Overhauser spectroscopy

The nonnal mode NMR refinement method of Brueschweiler and Case [50] can be applied to experimentally measurable quantities such as order parameters or nuclear Overhauser spectroscopy (NOSEY) intensities. Unlike the X-ray case, the expression of these quanti-... 

NOESY Homonuclear NOE (nuclear Overhauser) spectroscopy To elucidate structure of organic molecules To determine the spatial proximity of nuclei... 

Whittemore, N.A. et al., A quenched molecular dynamics-rotating frame Overhauser spectroscopy study of a series of semibiosynthetically monoacylated anthocyanins, J. Org. Chem., 69, 1663, 2004. 

For compounds that contain a limited number of fluorine atoms, het-eronuclear 19F-4H 2D NMR experiments such as 19F-4H HETCOR and 4H-19F heteronuclear Overhauser spectroscopy (HOESY) can provide considerable assistance distinguishing structural isomers and diastere-omers as well as for conformational analysis. HOESY experiments have been frequently used for conformational analysis of biomolecules containing fluorine labels.33... 

Are these groups proximal in space (via Overhauser spectroscopy) ... 

The through-space interactions can be probed via Overhauser spectroscopy. 

With suitable modification of the pulse sequences the para-hydrogen effect can be used to enhance the signals in many NMR experiments, for example, COSY, HMQC, HSQC, EXSY and Overhauser spectroscopy. ... 

I must admit that I was only remotely familiar with this work when my associate, Donald Davis, accidentally discovered some persistent artifacts in an experiment now known as rotating frame Overhauser spectroscopy. These artifacts showed magnetization transfer between J-coupled spins and to me the explanation for this transfer looked very similar to the so-called Hartmann-Hahn magnetization transfer, used in sohd state NMR to enhance sensitivity. Once the analogy was clear, it was quite straightforward to improve the magnetization transfer process and to make it work really well. 

The 2D sequence [80,81], referred to as HOESY (heteronuclear Overhauser spectroscopy. Fig. 8.52b), avoids the need for selective proton presaturation but naturally suffers from low sensitivity. The sequence parallels that of NOESY,... 

The term can usually be evaluated. Consequently, data from one- and two-dimensional nuclear Overhauser spectroscopy studies contribute to the coordination chemists understanding of three-dimensional solution structures and molecular association phenomena such as ion pairs.Distance constraints are usually qualitatively established, based on cross-peak intensities or volumes. Occasionally monitoring the build-up rates is preferred, in order to quantify internuclear distances. ... 

Chiappe et al. reported the use of rotating-frame Overhauser spectroscopy (ROESY) and HOESY to investigate two pyrazolium-based ILs with different anions [83]. Using homo- and heteronuclear NOE, they showed the presence of aggregation, how sensitive the aggregation is to steric hindrance, and the nature of anions. Specifically they found that aggregation motives are in a head-to-tail and head-to-head manner. From the HOESY experiments, the researchers probed the formation of loose ion pairs, which are also sensitive to steric effects. Castner s group has utilized H— F HOESY to probe-specific cation—anion interactions for isoelectronic... 

NOE Measurement of the NOE between the a protons of residue i and the amide protons of residue i + 1 provides NMR information about the protein sequence. The correct experimental path can be selected by comparing the NMR results with known amino acid sequences. However, NOEs arise from residues that are close together only in space, not in the chain sequence. For correct information about the geometry, there must be some way to distinguish between what is in the sequence and what is in the space. Several special programs are available to solve the problem, such as multidimensional NMR of NOESY (nuclear Overhauser and exchange spectroscopy) and ROESY (rotatory-frame Overhauser spectroscopy). Both offer some means to obtain the same Overhauser effect information for aU nuclei in a molecule by a single experiment. 

Quantum-chemical analysis of the polyhydrated DNA bases species is still very scarce. The available data are following. The dihydrated complexes of 7GUA and 9GUA molecules were investigated at the MP2/6-31G(d) level [119]. The trihydrated complex of uracil and the corresponding anion radical have been calculated using the 6-31+G(d) level at the HF approximation [127]. In addition, the trihydrated uracil complexes have been the subject of experimental investigations (ID and 2G heteronuclear Overhauser spectroscopy) [128]. 

G. Wagner, A. Kumar, and K. Wuthrich, Systematic application of two-dimensional proton nuclear magnetic resonance techniques for studies of proteins. 2. Combined use of correlated spectroscopy and nuclear Overhauser spectroscopy for sequential assignments of backbone resonances and elucidation of polypeptide secondary structures, Eur. J. Biochem. 114, 375 (1981). 

ROESY rotating frame nuclear overhauser spectroscopy... 

Heteronuclear Overhauser spectroscopy. 2D H- Li correlation between the Li cation and the copolymer evidencing the preferential soivatation by ethylene oxide segments. From P. Judeinstein, D. Reichert, E. R. deAzevedo, T. J. Bonagamba, Acta Chim. Slav., 2005, 52, 349-60." ... 

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