Covalent sidewall functionalization of SWNTs by nucleophilic addition of lithium amides

The synthesis and characterization of sidewall-functionalized SWNT derivatives (nPrNH)(n)-SWNTs containing n-propylamine addends is reported. The nucleophilic addition of in situ generated lithium n-propylamide to the sidewall of SWNTs and the subsequent reoxidation of charged intermediates of the type (nPrNH)(n)-SWNTn- leads to carbon nanotube derivatives with covalently attached amino groups. Based on the reaction sequence, a homogeneous dispersion of the carbon nanotube material is achieved as a result of the electrostatic repulsion of negatively charged intermediates. The solubility of the resulting propylamine-functionalized (nPrNH)(n)-SWNT material in organic solvents is drastically increased. The functionalized tubes were characterized in detail by Raman spectroscopy, thermogravimetric analysis (TGA/MS), X-ray photoelectron spectroscopy (XPS) and UV/Vis/NIR spectroscopy. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).