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13 C nuclear magnetic resonance of organophosphorus compounds XI —aminophosphines
Author(s) -
Gray George A.,
Nelson John H.
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.1270140103
Subject(s) - phenylphosphine , chemistry , lone pair , crystallography , stereochemistry , nuclear magnetic resonance , phosphine , molecule , organic chemistry , physics , catalysis
Natural abundance 13 C NMR studies have been carried out on a series of organophosphorus compounds possessing PN bonds. For the first time a one ‐ bond temperature‐dependent 13 C— 31 P nuclear spin coupling was observed for the P ‐phenyl carbons in bis( N , N ‐dibenzylamino)phenylphosphine (0‐9 Hz) and bis( N , N ‐diethylamino)phenylphosphine (0–2 Hz). This temperature‐dependent behavior can be rationalized in terms of free rotation about the phenyl phosphorus bond with concomitant hindered rotation about the PN bonds. A conformational preference for the nitrogen and phosphorus lone pairs to exist in the trans orientation is indicated. In the similarly substituted 5‐membered heterocyclic ring compound, 1,3‐dimethyl‐2‐phenyl‐1,3‐diazaphospholidine, the phenyl one‐bond coupling increases to (−) 42.1 Hz and becomes temperature independent. These data suggest that 1 J (PC) is very responsive to electronic effects.