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Nuclear magnetic resonance studies of internal rotation—III Rotational barriers in META ‐ and PARA ‐substituted N , N ‐dimethylcinnamamides
Author(s) -
Spassov S. L.,
Dimitrov V. S.,
Agova M.,
Kantschowska I.,
Todorova R.
Publication year - 1971
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.1270030509
Subject(s) - substituent , internal rotation , rotation (mathematics) , polar , nuclear magnetic resonance , conjugated system , chemistry , line (geometry) , resonance (particle physics) , computational chemistry , atomic physics , physics , stereochemistry , mathematics , geometry , quantum mechanics , polymer , engineering , mechanical engineering
The rotational barriers about the CN bond of eight m ‐ and p ‐substituted N , N ‐dimethyl cinnamamides have been determined by the iterative total line shape NMR method. The ΔG 298·2 −≠values have been correlated with the substituent constants σ, σ n and σ + . By comparison of the results with literature data, some conclusions about the accuracy of the barrier determination as well as the transmittance of polar effects in conjugated amides have been drawn.