High-Resolution Solution NMR at Very High Magnetic Fields (>1GHz)

Researchers interested in high-resolution NMR spectroscopy have long sought higher magnetic fields to enhance resolution and simplify spectra. Resistive or hybrid magnets can achieve substantially higher static fields than those available in superconducting magnets, but their spatial uniformity and temporal stability are unacceptable for high-resolution NMR applications. In this regard, intermolecular zero-quantum coherences induced by the distant dipolar field, combined with the Carr-Purcell-Meiboom-Gill (CPMG) pulse train, provide a generally applicable effective method for removing inhomogeneous broadening and Zeeman-field fluctuations while retaining chemical shift differences and scalar couplings. This is confirmed by experimental implementation and numerical simulation. The inhomogeneous linewidth in the 25T Keck magnet is reduced by a factor of ~50 to generate the first ever high-resolution NMR spectrum taken at very high magnetic field (>1GHz). This work was supported by NIH and NHMFL.