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Homonuclear Decoupling of 1 H Dipolar Interactions in Solids by means of Heteronuclear Recoupling
Author(s) -
Olsen Gregory L.,
Lupulescu Adonis,
Dumez JeanNicolas,
Emsley Lyndon,
Frydman Lucio
Publication year - 2014
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.201300102
Subject(s) - homonuclear molecule , heteronuclear molecule , chemistry , spins , residual dipolar coupling , magnetic dipole–dipole interaction , dipole , solid state nuclear magnetic resonance , nuclear magnetic resonance , molecular physics , atomic physics , nuclear magnetic resonance spectroscopy , physics , condensed matter physics , molecule , stereochemistry , organic chemistry
Line narrowing has been traditionally achieved in solid‐state 1 H NMR spectroscopy by applying pulse sequences that combine multiple‐pulse operations with magic‐angle spinning (MAS), to effectively average out the dipoledipole homonuclear Hamiltonian. The present study explores a new alternative that departs from the usual concept of directly acting on the strongly coupled spins with radiofrequency pulses; instead, we seek to achieve a net homonuclear dipolar decoupling in solids by exploring the reintroduction of MAS‐averaged heteronuclear dipolar couplings between the 1 H nuclei and directly bonded 13 C or 15 N nuclei. This recouplinganti‐recoupling (RaR) scheme thus relies on the recoupling of the dipolar interaction with heteronuclear spins, which, under fast MAS, will exceed the strength and will not commute with the homonuclear 1 H 1 H coupling one is intending to average out. Subsequent removal (“antiRecoupling”) of these heteronuclear interactions can lead to narrowed 1 H resonances, without ever pulsing on the aforementioned channel. The line‐narrowing properties of RaR are illustrated with numerical simulations and with experiments on model organic solids.