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Substituent chemical shifts in NMR. 1—Proton resonance spectra and geometries of norbornene, norbornane and adamantane
Author(s) -
Abraham Raymond J.,
Fisher Julie
Publication year - 1985
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.1260231014
Subject(s) - norbornane , norbornene , chemistry , adamantane , substituent , chemical shift , methylene , 2 norbornyl cation , computational chemistry , nmr spectra database , spectral line , crystallography , stereochemistry , organic chemistry , physics , monomer , astronomy , polymer
Abstract The molecular geometries and proton NMR spectra of norbornene, norbornane and adamantane are reported. The molecular geometries were refined from previous experimental determinations using MNDO and ab initio techniques to determine the positions of the hydrogen atoms. No evidence of any endo — endo interactions in norbornane was obtained from these calculations. High‐field proton NMR spectra allow the refinement of previous spectral analyses of adamantane and norbornane, and the complete analysis of the olefin decoupled eight spin system of norbornene. The chemical shifts of the parent compounds and cyclohexane under comparable conditions show minor but significant differences from previous values. The methine—methylene coupling in adamantane is 3.30 Hz. The long‐range couplings in norbornene were compared with those calculated by FPT/INDO and EHMO/VB methods. Only moderate agreement was obtained and possible reasons for this are examined.