Producing a dual-fluorescent molecule by tuning the energetics of excited-state intramolecular proton transfer
Producing a dual-fluorescent molecule by tuning the energetics of excited-state intramolecular proton transfer
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DOI：
10.1039/c5pp00088b
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发表时间：
2015-01-01
影响因子：
3.1
通讯作者：
Arai, Tatsuo
中科院分区：
文献类型：
--
作者：
Tasaki, Satomi;Momotake, Atsuya;Arai, Tatsuo
我们在此报告的选择性制备正常的，互变异构的，和双荧光分子与一个共同的ESIPT核心。已知2 '-羟基苯乙酮（OHAP）是经历激发态分子内氢转移（ESIPT）以从互变异构体的激发态显示荧光发射的典型分子。在本研究中，我们制备了一系列十个以OHAP为核心的荧光分子，并对其激发态性质进行了研究。这些分子的π-π * 吸收带的红移与取代基的π-扩展表明，由于取代基的OHAP单元的正常形式的激发能降低，而激发的互变异构体的能量似乎是独立的取代基的π-扩展。当芘或蒽在末端连接时（分子4和5），仅出现正常荧光，互变异构体荧光消失。蒽衍生物（分子10）显示双荧光，表明正常和互变异构体激发态是能量“平衡”。荧光寿命分析显示，10的ESIPT反应速率比其他衍生物慢得多，并且正常和互变异构体形式在激发态处于平衡。
We report herein the selective preparation of normal, tautomeric, and dual-fluorescent molecules with a common ESIPT core. 2'-Hydroxyacetophenone (OHAP) is known as a typical molecule that undergoes excited-state intramolecular hydrogen transfer (ESIPT) to display fluorescence emission from the excited state of the tautomer. In this study, a series of ten OHAP-cored fluorescent molecules were prepared and their excited state properties have been explored. The bathochromic shift of the pi-pi* absorption band with pi-extensions of substituents of these molecules indicates that the excitation energy of the normal form of the OHAP unit was reduced due to the substituents, while the energy of the excited tautomer appeared to be independent of the pi-extension of the substituents. When pyrene or anthracene was connected at the end (molecules 4 and 5), only normal fluorescence appeared, and the tautomer fluorescence disappeared. An anthracene derivative (molecule 10) displayed dual fluorescence, indicating that the normal and the tautomer excited states were energetically "balanced". A fluorescence lifetime analysis revealed the ESIPT reaction rate of 10 to be much slower than those of other derivatives and that the normal and tautomer forms were in equilibrium in the excited state.