o-Azophenylboronic Acid-Based Colorimetric Sensors for d-Fructose: o-Azophenylboronic Acids with Inserted Protic Solvent Are the Key Species for a Large Color Change
o-Azophenylboronic Acid-Based Colorimetric Sensors for d-Fructose: o-Azophenylboronic Acids with Inserted Protic Solvent Are the Key Species for a Large Color Change
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基于邻偶氮苯基硼酸的 d-果糖比色传感器：插入质子溶剂的邻偶氮苯基硼酸是产生大颜色变化的关键物质
DOI：
10.1021/acs.joc.0c01011
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发表时间：
2020
期刊：
影响因子：
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通讯作者：
Ishihara Koji
中科院分区：
文献类型：
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作者：
Suzuki Yota;Ikeda Ayumi;Ohno Keiji;Fujihara Takashi;Sugaya Tomoaki;Ishihara Koji
硼酸类化学传感器已被开发出来，但其检测机理研究较少。在本研究中，我们合成了100-偶氮苯硼酸衍生物（azoBs），并对azoBs的反应性和传感机理进行了基础研究，该衍生物经历了大的颜色变化，例如，从红色到黄色，在反应中与氯。用分光光度滴定法测定了它们的非pH依赖性生成常数，然后将其转化为pH 7.4时的条件生成常数K ′。11B NMR结果表明，在非质子溶剂中，azoB形成三角平面结构，而在质子溶剂中，它形成准四面体结构（azoB-ROH），其中质子溶剂分子（ROH）插入硼酸部分和偶氮基团之间.另外，紫外-可见光谱研究表明，ROH中偶氮B-ROHbyd-果糖在反应过程中的颜色变化是由ROH从偶氮B-ROHbyd-果糖中释放出来引起的。基于这项研究的结果，我们提出了一个指导方针，设计anazoB为基础的化学传感器，表现出高反应性对pH7.5和足够的颜色变化，以允许视觉检测pH7.5。
Many boronic acid-based chemosensors for saccharides have been developed; however, their detection mechanisms have seldom been studied. In this study, we synthesized 10o-azophenylboronic acid derivatives (azoBs) and conducted a fundamental study on the reactivity and the sensing mechanism ofazoBs, which undergoes a large color change, e.g., from red to yellow, upon a reaction with saccharides. Their pH-independent formation constants were determined by spectrophotometric titration and then converted to the conditional formation constantK′ at pH 7.4. A linear free energy relationship was established between logK′ and the pKaofazoB.11B NMR measurements indicate that in aprotic solvents,azoBforms a trigonal planar structure, while in protic solvents, it forms a quasi-tetrahedral structure (azoB-ROH) with a protic solvent molecule (ROH) inserted between the boronic acid moiety and the azo group. In addition, UV–vis spectroscopic studies showed that the color change during the reaction betweenazoBandd-fructose in ROH was caused by the release of the ROH fromazoB-ROHbyd-fructose. Based on the findings in this study, we proposed a guideline for designing anazoB-based chemosensor that exhibits high reactivity toward saccharides and a sufficient color change to allow for the visual detection of saccharides.