Carbon-13 spin diffusion in the determination of intermolecular structure in solids

Henrichs, P. M.; Linder, Max

doi:10.1016/0022-2364(84)90149-5

Cited by 44 publications

(39 citation statements)

References 8 publications

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“…However, this assumption is not confirmed by the experimental data. The T2 relaxation time of -40 ms during the transverse-magnetization spin diffusion found here is very similar to the T, r relaxation time of 40 ms reported for an unprotonated spe-hybridized sidegroup carbon in polystyrene [1][2][3][4]. Typical mixing times used in the spin-lock experiments are of the order of a few milliseconds [1][2][3][4].…”

Section: Comparison With Spin-lock Sequencessupporting

confidence: 62%

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Efficient spin diffusion of transverse13C magnetization

Zimmermann

Schmidt‐Rohr

1999

Appl. Magn. Reson.

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Relatively efficient spin diffusion among unprotonated carbons with large chemical-shift anisotropies can be achieved by a 13 C nuclear magnetic resonance multiple-pulse sequence with a lowduty cycle of -5% on the "C channel, which minimizes sample heating and reduces cumulative effects of pulse imperfections. The spin diffusion occurs among transverse-magnetization isochromats, while the total transverse magnetization is a conserved quantity under the average Hamiltonian. The "flipflop" term of the dipolar-coupling average Hamiltonian is the same as in the full dipolar coupling, i.e., its scaling factor is unity. For a sample of 40% 13 COO-labeled poly(vinyl acetate), with 13 C in ester groups accounting for 7% of all heavy atoms, magnetization equilibrates within 20 ms over a volume of (0.9 nm)', corresponding to a molecular mass of 500 Da, while the T 2 relaxation time of the total transverse magnetization is -40 ms. The spin diffusion coefficient is estimated as D = 3 ± 1.5 nm 2/s.

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Section: Comparison With Spin-lock Sequencessupporting

confidence: 62%

“…' 3C magnetization exchange or spin diffusion in nonspinning samples is useful for characterizing the local structure in amorphous polymers [1][2][3][4] and for measuring the size of dynamic heterogeneities near the glass transition (K. Schmidt-Rohr et al, unpubl. ), [5].…”

Section: Introductionmentioning

confidence: 99%

Efficient spin diffusion of transverse13C magnetization

Zimmermann

Schmidt‐Rohr

1999

Appl. Magn. Reson.

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“…It has been shown in high field NMR, that the rate of the spin diffusion relates directly to the distance between two spins as well as the orientations of the internuclear vectors [34]. The measurement of spin diffusion in solids by means of two dimensional spectroscopy in high field NMR [35,36,37,38,39,40] is based on the overlap of lines corresponding to different sites. In the overlap region, the eigenstates of the spin Hamiltonian are mostly degenerate, and therefore, the spins can undergo an energy conserving flip-flop process.…”

Section: Spin Diffusion In Zero Field Nmrmentioning

confidence: 99%

Scalar operators in solid-state NMR

Sun

1991

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“…For structurally heterogeneous materials like silk, however, the heterogeneous linewidth of MAS spectra is quite broad (6.5 ppm FWHH) and the main advantage of MAS, narrow lines and high signal-to-noise ratio, cannot be fully realized. Static experiments correlating CSA tensors [40][41][42] are therefore often better suited for the investigation of such materials. Even though the signal to noise ratio is lower, the sensitivity of the signal towards the structural parameters of interest is often higher.…”

Section: Introductionmentioning

confidence: 99%