Use of relaxation agent doping to shorten very long spin-lattice relaxation times in a magic-angle turning experiment.
A practical method is described for measuring the principal values of the chemical shift tensors in compounds with very long proton spin-lattice relaxation times (T1). This technique involves shortening the effective proton T1. by mixing a compound of interest with another compound having a much shorter T1 value. The doped mixture, partly consisting of a monophasic glass, allows efficient intermolecular spin diffusion between the two compounds. Using a slow magic-angle turning (MAT) experiment, we have successfully used such mixtures to measure the principal values of the chemical shift tensors of all the carbons in dibenzofuran in just four days. Without using this technique the experimental time required for the pure compound would have been several months.
Wang
W
W
Department of Chemistry, University of Utah, Salt Lake City 84112, USA.
Hu
J Z
JZ
Alderman
D W
DW
Pugmire
R J
RJ
Grant
D M
DM
D001572:Benzofurans / Q000737:chemistry; D005898:Glass / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D013997:Time Factors
D001572:Benzofurans; C023614:dibenzofuran