Organo-polyoxometalate-Based Hydrogen-Bond Catalysis
Résumé
Several urea-inserted organo-polyoxometalates (POMs) derived from polyoxotungstovanadate [P2V3W15O61] 9- were prepared. The insertion of the carbonyl into the polyoxometallic framework activates the urea toward Hydrogen-bond catalysis. This was shown on the Friedel-Crafts arylation of trans-b-nitrostyrene. Modelling shows that the most stable form of the organo-POMs features an antiparallel arrangement of the two N-H bonds, but that the likely catalytically active parallel form is accessible at room temperature. Finally, it is possible that the oxo substituents next to the vanadium atoms may help the approach of the nucleophile via H-bonding.
Domaines
ChimieOrigine | Fichiers produits par l'(les) auteur(s) |
---|