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Nuclear Magnetic Resonance Studies. IV. Proton Chemical Shifts and Coupling Constants of 2‐Norbornanols and Methyl‐Substituted 2‐Norbornanols
Author(s) -
Liu KwangTing
Publication year - 1976
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.197600001
Subject(s) - chemistry , chemical shift , extrapolation , coupling constant , europium , spectral line , proton , nuclear magnetic resonance , resonance (particle physics) , coupling (piping) , analytical chemistry (journal) , computational chemistry , atomic physics , ion , organic chemistry , mechanical engineering , mathematical analysis , physics , mathematics , particle physics , quantum mechanics , astronomy , engineering
The proton magnetic resonance spectra of the two isomeric 2‐norbornanols (I and II) and of eighteen of their methyl‐substituted derivatives (III to XX) under the influence of tris(dipivalomethanato)europium, Eu(dpm) 3 , have been measured. In all cases linear relationships between the observed shifts and the molar ratios of Eu(dpm) 3 to substrate were realized. The chemical shifts obtained from the extrapolation to zero concentration of Eu(dpm) 3 are in good agreement with the observed values. The coupling constants were found to be essentially unaffected by Eu(dpm) 3 . Consequently, determination of a chemical shift by extrapolation or of a coupling constant from the shifted spectrum appears to be justified. Reassignments of a number of signals are discussed. Chemical shifts, normalized induced shifts, and coupling constants are tabulated.