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- Title
Determination of the Dipole Moments of the Molecules of 4′‐Substituted 3‐Hydroxyflavones Using the Electrooptic Absorption Method.
- Authors
Nemkovich, N.A.; Baumann, W.; Pivovarenko, V.G.; Rubinov, A.N.
- Abstract
The dipole moments in the equilibrium ground (μg) and excited Franck–Condon states (μeFC) of the molecules of 4′‐(methoxy)‐3‐hydroxyflavone (FOM), 4′‐(dimethylamino)‐3‐hydroxyflavone (FME), and 4′‐N‐(15‐azacrown‐5(‐3‐hydroxyflavone (FCR) in 1,4‐dioxane were measured. Characteristic of these probes is excited‐state intramolecular proton transfer. For comparison, the dipole moments of the molecules of 4′‐(dimethylamino)‐3‐methoxyflavone (FME3ME) were measured, for which the excited‐state intramolecular proton transfer is lacking. It is established that in the case of FME, FCR, and FME3ME the dipole moments μg and μeFC are parallel to the absorption transition dipole moment ma responsible for absorption. Among the compounds studied, FOM has the least values of μg and μeFC, only 9.4·10-30 and 26.3·10-30 C·m, respectively. The dipole moments μg, μeFC and ma are not parallel to one another, and the angles between them lie in the range 4–55°. This effect is due to FOM not having a strong electron‐donating group, such as an amino group.
- Subjects
DIPOLE moments; MOLECULES; EQUILIBRIUM; FRANCK-Condon principle; MOLECULAR spectroscopy; ENERGY levels (Quantum mechanics); SPECTRUM analysis
- Publication
Journal of Applied Spectroscopy, 2003, Vol 70, Issue 2, p230
- ISSN
0021-9037
- Publication type
Article
- DOI
10.1023/A:1023865101529