Enhancement of the large stokes-shifted fluorescence emission from the 2-(2'-hydroxyphenyl)benzoxazole core in a dendrimer |
| |
Authors: | Ohshima Asuka Momotake Atsuya Nagahata Ritsuko Arai Tatsuo |
| |
Institution: | Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba-city, Ibaraki 305-8571, Japan. |
| |
Abstract: | The photochemical properties of a series of newly synthesized dendrimers, 4-6, having a 2-(2'-hydroxyphenyl)benzoxazole (HBO) core, were studied in benzene. The fluorescence quantum yields (Phi(f)) were determined to be 0.022, 0.030, and 0.038 for 4, 5, and 6, respectively, increasing in higher generation dendrimers. With transient absorption spectroscopy, the quantum yields of the isomerization from the (E)-keto form ((1)K(E)*) to the (Z)-keto form ((1)K(Z)) (Phi(E)(-->)(Z)) and those of intersystem crossing (Phi(isc)) can be estimated. Whereas Phi(E)(-->)(Z) values decreased in higher generation dendrimers, Phi(isc) values were almost the same among 4-6. The quantum yields of nonradiative decay (Phi(nr)) increased in higher generation dendrimers. The dendrimer structure also affected the reverse tautomerization process. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|