Photochemical "Triode" Molecular Signal Transducer
Photochemical "Triode" Molecular Signal Transducer
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DOI：
10.1021/ja1019595
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发表时间：
2010-05-12
影响因子：
15
通讯作者：
Gust, Devens
中科院分区：
文献类型：
--
作者：
Keirstead, Amy E.;Bridgewater, James W.;Gust, Devens
制备了一种由六苯基苯单元组成的六单元分子，其中五个双（苯乙炔基）蒽（BPEA）荧光团和一个二噻吩基乙烯光致变色剂。BPEA单元之间的单重态单重态能量转移发生在0.4和60 ps的时间尺度上，并且当二噻吩基乙烯处于开放形式时，BPEA单元在515 nm区域中发荧光，量子产率接近统一。当二噻吩基乙烯被UV光光异构化为在500-700 nm区域吸收的封闭形式时，封闭异构体通过能量转移强烈猝灭BPEA的所有激发单重态，导致荧光量子产率下降到接近零。这种光化学行为使六元组以类似于电子管或晶体管的方式起作用。当用350 nm的稳态光和调制强度的红光（>610 nm）照射六联体的溶液时，由350 nm光激发的BPEA荧光相应地被调制。荧光对应于电子管或晶体管的输出，而调制的红光对应于电子管的栅极信号或晶体管的栅极电压。频率调制、幅度调制和相位调制都被观察到。用较长波长的光调制强烈的较短波长荧光的不寻常能力可能有助于检测来自探针分子的荧光，而不会受到生物分子或纳米技术应用中其他发射体的干扰。
A molecular "hexad" in which five bis(phenylethynyl)anthracene (BPEA) fluorophores and a dithienylethene photochrome are organized by a central hexaphenylbenzene unit has been prepared. Singlet singlet energy transfer among the BPEA units occurs on the 0.4 and 60 ps time scales, and when the dithienylethene is in the open form, the BPEA units fluoresce in the 515 nm region with a quantum yield near unity. When the dithienylethene is photoisomerized by UV light to the closed form, which absorbs in the 500-700 nm region, the closed isomer strongly quenches all of the excited singlet states of BPEA via energy transfer, causing the fluorescence quantum yield to drop to near zero. This photochemical behavior permits the hexad to function in a manner analogous to a triode vacuum tube or transistor. When a solution of the hexad is irradiated with steady-state light at 350 nm and with red light (>610 nm) of modulated intensity, the BPEA fluorescence excited by the 350 nm light is modulated accordingly. The fluorescence corresponds to the output of a triode tube or transistor and the modulated red light to the grid signal of the tube or gate voltage of the transistor. Frequency modulation, amplitude modulation, and phase modulation are all observed. The unusual ability to modulate intense, shorter-wavelength fluorescence with longer-wavelength light could be useful for the detection of fluorescence from probe molecules without interference from other emitters in biomolecular or nanotechnological applications.