Nanosheets of graphene oxides display outstanding physical, chemical and electrical charasteristics and this is why this material has attracted a lot of interests in the chemical community. The presence of OH and free caroboxyl moieties on the surface renders this material water soluble, and this is a great pratical advantage.
In a short Chem Comm paper (DOI: 10.1039/c1cc15230k), indian researchers reported the use of graphene oxide as organocatalyst for an aza-Micheal reaction. The graphene oxide was synthesized by oxidation of graphene powder and fully characterized from the spectroscopical point of view (XRD, FTIR, UV-Vis). Subsequently the catalytic potential of graphene oxide nanosheets was examined for the aza-Michael addition of amine to activated olefines.
The reaction was defenitly influenced by the presence of grapgene oxide in catalytic amount and the full conversion could be obtained after only 5 minute of reaction time. The responsible for this huge activation are the oxigen containing functionalities on the surface of graphene oxide: in fact, the same reaction carried out in presence of reduced graphene was completed after a longer period of time (30 min).
Moreover, by a simple extraction, the graphene oxide could be recovered from the reaction mixture and reused for the same reaction without loss in yield or ee.
This discovery opens new horizons in the application of graphene oxide os organocatalyst.