A Density Functional Study of the C NMR Chemical Shifts in Functionalized Single-Walled Carbon Nanotubes.
The C NMR chemical shifts for functionalized (7,0), (8,0), (9,0), and (10,0) single-walled carbon nanotubes (SWNTs) have been studied computationally using gauge-including projector-augmented plane-wave (GIPAW) density functional theory (DFT). The functional groups NH, NCH, NCHOH, and CHNHCH have be...
| Publicado en: | Journal of the American Chemical Society Vol. 129; no. 14; pp. 4430 - 4440 |
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| Autores principales: | , , |
| Formato: | Artículo |
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American Chemical Society
4/11/2007
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| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=24824552&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 24824552 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 4/11/2007 vid: 129 iid: 14 pid: 997 pub: American Chemical Society artinfo: ui: 24824552 10.1021/ja069110h ppf: 4430 ppct: 10 formats: tig: atl: A Density Functional Study of the C NMR Chemical Shifts in Functionalized Single-Walled Carbon Nanotubes. aug: au: Zurek, Eva Pickard, Chris J. Autschbach, Jochen affil: Max-Planck-Institut für Festkörperforschung, Heisenbergstrassel, 70569 Stuttgart, Germany School of Physics & Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS, Scotland Department of Chemistry, State University of New York, Buffalo, Buffalo, New York 14260-3000 su: Density functionals Carbon nanotubes Nuclear magnetic resonance Functional groups Carbon Chemical reactions sug: subj: Density functionals Carbon nanotubes Nuclear magnetic resonance Functional groups Carbon Chemical reactions ab: The C NMR chemical shifts for functionalized (7,0), (8,0), (9,0), and (10,0) single-walled carbon nanotubes (SWNTs) have been studied computationally using gauge-including projector-augmented plane-wave (GIPAW) density functional theory (DFT). The functional groups NH, NCH, NCHOH, and CHNHCH have been considered, and different sites where covalent addition or substitution may occur have been examined. The shifts of the carbons directly attached to the group are sensitive to the bond which has been functionalized and may, therefore, be used to identify whether the group has reacted with a parallel or a diagonal CC bond. The addition of NH to a parallel bond renders the functionalized carbons formally sp³-hybridized, yielding shifts of around 44 ppm, independent of the SWNT radius. Reaction with a diagonal bond retains the formal sp² hybridization of the substituted carbons, and their shifts are slightly lower or higher than those of the unsubstituted carbon atoms. The calculated 1H NMR shifts of protons in the functional groups are also dependent upon the SWNT-group interaction. Upon decreasing the degree of functionalization for the systems where the group is added to a parallel bond, the average chemical shift of the unfunctionalized carbons approaches that of the pristine tube. At the same time, the shifts of the functionalized carbons remain independent upon the degree of functionalization. For the SWNTs where N-R attaches to a parallel bond, the average shift of the sp² carbons was found to be insensitive to the substituent R. Moreover, the shifts of the functionalized sp³ carbons, as well as of the carbons within the group itself, are independent of the SWNT radius. The results indicate that a wealth of knowledge may be obtained from the C NMR of functionalized SWNTs. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2007 holdings: @attributes: islocal: N |
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