Cycloaddition of Nitrile Imines to Graphene. a Theoretical and Experimental Approach

Graphene is a unique material with outstanding mechanical and electronic properties.¹ The modulation of the electronic properties of graphene by chemical functionalization as well as the control over the opening of its band gap are of great interest, because of the potential of this material for a wide range of applications.²

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 [60]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.

References:

[1] V. Georgakilas, M. Otyepka, B. Bourlinos, V. Chandra, N. Kim, K. C. Kemp, P. Hobza, R. Zboril and K. S. Kim Chem. Soc. Rev. 2012, 112, 6156.

[2] F. M. Koehler and W. J. Stark, Acc. Chem. Res. 2013, 46, 2297.

[3] L. Rodriguez, M. A. Herranz and N. Martin, Chem. Commun. 2013, 49, 3721.

[4] M. Quintana, E.  Vazquez and M. Prato, Acc. Chem. Res. 2013, 46, 138.

[5] M. Álvaro, P. Atienzar, P. de la Cruz, J. L. Delgado, H. García and F. Langa, J. Phys. Chem. B 2004, 108, 12691;

[6] J. L. Delgado, N. Martín, P. de la Cruz and F. Langa, Chem. Soc. Rev. 2011, 40, 5253.