| Autor: |
V.V.Gromak, Avakyan, V. G., Pashkovskii, F. S., Lakhvich, O. F., Skorodumov, E. V., Khlebnikova, T. S. |
| Předmět: |
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| Zdroj: |
Journal of Applied Spectroscopy; Jan/Feb2003, Vol. 70 Issue 1, p14-26, 13p |
| Abstrakt: |
The tautomerism, spectral properties, and properties of intramolecular hydrogen bonds in 2‐formylcyclopentane‐1,3‐dione (FCPD) have been investigated by the methods of nonempirical quantum chemistry (calculations by the ab initio and DFT methods) and IR and 13C NMR spectroscopy. It is shown that FCPD in a crystalline form, as also does malonic dialdehyde, exists as self‐associated enolized molecules with an “open” chelate ring. It is found that in solutions in CCl4 the compound investigated exists as an equilibrium mixture of its exo‐ and endoenolic forms, with predominance of the former. The IR spectra of the solutions of FCPD in CCl4 fix the presence of small amounts of the associate formed from the anionic and protonated forms of the substance. For the first time, the energies of the intramolecular H bonds of the endo‐ and exoenolic tautomeric forms in FCPD have been estimated theoretically. They appeared to be equal to 3.69 and 4.91 kcal·mole-1, respectively. The possible mechanisms of enol‐enolic interconversions of FCPD have been discussed. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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