Efficient symmetry-based homonuclear dipolar recoupling of quadrupolar spins: double-quantum NMR correlations in amorphous solids

Phys Chem Chem Phys. 2008 Nov 28;10(44):6635-44. doi: 10.1039/b808295b. Epub 2008 Sep 30.

Abstract

We report novel symmetry-based pulse sequences for exciting double-quantum (2Q) coherences between the central transitions of half-integer spin quadrupolar nuclei in the NMR of rotating solids. Compared to previous 2Q-recoupling techniques, numerical simulations and 23Na and 27Al NMR experiments on Na2SO4 and the open-framework aluminophosphate AlPO-CJ19 verify that the new dipolar recoupling schemes display higher robustness to both radio-frequency field inhomogeneity and to spreads in resonance frequencies. These advances allowed for the first demonstration of 2Q-recoupling in an amorphous solid for revealing its intermediate-range structural features, in the context of mapping 27Al-27Al connectivities between the aluminium polyhedra (AlO4, AlO5 and AlO6) of a lanthanum aluminate glass (La0.18Al0.82O1.5).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aluminum Compounds / chemistry*
  • Computer Simulation
  • Glass / chemistry*
  • Lanthanum / chemistry
  • Magnetic Resonance Spectroscopy / methods*
  • Molecular Structure
  • Quantum Theory
  • Rotation
  • Sulfates / chemistry*

Substances

  • Aluminum Compounds
  • Sulfates
  • sodium sulfate
  • Lanthanum