Combining STMAS and CRAMPS NMR spectroscopy: High-resolution HETCOR NMR spectra of quadrupolar and 1H nuclei in solids

High-resolution two-dimensional (2D) heteronuclear correlation spectra between half-integer quadrupolar and 1H nuclei have been obtained combining Satellite Transition Magic-Angle Spinning (STMAS) and wPMLG3 CRAMPS methods. The experiments use split-t1 versions of DQ/DQF-STMAS adapted to 3/2 and 5/2 spins to obtain a 23Na and 27Al isotropic dimension, respectively. Transfer of magnetization from quadrupolar nuclei to protons has been achieved by cross-polarization, and high-resolution 1H spectra have been recorded using the wPMLG3 decoupling during the t2 evolution period. The performance of the pulse sequences have been tested on the templated microporous aluminophosphate IST-1 and trisodium citrate employing a B0 field of 9.4 T.

Two high-resolution 2D 23Na/27Al-1H STMAS-CP-HETCOR-CRAMPS NMR experiments are reported and applied in two materials, combining split-t1-DQF/DQ-STMAS and wPMLG3 segments.