title: Symmetry-based recoupling of 17O-1H spin pairs in magic-angle spinning NMR.
abstract: We have performed magic-angle-spinning solid-state NMR experiments in which protons are recoupled to oxygen-17 nuclei by applying a symmetry-based recoupling sequence at the proton Larmor frequency. Two-dimensional quadrupole-dipole correlation spectra are produced, in which the second-order quadrupolar shift of the oxygen-17 central transition is correlated with the recoupled heteronuclear dipole-dipole interaction. These spectra are sensitive to the relative orientation of the electric field gradient at the site of the oxygen-17 nucleus and the O-H internuclear vector. We also demonstrate experiments in which polarization is transferred from protons to oxygen-17, and show that oxygen-17 signals may be selected according to the protonation state of the oxygen site. We discuss the small observed value of the heteronuclear dipolar splitting in the central-transition oxygen-17 spectra.
authors.affiliation: School of Chemistry, Southampton University, Highfield, Southampton, SO17 1BJ, UK.
authors.forename: Jacco D
authors.initials: JD
authors.lastname: van Beek
authors.forename: Ray
authors.initials: R
authors.lastname: Dupree
authors.forename: Malcolm H
authors.initials: MH
authors.lastname: Levitt