Selenium-77 NMR chemical shifts of five-membered selenium and sulphur heterocycles with CSe, CS, and CO groups
✍ Scribed by Helmut Poleschner; Reiner Radeglia; Hinrich Meyer
- Publisher
- John Wiley and Sons
- Year
- 1984
- Tongue
- English
- Weight
- 427 KB
- Volume
- 22
- Category
- Article
- ISSN
- 0749-1581
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✦ Synopsis
This paper reports the 77Se NMR chemical shifts of 1,34thiole-, 1,3-thiaselenole-and 1,3-diselenole-2ones, -thiones and -selones, of the corresponding saturated compounds 1,3-diselenolane-2-one, -thione and -selone, and the 1,3-thiaselenolium tetralluoroborates, either unsubstituted or substituted by morpholino, ethylthio or ethylseleno groups in the 2-position. The 77Se chemical shift values of the ring selenium and the C==Se groups are compared with the 13C chemical shift values of neighbouring carbon atoms. The relationships between the "Se chemical shifts of the M e groups and the wavelengths of their n+.rr* absorption in the W-visible spectrum are discussed with respect to the signi6cance of the A E term in the contribution of the paramagnetic screening and the eleclron density distribution.