Characterizing Covalently Sidewall-Functionalized Single-Walled Carbon Nanotubes by Using¹H NMR Spectroscopy

Abstract

Unambiguous evidence for covalent sidewall functionalization of single-walled carbon nanotubes (SWCNTs) has been a difficult task, especially for nanomaterials in which slight differences in functionality structure produce significant changes in molecular characteristics. Nuclear magnetic resonance (NMR) spectroscopy provides clear information about the structural skeleton of molecules attached to SWCNTs. In order to establish the generality of proton NMR as an analytical technique for characterizing covalently functionalized SWCNTs, we have obtained and analyzed proton NMR data of SWCNT-substituted benzenes across a variety of para substituents. Trends obtained for differences in proton NMR chemical shifts and the impact of o-, p-, and m-directing effects of electrophilic aromatic substituents on phenyl groups covalently bonded to SWCNTs are discussed.

Direct Spectroscopic Evidence for Charge-Assisted Hydrogen-Bond Formation between Ionizable Organic Chemicals and Carbonaceous Materials

“…Specifically, the sorption samples of CNTs were taken out after shaking at 150 rpm in the dark at 25 ± 1 °C for 48 h, and the supernatant was removed after centrifugation at 3000 rpm for 20 min. Then, the solid samples were freeze-dried for 24 h, and each (0.2 mg) sample was resuspended in 3 mL of DMSO- d 6 and sonicated for 30 min . Subsequently, the resulting solution was added by a pipette into a 5 mm NMR tube for 1 H NMR (Ascend 600, Bruker, Germany) analysis (see Text S5 for the details).…”

“…Then, the solid samples were freeze-dried for 24 h, and each (0.2 mg) sample was resuspended in 3 mL of DMSO-d 6 and sonicated for 30 min. 47 Subsequently, the resulting solution was added by a pipette into a 5 mm NMR tube for 1 H NMR (Ascend 600, Bruker, Germany) analysis (see Text S5 for the details).…”

Characterization of carbon nanotubes and analytical methods for their determination in environmental and biological samples: A review

“…The advantages of IR and FT-IR for the characterization of functionalized nanotubes are simplicity, rapidity, low cost, ready availability and easy sample preparation. Other spectroscopic procedures, such as nuclear magnetic resonance (NMR) [39,82], have also been used in conjunction with IR to assess the effectiveness of the modification and functionalization of nanotubes.…”