Hydrodefluorination of carbon–fluorine bonds by the synergistic action of a ruthenium–palladium catalyst

Abstract

Catalytic hydrodefluorination of organic molecules is a major organometallic challenge, owing to the strength of C-F sigma bonds, and it is a process with multiple industrial applications. Here we report a new heterodimetallic ruthenium-palladium complex based on a triazolyldi-ylidene ligand. The complex is remarkably active in the hydrodefluorination of aromatic and aliphatic carbon-fluorine bonds under mild reaction conditions. We observe that both metals are required to promote the reaction process. The overall process implies that the palladium fragment facilitates the C-F activation, whereas the ruthenium centre allows the reduction of the substrate via transfer hydrogenation from isopropanol/sodium t-butoxide. The activity of this heterodimetallic complex is higher than that shown by a mixture of the related homodimetallic complexes of ruthenium and palladium, demonstrating the catalytic benefits of the heterodimetallic complex linked by a single-frame ligand.

Immobilization of Pyrene-Tagged Palladium and Ruthenium Complexes onto Reduced Graphene Oxide: An Efficient and Highly Recyclable Catalyst for Hydrodefluorination

“…Also, the mechanism for this process is different than the mechanism for our previously described homogeneous Ru-Pd catalyst. 6 In this case, we believe that the C-F activation should be promoted by the palladium nanoparticles, while the introduction of the hydrogen by transfer hydrogenation should be facilitated by the ruthenium heterogenised complex, and therefore the synergistic action between the two metals is crucial for explaining the superior activity of the catalyst.…”

Tandem Suzuki–Miyaura/transfer hydrogenation reaction catalyzed by a Pd–Ru complex bearing an anionic dicarbene

“…Bimetallic systems have become the subject of current research as they are expected to induce cooperative effects among the involved metals [3][4][5][6][7][8][9]. For the Suzuki-Miyaura/transfer hydrogenation transformation entailing C-C and C-H bond forming reactions, catalysts are mainly based on heterogeneous systems [4,10] and enzymes [11][12][13][14][15].…”

Palladium-Mediated Organofluorine Chemistry

“…257 Catalytic hydrodefluorination of fluorobenzene and substituted fluoroarenes has been carried out with a heterometallic homogeneous Pd-Ru catalyst using isopropanol and a base as a hydrogen source (Scheme 84). 258 The presence of both metals in the same complex is needed for an efficient catalysis and neither the homonuclear palladium or rhodium analogue dimers nor a mixture of both homonuclear complexes have the high activity observed for the heteronuclear complex. The system is also capable of complete hydrodefluorination of benzylic trifluoromethyl substituents (Scheme 84).…”