Nitrogen and oxygen nuclear quadrupole and nuclear magnetic resonance spectroscopic study of NO bonding in pyridine 1‐oxides

Peter M. Woyciesjes, Nathan Janes, S. Ganapathy, Yukio Hiyama, Theodore L. Brown, Eric Oldfield

Research output: Contribution to journalArticlepeer-review

Abstract

14N nuclear quadrupole resonance (NQR) spectra of the NO functional group in a series of 4‐substituted pyridine 1‐oxides (R = H, CH3, C6H5, OCH3, OCH2C6H5, Cl, CN, NO2) and the natural abundance 17O NQR and nuclear magnetic resonance (NMR) solution spectra of a number of selected systems were obtained. The orientations of the principal axes of the 14N electric field gradient tensor (efg) in the NO group were determined using a Townes‐Dailey treatment of the NQR results, combined with a 13C cross‐polarization magic‐angle sample‐spinning NMR line shape analysis of carbons bonded directly to nitrogen. The major principal axis (Z) is coincident with the NO bond. The orientation of the principal (Z) axis of the 17O efg tensor also lies along the N‐O bond, as determined by Townes‐Dailey analysis. The NO π‐bond orders show considerable sensitivity to the nature of the para‐substituent, ranging from 0.17 to 0.31. 17O and 15N NMR chemical shifts parallel these changes in π‐bond order.

Original languageEnglish (US)
Pages (from-to)315-321
Number of pages7
JournalMagnetic Resonance in Chemistry
Volume23
Issue number5
DOIs
StatePublished - May 1985

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)

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