Cycloaddition of Nitrile Imines to Graphene. a Theoretical and Experimental Approach
Due to the lower reactivity of graphene, compared to other carbon nanostructures, the range of reactions available for functionalization of this material is smaller than in the case of other carbon nanostructures as fullerene or carbon nanotubes.
Although most of the studies involving graphene functionalization has been performed by amidation of the carboxylic groups at the edges or by using diazonium salts,3 examples of 1,3-dipolar cycloaddition of azomethine ylide have been also described,4 but there are not examples in the literature of cycloaddition of other less reactive dipoles as nitrile imines or nitrile oxides.
In most cycloaddition reactions to fullerene, the LUMO of the fullerene cage is shifted to higher values by 0.15 eV. Nevertheless, we have previously demonstrated that, in the cycloaddition of nitrile imines to fullerenes, affording pyrazolinofullerenes, the LUMO of C60 is not shifted to higher values due to the electron-acceptor character of the pyrazoline ring.5,6 So, cycloaddition of nitrile imines to graphene, if the reaction works, can be useful to modulate the band-gap in a different way than other cycloaddition reactions.
We present here the theoretical and experimental studies on the 1,3-dipolar cycloaddition of nitrile imines to graphene.
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