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High resolution NMR spectroscopy of heteroaromatic cations. I. 13 C 1 H coupling constants in the pyridinium cation
Author(s) -
Sándor P.,
Radics L.
Publication year - 1980
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270140205
Subject(s) - pyridinium , chemistry , pyridine , electronegativity , coupling constant , spectral line , proton , substituent , chemical shift , nmr spectra database , spectroscopy , resonance (particle physics) , tetrafluoroborate , analytical chemistry (journal) , stereochemistry , medicinal chemistry , ionic liquid , atomic physics , organic chemistry , physics , particle physics , quantum mechanics , astronomy , catalysis
High‐resolution 1 H{ 14 N} and proton‐coupled natural‐abundance 13 C{ 14 N} double resonance spectra have been recorded for pyridinium tetrafluoroborate dissolved in CD 3 CN. Iterative analysis of these spectra has provided the accurate values and relative signs of all possible long‐range 13 C— 1 H coupling constants. These are compared with the respective values in pyridine and pyridine‐ N ‐oxide and discussed in terms of the relationship with the electronegativity of the N ‐substituent. Experimental conditions allowing the observation of well‐resolved proton‐coupled 13 C NMR spectra of charged heteroaromatics are also presented.