Observation of satellite signals due to scalar coupling to spin-1 /2 isotopes in solid-state nuclear magnetic resonance spectroscopy

摘要

A method is introduced to select the signal from a spin-1 / 2 nucleus I specifically bound to another spin-1/2 nucleus S for solid-state magic angle spinning nuclear magnetic resonance (NMR) spectroscopy via correlation through the heteronuclear J coupling.This experiment is analogous to the bilinear rotation decoupling (BIRD) sequence in liquid-state NMR spectroscopy which selects for signals from 1H directly bound to 13C.The spin dynamics of this modified BIRD experiment is described using the product-operator formalism,where experimental considerations such as rotor synchronization and the effect of large chemical shielding anisotropics on / and S are discussed.Two experiments are proposed that accommodate large chemical shielding anisotropics on S:(1) by stepping the inversion pulse frequency through the entire S spectral range or (2) by adiabatically inverting the S spins.Both these experiments are shown to successfully select the signal of F bound to 129Xe in XeF+salts,removing the contributions from isotopomers containing non-spin-112 Xe isotopes.The feasibility in obtaining isotope-selective 19F spectra of inorganic fluoride compounds is discussed,and further modifications are proposed to expand the application to other chemical systems.