Related Experiment Video
Updated: Jun 21, 2026

Catalytic Reactions at Amine-Stabilized and Ligand-Free Platinum Nanoparticles Supported on Titania During Hydrogenation of Alkenes and Aldehydes
Published on: June 24, 2022
Carbohydrate-derived 1,3-diphosphite ligands as chiral nanoparticle stabilizers: promising catalytic systems for
Aitor Gual1, Cyril Godard, Karine Philippot
1Department de Química Física I Inorgànica, Universitat Rovira I Virigli, Tarragona, Spain.
Abstract:
Metallic Ru, Rh, and Ir nanoparticles were prepared by the decomposition of organometallic precursors under H(2) pressure in the presence of 1,3-diphosphite ligands, derived from carbohydrates, as stabilizing agents. Structural modifications to the diphosphite backbone were found to influence the nanoparticles' size, dispersion, and catalytic activity. In the hydrogenation of o- and m-methylanisole, the Rh nanoparticles showed higher catalytic activity than the corresponding Ru nanoparticles. The Ir nanoparticles presented the lowest catalytic activity of the series. In all cases, the hydrogenation of o-methylanisole gave total selectivity for the cis-product, however, the ee of the product was always less than 6 %. A maximum of 81 % cis-selectivity was obtained for the hydrogenation of m-methylanisole, however, no asymmetric induction was observed. These results show that the catalytic activity is affected by a combination of influences from the substrate, the diphosphite ligands, and the metallic nanoparticles.
Related Concept Videos
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
Reduction of Alkenes: Catalytic Hydrogenation
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the surface of...
Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Stability of Conjugated Dienes
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.
Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration
Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide

