Photochemical stabilization of terthiophene and its utilization as a new sensing element in the fabrication of monolayer-chemistry-based fluorescent sensing films.
Photochemical stabilization of terthiophene and its utilization as a new sensing element in the fabrication of monolayer-chemistry-based fluorescent sensing films.
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DOI：
10.1021/am2000592
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发表时间：
2011-04
影响因子：
9.5
通讯作者：
Taihong Liu;Liping Ding;G. He;Yang Yang-Yang;Wenliang Wang;Yu Fang
中科院分区：
文献类型：
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作者：
Taihong Liu;Liping Ding;G. He;Yang Yang-Yang;Wenliang Wang;Yu Fang
为了提高α-噻吩（3T）在空气中的光化学稳定性，我们特意在其共轭主链中引入了一个萘单元，得到了一个荧光化合物，5-（1-萘基）-2,2′：5′，2′-噻吩（NA-3T）。该化合物进一步用作传感元件，用于制备基于单层化学的荧光传感膜。结果表明，所制备的薄膜对苦味酸（PA）的存在具有高度的敏感性和选择性。检出限为3.2 × 10(-7) mol/L。由于质子从PA转移到间隔物中的氨基，膜对PA的高灵敏度归因于膜与分析物的特异性结合，这与荧光寿命测量显示的猝灭的静态性质一致。进一步的实验表明，传感过程是完全可逆的，不受普通有机溶剂、酸和碱等的干扰。此外，如果保存得当，薄膜至少在半年内是稳定的。更重要的是，本文的工作使得利用寡硫吩作为一类新的传感元件成为可能，它可能结合了共轭聚合物或低聚物的优点和低分子质量荧光化合物的优点。这一努力无疑扩大了寡硫噻吩的应用，并为创造基于单层化学的荧光传感薄膜提供了空间。
To improve the photochemical stability of α-terthiophene (3T) in air, we purposely introduced a naphthalene unit into its conjugated backbone, resulting in a fluorescent compound, 5-(1-naphthyl)-2,2':5',2''-terthiophene (NA-3T). The compound was further employed as a sensing element for the fabrication of a monolayer-chemistry based fluorescent sensing film. It was demonstrated that the fabricated film is highly sensitive and selective to the presence of picric acid (PA). The detection limit was found to be 3.2 × 10(-7) mol/L. The high sensitivity of the film to PA has been attributed to the specific binding of the film to the analyte because of proton transfer from PA to the amino group in the spacer, which is in accordance with the static nature of the quenching as revealed by fluorescence lifetime measurements. Further experiments demonstrated that the sensing process is fully reversible and free of interference from common organic solvents, acids and bases, etc. In addition, the film is stable, at least, within half a year provided it is properly preserved. More importantly, the present work makes it possible to use oligothiophenes as a new class of sensing elements, which may combine the advantages of conjugated polymers or oligomers and those of fluorescent compounds of low-molecular masses. This effort enlarges, definitely, the applications of oligothiophenes and the space for creating monolayer-chemistry based fluorescent sensing films.