Photochemie arylsubstituierter Δ2-1,3,4-Oxadiazoline. II. Zum Einfluß der Substituenten und des Lösungsmittels auf die Absorptions- und Fluoreszenzeigenschaften arylsubstituierter Δ2-1,3,4-Oxadiazoline

✍ Scribed by Dr. C. H. Csongár; Dr. R. Socher; Prof. Dr. G. Tomaschewski

• Publisher: John Wiley and Sons
• Year: 1982
• Tongue: English
• Weight: 441 KB
• Volume: 324
• Category: Article
• ISSN: 1615-4150
• DOI: 10.1002/prac.19823240209

✦ Synopsis

Photochemistry of Arylsubstituted Δ^2^‐1,3,4‐Oxadiazolines. II. The Influence of the Substituents and the Solvent on the Absorption and Fluorescence Properties of Arylsubstituted Δ^2^‐1,3,4‐Oxadiazolines

The electronic absorption and the fluorescence spectra of 16 arylsubstituted Δ^2^‐1,3,4‐oxadiazolines were measured in benzene at room temperature.

The push‐pull effect of the substituents supports an increasing intramolecular charge‐transfer in the electronically excited singlet state, which increases its dipole moment relative to the ground state.

The significant linear correlation of the Hammett σ~p~‐values with the energies of the fluorescence and absorption maxima of the Δ^2^‐oxadiazolines, p‐substituted in the phenylring at the C 2‐atom, demonstrate these intramolecular charge transfer.

The titel compounds demonstrate with increasing solvent polarity a bathochromic shift of the absorption maxima.

For some oxadiazolines the dipole moment for the excited singlet state proved to be about 30 Cm as Stoke's shift dipendency from the solvent indicate.