| Autor: |
L.H. Sutcliffe, D.J. Cowley |
| Rok vydání: |
1969 |
| Předmět: |
|
| Zdroj: |
Spectrochimica Acta Part A: Molecular Spectroscopy. 25:1663-1670 |
| ISSN: |
0584-8539 |
| DOI: |
10.1016/0584-8539(69)80153-4 |
| Popis: |
Chemical shifts have been measured for a series of nitrobenzenes in tetrahydrofuran + cyclo hexane mixtures of various compositions. From shifts obtained in pure cyclo hexane it was concluded that the meta -hydrogen shifts can be accounted for with a reasonable set of parameters and that the non-planarity of the nitrobenzenes does not alter the shifts by more than about 0·05 ppm. Shifts for the para position are normal which indicates that the resonance and electric field effects of the nitro group at the para position are largely unaffected by steric hindrance. By contrast, the ortho -hydrogen shifts are very dependent on the angle of twist of the nitro group. From the solvent effects observed it may be concluded that weak hydrogen-bonded 1:1 donor-acceptor complexes exist in solutions of nitrobenzenes in tetrahydrofuran. The chemical shifts of the bands from the complexes are about 0·5 ppm downfield relative to those of the free acceptors and the association constants are about 0·10 M −1 at 23°C. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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