Confined propagation of covalent chemical reactions on single-walled carbon nanotubes

Nat Commun. 2011 Jul 12:2:382. doi: 10.1038/ncomms1384.

Abstract

Covalent chemistry typically occurs randomly on the graphene lattice of a carbon nanotube because electrons are delocalized over thousands of atomic sites, and rapidly destroys the electrical and optical properties of the nanotube. Here we show that the Billups-Birch reductive alkylation, a variant of the nearly century-old Birch reduction, occurs on single-walled carbon nanotubes by defect activation and propagates exclusively from sp(3) defect sites, with an estimated probability more than 1,300 times higher than otherwise random bonding to the 'π-electron sea'. This mechanism quickly leads to confinement of the reaction fronts in the tubular direction. The confinement gives rise to a series of interesting phenomena, including clustered distributions of the functional groups and a constant propagation rate of 18 ± 6 nm per reaction cycle that allows straightforward control of the spatial pattern of functional groups on the nanometre length scale.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Alkylation
  • Cobalt / chemistry
  • Electric Conductivity
  • Electrons*
  • Graphite / chemistry
  • Microscopy, Electron, Scanning
  • Molybdenum / chemistry
  • Nanotubes, Carbon / chemistry*
  • Pyrenes / chemistry
  • Spectrum Analysis, Raman
  • Thermogravimetry

Substances

  • HiPco compound
  • Nanotubes, Carbon
  • Pyrenes
  • molybdate
  • Cobalt
  • Graphite
  • Molybdenum