Measurement of hetero-nuclear distances using a symmetry-based pulse sequence in solid-state NMR

Phys Chem Chem Phys. 2010 Aug 28;12(32):9395-405. doi: 10.1039/b926546e. Epub 2010 Jun 24.

Abstract

A Symmetry-based Resonance-Echo DOuble-Resonance (S-REDOR) method is proposed for measuring hetero-nuclear dipolar couplings between two different spin-1/2 nuclei, under fast magic-angle spinning. The hetero-nuclear dipolar couplings are restored by employing the SR4 sequence, which requires the rf-field strength to be only twice the spinning frequency. The S-REDOR experiment is extended to S-RESPDOR (Symmetry-based Resonance-Echo Saturation-Pulse DOuble-Resonance) for determining dipolar coupling between a spin-1/2 nucleus (e.g.(13)C) and (14)N. It is demonstrated that S-REDOR and S-RESPDOR methods suppress efficiently the homo-nuclear dipolar interaction of the irradiated nucleus and benefit from high robustness to the rf-field inhomogeneity, chemical shielding and dipolar truncation. Therefore, these methods allow the measurement of (13)C/(14,15)N distances, with (13)C observation, in uniformly (13)C-labeled samples. Furthermore, we provide analytical solutions for the S-REDOR and S-RESPDOR dephasing curves. These solutions facilitate the measurement of hetero-nuclear distances from experimental data.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbon Isotopes / chemistry
  • Isotope Labeling
  • Magnetic Resonance Spectroscopy*
  • Nitrogen Isotopes / chemistry

Substances

  • Carbon Isotopes
  • Nitrogen Isotopes