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Experimental boundaries of the quantum rotor induced polarization (QRIP) in liquid state NMR
Author(s) -
Icker Maik,
Fricke Pascal,
Grell Toni,
Hollenbach Julia,
Auer Henry,
Berger Stefan
Publication year - 2013
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.4021
Subject(s) - chemistry , polarization (electrochemistry) , hyperpolarization (physics) , quantum tunnelling , polarizability , condensed matter physics , quantum , chemical physics , nuclear magnetic resonance spectroscopy , quantum mechanics , stereochemistry , physics , molecule , organic chemistry
The Haupt‐effect is a rather seldom used hyperpolarization method. It is based on the interdependence between nuclear spin states and rotational states of nearly free rotating methyl groups having C 3 symmetry. A sudden change in temperature from 4.2 K to room temperature by fast dissolution yields considerably enhanced 13 C and 1 H resonance signals. This phenomenon is now termed quantum rotor induced polarization. More than 40 substances have been studied by this approach in order to identify them as polarizable by the ‘Haupt‐effect in the liquid state’. Influencing factors have been analyzed systematically. It could be concluded that substances having a high tunneling frequency, which is due to a small and narrow potential barrier, are most likely to feature quantum rotor induced polarization‐enhanced signals. Copyright © 2013 John Wiley & Sons, Ltd.