Amphi Sciences de la Matière, site Monod
Performances of catalysts and more generally of functional materials are mainly controlled by our ability to generate specific sites/objects (organometallic complexes, nanoparticles, uniform thin films...) onto supports (powders or flat surfaces). In this context, we will discuss here rational approaches to yield functional materials containing well-defined surface-species.
The controlled grafting of organometallic complexes via reactivity with surface hydroxyl groups to yield isolated catalytically active organometallic surface fragments or nanoparticles will be discussed first.
The development of synthetic methods allowing the preparation of well-defined functional materials containing either organic fragments or highly active metallo-N-heterocyclic carbene complexes (M-NHC) will also be shown. All the resulting solids
were fully characterized using several techniques and
particularly by advanced solid-state NMR using Dynamic Nuclear Polarization, allowing the molecular description of surface species. Of the different materials, solids containing M-NHC (M = Ru and Ir) sites will be presented. These materials exhibit enhanced catalytic performances compared to those of molecular homologues in solution. These remarkable performances were attributed to surface site isolation which suppresses bimolecular deactivation processes and to beneficial interactions between the silica surface and the M-NHC centers.