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NMR of terminal oxygen. 9 — 17 O NMR of the PO ‘double bond’: Phosphine oxides, phosphinates, phosphonates, acylphosphonates and related compounds
Author(s) -
Dahn Hans,
Van Toan Vien,
UngTruong MyNgoc
Publication year - 1992
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260301112
Subject(s) - chemistry , geminal , phosphine , oxygen , alkyl , nmr spectra database , oxygen atom , phosphine oxide , medicinal chemistry , phosphorus 31 nmr spectroscopy , stereochemistry , phosphorus , nuclear magnetic resonance spectroscopy , crystallography , ring (chemistry) , double bond , spectral line , molecule , organic chemistry , catalysis , astronomy , physics
The 17 O NMR spectra of phosphorus‐bound oxygen atoms in secondary phosphine oxides (R 2 HPO, 1), alkyl phosphinates [RHP(O)OR′, 2 and R 2 P(O)OR′, 3], dialkyl phosphonates [RP(O)(OR′) 2 , 4], dialkyl acylphosphonates [RCOP(O)(OR′) 2 , 5] and some related compounds were measured. The signals of terminal O appear at high field, only slightly downfield from those of bridge O. Compared with carbonyl O, terminal PO shows lower sensitivity to structural variations, notably to geminal groups (with the exception of Cl and Br), and a very low sensitivity to arene ring substituents. The difference is discussed in terms of π‐bond character; the carbonyl oxygen of RCOP(O)OR′) 2 is sensitive to variations in structure.