DOI: 10.1002/chem.200901408 Microwave-Assisted Functionalization of Carbon Nanostructures in Ionic Liquids Ivan Guryanov, [a] Francesca Maria Toma, [b, d] Alejandro Montellano López, [b] Mauro Carraro, [a] Tatiana Da Ros, [b] Guido Angelini, [c] Eleonora DAurizio, [c] Antonella Fontana,* [c] Michele Maggini,* [a] Maurizio Prato,* [b] and Marcella Bonchio* [a] Dedicated to the Centenary of the Italian Chemical Society Introduction Research on carbon nanostructures (CNS), such as ful- lerenes, carbon nanotubes, and graphene, has recently been the focus for scientists from many disciplines, owing to their exclusive structures and properties. Shortly after their dis- covery, the fullerenes were subjected to extensive studies of chemical modification to understand their reactivity and to tune their properties. [1] Exohedral addition of organic groups helps to control solubility, morphology in the solid state, and electronic properties of the fullerene core. The azomethine ylide cycloaddition, yielding fulleropyrrolidines (FPs), [2] has contributed significantly to the development of new nanocarbon-based materials for strategic fields such as solar energy conversion or molecular medicine. [3] FP synthe- sis tolerates many functional groups and is significantly ac- celerated by microwave (MW) irradiation. [4, 5] Several FPs have been prepared under MW irradiation by Langa and co- workers, with yields up to 37 % and interesting regioselectiv- ities in the case of additions to C 70 . [4] In these reactions, tolu- ene, benzene, or o-dichlorobenzene (o-DCB) have been Abstract: The effect of microwave (MW) irradiation and ionic liquids (IL) on the cycloaddition of azomethine ylides to [60]fullerene has been investi- gated by screening the reaction proto- col with regard to the IL medium com- position, the applied MW power, and the simultaneous cooling of the system. [60]Fullerene conversion up to 98 % is achieved in 2–10 min, by using a 1:3 mixture of the IL 1-methyl-3-n-octyl imidazolium tetrafluoroborate ([omim]BF 4 ) and o-dichlorobenzene, and an applied power as low as 12 W. The mono- versus poly-addition selec- tivity to [60]fullerene can be tuned as a function of fullerene concentration. The reaction scope includes aliphatic, aromatic, and fluorous-tagged (FT) de- rivatives. MW irradiation of IL-struc- tured bucky gels is instrumental for the functionalization of single-walled carbon nanotubes (SWNTs), yielding group coverages of up to one function- al group per 60 carbon atoms of the SWNT network. An improved perfor- mance is obtained in low viscosity bucky gels, in the order [bmim]BF 4 > [omim]BF 4 > [hvim]TF 2 N (bmim = 1- methyl-3-n-butyl imidazolium ; hvim = 1-vinyl-3-n-hexadecyl imidazolium). With this protocol, the introduction of fluorous-tagged pyrrolidine moieties onto the SWNT surface (1/108 func- tional coverage) yields novel FT-CNS (carbon nanostructures) with high af- finity for fluorinated phases. Keywords: cycloaddition · fuller- ACHTUNGTRENNUNGenes · ionic liquids · microwave chemistry · nanotubes [a] Dr. I. Guryanov, Dr. M. Carraro, Prof. M. Maggini, Dr. M. Bonchio ITM-CNR and Department of Chemical Sciences University of Padova Via Marzolo, 1, 35131 Padova (Italy) Fax: (+ 39) 049-8275239 E-mail: michele.maggini@unipd.it marcella.bonchio@unipd.it [b] Dr. F. M. Toma, Dr. A. Montellano López, Dr. T. Da Ros, Prof. M. Prato Dipartimento di Scienze Farmaceutiche, INSTM unit of Trieste Piazzale Europa 1, 34127 Trieste (Italy) Fax: (+ 39) 040-52572 E-mail: prato@units.it [c] Dr. G. Angelini, Dr. E. DAurizio, Prof. A. Fontana Dipartimento di Scienze del Farmaco Università “G. d’Annunzio” Via dei Vestini, 66013 Chieti (Italy) Fax: (+ 39) 0871-3554461 E-mail : fontana@unich.it [d] Dr. F.M. Toma SISSA Via Beirut 2-4, 34151 Trieste (Italy) Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/chem.200901408. Chem. Eur. J. 2009, 15, 12837 – 12845  2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 12837 FULL PAPER