title: Cyclodextrin-based PNN supramolecular assemblies: a new class of pincer-type ligands for aqueous organometallic catalysis.
abstract: Water-soluble cyclodextrins (CDs) bearing two nitrogen atoms as metal coordinating sites have been synthesized. An appropriate phosphane could be included within their cavity through the primary face to form self-assembled PNN supramolecular edifices. Once the PNN ligands were coordinated to platinum, the resulting complexes proved to be very effective as catalysts in a domino reaction, where a Pt-catalyzed reduction of nitrobenzene was followed by a Paal-Knorr pyrrole reaction. In the nitrobenzene reduction, the modified CDs acted both as first- and second-sphere ligands. Contrary to an acyclic glucopyranose-based NN ligand unable to interact with a phosphane ligand, the CD-based PNN ligands stabilized the catalytic species in water by supramolecular means. Interestingly, the product and the water-soluble Pt-catalyst could be recovered in two different phases once the reaction was complete.
authors.affiliation: Université d'Artois, Unité de Catalyse et de Chimie du Solide - UCCS, CNRS UMR 8181, Faculté des Sciences Jean Perrin, SP18, 62307 Lens Cedex, France. frederic.hapiot@univ-artois.fr.
authors.forename: S
authors.initials: S
authors.lastname: Menuel
authors.forename: E
authors.initials: E
authors.lastname: Bertaut
authors.forename: E
authors.initials: E
authors.lastname: Monflier
authors.forename: F
authors.initials: F
authors.lastname: Hapiot
mesh_terms: D002384:Catalysis; D056831:Coordination Complexes / Q000737:chemistry*; D003505:Cyclodextrins / Q000737:chemistry*; D008024:Ligands; D009578:Nitrobenzenes / Q000737:chemistry; D010084:Oxidation-Reduction; D010720:Phosphines / Q000737:chemistry; D010984:Platinum / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D056831:Coordination Complexes; D003505:Cyclodextrins; D008024:Ligands; D009578:Nitrobenzenes; D010720:Phosphines; D014867:Water; D010984:Platinum; C036077:nitrobenzene; C044646:phosphine