From hydroxycetylammonium salts to their chiral counterparts. A library of efficient stabilizers of Rh(0) nanoparticles for catalytic hydrogenation in water

Abstract

Nowadays, the nanometer-size and shape control of metallic species remains a strategic research area in material development due to their particular physical and chemical properties. Among their various applications, catalysis has emerged as one of the most pertinent due to its large range of potentialities. From now on, noble metal nanoparticles (NPs) are considered as an unavoidable family of catalysts, at the border between heterogeneous bulk materials and molecular complexes. The design of stable noble metal nanoparticles in various solvents such as ionic liquids, fluorous or organic media has become a concern over the past few years. Nevertheless, for economic and ecological purposes, the development of green approaches remains an active research area, as well as the reusability of nanocatalysts. In this context, the stabilisation in colloidal suspension of nanoparticles, thus providing a catalyst recycling thanks to a biphasic approach constitutes an efficient alternative to the heterogeneization of the nanocatalysts. Among the various water-soluble protective agents, easily modulated surfactants proved to be attractive candidates to efficiently stabilize catalytically active nanospecies in aqueous media. Here, we review our recent progresses in the hydrogenation of benzene derivatives by rhodium nanoparticles which were capped by an ammonium salts bearing an achiral or chiral polar head group.