Six-membered ring phosphorus heterocycles. : Use of europium shift reagent in the analysis of the P.M.R. spectrum of trans-2-methyl-5-t-butyl-2-oxo-1,3,2-dioxaphosphorinane
✍ Scribed by K.C. Yee; W.G. Bentrude
- Publisher
- Elsevier Science
- Year
- 1971
- Tongue
- French
- Weight
- 199 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0040-4039
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✦ Synopsis
A considerable amount of work has been published1 in the past few years concerning the conformations of saturated six-membered ring heterocycles containing phosphorus including phosphites, phosphates, phosphonites and phosphonates.
The bulk of these investigations has involved analysis of very complex non-first order spectra of the AA'BB'X or AA'BB'XY type using iterative computer analysis procedures.
Recently, the lanthanide complexes have been shown to be powerful shift reagents for the simplification of nmr spectra*. We report here the use of tris(dipivalomethanato)europium (III) ,
Eu(dpm) 3, to give greatly simplified spectra for m-2-methyl-5-t-butyl-2-oxo-1,3,2-dioxaphosphorinane, (I) .
rd We previously reported results of analysis of chemical shifts and coupling constants for this compound using an ABXY approximation for the methylene region of the spectrum followed by iterative analysis of the AA'BB'XY system using the LAOCN3 program.3 The trans stereochemistry and chair-form conformation for I in the solid state had been established by X-ray crystallography.* Addition of tris(dipivalomethanato)europium (III), Eu(dpm),, in incremental amounts to a 0.2 M solution of I in CCL, gave downfield shifts which were linear in concentration of added Eu(dpm),