We describe a new synthetic strategy to produce multifunctionalized carbon nanotubes using a combination of two different addition reactions, the 1,3-dipolar cycloaddition of azomethine ylides and the addition of diazonium salts, both via a simple and fast microwave-induced method. The presence of multifunctionality on the SWNTs has been confirmed using the most useful techniques for the characterization of carbon nanotubes. The doubly functionalized SWNTs can be considered potentially useful for many interesting applications.

We report a new approach that uses microwaves to rapidly functionalize carbon nanotubes by using 1,3-dipolar cycloaddition of aziridines, well-known precursors to azomethine ylides, in solvent-free conditions. The efficiency of our microwave-mediated protocol is confirmed by comparison to a similar protocol in classical conditions for the azomethine ylides in DMF. Under these latter conditions, the reaction proceeds in 5 days (against 1 h under microwave irradiation), and the functionalization degree is much lower, as confirmed by thermogravimetric analysis and Raman spectroscopy. With our procedure, we easily scale-up the reaction up to 250 mg of functionalized MWNT in 1 h. We also provide an indirect proof of the covalent sidewall functionalization of the tubes.