each equipped with a C(O)NH(CH 2 ) 3 Si(OMe) 3 linker, covalently onto the surface of a neat silica SBA‐15 support 27. The catalytic activity of this catalyst and 9@Fe 2 O 3 was investigated under identical conditions.…”

Wilkinson‐Type Immobilized Catalyst on Diamond Nanoparticles for Alkene Reduction

“…Wang et al. functionalized a mesoporous SBA‐15 support with a triphenylphosphine rhodium carbonyl complex and found excellent activity for olefin hydrogenation . A series of alumina/heteropolyacid anchored Wilkinson catalysts have shown to be active towards the reduction of 1‐hexene with 85 % of conversion …”