Ultra high field NMR

M. Yagi-Utsumi and K Kato, A Systematic Approach to Structural Glyco-biology by Using Ultra-High Field NMR Spectroscopy and Multidimensional HPLC , Kagaku to Seibutsu, 2009, 47, 261. 

We have referred to the various interactions which can cause line broadening in the solid state. One of these, which is normally not a problem in liquid state NMR, is due to the fact that the chemical shift itself is a tensor, i.e. in a coordinate system with orthogonal axes x, y and z its values along these axes can be very different. This anisotropy of the chemical shift is proportional to the magnetic field of the spectrometer (one reason why ultra-high field spectrometers are not so useful), and can lead in solid state spectra to the presence of a series of spinning sidebands, as shown in the spectra of solid polycrystalline powdered triphenylphosphine which follows (Fig. 49). In the absence of spinning, the linewidth of this sample would be around 75 ppm ... 

Fig. 8 13C and 29Si MAS-NMR of two SiC polytypes. Left panel-, see text for assignments. Right panel-. Experimental and calculated ultra-slow MAS-NMR spectra at ultra-high field of 21.1 T. Modified and reprinted with permission from [133]. Copyright 2009 by the American Chemical Society... 

P. J. Pallister, I. L. Moudrakovski and J. A. Ripmeester, Mg-25 ultra-high field solid state NMR spectroscopy and first principles calculations of magnesium compounds. Phys. Chem. Chem. Phys., 2009,11,11487-11500. 

K. Shimoda, Y. Tobu, M. Hatakeyama, T. Nemoto and K. Saito, Structural investigation of Mg local environments in silicate glasses by ultra-high field Mg 3QMAS NMR spectroscopy. Am. Mineral, 2007, 92, 695-698. 

Verhoeven MA, Creemers AFL, Bovee-Geurts PHM et al (2001) Ultra-high-field MAS NMR assay of a multispin labeled ligand bound to its G-protein receptor target in the natural membrane environment electronic stmcture of the retinylidene chromophore in rhodopsin. Biochemistry (Mosc) 40 3282-3288... 

Kennedy, G.J., Afeworki, M., and Hong, S.B. 2002. Probing the non-random aluminum distribution in zeolite merlinoite with ultra-high-field (18.8 T) A1 and Si MAS NMR. Micropor. Mesopor. Mater. 52 55-59. 

There has been significant recent progress in solid-state NMR techniques and hardware. In particular, the advent of ultra-high magnetic fields, which improve... 

The signal-to-noise (S/N) ratio in Sn or X NMR spectra has to be considered more seriously if one wants to detect the coupling between Sn and a rare spin-1/2 nucleus. Conditions close to those reported for ultra high resolution (UHR) NMR [16] should be observed in order to exclude most unwanted contributions (e.g. temperature gradients in the samples, field inhomogeneity to the linewidth of the Sn or X resonances). 

While NMR spectroscopy has provided much information about many aspects of channel structure and properties, many questions remain unanswered. With the advent of ultra-high magnetic field strengths and new techniques, such as TROSY, " which permits the NMR analysis of the structure, dynamics and interactions of proteins whose size is in the 100 kDa range and above, the future seems very bright for the application of NMR spectroscopy to the study of ion-transporting biological channels. 

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