Exohedral sidewall reactions of single walled carbon nanotubes

For the study of sidewall reactivity, pristine SWNTs in high purity are required. This can be achieved by dispersing the raw material, prepared by arc discharge, in a laurylsulfate (SDS) solution and subsequent centrifugation [1]. To remove the SDS, the supernatant suspension has to be washed with ethanol. After drying, the SWNTs can be re-suspended in different organic solvents, such as tetrachloroethane (TCE) or THF. These mixtures are suitable for reactions of azides, carbenes and radicals with the SWNT sidewall. A large excess of an alkyloxycarbonyl azide was added to a SWNT/TCE suspension in order to react with the sidewalls in a $[2+1]$ cycloaddition via a nitrene intermediate, which is formed by nitrogen loss. The nucleophilic attack of an carbene in THF at low temperature should also be possible. In addition to microscopic methods, we used VIS/NIR-, and NMR-spectroscopy for bulk characterization.