Photoinduced Redox Cycle of Riboflavin at a Water/Oil Interface
Photoinduced Redox Cycle of Riboflavin at a Water/Oil Interface
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DOI：
10.2116/analsci.20.1587
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发表时间：
2004-11
影响因子：
1.6
通讯作者：
S. Ishizaka;N. Kitamura
中科院分区：
文献类型：
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作者：
S. Ishizaka;N. Kitamura
利用稳态和时间分辨全内反射（TIR）荧光光谱直接研究了核黄素（RF）在水/CCL界面上的光诱导氧化还原反应循环。在水/CCL界面处观察到的RF的全内反射荧光光谱的最大波长为517 nm，归属于RF中异咯嗪发色团的激发单重态的n-n* 跃迁。另一方面，在存在V，V-双十八烷基-[1，3，5]三嗪-2，4，6-三胺（DTT）作为CCL相中RF的客体的情况下，在长时间的激光照射（400 nm）下，在480 nm附近出现新的TIR荧光带。此外，在水相中乙酸的存在下，在480 nm附近的荧光强度增加。详细的研究表明，新的荧光带应归因于1，5-二氢黄素（RFH 2）。结果表明，RFH 2是通过水/CCL界面上形成的RF-DTT氢键复合物的光反应生成的，并结合TIR条件下的荧光光谱/动力学测量以及瞬态吸收光谱对反应机理进行了讨论.
A photoinduced redox reaction cycle of Riboflavin (RF) at a water/CCL interface was studied directly by means of both steady-state and time-resolved total internal reflection (TIR) fluorescence spectroscopies. The TIR fluorescence spectrum of RF observed at the water/CCL interface with the maximum wavelength of 517 nm was assigned to the n-n* transition from the excited singlet-state of the isoalloxazine chromophore in RF. Upon prolonged laser irradiation (400 nm) in the presence of V,V-dioctadecyl-[1,3,5]triazine-2,4,6-triamine (DTT) as a guest for RF in the CCL phase, on the other hand, a new TIR fluorescence band appeared at around 480 nm. Furthermore, the fluorescence intensity at around 480 nm increased in the presence of acetic acid in the water phase. Detailed studies demonstrated that the new fluorescence band should be ascribed to 1,5-dihydoroflavin (RFH2). The present results indicated that RFH2 was produced through the photoreaction of the RF-DTT hydrogen-bonded complex formed at the water/CCL interface, whose reaction mechanisms were discussed on the basis of the results observed by fluorescence spectra/dynamics measurements under the TIR conditions as well as by transient absorption spectroscopy.