Solid-state proton multiple-quantum NMR spectroscopy with fast magic angle spinning

Triple-quantum correlation NMR experiments in solids using J-couplings

“…The t 1 time increment and the τ/2 delays in the TQ excitation and reconversion periods were synchronized with the rotor period. 13 C and 31 P chemical shifts were referenced relative to Si(CH 3 ) 4 and a 85% H 3 PO 4 solution, respectively. The pulse programs and phase cycles used to record the spectra are available upon request from the authors.…”

“…In this context, various experiments have been developed to obtain two-dimensional (2D) double-quantum -singlequantum (DQ-SQ) correlation spectra of coupled spin-½ systems under magic angle spinning (MAS) which is required for enhanced spectral resolution and sensitivity. Many of these methods employ pulse sequences which reintroduce the MAS-averaged through-space homonuclear dipolar interaction, to obtain DQ-SQ correlation spectra which reflect the through-space atomic proximities [3][4][5][6][7][8][9][10]. Alternatively, pulse sequences based on throughbond isotropic J-couplings, like the INADEQUATE [11] and refocused INADEQUATE [12] experiments, have also been applied efficiently to obtain through-bond DQ-SQ correlation spectra for large range of materials [12][13][14][15][16][17][18][19][20][21][22][23].…”

“…In phosphate glasses, homonuclear through-bond [22,23] and through-space [24][25] DQ-SQ correlation methods have been applied successfully to probe P-O-P connectivities between the various network former PO 4 tetrahedral units (Q n with n bridging oxygen atoms). These experiments provide enhanced spectral resolution relative to the conventional MAS spectra allowing the distinction between Q n units bonded to different types of PO 4 to be made and giving evidence of a chain length distribution in the disordered network [22][23][24][25].…”

Highly Ordered Columnar Structures from Hexa-peri-hexabenzocoronenes—Synthesis, X-ray Diffraction, and Solid-State Heteronuclear Multiple-Quantum NMR Investigations

“…As in 1 H solid-state DQ MAS spectra, the signal in the MQ dimension can be distributed over several orders of spinning side bands, with intensities depending on the dipolar coupling and the spinning frequency. [10] These side-band intensities can then be used to quantitatively evaluate the heteronuclear dipolar coupling of site-resolved 13 C atoms to their neighboring protons. The sensitivity of the technique to dipolar couplings of different magnitudes can be chosen by simply changing the so-called recoupling time t rcpl , which corresponds to the number of rotor periods (t R ) used to excite the MQ modes.…”

NMR parameters in alkali, alkaline earth and rare earth fluorides from first principle calculations

“…In inorganic crystalline fluorides, various 2D heteronuclear correlation MAS experiments (CP-MAS HETCOR, 9 TEDOR-MQMAS, 10 probe heteronuclear spatial proximities. In oxyfluoride 25,26 and in fluoride materials, 17,23,24,27 the fluorine-fluorine proximities or through bond connectivities evidenced through 2D 19 F double-quantum single-quantum 28 (DQ-SQ) MAS correlation experiments were also used to assign the 19 F resonances. However, in the case of distinct fluorine sites having the same connectivity scheme and relatively similar inter-atomic distances, these 2D correlation NMR methods do not allow a straightforward assignment of the 45 corresponding resonances.…”