Solid-state NMR analyses

In order to get more detailed information about the motions associated with the relaxation in PET and to understand the differences observed between mechanical and dielectric data, NMR was used, as well as NMR on PET samples selectively deuterated either on the phenyl rings or on the ethylene glycol units [12]. Due to the higher frequency range corresponding to NMR experiments (10 Hz), the extrapolation of the dielectric results leads to the occurrence of the motions involved in the relaxation around 25 °C, which is effectively observed. 

First of all, these investigations confirm that there is no detectable mobility of the ethylene groups in PET below the glass transition temperature. 

As regards the phenyl ring motions, interesting features are obtained from measurements of chemical shift anisotropy of protonated and unpro-tonated aromatic carbons. The chemical shift parameters are orthogonal to each other, with a and 022 in the phenyl plane and (733 bisecting the phenyl plane. 

It can be seen in Fig. 14 that, as the temperature increases, there is a decrease in the chemical shift anisotropy (a33-an) of protonated carbons, indicating an increase in the mobility of the aromatic rings at higher tern- 

As seen from Fig. 15, in the case of unprotonated aromatic para carbons, a phenyl ring yr-flip does not change the orientation of the chemical shift anisotropy tensor components and, thus, this jr-flip does not affect the NMR response of such para carbons, whereas phenyl ring oscillations do. 

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Strandberg E, Wadhwani P, Tremouilhac P, Durr UHN, Ulrich AS (2006) Solid-state NMR analysis of the PGLa peptide orientation in DMPC bilayers structural fidelity of H-2-labels versus high sensitivity of F-19-NMR. Biophys J 90 1676-1686... 

Esteban-Martin S, Strandberg E, Salgado J, Ulrich AS (2010) Solid state NMR analysis of peptides in membranes influence of dynamics and labeling scheme. BBA-biomembranes 1798 252-257... 

Cao X, Oik D, Chappell M, Cambardella CA, Miller LF, Mao J. Solid-state NMR analysis of soil organic matter fractions from integrated physical-chemical extraction. Soil Sci. Soc. Am. J. 2011 75 1374-1384. 

Kajiya K, Kumazawa S, Naito A, Nakayama T. 2008. Solid-state NMR analysis of the orientation and dynamics of epigallocatechin gallate, a green tea polyphenol, incorporated into lipid bilayers. Magn Reson Chem 46 174-177. 

Sample Preparation for Solid-State NMR. The amount of sample needed for solid-state NMR analysis depends on the size of the rotor used. Between 75 and 100 mg of sample is needed to fill a 4-mm rotor whereas 7-mm rotors require... 

Recently, solid-state 13C NMR has been widely applied for the characterisation of vulcanised rubber systems [10] with several reviews published covering the solid-state NMR analysis of crosslinked elastomers [11, 12],... 

Jeffrey GA, Wood RA, Pfeffer PE, Hicks KB (1983) Crystal structure and solid-state NMR analysis of lactulose. J Am Chem Soc 105 2128-2133... 

This could be proved by solid-state NMR analysis, showing that the T3 content increases with curing time at the expense of the diphenyl T1 content (index means the number of oxygen bridges to other silicon atoms of the considered silicon atom). It was of interest to investigate how far the stress dissipation ability of the seal can be improved without reducing the sealing properties. Moreover, it was of further interest for practical reasons how far these systems are able to be adapted to polyimide surfaces in connection with copper as a counterpart. 

F.G. Vogt, J.S. Clawson, M. Strohmeier, A.J. Edwards, T.N. Pham, S.A. Watson, Solid-state NMR analysis of organic cocrystals and complexes, Cryst. Growth Des. 9 (2009) 921-937. 

Grage, S. L., Suleymanova, A. V., Afonin, S., et al. (2006) Solid state NMR analysis of the dipolar couplings within and between distant CF3-groups in a membrane-bound peptide. Journal of Magnetic Resonance, 183, 77-86. 

Photoyellowing of lignocellulosic materials has been studied with a new technique based on solid-state NMR analysis of C-enriched dehydrogenation polymer in cell wall tissue. The NMR analysis of unirradiated and irradiated tissue revealed a decrease in the relative amount of coniferalde-hyde and/or coniferyl alcohol end-groups during irradiation. 

The less stable form, silk I, has remained poorly understood [37]. In general, attempts to induce orientation of its polymer chain tend to cause the silk I to convert to the more stable silk II. If an oriented silk fibroin sample with silk I form can be obtained, the solid-state NMR analysis for an oriented molecular system described here may be used to determine the atomic coordinates of silk fibroin with the silk I form. 

Creemers AFL, Bovee-Geurts FILM, DeGrip WJ et al (2004) Solid-state NMR analysis of ligand-receptor interactions reveals an induced misfit in the binding site of isorhodopsin. Biochemistry (Mosc) 43 16011-16018... 

RFDR methodology has been used to measure inter-fluorine distances of up to 12 A (-I-/-2 A) [255], this application is expected to be of great utility in the solid state NMR analysis of fluorine containing pharmaceuticals. RFDR can be used to provide distance measurements between a labelled nucleus and others of the same isotope at natural abundance. For instance, such measurements were made between a singly labelled guest molecule and the natural abundance carbons of the host in an organic clathrate [256]. 

The combined use of the utility of solid-state NMR analysis of ring dynamics. 

Pringle, J.M., D.R. MacFarlane, and M. Forsyth. 2005. Solid state NMR analysis of polypyrrole grown in a phosphonium ionic liquid. Synth Met 155 684. 

Solid-state NMR analysis is useful for special purposes, especially for understanding chemical changes caused by oxidation or other degradation reactions. 

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