Two-dimensional magic-angle-spinning NMR of partially ordered systems

Harbison, O.S.; Spieß, Hans Wolfgang

doi:10.1016/0009-2614(86)85131-4

Cited by 77 publications

(18 citation statements)

References 16 publications

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“…Two-dimensional magic-angle-spinning NMR (2D-MAS-NMR) is a new, powerful tool for a quanti- K 625 tative analysis of oriented systems [13][14][15]. The sideband pattern measured in a 2D-MAS-NMR experiment is governed by the chemical shielding tensor.…”

Section: Introductionmentioning

confidence: 99%

Orientation of the diphenylene propane unit in stretched polycarbonate from two-dimensional magic-angle-spinning NMR

Vogt

Dettenmaier

Spiess

et al. 1990

Colloid & Polymer Sci

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Two-dimensional magic-angle-spinning (2D-MAS) NMR has been used to measure the orientation parameter, P2, of the diphenylene propane unit in bisphenol-A polycarbonate oriented by stretching to various extension ratios, ~, at T = 295 K and T = 403 K. P2 is proportional to the birefringence An, with a maximum birefringence Ano = 0.189. There is some evidence that the order parameter P~ of the DPP units with respect to the chain axis deviates from unity. Ano is therefore expected to be different from the birefringence, An'o, of perfectly aligned chains of polycarbonate. The experimental resuks obtained for P2(~) are compared to those predicted by the aggregate model.

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Section: Introductionmentioning

confidence: 99%

Orientation of the diphenylene propane unit in stretched polycarbonate from two-dimensional magic-angle-spinning NMR

Vogt

Dettenmaier

Spiess

et al. 1990

Colloid & Polymer Sci

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“…2 must stem from the difference in the cancellation between DD and CSA interactions. Although 15 N-1 H E and 15 N-1 H Z bonds are assumed to have the same length (1.02 Å ) for most NMR applications, the 15 N-1 H E bond is likely to be 1-2% shorter than the 15 N-1 H Z bond [49,50], resulting in up to 4% larger DD interaction and possibly a 10% difference in the TROSY effect. But this is still marginal to account for the large difference in the relaxation rates.…”

Section: Resultsmentioning

confidence: 99%

TROSY of side-chain amides in large proteins

Liu

Yao

et al. 2007

Journal of Magnetic Resonance

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By using the mixed solvent of 50% H2O/50% D2O and employing deuterium decoupling, TROSY experiments exclusively detect NMR signals from semideuterated isotopomers of carboxamide groups with high sensitivities for proteins with molecular weights up to 80 kDa. This isotopomer-selective strategy extends TROSY experiments from exclusively detecting backbone to both backbone and side-chain amides, particularly in large proteins. Because of differences in both TROSY effect and dynamics between 15N-H(E){D(Z)} and 15N-H(Z){D(E)} isotopomers of the same carboxamide, the 15N transverse magnetization of the latter relaxes significantly faster than that of the former, which provides a direct and reliable stereospecific distinction between the two configurations. The TROSY effects on the 15N-H(E){D(Z)} isotopomers of side-chain amides are as significant as on backbone amides.

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“…3. (9), on the other hand, contains the essence of the original two-dimensional rotor-synchronized method of Harbison et al [12]. Note that the molecular frame is not necessarily coincident with the principal axes frame of the chemical shift tensor.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…The ORDERexperiment [ l l ] (ORientation Distributions with Enhanced Resolution) is a three-dimensional MAS NMR method based on an expansion of the rotorsynchronized two-dimensional technique of Harbison et al [12,131. The latter exploits the variation of the phase and amplitude of the spinning sidebands [14] from an ordered sample with the position of the MAS rotor at the time of excitation, by relating the initial rotor position to an evolution time, tl, which forms the basis of the first of two dimensions in a two-dimensional experiment.…”

Section: Introductionmentioning

confidence: 99%

The orientation distribution in an industrial sample of poly(p‐phenylenetere‐phthalamide) determined by two‐ and three‐dimensional NMR techniques

et al. 1993

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Two new solid-state N M R methods for measuring orientation distributions in partially ordered solids are applied to high tensile-strength fibre polymers. Both methods use the anisotropy ofthe carbon-13 chemical shift tensor as a probe for local molecular directions, but they differ in the manner in which the information is extracted and complement one other. The spectral resolution is higher in the ORDER (ORientation Distributions with Enhanced Resolution) experiment, which employs rotor-synchronized three-dimensional magic angle spinning (MAS) NMR, while the angular precision with which the orientation distribution can be determined is higher in the DECODER(Direction Exchange with Correlation ofOrientation Distribution Evaluation and Reconstruction) experiment. The utility ofthe two techniques is demonstrated by their applicationto the study of industrially produced poly(p-phenyleneterephthalamide) fibres. Both give the same result for the width (x = 13 ") and the order parameters ( = 0.85, = 0.57, = 0.34, = 0.14) of the orientation distribution.

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Two-dimensional magic-angle-spinning NMR of partially ordered systems

Cited by 77 publications

References 16 publications

Orientation of the diphenylene propane unit in stretched polycarbonate from two-dimensional magic-angle-spinning NMR

Orientation of the diphenylene propane unit in stretched polycarbonate from two-dimensional magic-angle-spinning NMR

TROSY of side-chain amides in large proteins

The orientation distribution in an industrial sample of poly(p‐phenylenetere‐phthalamide) determined by two‐ and three‐dimensional NMR techniques

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