2H chemical shift anisotropies from high-field 2H MAS NMR spectroscopy

Hauch, Anne; Bildsøe, Henrik; Jakobsen, Hans J.; Skibsted, Jørgen

doi:10.1016/j.jmr.2003.09.007

Cited by 21 publications

(17 citation statements)

References 52 publications

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“…Results from literature for the assignment of species 3 to μ 2 -OH groups interacting with neighbored lattice protons as published for boehmite (δ iso ( 2 H) = 7.4 ppm) cannot be supported by the present study because the signal disappears in our samples after gentle dehydration.…”

Section: Discussioncontrasting

confidence: 64%

“…The corresponding 2 H MAS NMR spectra (Figure ) show also differences with deuteration degree, less in the relative extension of the spinning side bands but in different contributions of various species relative to each other. From the general shape of the 2 H MAS NMR spectra it is clear that deuteration affects not only one H-site (see also refs − ).…”

Section: Resultsmentioning

confidence: 99%

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Crystalline Aluminum Hydroxide Fluorides AlF_x(OH)_3−x·H₂O: Structural Insights from ¹H and ²H Solid State NMR and Vibrational Spectroscopy

et al. 2010

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For the first time, 1H/2H MAS NMR signals of crystalline hydroxide fluorides AlF x (OH)3−x ·H2O, as well as of the dehydrated samples, both with pyrochlore structure, were resolved, identified, and assigned in direct correlation with vibrational bands of respective FT IR spectra. The use of magnetically diluted samples in combination with 1H spin−echo experiments, 2H MAS, and 19F−2H CP and 1H−2H CP MAS NMR experiments gave information on different 2H (1H) sites in relation to present structural motifs known from the crystal structure.

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Section: Discussioncontrasting

confidence: 64%

Section: Resultsmentioning

confidence: 99%

Crystalline Aluminum Hydroxide Fluorides AlF_x(OH)_3−x·H₂O: Structural Insights from ¹H and ²H Solid State NMR and Vibrational Spectroscopy

et al. 2010

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“…This quadrupole splitting, Δν Q , depends on the anisotropy of the environment and the direction of the material alignment axis relative to the externally applied magnetic field. For a uniaxial system with η Q = 0, the quadrupole splitting Δν Q may be written as ,, where C Q is the quadrupole coupling constant (∼260 kHz for a rigid O–D bond) and S the oriental order parameter of the O–D bond with respect to the alignment axis of the material …”

Section: Resultsmentioning

confidence: 99%

Morphological Anisotropy and Proton Conduction in Multiblock Copolyimide Electrolyte Membranes

et al. 2014

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Performance improvement of advanced polymer electrolyte membranes requires control over the morphology as it plays an important role for mechanical, thermal, and proton transport properties. The ionic domain orientation of films cast from sulfonated block copolymer solutions is generally anisotropic, and to maximize proton conductivity in fuel cell applications, hydrophilic channel alignment is desirable. In this work, a series of multiblock copolymers based on sulfonated copolyimides were synthesized and characterized by NMR, TEM and AFM microscopy, and impedance spectroscopy. For constant ion exchange capacity, the higher the block length, the higher the proton conductivity and water uptake for a given relative humidity. A random copolymer exhibited the lowest performance, in particular at low relative humidity, caused by a reduced phase separation as derived from AFM and TEM measurements. Orientational order probed by 2 H NMR on absorbed D 2 O showed preferential alignment in the through-plane direction. However, proton pulsed-field-gradient (PFG) NMR along the two orthogonal membrane directions revealed water diffusion to be faster in-plane than in the through-plane direction. This difference in diffusion is attributed to a lamella-like structure composed of rather short, through-plane hydrophilic channels in our systems. For the block copolyimide with the highest block length, two distinct diffusion processes could be identified. This is ascribed to a superimposed morphology on the micrometer scale, leading to an opaque appearance of the membrane.

