Open AccessFreezing of Molecular Motions Probed by Cryogenic Magic Angle Spinning NMR
Author(s) -
Maria Concistrè,
Elisa Carignani,
Silvia Borsacchi,
Ole G. Johannessen,
Benedetta Mennucci,
Y. Yang,
Marco Geppi,
Malcolm H. Levitt
Publication year - 2014
Publication title -
the journal of physical chemistry letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.563
H-Index - 203
ISSN - 1948-7185
DOI - 10.1021/jz4026276
Subject(s) - magic angle spinning , spinning , magic angle , molecular dynamics , nmr spectra database , nuclear magnetic resonance spectroscopy , molecule , cryogenic temperature , spectral line , chemistry , materials science , chemical physics , crystallography , computational chemistry , polymer chemistry , stereochemistry , physics , organic chemistry , astronomy , composite material
Cryogenic magic angle spinning makes it possible to obtain the NMR spectra of solids at temperatures low enough to freeze out most molecular motions. We have applied cryogenic magic angle spinning NMR to a crystalline small-molecule solid (ibuprofen sodium salt), which displays a variety of molecular dynamics. Magic angle (13)C NMR spectra are shown for a wide range of temperatures, including in the cryogenic regime down to 20 K. The hydrophobic and hydrophilic regions of the molecular structure display different behavior in the cryogenic regime, with the hydrophilic region remaining well-structured, while the hydrophobic region exhibits a broad frozen conformational distribution.