Resonant solids

The majority of double-resonance solid-state NMR experiments involving spin-1/2 nuclei use transfer of nuclear polarization via dipolar cross polarization (CP) to enhance polarization of the diluted spins S with small gyromagnetic ratio ys and significant longitudinal relaxation time T at the expense of abundant spins I with large y, and short 7 [215]. Typically, CP is used in combination with MAS, to eliminate the line broadening due to CS A, as well as with heteronuclear decoupling. To achieve the / S CP transfer, a (n/2)y pulse is applied at the I spin frequency,... 

When the crystallography of compounds related by polymorphism is such that nuclei in the two structures are magnetically nonequivalent, it will follow that the resonances of these nuclei will not be equivalent. Since it is normally not difficult to assign organic functional groups to observed resonances, solid state NMR spectra can be used to deduce the nature of polymorphic variations, especially when the polymorphism is conformational in nature. Such information is extremely valuable at the early states of drug development when solved single crystal structures for each polymorph or solvate species may not yet be available. 

Fig. 8.3 Transducing methods (a) Resonant wavelength shift scheme monitor A2p between the reference resonance (solid) and the resonance under sensing (dash) and (b) intensity variation scheme monitor A/ at a selected wavelength...

Grey, C.P., Veeman, W.S., and Vega, A.J. (1993) Rotabonal echo N/ C/ H triple resonance solid-state nuclear magnebc resonance a probe of C- N internuclear distances. J. Chem. Phys., 98, 7711-7724. 

NMR-spectroscopic investigations of dendrimers can provide comparable information. Thus Wooley et al. used REDOR (Rational Echo Double-Resonance) solid state NMR experiments for the study of the density distribution and back-folding of terminal groups in fifth-generation poly(benzyl ether) dendrimers... 

Fig. 20. Experimental setup for applications of the SPECIFIC CP experiment in the context of triple-resonance solid-state NMR experiments. After an initial broadband adiabatic CP step from protons to the I nuclei, SPECIFIC transfer to the observed 5 nucleus occurs during the mixing time tm. The resulting signal represents a dipolar and chemical shift-filtered spectrum and can be controlled by variation of the carrier frequencies and the radiofrequency during the SPECIFIC transfer. A conventional HETCOR experiment is obtained by the introduction of an evolution time t. (Adapted from Baldus et al.215 with permission.)...

Mani, R., Tang, M., Wu, X., et al. (2006) Membrane-bound dimer structure of a beta-hairpin antimicrobial peptide from rotational-echo double-resonance solid-state NMR. Biochemistry, 45(27), 8341-8349. 

ENDOR Electron Nuclear Double Resonance Solids, liquids R.E. + microwave radiation in magn. field. Microwave absorption - - Hypertine Inleracllon -> local atomic siruclure 64... 

NCR Nuclear Quadrupole Resonance Solids R.E. radiation 0.5- 1000 MHz R.E. absorption - - Asymmelry ot the charge distribution al Ihe nucleus 66,69... 

P-23 - Characterization of acidic sites in zeolites by heteronuclear double resonance solid state NMR... 

N.S. Astrof, R.G. GrifEn, Soft-triple resonance solid-state NMR experiments for assignments of U-13C, 15 N labeled peptides and proteins, J. Maen. Reson. 

Figure 18.2 Schematic diagram showing the potential curves for the ground state, the repulsive intermediate states and two of the Rydberg states of CH3I. The vertical arrows show the one-colour, non-resonant (dashed arrows), and the two-colour, resonant (solid arrows) routes for two-photon excitation to the Rydberg states. Note that resonance with the repulsive intermediate state (two-colour excitation) leads to stretching of the C-I bond and this changes the Franck-Condon window for excitation to the Rydberg state, favouring the C-I vibrational mode V3. Reproduced from Min etal, J. Photochem. Photobiol., 1996, 100 9, with permission of Elsevier...

Q. Luo, et al.. Unambiguously distinguishing Si[3Si,lAl] and Si[3Si,10H] structural units in zeolite by H/ Si/ Al triple-resonance solid-state NMR spectroscopy, solid state NMR spectroscopy. Solid State Nucl. Magn. Reson. 28 (2005) 9—12. 

Fig. 31, On-resonance (solid) and off-resonance (dashed) EDCs for CeCue- The difference curve is shown within about 2eV of p. (After Alson and Arko 1985.)...

Fig. 10.18. Top panel Bright beam PAI spectra within the first 5 GHz detuning to the red of resonance. Solid trace is parallel polarization. Dotted trace is perpendicular polarization. Peak numbered labels are for reference only. Bottom panel PAI spectra obtained from a conventional MOT, from Fig. 5 of Ref. 65.

NQR Nuclear Quadrupole Resonance Solids R.F radiation 0.6-1000 MHz R.F. absorption Asymmetry of the charge distribution at the nucleus 66,69... 

Fig. 40. The temperature dependence of the modulation wave vector in a Hoo jEto, alloy. The X-ray data were taken at the (0,0,4+q) satellite at the Ho L , resonance (solid circle, 8069 eV) and at the Er L, resonance ( , 8358 eV). Also shown are neutron measurements (open circles) taken at the (0,0,2- ) satellite. (From Pengra...

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