Double-quantum homonuclear NMR correlation spectroscopy of quadrupolar nuclei subjected to magic-angle spinning and high magnetic field

Broadband finite-pulse radio-frequency-driven recoupling (fp-RFDR) with (XY8)41 super-cycling for homo-nuclear correlations in very high magnetic fields at fast and ultra-fast MAS frequencies

“…In order to fully assign this region, a DQ-SQ 13 C correlation using BR2 1 2 was performed (Fig. S6) [24,51,52]. It is to be noted that DQ-SQ and SQ-SQ experiments perfectly complement each other.…”

“…These methods comprise SPC-5 [45,46], DREAM [23,47], CMpRR [42], COMICS [42], Radio-Frequency-Driven Recoupling (RFDR) [48], finite-pulse RFDR (fp-RFDR) [49,50], BR2 1 2 [24,51,52], etc. However, only methods requiring low rf power, such as DREAM, fp-RFDR and BR2 1 2 , are applicable at MAS speeds faster than 40 kHz [17,23,24].…”

Double-quantum homonuclear correlations of spin I=5/2 nuclei

“…For this category, and in general when working with quadrupolar nuclei, very weak RF pulses that are selective to the CT are usually employed in order to avoid leakages of coherence due to adiabatic passages [21]. For this reason in order to match the x MAS /2 or x MAS rotary resonance condition [22,23] for weak RF irradiation the spinning speed must also be low. This condition severely limits the applicability of this experiment to real systems containing half-integer quadrupolar nuclei, which require rapid MAS due to the large quadrupolar interaction.…”

Solid-State NMR Studies of Zeolites

“…By utilizing a sensitivity-enhanced 2D 27 Al DQ MAS NMR technique [ 106 ], the spatial proximities among various Al species in dealuminated HY zeolites were demonstrated. Figure 7.14 shows 2D 27 Al DQ MAS NMR spectra of parent HY and calcined HY zeolites.…”