Solid-State ¹³C NMR Assignment of Carbon Resonances on Metallic and Semiconducting Single-Walled Carbon Nanotubes

Abstract

Solid-state 13C NMR spectroscopy was used to investigate the chemical shift of nanotube carbons on m- and s-SWNTs (metallic and semiconducting single-walled nanotubes) for samples with widely varying s-SWNT content, including samples highly enriched with nearly 100% m- and s-SWNTs. High-resolution 13C NMR was found to be a sensitive probe for m- and s-SWNTs in mixed SWNT samples with diameters of ∼1.3 nm. The two highly enriched m- and s-SWNT samples clearly exhibited features for m- and s-SNWT 13C nuclei (∼123 and 122 ppm, respectively) and were successfully fit with a single Gaussian, while five mixed samples required two Gaussians for a satisfactory fit.