"Click" on Tubes: a Versatile Approach Towards Multimodal Functionalization of Carbon Nanotubes

Different synthetic approaches have been successfully applied to the CNT multifunctionalization. All of them take advantage from well-established organic approaches, spanning from the combination/exploitation of different organic protocols to the covalent anchoring of masked functionalities bearing orthogonally cleavable protecting groups and site-selective functionalization of the opposite tube ends on VA-MWCNTs exposed at different photoreactive solutions. Herewith, we present a versatile and efficient organometallic protocol to the functionalization and/or multifunctionalization of CNTs starting from covalently modified CNTs bearing phenylazido pendant arms. Their subsequent exposure to terminal acetylenes under copper(I)-catalyzed conditions (CuAAC or "click" chemistry) allows for the homo- or hetero-decoration of the CNT sidewalls with more complex organic/organometallic guests. Such an approach has been successfully exploited in the presence of a number of organic and organometallic terminal alkynes, or mixture thereof, thus imparting multimodality to the resulting nanocarbon materials. Synthetic details and complete spectroscopic and morphologic characterization of the novel functionalized materials will be discussed.