High-resolution two-dimensional NMR spectra of half-integer-spin quadrupolar nuclei from one-dimensional projections

Abstract

We present a technique providing high-resolution spectra of quadrupolar nuclei with half-integer nuclear spin displaying significant second-order linebroadening. The technique, dubbed chemical shift-quadrupolar projection-reconstruction of one-dimensional spectra (CQ-PRODI) exploits the different magnetic field dependence of the chemical shift and second-order quadrupolar effect. Onedimensional spectra recorded at different magnetic field strengths are represented as projections along different directions in the two-dimensional spectrum that correlates the chemical shift and the second-order quadrupolar lineshape. We present CQ-PRODI spectra for 27 Al in 9Al 2 O 3 •2B 2 O 3 and for 71 Ga in β-Ga 2 O 3 which display resolution of all sites in the chemical shift dimension.

Solid-State NMR Spectroscopy of Metal–Organic Framework Compounds (MOFs)

“…The MQMAS experiment is meanwhile one of the most frequently applied techniques for the investigation of quadrupolar nuclei (see below). In 2007 Vosegaard and Massiot developed a method called “chemical shift-quadrupolar projection-reconstruction of one-dimensional spectra” (CQ-PRODI [ 83 ]). CQ-PRODI is based on the correlation of chemical shifts with the second-order quadrupolar line shapes from multiple spectra recorded at different B 0 strengths, which allows the construction of high-resolution spectra.…”

Impact of selective excitation on carbon longitudinal relaxation: Towards fast solid-state NMR techniques

“…In solid-state NMR, isolated attempts to use single-scan and projection-reconstruction spectroscopy have been presented [18][19][20]. A broad application of these techniques is however limited due to the low sensitivity of the heteronuclei detection usually used in solidstate NMR.…”

Single-Crystal NMR Spectroscopy

“…Hence, for powdered samples it has been necessary to use advanced techniques such as dynamic-angle spinning to achieve site-specific resolution [96]. We later proposed a projectionreconstruction method that used one-dimensional spectra from different magnetic field strengths to reconstruct a two-dimensional correlation experiment with spectral resolution [97]. Most interestingly, Hung and Gan recently demonstrated that by using low-power STMAS it is now possible to resolve such sites, which seems to be of broad applicability [98].…”