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Effects of some phosphorus substituents on the carbon‐13 chemical shifts of alkyl chains
Author(s) -
Quin Louis D.,
Gordon Michael D.,
Lee Shin Ok
Publication year - 1974
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.1270060912
Subject(s) - steric effects , chemical shift , chemistry , alkyl , phosphorus , carbon fibers , nmr spectra database , carbon 13 nmr , shielding effect , stereochemistry , medicinal chemistry , spectral line , crystallography , organic chemistry , materials science , physics , layer (electronics) , astronomy , composite number , composite material
The carbon‐13 NMR spectra of 16 aliphatic phosphorus compounds with ‐PCl 2 , ‐P(OCH 3 ) 2 , ‐P(CH 3 ) 2 or ‐PS(CH 3 ) 2 groups were determined and interpreted on the basis of the usual α, β‐deshielding and γ‐shielding effects. The α‐effects of all the groups were quite large (15 to 30 ppm), though the β‐effects were small (0 to 3 ppm). The γ‐effects were also small (0·2 to 1·6 ppm), but of significance in suggesting reduced steric compression relative to that found for methyl and most of the common organic functional groups. This may be attributed to the greater length of the CP bond. The phosphorus‐31 NMR spectra of these compounds also show the existence of interaction with γ‐carbons by exhibiting small additive upfield shifts.