SPAM-MQ-HETCOR: an improved method for heteronuclear correlation spectroscopy between quadrupolar and spin-1/2 nuclei in solid-state NMR.
The recently introduced concept of soft pulse added mixing (SPAM) is used in two-dimensional heteronuclear correlation (HETCOR) NMR experiments between half-integer quadrupolar and spin-1/2 nuclei. The experiments employ multiple quantum magic angle spinning (MQMAS) to remove the second order quadrupolar broadening and cross polarization (CP) or refocused INEPT for magnetization transfer. By using previously unexploited coherence pathways, the efficiency of SPAM-MQ-HETCOR NMR is increased by a factor of almost two without additional optimization. The sensitivity gain is demonstrated on a test sample, AlPO(4)-14, using CP and INEPT to correlate (27)Al and (31)P nuclei. SPAM-3Q-HETCOR is then applied to generate (27)Al-(31)P spectra of the devitrified 41Na(2)O-20.5Al(2)O(3)-38.5P(2)O(5) glass and the silicoaluminophosphate ECR-40. Finally, the method allowed the acquisition of the first high resolution solid-state correlation spectra between (27)Al and (29)Si.
Ames Laboratory, Iowa State University, Ames, IA 50011-3020, USA.
Jerzy W
JW
Wiench
Gregory
G
Tricot
Laurent
L
Delevoye
Julien
J
Trebosc
James
J
Frye
Lionel
L
Montagne
Jean-Paul
JP
Amoureux
Marek
M
Pruski
D000535:Aluminum / Q000737:chemistry; D017607:Aluminum Compounds / Q000737:chemistry; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D010104:Oxygen Radioisotopes / Q000737:chemistry; D010710:Phosphates / Q000737:chemistry; D010758:Phosphorus / Q000737:chemistry; D012825:Silicon / Q000737:chemistry
D017607:Aluminum Compounds; D010104:Oxygen Radioisotopes; D010710:Phosphates; D010758:Phosphorus; D000535:Aluminum; C012714:aluminum phosphate; D012825:Silicon