Long-lived nuclear spin states in methyl groups and quantum-rotor-induced polarization

Benno Meier, Jean Nicolas Dumez, Gabriele Stevanato, Joseph T. Hill-Cousins, Soumya Singha Roy, Pär Haìškansson, Salvatore Mamone, Richard C D Brown, Giuseppe Pileio, Malcolm H. Levitt*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Substances containing rapidly rotating methyl groups may exhibit long-lived states (LLSs) in solution, with relaxation times substantially longer than the conventional spin-lattice relaxation time T1. The states become long-lived through rapid internal rotation of the CH3 group, which imposes an approximate symmetry on the fluctuating nuclear spin interactions. In the case of very low CH3 rotational barriers, a hyperpolarized LLS is populated by thermal equilibration at liquid helium temperature. Following dissolution, cross-relaxation of the hyperpolarized LLS, induced by heteronuclear dipolar couplings, generates strongly enhanced antiphase NMR signals. This mechanism explains the NMR signal enhancements observed for 13C-γ-picoline (Icker, M.; Berger, S. J. Magn. Reson. 2012, 219, 1-3).

Original languageEnglish
Pages (from-to)18746-18749
Number of pages4
JournalJournal of the American Chemical Society
Issue number50
Early online date20 Nov 2013
Publication statusPublished - 18 Dec 2013

Cite this