INEPT Experiments Involving Quadrupolar Nuclei in Solids

✍ Scribed by Hsien-Ming Kao; Clare P Grey

• Book ID: 102596487
• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 217 KB
• Volume: 133
• Category: Article
• ISSN: 1090-7807
• DOI: 10.1006/jmre.1998.1455

✦ Synopsis

Coherence transfer from quadrupolar 27 Al (I ‫؍‬ 5 2 ) nuclei to 31 P (I ‫؍‬ 1 2 ) via INEPT experiments is investigated. 27 Al 3 31 P INEPT experiments on a (CH 3 ) 3 P-AlCl 3 complex in zeolite NaX are performed, and the results demonstrate that the 31 P INEPT signals strongly depend on whether or not the 27 Al pulses are applied synchronously with the rotor period, and on the length of the 27 Al pulses. A density-matrix calculation involving the use of the spin operators for spin 3 2 and 1 2 nuclei has been performed to help understand the evolution behavior of the density matrix under the influence of the quadrupolar interaction, the dipolar and J-couplings, and the pulse lengths applied to the quadrupolar nuclei. The theoretical predictions obtained from these calculations are consistent with the INEPT experimental observations.