Double-quantum ~(19)F-~(19_F dipolar recoupling at ultra-fast magic angle spinning NMR: application to the assignment of ~(19)F NMR spectra of inorganic fluorides

摘要

A broadband dipolar recoupling method robust to chemical shift is introduced to observe ~(19)F_~(19)F proximities in fluoroaluminates in high magnetic field and at ultra-fast magic angle spinning (> 60 kHz).~(19)F nucleus has the advantage of a spin quantum number equal to 1/2, a high gyromagnetic ratio (γ_(19F) = 0.94γ_(1H)) and a 100% natural isotopic abundance, leading to a very high nuclear magnetic resonance (NMR) receptivity. Moreover, the ~(19)F isotropic chemical shifts (δ_(iso)) span over a wide frequency range (≈800 ppm) giving a high spectrum sensitivity to variations of the local environment of the fluorine atoms.