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Dynamic 13 C NMR: A study of aryl‐substituted 1‐phenyl‐3,3‐tetramethylenetriazenes
Author(s) -
Foster N.,
Pestel B.
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.1260230206
Subject(s) - chemistry , aryl , spectral line , carbon 13 nmr , nmr spectra database , resonance (particle physics) , molecule , proton nmr , dipole , nuclear magnetic resonance spectroscopy , computational chemistry , stereochemistry , organic chemistry , atomic physics , alkyl , physics , astronomy
The temperature‐dependent 13 C NMR spectra of a series of para ‐substituted 1‐phenyl‐3,3‐tetramethylenetriazenes have been analyzed by the band width method. Electron‐donating substituents clearly accelerate the rate of rotation about the N‐2N‐3 bond in the triazenes; electron withdrawers retard that motion. The exchange averaging process observed in the carbon spectra obeys a linear free energy relationship when Hammett σ* parameters are used in the correlation. These results corroborate those already obtained by analysis of 1 H NMR spectra of similar triazenes, regarding the likely contribution of a 1,3‐dipolar resonance form to the ground state of the molecule.