Excited-state relaxation of some aminoquinolines
<p>The absorption and fluorescence spectra, fluorescence quantum yields and lifetimes, and fluorescence rate constants (<mml:math> <mml:mrow> <mml:msub> <mml:mi>k</mml:mi> <mml:mi>f</mml:mi> </mml:msub> </mml:mrow> </mm...
Saved in:
| Format: | Article |
|---|---|
| Language: | English |
| Published: |
Wiley
2006-01-01
|
| Series: | International Journal of Photoenergy |
| Online Access: | http://www.hindawi.com/GetArticle.aspx?doi=10.1155/IJP/2006/35610 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | <p>The absorption and fluorescence spectra, fluorescence quantum yields and lifetimes, and fluorescence rate constants (<mml:math> <mml:mrow> <mml:msub> <mml:mi>k</mml:mi> <mml:mi>f</mml:mi> </mml:msub> </mml:mrow> </mml:math>) of 2-amino-3-(<mml:math> <mml:msup> <mml:mn>2</mml:mn> <mml:mo>′</mml:mo> </mml:msup> </mml:math>-benzoxazolyl)quinoline (<bold>I</bold>), 2-amino-3-(<mml:math> <mml:msup> <mml:mn>2</mml:mn> <mml:mo>′</mml:mo> </mml:msup> </mml:math>-benzothiazolyl)quinoline (<bold>II</bold>), 2-amino-3-(<mml:math> <mml:msup> <mml:mn>2</mml:mn> <mml:mo>′</mml:mo> </mml:msup> </mml:math>-methoxybenzothiazolyl)-quinoline (<bold>III</bold>), 2-amino-3-(<mml:math> <mml:msup> <mml:mn>2</mml:mn> <mml:mo>′</mml:mo> </mml:msup> </mml:math>-benzothiazolyl)benzoquinoline (<bold>IV</bold>) at different temperatures have been measured. The shortwavelength shift of fluorescence spectra of compounds studied (23–49 nm in ethanol) as the temperature decreases (the solvent viscosity increases) points out that the excited-state relaxation process takes place. The rate of this process depends essentially on the solvent viscosity, but not the solvent polarity. The essential increasing of fluorescence rate constant <mml:math> <mml:mrow> <mml:msub> <mml:mi>k</mml:mi> <mml:mi>f</mml:mi> </mml:msub> </mml:mrow> </mml:math> (up to about 7 times) as the solvent viscosity increases proves the existence of excited-state structural relaxation consisting in the mutual internal rotation of molecular fragments of aminoquinolines studied, followed by the solvent orientational relaxation.</p> |
|---|---|
| ISSN: | 1110-662X |