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Fluorescent sensors for anions have been extensively studiedsince the sensing of fluoride anions is of special interest due totheir importance in biological and industrial systems.7 Recently,Zˇinic′ and co-workers reported on fluoride sensing witha gel based on oxalamide-derived anthraquinone.8 The gelshowed the color change and the gel-to-sol phase transition inthe presence of fluoride anion, which may provide the basis forthe development of the sensing of fluoride with the naked eye.In this communication, we designed a low molecular massmolecule 1 composed of the 2-(20-hydroxyphenyl)benzoxazole(HPB) unit, urea groups, and long alkyl chains, which couldfunction as p–p interactions, hydrogen bonding, and van derWaals interactions, respectively [Fig. 1(A)]. As already reportedin detail, HPB has two tautomers with two emission maxima ofthe enol (weak fluorescence) and keto (strong fluorescence)forms by excited state intramolecular proton transfer (ESIPT)(see Scheme S2 in the ESIw).9 The intramolecular hydrogenbonding in HPB can be altered by the presence of fluoride anionregardless of its monomeric or polymeric form, which showed avisually noticeable color change as reported earlier.9b,c Ourinterest is focused on the following: (1) gelator 1 adopts a flatconformation in the aggregation state originating from intramolecularhydrogen bonding in the HPB unit, which mayinduce a facilitated proton transfer between the hydroxyl protonof benzene ring and the nitrogen of the benzoxazole group;(2) the hydroxyl groups in HPB are able to selectively interactwith fluoride anions, which may provide the color changes; (3)the urea moieties are able to bind with fluoride anions; therefore,intermolecular hydrogen bonding between neighboringurea moieties would be disrupted in the presence of fluorideanion, which may bring about the gel-to-sol transition. 为阴离子荧光传感器被广泛研究 由于氟阴离子传感特别感兴趣，是因为 在生物的重要性和工业systems.7最近， ? 伊尼奇'和合作的传感氟报工人 在oxalamide凝胶为基础的衍生anthraquinone.8的凝胶 显示颜色的变化和凝胶的溶胶相过渡 氟化物的负离子，可提供一个基础的存在 在发展中的氟化物传感用肉眼。 在这个沟通，我们设计了一种低分子量 分子1 2组成 - （20 -羟基苯基）苯并恶唑 （合盈）单位，尿素组和烷基链长，这可能 函数为P磷的相互作用，氢键和范德华 瓦尔斯相互作用，分别[图。 1（a）条]。正如已经报道 详细，HPB已经两个不同的异构体排放最大值 烯醇式（弱荧光）和酮（强荧光） 形式的激发态分子内质子转移（ESIPT） （见ESIw计划S2）的0.9的分子内氢键 在合盈键可以改变的氟离子的存在 无论其单体或聚合体的形式，显示1 如报道earlier.9b视觉颜色变化明显，荤我们 兴趣主要集中在以下方面：（1）胶凝1采用了平面 构象分子聚集的原始状态 氢键在合盈单位，这可能 诱使之间的羟基质子促进质子转移 对苯环和苯并组氮; （2）合盈的羟基能选择性地互动 与氟阴离子，可提供的颜色变化（3） 尿素基被氟化物能与阴离子结合，因此， 分子间氢键相邻 尿素部族会受到影响的氟存在 负离子，而可能带来的对凝胶溶胶过渡。希望能帮助你 |
