Characterizing Covalently Sidewall-Functionalized SWNTs

Abstract

Pristine single-walled carbon nanotubes (p-SWNTs) were converted to 4-chlorophenyl-SWNTs 1 via treatment with 4-chlorophenylamine and isoamylnitrite, and subsequently to 4-mercaptophenyl-SWNTs 2 by using sodium ethanethiolate. Products 1 and 2 were characterized by Raman, UV/vis/NIR, TGA, IR, and 1H NMR. We report a COSY 1H NMR of 1, which appears to be the first such spectrum reported for a covalently sidewall-functionalized SWNT.

Effect of Single-Walled Carbon Nanotube Association upon 1H NMR Spectra of Representative Organonitrogen Compounds

“…SWCNTs are promising candidates for semiconductors in field effect transistors,2 sensors for highly sensitive and selective molecular detection,3a specific protein detection3b and memory elements 4. However, due to strong van der Waals interactions between SWCNT sidewalls, they exist as bundles,1g so a key challenge for exploiting SWCNTs widely is overcoming their nonpolar nature, which fosters a solvation problem and restricts their stable dispersion, solubilization, and separation 5–7. Different and improved dispersal techniques are needed in order to increase SWCNT reactivities, take advantage of their novel structural, electrical, and mechanical properties,8 attain higher purities,6d,f and enable their alignment for molecular device development 4…”

“…Recently, the effect of SWCNT association upon amides was investigated,5b in order to ascertain the molecular characteristics giving rise to the unusual capability of amides, especially DMF, to solvate SWCNTs. It is desirable to compare and contrast these characteristics of DMF versus those of NMP.…”

Spectroscopic Investigation of Modified Single Wall Carbon Nanotube (SWCNT)

“…The higher frequency tangential displacement G modes near ~ 1590 cm -1 and the second order G' peaks near 2600 cm -1 are sensitive to the charge exchanged between nanotubes and the guest moiety. The shape and the intensity of D-mode at 1290 -1320 cm -1 corresponds to the sp 3 -hybridized carbon atoms [4], which is correlated with the extent of nanotube sidewall defects and chemical sidewall functionalization [14]. The D*-mode also serves to show the disorder and defects of graphitic walls.…”

“…The first step to functionalize the relatively inert CNT surface is to oxidize the CNTs. The various oxidation methods have used for this purpose [4][5][6][7][8]. Liquid phase oxidation is a very simple method to make nanotubes more easily dispersible or soluble in liquids; it is necessary to physically or chemically attach functional groups to their sidewalls without changing significant properties and also opens the closed ends of CNTs [9].…”

Binding studies of hydroxylated Multi-Walled Carbon Nanotubes to hemoglobin, gamma globulin and transferrin

“…This mode remains sensitive to the charge exchanged between nanotubes and the guest moiety. The shape and the intensity of D-mode at around 1290-1320 cm − 1 corresponds to the sp 3 -hybridized carbon atoms [20], and correlates with the extent of nanotube sidewall defects and chemical sidewall functionalization [21]. In general, D-band remains as a useful diagnostic of disorder in the hexagonal framework of the tubes, whereas, the G-band, which is close to that for graphite and possesses E 2g symmetry of the inner layer mode, representing the degree of crystallinity [22].…”