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Updated: Jun 11, 2026

Resonance Raman Spectroscopy of Extreme Nanowires and Other 1D Systems
07:44

Resonance Raman Spectroscopy of Extreme Nanowires and Other 1D Systems

Published on: April 28, 2016

金属および半導体単壁カーボンナノチューブに対する炭素共鳴の固体13C NMR割り当て

Chaiwat Engtrakul1, Mark F Davis, Kevin Mistry

  • 1National Renewable Energy Laboratory, Golden, Colorado 80401, USA. Chaiwat.Engtrakul@nrel.gov

Journal of the American Chemical Society
|July 3, 2010
PubMed
まとめ

固体炭素13核磁気共振 (13C NMR) スペクトロスコピーは,金属 (m-SWNT) と半導体 (s-SWNT) の単一壁ナノチューブを効果的に区別する. このテクニックは,SWNTの混合物を,その独特の化学的シフトに基づいて分析するための繊細な方法を提供します.

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Carbon-13 (¹³C) NMR: Overview01:10

Carbon-13 (¹³C) NMR: Overview

Carbon-13 is a naturally occurring NMR-active isotope of carbon with a low natural abundance of 1.1%. In contrast, carbon-12 is the most abundant isotope of carbon with zero nuclear spin. Therefore, it is NMR inactive. The gyromagnetic ratio of carbon-13 is smaller than that of protons. As a result, carbon-13 resonance is about 6000 times weaker than proton resonance. For a given magnetic field strength, the resonance frequency of carbon-13 is about one-fourth of the resonance frequency for...
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¹³C NMR: ¹H–¹³C Decoupling

The probability of having two carbon-13 atoms next to each other is negligible because of the low natural abundance of carbon-13. Consequently, peak splitting due to carbon-carbon spin-spin coupling is not observed in spectra. However, protons up to three sigma bonds away split the carbon signal according to the n+1 rule, resulting in complicated spectra.
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
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When proton-coupled carbon-13 spectra are simplified by a broadband proton decoupling technique, structural information about the coupled protons is lost. Distortionless enhancement by polarization transfer (DEPT) is a technique that provides information on the number of hydrogens attached to each carbon in a molecule. While the DEPT experiment utilizes complex pulse sequences, the pulse delay and flip angle are specifically manipulated. The resulting signals have different phases depending on...
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NMR Spectroscopy: Chemical Shift Overview

The position of the absorption signal of a sample is reported relative to the position of the signal of tetramethylsilane (TMS), which is added as an internal reference while recording spectra. The difference between the absorption frequencies of the sample and TMS (in Hz) is divided by the spectrometer operating frequency (in MHz) to obtain a dimensionless quantity called the chemical shift. It is reported on the δ (delta) scale and expressed in parts per million.
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