Epitaxial growth of single-wall carbon nanotubes

Charged Carbon Nanomaterials: Redox Chemistries of Fullerenes, Carbon Nanotubes, and Graphenes

“…29 Analogously, fullerenes may be seen as two SWCNT caps with an (infinitely or very) short SWCNT between the caps. The best-known fullerene, C 60 , has icosahedral symmetry (I h ), composed of 20 hexagons of a graphene sheet (Figure 2), folded to give 12 pentagons (to satisfy the Euler formula 30 ) with all carbons equivalent and displaying near-sp 2 hybridization. 31 In the solid state at room temperature, C 60 packs as face-centerd-cubic 32 with a unit cell parameter of 14.2 Å.…”

“…As for SWCNTs, fullerenes can also be filled endohedrally, usually during the initial fullerene syntheses; 177 postsynthesis fillings are rare. 178 While the (endohedral) dopant may not dissociate from the doped fullerene, group 1 M@C 60 itself may act as a reducing agent, to give the [M@ C 60 ] + ion, 179 which may form (monoclinic) crystals. 188 ).…”

“…The two-dimensional structure of graphene had long been discussed theoretically but was not isolated 7 and fully characterized until 2004. Whereas C 60 and SWCNTs were originally synthesized by laser ablation and arc discharge processes, 8 graphene was originally prepared by the mechanical exfoliation of graphite using the "scotchtape" method. Research over the last 30 years has led to a wide array of other techniques for the synthesis of these materials, notably chemical vapor deposition 9,10 (CVD) and more recently low temperature organic synthesis.…”

“…There are six fundamental CCNs based on the sign of charge and the parent nanocarbon type: fulleride (C 60 n− ), fullerenium (C 60 n+ ), nanotubide (SWCNT n− ), nanotubium (SWCNT n+ ), graphenide (C n m− ), and graphenium (C n m+ ). While the properties between CCNs vary substantially due to the differences in the degree and sign of charging, intrinsic nanocarbon electronic structure, and dimensionality, there are common factors between CCNs in terms of reactivity, synthetic approach, and structure in both solid and solution.…”

“…213 For acceptor compounds, most Lewis acids can intercalate graphite and nanotube bundles, including sulfuric acid, 153,214 a large array of metal halides, 215−217 and bromine; 218,219 iodine is capable of doping nanotube bundles 166,220 (albeit with lower charge transfer versus bromine 221 ) but does not easily form a GIC, attributed to its lower electron affinity. 222 These mild dopants do not form the C 60 n+ fullerenium ions; compounds may form, but there is no formal electron transfer, 223,224 as oxidation requires a redox potential greater than common oxidants. 171 Instead, highly oxidizing, non-nucleophilic specialist acceptors must be used, notably the halocarboranes 225,226 and arsenic pentafluoride.…”