Application of the Carr−Purcell Meiboom−Gill Pulse Sequence for the Acquisition of Solid-State NMR Spectra of Spin-1/2 NucleiThe Journal of Physical Chemistry A (2004)
The quadrupolar Carr−Purcell Meiboom−Gill (QCPMG) pulse sequence has received much attention in the recent literature for use in the rapid acquisition of solid-state NMR spectra of half-integer quadrupolar nuclei. Herein we investigate the application of the CPMG pulse sequence to enhance the signal-to-noise ratio in the static NMR spectra of spin-1/2 nuclei. CPMG is coupled with techniques such as cross-polarization (CP) and two-pulse phase-modulated (TPPM) proton decoupling. The CPMG and CP/CPMG pulse sequences are applied to a series of different NMR nuclides, including 113Cd, 199Hg, 207Pb, 15N and 109Ag. Standard113Cd CP/MAS, MAS and static NMR spectra of Cd(NO3)2·4H2O are compared with corresponding 113Cd CPMG and CP/CPMG NMR spectra. Piecewise-acquired wide-line CPMG199Hg and 207Pb NMR spectra of (CH3COO)2Hg and (CH3COO)2Pb·3H2O, which are so broad that they cannot be uniformly excited by a single short pulse, reveal that chemical shielding tensor parameters can be determined from these rapidly acquired spectra more accurately than with corresponding CP/MAS spectra. CP/CPMG NMR is also applied to acquire NMR spectra of low-γ nuclei such as 15N in 15NH415NO3 (98%-enriched) and 109Ag in AgSO3CH3. The signal obtained from CPMG NMR experiments on stationary samples is comparable to corresponding MAS spectra and much higher than for conventional static NMR spectra, providing an interesting alternative for investigating spin-1/2 nuclei with broad powder patterns.
Publication DateJuly 30, 2004
Citation InformationIvan Hung, Aaron J. Rossini and Robert W. Schurko. "Application of the Carr−Purcell Meiboom−Gill Pulse Sequence for the Acquisition of Solid-State NMR Spectra of Spin-1/2 Nuclei" The Journal of Physical Chemistry A Vol. 108 Iss. 34 (2004) p. 7112 - 7120
Available at: http://works.bepress.com/aaron-rossini/27/