Diiodobodipy-styrylbodipy Dyads: Preparation and Study of the Intersystem Crossing and Fluorescence Resonance Energy Transfer

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• 作者：Zhijia Wang ; Yun Xie ; Kejing Xu ; Jianzhang Zhao ; Ksenija D. Glusac
• 刊名：Journal of Physical Chemistry A
• 出版年：2015
• 出版时间：July 2, 2015
• 年：2015
• 卷：119
• 期：26
• 页码：6791-6806
• 全文大小：847K
• ISSN：1520-5215

文摘

2,6-Diiodobodipy-styrylbodipy dyads were prepared to study the competing intersystem crossing (ISC) and the fluorescence-resonance-energy-transfer (FRET), and its effect on the photophysical property of the dyads. In the dyads, 2,6-diiodobodipy moiety was used as singlet energy donor and the spin converter for triplet state formation, whereas the styrylbodipy was used as singlet and triplet energy acceptors, thus the competition between the ISC and FRET processes is established. The photophysical properties were studied with steady-state UV鈥搗is absorption and fluorescence spectroscopy, electrochemical characterization, and femto/nanosecond time-resolved transient absorption spectroscopies. FRET was confirmed with steady state fluorescence quenching and fluorescence excitation spectra and ultrafast transient absorption spectroscopy (k_FRET = 5.0 脳 10¹⁰ s^鈥?). The singlet oxygen quantum yield (桅_螖 = 0.19) of the dyad was reduced as compared with that of the reference spin converter (2,6-diiodobodipy, 桅_螖 = 0.85), thus the ISC was substantially inhibited by FRET. Photoinduced intramolecular electron transfer (ET) was studied by electrochemical data and fluorescence quenching. Intermolecular triplet energy transfer was studied with nanosecond transient absorption spectroscopy as an efficient (桅_TTET = 92%) and fast process (k_TTET = 5.2 脳 10⁴ s^鈥?). These results are useful for designing organic triplet photosensitizers and for the study of the photophysical properties.