Resolution enhancement in 1D solid-state NMR spectra of spin-9/2 quadrupolar nuclei

NMR is an insensitive spectroscopy, which often requires numerous accumulations, especially for 2D high-resolution methods (MQMAS and STMAS) for quadrupolar nuclei in solids. This may be a very important limitation for the case of insensitive nuclei, where a 1D spectrum with better resolution than the central-transition is then highly desirable. This problem has been addressed for the case of spin-5/2 nuclei by the Double-Quantum Filtered Satellite Transition Spectroscopy: DQF-SATRAS-ST(1). We extend this concept to the spin-9/2 nuclei with the SATRAS-ST(2) method. This method allows the observation of 1D spectra with a much better resolution than that observed in the isotropic projection of 2D MQ/ST(1)-MAS spectra. This enhanced resolution results from the much smaller homogeneous broadening that occurs on the SATRAS-ST(2) method as compared to MQ/ST(1)-MAS spectra. The main interest in this method is for well-crystallized samples.