High resolution heteronuclear correlation NMR spectroscopy between quadrupolar nuclei and protons in the solid state

• Published in: Journal of magnetic resonance (1997) Vol. 169; no. 2; pp. 342 - 350
• Main Authors: Goldbourt, A, Vinogradov, E, Goobes, G, Vega, S
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-08-2004
• Subjects: FAM pulses; Half-integer quadrupolar nuclei; HETCOR; High-resolution proton NMR; MQMAS; PMLG; Solid state NMR; wPMLG; FAM pulses; Solid state NMR; High-resolution proton NMR; MQMAS; Half-integer quadrupolar nuclei; PMLG; wPMLG; HETCOR
• ISSN: 1090-7807; 1096-0856
• DOI: 10.1016/j.jmr.2004.05.013

A high resolution two-dimensional solid state NMR experiment is presented that correlates half-integer quadrupolar spins with protons. In this experiment the quadrupolar nuclei evolve during
t
1 under a split-t1, FAM-enhanced MQMAS pulse scheme. After each
t
1 period ending at the MQMAS echo position, single quantum magnetization is transferred, via a cross polarization process in the mixing time, from the quadrupolar nuclei to the protons. High-resolution proton signals are then detected in the
t
2 time domain during
wPMLG5* homonuclear decoupling. The experiment has been demonstrated on a powder sample of sodium citrate and
23Na–
1H 2D correlation spectra have been obtained. From the HETCOR spectra and the regular MQMAS spectrum, the three crystallographically inequivalent Na
+ sites in the asymmetric unit were assigned. This MQMAS-
wPMLG HETCOR pulse sequence can be used for spectral editing of half-integer quadrupolar nuclei coupled to protons.