Active hydrogenation Rh nanocatalysts protected by new self-assembled supramolecular complexes of cyclodextrins and surfactants in water

Nguyet Trang Thanh Chau (1) , Stéphane Menuel (2) , Sophie Colombel-Rouen (1) , Miguel Guerrero (3, 4) , Eric Monflier (2) , Karine Philippot (4, 3) , Audrey Denicourt-Nowicki (1) , Alain Roucoux (5, 1)

1 ISCR - Institut des Sciences Chimiques de Rennes
2 UCCS Équipe Catalyse Supramoléculaire
3 IUT de Tarbes
4 LCC - Laboratoire de chimie de coordination
5 ENS Rennes - École normale supérieure - Rennes

The stability of inclusion complexes between randomly methylated β-cyclodextrin (RaMeCD) or its leucine-grafted analogue (RaMeCDLeu) with two hydroxylated ammonium surfactants was investigated. The binding isotherms and complexation constants were measured using the Isothermal Titration Calorimetry (ITC) technique. These host-guest inclusion complexes were used as protective agents during the formation of rhodium(0) nanoparticles by chemical reduction of rhodium trichloride in water. The amount of protective agent was adjusted in order to ensure both stability and reactivity of the rhodium nanocatalysts under the catalytic conditions. The size and dispersion of air-stable and water-soluble rhodium suspensions were determined by Transmission Electron Microscopy (TEM) analyses. These spherical nanoparticles, with sizes between 1.20 to 1.50 nm according to the nature of inclusion complexes, were evaluated in the biphasic hydrogenation of various reducible compounds (olefins, linear or aromatic ketones), showing promising results in terms of activity and selectivity.

Keywords: Isotherms; Chemical reduction; Catalytic conditions; Complexation constants; Host-guest inclusion complexes; Hydrogenation; Surface active agents; Supramolecular chemistry; Rhodium; Ketones; Nanoparticles; Transmission electron microscopy; Rhodium compounds; Ammonium surfactants; High resolution transmission electron microscopy; Cyclodextrins; Amino acids; Isothermal titration calorimetry; Supramolecular complexes; Spherical nanoparticles

Domains: Chemical Sciences; Catalysis

Nguyet Trang Thanh Chau, Stéphane Menuel, Sophie Colombel-Rouen, Miguel Guerrero, Eric Monflier, et al.. Active hydrogenation Rh nanocatalysts protected by new self-assembled supramolecular complexes of cyclodextrins and surfactants in water. RSC Advances, 2016, 6 (109), pp.108125-108131. ⟨10.1039/C6RA21851B⟩. ⟨hal-01416441⟩