SUBPICOSECOND TRANSIENT ABSORPTION STUDY OF INTERMOLECULAR ELECTRON-TRANSFER BETWEEN SOLUTE AND ELECTRON-DONATING SOLVENTS
SUBPICOSECOND TRANSIENT ABSORPTION STUDY OF INTERMOLECULAR ELECTRON-TRANSFER BETWEEN SOLUTE AND ELECTRON-DONATING SOLVENTS
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DOI：
10.1021/j100199a039
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发表时间：
1992-10-01
影响因子：
--
通讯作者：
YOSHIHARA, K
中科院分区：
文献类型：
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作者：
KANDORI, H;KEMNITZ, K;YOSHIHARA, K
尼罗蓝A在无扩散、供电子溶剂体系如N，N-二甲基苯胺（DMA）或苯胺（AN）中经历超快荧光猝灭，其中最短荧光衰减时间达到10（-13）s，如飞秒荧光上转换研究所揭示的[小林，T.;等人，Chem.Phys.Lett. 1991，180，416]。在本文中，反应机理进行了更详细的研究，亚皮秒瞬态吸收光谱。通过直接检测产物的吸收，即，还原尼罗蓝（470 nm）和溶剂阳离子（470 nm，DMA+; 405 nm，AN+），我们建立了荧光猝灭，如前所述，由于电子转移反应。在本发明的用于前向和后向电子转移的小自由能差的系统中，反向电子转移发生在皮秒时间尺度上，即，4.0在DMA中为2.7ps，在AN中为2.7ps，并且本系统在小于10 ps内执行电荷分离和重组的完整循环。
Nile blue A experiences ultrafast fluorescence quenching in diffusionless, electron-donating solvent systems such as N,N-dimethylaniline (DMA) or aniline (AN), in which the shortest fluorescence decay time reaches 10(-13) s, as revealed by femtosecond fluorescence up-conversion studies [Kobayashi, T.; et al. Chem. Phys. Lett. 1991, 180, 416]. In the present paper, the reaction mechanism is studied in more detail by subpicosecond transient absorption spectroscopy. By directly detecting the absorption of the products, namely, reduced nile blue (470 nm) and the solvent cation (470 nm, DMA+; 405 nm, AN+), we established that the fluorescence quenching is, as previously proposed, due to an electron-transfer reaction. In the present systems of small free energy difference for forward and backward electron transfer, the reverse electron transfer occurs on a picosecond time scale, i.e., 4.0 ps in DMA and 2.7 ps in AN, and the present systems perform a full cycle of charge separation and recombination in less than 10 ps.