Microwave-assisted functionalization of carbon nanostructures in ionic liquids.
The effect of microwave (MW) irradiation and ionic liquids (IL) on the cycloaddition of azomethine ylides to [60]fullerene has been investigated by screening the reaction protocol with regard to the IL medium composition, 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 selectivity to [60]fullerene can be tuned as a function of fullerene concentration. The reaction scope includes aliphatic, aromatic, and fluorous-tagged (FT) derivatives. MW irradiation of IL-structured bucky gels is instrumental for the functionalization of single-walled carbon nanotubes (SWNTs), yielding group coverages of up to one functional group per 60 carbon atoms of the SWNT network. An improved performance 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 functional coverage) yields novel FT-CNS (carbon nanostructures) with high affinity for fluorinated phases.
ITM-CNR and Department of Chemical Sciences, University of Padova, Via Marzolo, 1, 35131 Padova, Italy.
Ivan
I
Guryanov
Francesca Maria
FM
Toma
Alejandro
A
Montellano López
Mauro
M
Carraro
Tatiana
T
Da Ros
Guido
G
Angelini
Eleonora
E
D'Aurizio
Antonella
A
Fontana
Michele
M
Maggini
Maurizio
M
Prato
Marcella
M
Bonchio
D000447:Aldehydes / Q000737:chemistry; D001391:Azo Compounds / Q000737:chemistry; D002244:Carbon / Q000737:chemistry*; D002722:Chlorobenzenes / Q000737:chemistry; D003080:Cold Temperature; D037741:Fullerenes / Q000737:chemistry; D052578:Ionic Liquids / Q000737:chemistry*; D007700:Kinetics; D008872:Microwaves; D049329:Nanostructures / Q000737:chemistry*; D013882:Thiosemicarbazones / Q000737:chemistry
D000447:Aldehydes; D001391:Azo Compounds; D002722:Chlorobenzenes; D037741:Fullerenes; D052578:Ionic Liquids; D013882:Thiosemicarbazones; C512188:azomethine; C004726:2-dichlorobenzene; D002244:Carbon; C069837:fullerene C60