The non-radiative processes from the S1 state of aminoanthraquinones: a steady state and time-resolved study

✍ Scribed by V.J.P. Srivatsavoy; B. Venkataraman; N. Periasamy

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 905 KB
• Volume: 68
• Category: Article
• ISSN: 1010-6030
• DOI: 10.1016/1010-6030(92)85181-s

✦ Synopsis

The non-radiative processes of deactivation from the lowest singlet excited state of aminoanthraquinones have been studied using steady state and time-resolved methods. The fluorescence decay rate constant kf correlates well with the solvent polarity parameter E,(30) in non-hydrogen-bonding solvents. Large deuterium isotope effects in fluorescence lifetimes rr and quantum yields & are observed in the case of l-amino and 1-methylamino anthraquinones, where the S, state is mainly deactivated through internal conversion to the ground state. The temperature dependence of the fluorescence quantum yields of various aminoanthraquinones was also investigated. C& and 7t exhibited strong temperature dependences in the case of 1-acetylaminoanthraquinone.

In the case of l-acetylaminoanthraquinone, intersystem crossing to the triplet state is a major deactivation channel from the S1 and in this derivative a close-lying T2 state seems to be responsible for the high kk rate.