Probing Chiral Selective Reactions Using a Revised Kataura Plot for the Interpretation of Single-Walled Carbon Nanotube Spectroscopy

Abstract

Raman spectroscopy on surfactant-dispersed, aqueous suspensions of single-walled carbon nanotubes is used to verify the energies of interband transitions and validate the spectral assignments of semiconducting and metallic nanotubes determined by spectrofluorimetry for the former and Raman excitation profiles for the latter. The results are compiled into an experimentally based mapping of transition versus nanotube diameter to revise those previously employed using single-electron theoretical treatments. Because this mapping provides the transitions associated with a precise chiral wrapping of a particular nanotube, it allows the monitoring of reaction pathways that are selective to the nanotube chirality vector. This is demonstrated using a model electron-transfer reaction of 4-chlorobenzenediazonium shown to be selective for metallic over semiconducting carbon nanotubes via charge-transfer stabilization of complexes at the surfaces of the former.