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Electronic and steric effects in arylphosphoramidates and phosphorimidates as monitored by carbon‐13 nuclear magnetic resonance
Author(s) -
Buchanan G. W.,
Morin F. G.
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.1270140618
Subject(s) - steric effects , lone pair , chemical shift , delocalized electron , vicinal , chemistry , ring (chemistry) , resonance (particle physics) , electronic effect , electron delocalization , aryl , crystallography , stereochemistry , photochemistry , nuclear magnetic resonance , molecule , organic chemistry , alkyl , atomic physics , physics
13 C NMR chemical shifts and 13 C 31 P couplings are reported for ten arylphosphoramidates and five arylphoshorimidates. The para ‐carbon chemical shifts in the phosphoramidates are interpreted in terms of substantial nitrogen lone pair delocalization into the aromatic ring, a phenomenon which is subject to steric inhibition of resonance. By contrast, in the phosphorimidates the electron release into the phenyl ring is not attenuated by steric congestion. Conformational changes about the arylN bond in all compounds have been monitored by vicinal 31 PNC 13 C couplings.