NMR longitudinal relaxation enhancement in metal halides by heteronuclear polarization exchange during magic-angle spinning

A.A. Shmyreva, M. Safdari, I. Furó, S.V. Dvinskikh

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6 Citations (Scopus)

Abstract

© 2016 Author(s).Orders of magnitude decrease of 207Pb and 199Hg NMR longitudinal relaxation times T1 upon magic-angle-spinning (MAS) are observed and systematically investigated in solid lead and mercury halides MeX2 (Me = Pb, Hg and X = Cl, Br, I). In lead(ii) halides, the most dramatic decrease of T1 relative to that in a static sample is in PbI2, while it is smaller but still significant in PbBr2, and not detectable in PbCl2. The effect is magnetic-field dependent but independent of the spinning speed in the range 200-15 000 Hz. The observed relaxation enhancement is explained by laboratory-frame heteronuclear polarization exchange due to crossing between energy levels of spin-1/2 metal nuclei and adjacent quadrupolar-spin halogen nuclei. The enhancement effect is also present in lead-containing organometal halide perovskites. Our results demonstrate that in affected samples, it is the relaxation data recorded under non-spinning conditions that characterize the local properties at the metal sites. A pract
Original languageEnglish
Pages (from-to)224201_1-5
JournalJournal of Chemical Physics
Volume144
Issue number22
DOIs
Publication statusPublished - 2016

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