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The molecular structure of allenes and ketenes. XIV —semi‐empirical descriptions of 13 C chemical shifts of ketene imines and deduced from the effects of isoelectronic substitutions in allenes
Author(s) -
Runge Wolfgang
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.1270140106
Subject(s) - ketene , chemistry , computational chemistry , chemical shift , transition state , carbon fibers , symmetry (geometry) , stereochemistry , organic chemistry , materials science , mathematics , geometry , composite number , catalysis , composite material
An essentially algebraic model for semi‐empirical calculations of 13 C chemical shicts of ketene imines and ketenes is presented which utilizes geometrical and non‐geometrical aspects of symmetry. In particular, emphasizing isoelectronic substitution as a generalized symmetry principle, it is shown that approximation functions for the description of 13 C chemical shifts of ketene imines and ketenes can be deduced from those used for the allenes, and that the parameters which are necessary for the calculations of the carbon resonances of the heterocumulenes are simply related to those used for the allenes. A comparison between calculated and experimental 13 C chemical shifts of complex ketene imines and ketenes demonstrates the relevance of the suggested model.