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NMR Study of Nuclear Spin Polarization during Chemical Reactions with Ortho Hydrogen
Author(s) -
Bargon Joachim,
Kandels Jörg,
Woelk Klaus
Publication year - 1990
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.199000581
Subject(s) - polarization (electrochemistry) , hydrogen , chemistry , radical , spectral line , molecule , spin polarization , hydrogen molecule , nuclear magnetic resonance , analytical chemistry (journal) , atomic physics , physics , nuclear physics , organic chemistry , electron , astronomy
Polarization signals in NMR spectra do not necessarily point to reactions via radicals . This is confirmed by hydrogenations (a) with enriched ortho and para hydrogen, in which polarization signals were observed in each case, albeit with different intensity and reversed sequence of emission and absorption. The intensity ratio can be correlated with the ratio of the ortho and para hydrogen, and thus it is unequivocally confirmed that the nuclear spin states of the H 2 molecules are responsible for the non‐equilibrium occupation of the product nuclear spin level.