Extremely large one-bond 31P13C and two-bond 31P18O isotope shifts in [(H3C)2CH]3SiOCP, a new representative of λ3-phosphaalkynes, and isotope shifts of several derivatives and some λ3-phosphaalkenes
✍ Scribed by Gernot Heckmann; Gerd Becker; Hans Kraft
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 93 KB
- Volume
- 37
- Category
- Article
- ISSN
- 0749-1581
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✦ Synopsis
The structure of the heteroatom-substituted 3 -phosphaalkyne [(H 3 C 2 CH] 3 Si-O-C P (1) was derived from the 31 P, 13 C, 29 Si and 17 O NMR spectra. The phosphorus atom of the non-isotope-enriched compound exhibits an extremely negative 31 P 13 C one-bond and 31 P 18 O two-bond isotope shift of 0.209 and 0.094 ppm, respectively. The 31 P 1 H NMR spectrum shows all carbon, silicon and oxygen satellite signals of the [mono-13 C]-, [mono-29 Si]-and [mono-18 O]-as well as the [bis-13 C, 29 Si]-and [bis-13 C, 13 C]isotopomers; even over five bonds a 31 P 13 C isotope effect can also be observed. Additivity of the corresponding isotope effects has been confirmed. The coupling constant 1 J 31 P, 13 C) is unexpectedly large, 91.9 Hz. 31 P 13 C one-bond isotope shifts of other 3 -phosphaalkynes and 3 -phosphaalkenes are presented and discussed.