Efficient dipolar double quantum filtering under magic angle spinning without a (1)H decoupling field.
We present a systematic study of dipolar double quantum (DQ) filtering in (13)C-labeled organic solids over a range of magic-angle spinning rates, using the SPC-n recoupling sequence element with a range of n symmetry values from 3 to 11. We find that efficient recoupling can be achieved for values n⩾7, provided that the (13)C nutation frequency is on the order of 100kHz or greater. The decoupling-field dependence was investigated and explicit heteronuclear decoupling interference conditions identified. The major determinant of DQ filtering efficiency is the decoupling interference between (13)C and (1)H fields. For (13)C nutation frequencies greater than 75kHz, optimal performance is observed without an applied (1)H field. At spinning rates exceeding 20kHz, symmetry conditions as low as n=3 were found to perform adequately.
Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Joseph M
JM
Courtney
Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Electronic address: rienstra@illinois.edu.
Chad M
CM
Rienstra
D008279:Magnetic Resonance Imaging
Dipolar recoupling; Double quantum filtering; Fast magic-angle spinning; Heteronuclear decoupling; Proteins