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“…[3][4][5] Owing to its large magnitude, it is often relatively straightforward to measure the quadrupolar interaction accurately, but this is usually not the case for the 2 H shift interaction, which, particularly in a diamagnetic solid, can be two to three orders of magnitude weaker than the quadrupolar interaction. 6,7 In paramagnetic solids, the shift interaction can be significantly larger than in diamagnetic materials. [8][9][10][11] The mechanism in insulating solids for this increased interaction strength is the presence of unpaired electrons at localized centers ͑e.g., Cu 2ϩ , Fe 3ϩ , Mn 2ϩ , or Nd 3ϩ ions͒ and the partial quenching of the resulting electron-nucleus dipoledipole and Fermi contact interactions by rapid electronic spin-lattice relaxation to leave each electronic spin acting as a classical local magnetic field.…”

Section: Introductionmentioning

confidence: 99%

Separation of quadrupolar and chemical/paramagnetic shift interactions in two-dimensional H2 (I=1) nuclear magnetic resonance spectroscopy

Antonijevic

Wimperis

2005

The Journal of Chemical Physics

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A novel two-dimensional (2)H (spin I=1) nuclear magnetic resonance technique is introduced for determination of both quadrupole and chemical/paramagnetic shift tensors and their relative orientation. The new method is based upon the well-known quadrupolar-echo experiment and is designed to refocus the quadrupolar interaction at the end of the t(1) evolution period while retaining the modulation introduced by the shift interaction. As a result, a projection of the resulting two-dimensional spectrum onto its F(1) dimension yields a shift anisotropy powder lineshape free from any quadrupolar broadening. The chemical/paramagnetic shifts appear in both F(1) and F(2) dimensions and are thus spread along a +1 frequency gradient; hence, a projection orthogonal to this gradient yields the pure quadrupolar powder lineshape, free from all shift interaction effects. The relative orientation of the quadrupole and shift tensors can be obtained by analysis of the full two-dimensional correlation lineshape. Unlike the well-known double-quantum experiment, the new method is, in principle, equally effective for all values of the quadrupolar splitting, including zero. The properties of the new technique are demonstrated using computer simulation and methods for the extraction of quadrupole and shift tensor parameters are described. The new technique is applied to (diamagnetic) benzoic acid-d(1) (C(6)H(5)CO(2)D) and (paramagnetic) copper(II) chloride dihydrate-d(4) (CuCl(2).2D(2)O).

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2H chemical shift anisotropies from high-field 2H MAS NMR spectroscopy

Cited by 21 publications

References 52 publications

Crystalline Aluminum Hydroxide Fluorides AlF_x(OH)_3−x·H₂O: Structural Insights from ¹H and ²H Solid State NMR and Vibrational Spectroscopy

Crystalline Aluminum Hydroxide Fluorides AlF_x(OH)_3−x·H₂O: Structural Insights from ¹H and ²H Solid State NMR and Vibrational Spectroscopy

Morphological Anisotropy and Proton Conduction in Multiblock Copolyimide Electrolyte Membranes

Separation of quadrupolar and chemical/paramagnetic shift interactions in two-dimensional H2 (I=1) nuclear magnetic resonance spectroscopy

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2H chemical shift anisotropies from high-field 2H MAS NMR spectroscopy

Cited by 21 publications

References 52 publications

Crystalline Aluminum Hydroxide Fluorides AlFx(OH)3−x·H2O: Structural Insights from 1H and 2H Solid State NMR and Vibrational Spectroscopy

Crystalline Aluminum Hydroxide Fluorides AlFx(OH)3−x·H2O: Structural Insights from 1H and 2H Solid State NMR and Vibrational Spectroscopy

Morphological Anisotropy and Proton Conduction in Multiblock Copolyimide Electrolyte Membranes

Separation of quadrupolar and chemical/paramagnetic shift interactions in two-dimensional H2 (I=1) nuclear magnetic resonance spectroscopy

Contact Info

Product

Resources

About

Crystalline Aluminum Hydroxide Fluorides AlF_x(OH)_3−x·H₂O: Structural Insights from ¹H and ²H Solid State NMR and Vibrational Spectroscopy

Crystalline Aluminum Hydroxide Fluorides AlF_x(OH)_3−x·H₂O: Structural Insights from ¹H and ²H Solid State NMR and Vibrational Spectroscopy