Energy Dissipation Processes of Singlet-excited 1-Hydroxyfluorenone and its Hydrogen-bonded Complex with N-methylimidazole¶
Energy Dissipation Processes of Singlet-excited 1-Hydroxyfluorenone and its Hydrogen-bonded Complex with N-methylimidazole¶
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单线态激发的1-羟基芴酮及其与N-甲基咪唑的氢键配合物的能量耗散过程¶
DOI：
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发表时间：
2004
影响因子：
3.3
通讯作者：
H. Inoue
中科院分区：
文献类型：
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作者：
K. Sebők;L. Biczók;A. Morimoto;T. Shimada;H. Inoue
研究了溶剂、pH和与N-甲基咪唑(MIM)的氢键对1-羟基荧酮(1HOF)光物理性质的影响。荧光寿命、荧光量子产额和三重态产额的测量表明，在非极性介质中，系间交叉是主要过程，其速率常数随溶剂极性的增加而显著减小。醇中内转化的加速与分子间氢键的强度平行。在环己烷中，由于分子内氢键的作用，单重态激发态的能量耗散较快。光吸收时，1HOF的pKa从10.06降至5.0，H3O+猝灭了单重态激发的分子，这是一个几乎受扩散控制的反应。在甲苯中加入MIM，观察到双荧光现象，这归因于激发态氢键离子对的可逆形成。通过对稳态和时间分辨荧光结果的综合分析，得到了不同失活途径的速率常数。
Abstract Effects of solvent, pH and hydrogen bonding with N-methylimidazole (MIm) on the photophysical properties of 1-hydroxyfluorenone (1HOF) have been studied. Fluorescence lifetime, fluorescence quantum yield and triplet yield measurements demonstrated that intersystem crossing was the dominant process in apolar media and its rate constant significantly diminished with increasing solvent polarity. The acceleration of internal conversion in alcohols paralleled the strength of intermolecular hydrogen bonding. The faster energy dissipation from the singlet-excited state in cyclohexane was attributed to intramolecular hydrogen bonding. The pKa of 1HOF decreased from 10.06 to 5.0 on light absorption, and H3O+ quenched the singlet-excited molecules in a practically diffusion-controlled reaction. On addition of MIm in toluene, dual fluorescence was observed, which was attributed to reversible formation of excited hydrogen-bonded ion pair. Rate constants for the various deactivation pathways were derived from the combined analysis of the steady-state and the time-resolved fluorescence results.
影响因子：
15
作者：
Sessler, JL;Sathiosatham, M;Wiederrecht, G
通讯作者：
Wiederrecht, G