Multiple relaxation pathways in photoexcited dimethylaminonitro- and dimethylaminocyano-stilbenes

doi:10.1016/0009-2614(93)80075-Z

Chemical Physics Letters

Volume 208, Issues 1–2, 4 June 1993, Pages 48-58

https://doi.org/10.1016/0009-2614(93)80075-Z Get rights and content

Abstract

The photophysical behaviour of para-nitro-, para-cyano- and meta-nitro-4′-dimethylaminostilbenes is compared and explained. The increase of the fluorescence quantum yield with solvent polarity is the result of a negative solvatokinetic behaviour of the nonradiative channel leading to the ground state via the double-bond twisted species P* which is of low-polarity nature. The maximum in the fluorescence quantum yield at intermediate solvent polarities, observable for the nitro compounds, is due to a further nonradiative channel specifically linked with the nitro group and with positive solvatokinetic behaviour. This quenching channel becomes important for high-polarity solvents but is absent for compounds without the nitro group. TICT state formation (twisted nitro group) as a candidate for this channel is discussed.

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Multiple relaxation pathways in photoexcited dimethylaminonitro- and dimethylaminocyano-stilbenes

Abstract

J. Mol. Struct.

J. Photochem. Photobiol.

J. Phys. Chem.

Z. Naturforsch.

J. Luminescence

J. Photochem.

Chem. Phys. Letters

Opt. Commun.

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J. Photochem. Photobiol.

J. Phys. Chem.

Angew. Chem. Intern. Ed. Engl.

Ber. Dtsch. Chem. Ges.

J. Am. Chem. Soc.

J. Chem. Phys.

J. Chem. Phys.

J. Chem. Phys.

J. Chem. Phys.

J. Chem. Phys.

Angew. Chem.

J. Phys. Chem.

J. Photochem.

Z. Naturforsch.

Chem. Phys. Letters

J. Am. Chem. Soc.

Angew. Chem.

Angew. Chem. Intern. Ed. Engl.

J. Am. Chem. Soc.