Intermolecular hydrogen bonding and temperature effects on internal conversion in xanthene dyes

✍ Scribed by M.M. Martin

• Publisher: Elsevier Science
• Year: 1976
• Tongue: English
• Weight: 613 KB
• Volume: 43
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(76)85314-6

✦ Synopsis

The temperattu:-dependence (between 0°C and 50°C) of the fluorescence yield and the radiative lifetime of a fluorescein derivative (6-hydroxy-%phenyl-fluuron) was determined in alkaline solutions of CF$X~Off ,:HaO, CHaOH, CHJCH~OH, HCONP2, HCO?J(CH3)2 ;and CH&X!H~. In the hydrogen bonding solvents as well as in-the non hydrogtin boncltigsolvents, the fluorescence yield decreases with increa&ng temperature. The radiative lif&tiiuk remaitis nearljr constant. The variation of the fluorkerke yield was shtiwn to be due to the existence of an activation energy EA for the S&Se lntern&knversion process. It' was found that EA increases linearly with the change, due to the electronic excitation, in the energy of the solutesolvent hydrogen bonding.