Elucidation of a detection mechanism of fluorescent sensor based on photo-induced electron transfer for water
Elucidation of a detection mechanism of fluorescent sensor based on photo-induced electron transfer for water
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阐明基于水的光诱导电子转移的荧光传感器的检测机制
DOI：
10.1039/d2nj04153g
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发表时间：
2022
影响因子：
3.3
通讯作者：
Yousuke Ooyama
中科院分区：
文献类型：
--
作者：
Takuma Fumoto;Keiichi Imato;Yousuke Ooyama
为了阐明光诱导电子转移（PET）型水荧光传感器的检测机理，我们通过对蒽-氨基甲基-4-氰苯硼酸（AminoMeCNPhenylB -2）的蒎醇酯（Pin）的脱保护，合成了蒽-（氨甲基）-4-氰苯硼酸（AminoMeCNPhenylB -2） TF-2。对于of -2，在没有水的情况下，PET从氨基部分的氮原子发生到光激发的荧光团（蒽）骨架，导致荧光猝灭（PET活性态）。当水加入到of -2溶液中，由于与水分子相互作用形成PET非活性（荧光）物质of - 2w或of - 2wh，荧光发射明显增强，这是通过1H NMR光谱测量确定的。另一方面，即使在没有水的情况下，TF-2也表现出强烈的荧光发射，在TF-2溶液中加水，其荧光强度的变化可以忽略不计。未加水的TF-2溶液的1H NMR谱清楚地表明，通过B(OH)2部分的羟基与氨基部分的氮原子之间的分子内OH⋯N氢键形成PET非活性（荧光）物质TF-2H。对于TF-2，单晶x射线结构分析以及密度泛函理论（DFT）计算揭示了分子内OH⋯N氢键的存在，即TF-2H的形成。有趣的是，加入水的TF-2溶液的1H NMR谱显示，与水分子相互作用存在PET非活性（荧光）物质TF-2W或TF-2WH，与of -2的情况一样。因此，我们发现，对于基于蒽-氨基ecnphenylbpin结构的PET型荧光传感器来说，BPin片段不仅是在没有水的情况下激活PET，导致荧光猝灭所必需的，而且在加入水的情况下形成PET非活性（荧光）物质所必需的。本研究为建立有效的pet型水荧光传感器提供了分子设计方向，并为水的蒽-氨基- ecnphenylbpin结构的检测机制提供了结论。
In order to elucidate a detection mechanism of a photo-induced electron transfer (PET)-type fluorescent sensor for water, we have synthesized anthracene-(aminomethyl)-4-cyanophenylboronic acid (AminoMeCNPhenylB(OH)2) TF-2 by the deprotection of pinacol ester (Pin) of anthracene-AminoMeCNPhenylBPin OF-2. For OF-2, the PET takes place from the nitrogen atom of the amino moiety to the photoexcited fluorophore (anthracene) skeleton in the absence of water, leading to fluorescence quenching (PET active state). When water was added to the OF-2 solution, a drastic enhancement of the fluorescence emission is observed due to the formation of the PET inactive (fluorescent) species OF-2W or OF-2WH by interaction with water molecules which has been determined by 1H NMR spectral measurements. On the other hand, even in the absence of water TF-2 exhibits intense fluorescence emission and addition of water to the TF-2 solution shows a negligible change in the fluorescence intensity. The 1H NMR spectra of the TF-2 solution without the addition of water clearly indicated the formation of the PET inactive (fluorescent) species TF-2H by the intramolecular OH⋯N hydrogen bonding between the hydroxyl group of the B(OH)2 moiety and the nitrogen atom of the amino moiety. For TF-2, single-crystal X-ray structural analysis as well as density functional theory (DFT) calculations revealed the existence of the intramolecular OH⋯N hydrogen bonding, that is, the formation of TF-2H. Interestingly, the 1H NMR spectra of the TF-2 solution with the addition of water showed the existence of the PET inactive (fluorescent) species TF-2W or TF-2WH by interaction with water molecules, as with the case of OF-2. Consequently, it was found that for the PET-type fluorescent sensor based on the anthracene-AminoMeCNPhenylBPin structure, the BPin moiety is essential not only to activate the PET in the absence of water, leading to fluorescence quenching, but also to form the PET inactive (fluorescent) species upon the addition of water. This work provides a direction in molecular design toward creating an effective PET-type fluorescent sensor for water as well as a conclusive detection mechanism of the anthracene-AminoMeCNPhenylBPin structure for water.