Academic Journal
Bicyclo[3.2.1]octa-2,6-dienyllithium and -potassium Chemistry Solvation, Aggregation, and 119 Sn- 7 Li Coupling of Stannylated Derivatives
| العنوان: | Bicyclo[3.2.1]octa-2,6-dienyllithium and -potassium Chemistry Solvation, Aggregation, and 119 Sn- 7 Li Coupling of Stannylated Derivatives |
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| المؤلفون: | Hertkorn, Norbert, Köhler, Frank H. |
| المصدر: | Zeitschrift für Naturforschung B ; volume 45, issue 6, page 848-856 ; ISSN 1865-7117 0932-0776 |
| بيانات النشر: | Walter de Gruyter GmbH |
| سنة النشر: | 1990 |
| الوصف: | The 13 C NMR spectra of bicyclo[3.2.1]octa-2,6-dienyl anion (1) as the lithium (1 Li) and the potassium salt (1 K) were recorded at various temperatures and in different solvents. The results show 1K to exist as a contact ion pair (CIP), whereas for 1 Li solvent separated ions (SSIP) are also found as the temperature is lowered and when the solvating power of the solvent is increased. In the 7 Li NMR spectra at very low temperature the signals of the SSIP disappear and only those of a monomeric CIP and a triple ion (1 Li 1) consisting of two carbanions and one lithium cation are present. For independent confirmation, the hitherto unknown 6-, 7-, and 3-trimethylstannyl substituted bicyclo[3.2.1]octa-2,6-dienyllithium derivatives 2 a Li, 2 b Li, and 3 Li were synthesized and also studied by 119 Sn, 13 C, and 1 H NMR. According to the temperature dependence of the δ( 13 C)-values the CIP/SSIP-equilibrium of 2 a Li in THF/TMEDA is shifted to the CIP side. The observation of a unique 119 Sn- 7 Li coupling (6.2 Hz) shows that at –90 °C a species containing 2 a and lithium exists under slow exchange conditions. A similar coupling of 3.5 Hz can be estimated for 3Li. A mixture of the epimeric carbanions 2a and 2 b yields two sets of 13 C NMR signals which are due to the diastereomeric triple ions 2 aLi 2 a and 2 aLi 2 b. |
| نوع الوثيقة: | article in journal/newspaper |
| اللغة: | English |
| DOI: | 10.1515/znb-1990-0616 |
| DOI: | 10.1515/znb-1990-0616/xml |
| DOI: | 10.1515/znb-1990-0616/pdf |
| الاتاحة: | http://dx.doi.org/10.1515/znb-1990-0616 https://www.degruyter.com/view/journals/znb/45/6/article-p848.xml https://www.degruyter.com/document/doi/10.1515/znb-1990-0616/xml https://www.degruyter.com/document/doi/10.1515/znb-1990-0616/pdf |
| Rights: | http://creativecommons.org/licenses/by-nc-nd/3.0/ |
| رقم الانضمام: | edsbas.D50E42EA |
| قاعدة البيانات: | BASE |
| DOI: | 10.1515/znb-1990-0616 |
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