title: Confined propagation of covalent chemical reactions on single-walled carbon nanotubes.
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.
authors.affiliation: Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: Shunliu
authors.initials: S
authors.lastname: Deng
authors.forename: Yin
authors.initials: Y
authors.lastname: Zhang
authors.forename: Alexandra H
authors.initials: AH
authors.lastname: Brozena
authors.forename: Maricris Lodriguito
authors.initials: ML
authors.lastname: Mayes
authors.forename: Parag
authors.initials: P
authors.lastname: Banerjee
authors.forename: Wen-An
authors.initials: WA
authors.lastname: Chiou
authors.forename: Gary W
authors.initials: GW
authors.lastname: Rubloff
authors.forename: George C
authors.initials: GC
authors.lastname: Schatz
authors.forename: YuHuang
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000478:Alkylation; D003035:Cobalt / Q000737:chemistry; D004553:Electric Conductivity; D004583:Electrons; D006108:Graphite / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D008982:Molybdenum / Q000737:chemistry; D037742:Nanotubes, Carbon / Q000737:chemistry*; D011721:Pyrenes / Q000737:chemistry; D013059:Spectrum Analysis, Raman; D013818:Thermogravimetry
chemical_list: C550269:HiPco compound; D037742:Nanotubes, Carbon; D011721:Pyrenes; C044659:molybdate; D003035:Cobalt; D006108:Graphite; D008982:Molybdenum