Studies on tetraborane(8) carbonyl, B4H8·CO: its isomeric composition in the gas phase and in solution, and its reactions with alkenes1Dedicated to Professor Ken Wade on the occasion of his 65th birthday in recognition of his outstanding contributions to the chemistry of the boranes, organometallics, and Main Group chemistry generally.1
| Autor: | Simon J. Cranson, Mark A. Fox, Robert Greatrex, Norman N. Greenwood |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
chemistry.chemical_classification
Stereochemistry Chemical shift Organic Chemistry Tetraborane Ab initio Boranes Biochemistry Medicinal chemistry Inorganic Chemistry Propene NMR spectra database chemistry.chemical_compound chemistry Materials Chemistry Proton NMR Physical and Theoretical Chemistry Alkyl |
| Zdroj: | Journal of Organometallic Chemistry. 550:207-212 |
| ISSN: | 0022-328X |
| DOI: | 10.1016/s0022-328x(97)00180-0 |
| Popis: | 11 B NMR spectra of tetraborane(8) carbonyl, B 4 H 8 ·CO 1 , reveal a changeover in the distribution of isomers in going from toluene solution to the gas phase. Fortuitously the distribution is 60:40 in each case, but comparison with published electron diffraction data and ab initio/IGLO computations indicates that the CO group is disposed endo with respect to the B 4 `butterfly' framework in the predominant isomer in the gas phase, and exo in solution. The results also allow conclusions to be drawn about the geometries of other B 4 H 8 ·L isomers on the basis of their reported proton NMR chemical shifts. Reactions of B 4 H 8 ·CO with ethene and propene at ca. 30 bar yield products, R 4 B 4 H 4 ·CO (R=Et 2 or Pr 3 3 ), in which all four wingtip hydrogen atoms of the tetraborane carbonyl have been replaced by alkyl groups. Variable-temperature 11 B and 1 H NMR spectra of 2 and 3 reveal interesting fluxional behaviour. |
| Databáze: | OpenAIRE |
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