ODESSA, a New 1D NMR Exchange Experiment for Chemically Equivalent Nuclei in Rotating Solids

✍ Scribed by V. Gérardy-Montouillout; C. Malveau; P. Tekely; Z. Olender; Z. Luz

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 204 KB
• Volume: 123
• Category: Article
• ISSN: 1064-1858
• DOI: 10.1006/jmra.1996.0208

✦ Synopsis

A new 1D NMR exchange experiment in the slow-motion regime intensity of the spinning sideband pattern. Analysis of such of spinning solids, with chemically equivalent nuclei exhibiting spectra, recorded either off the magic angle (6, 7) or at the quadrupole coupling or chemical-shift anisotropy, is proposed. It magic angle (8)(9)(10)(11)(12)(13)(14), can be quantitatively interpreted in consists of the usual three-pulse sequence for 2D exchange specterms of specific dynamic processes in the solid.

troscopy, P1-t 1 -P2-t m -P3-t-acquisition, but with the

The second type of exchange experiment on spinning samevolution time fixed at one-half a spinning period, t 1 Å T R /2, and ples corresponds to the slow-motion regime, where the rate a mixing time equal to an integer multiple thereof, t m Å GT R .

of the dynamic process is slower than 1/T 2 but faster than,

The magnetic polarizations associated with the various spinning or on the order of, 1/T 1 . These include various types of sidebands are then polarized in alternate directions at the beginmagnetization-transfer experiments analogous to 1D spin ning of the mixing time. Dynamic processes during t m redistribute alignment (15) and hole burning (16)(17)(18)(19)(20) or to 2D exchange the polarizations, resulting in modified sideband patterns during the detection time, t. Experimental results are presented for car-spectroscopy (21). For example, in a system with several bon-13 and deuterium in dimethyl sulfone, which undergoes motypes of chemically inequivalent spins, one can monitor lecular reorientation in the solid state. The results are compared magnetization transfer between spinning sidebands belongwith simulations which include the effect of reorientation and ing to different nuclear species by introducing in the preparalongitudinal relaxation.