STUDY OF DUAL FLUORESCENCE OF FLUORINATED BENZOAZOLES AND THEIR APPLICATION AS CHEMOSENSORS

含氟苯并唑双荧光的研究及其作为化学传感器的应用

• 批准号: 14550811
• 负责人: TANAKA Kiyoshi
• 金额: $ 2.3万
• 依托单位: SEIKEI UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14550811/
• 关键词: benzoxazole; imidazopyridine; fluorophore; chemosensor; metal cation recognition; excited state intramolecular proton transfer; Stokes shift; hydroxyfluorophenyl; 多重蛍光; 多重分子センサー; ヒドロキシフルオロフェニル基; 緑色蛍光; フルオロフェニル基; ベンゾチアゾール; バンゾオキサゾール; 二重蛍光

2-(2-Hydroxyfluorophenyl)benzoxazole having imidazole moiety 1 is synthesized and its dual fluorescence is applied to a multiple chemosensor for metal cations ; addition of Al^<3+>, Zn^<2+>, or Mg^<2+> causes the green emission together with slight blue emission in chloroform-acetonitrile, the enhancement ratio of both emissions being dependent on the captured metal cations. The green emission is ascribed to the ligation of the metal cation on the imidazole nitrogen atom, and the resulting positive character of nitrogen atom is inductively communicated to the hydroxyl group, to recover its hydrogen bonding ability leading to the excited state intramolecular proton transfer (ESIPT) process. The green emission is found with 2-(2-aminofluorophenyl)benzoxazole derivatives, particularly with 2-(2-pentafluorobenzamido-3,4,5,6- tetrafluorophenyl)benzoxazole. The green emission is enhanced in nonpolar solvents, resulting in the considerably large Stokes shift. Moreover, in place of the benzoxazole ring system, the corresponding fluorophores constituted by imidazopyridine ring system are synthesized and their recognition ability is disclosed. 2-(3,4,5,6-Tetrafluoro-2-hydroxyphenyl)imidazopyridine (2) is demonstrated to have a high potential as a fluorescent chemosensor for a metal cation, which can signal a distinct wavelength emission corresponding to each captured metal cation. When 2 senses Zn^<2+> cation in acetonitrile solution, it causes the blue emission around 430 nm wavelength; and when 2 senses Al^<3+> and Hg^<2+>, it signals the sky blue emission around 370 nm wavelength. This ability is attributable to the complex in which the attached hydroxyl groups and the coordinated water molecules on the metal cation link via the hydrogen bondings to the 1-nitrogen atom and to the 2-fluorine atom of 2.

合成了具有咪唑基团1的2-（2-羟基氟苯基）苯并恶唑，并将其双荧光应用于金属阳离子的多重化学传感器；在氯仿-乙腈中加入Al^<3+>、Zn^<2+>或Mg^<2+>会产生绿色发射和轻微的蓝色发射，两种发射的增强比取决于捕获的金属阳离子。绿色发光归因于咪唑氮原子上的金属阳离子的连接，由此产生的氮原子的正电荷被诱导传递到羟基上，恢复其氢键能力，导致激发态分子内质子转移（ESIPT）过程。绿色辐射见于2-（2-氨基氟苯基）苯并恶唑衍生物，特别是2-（2-五氟苯并脒-3,4,5,6-四氟苯基）苯并恶唑。在非极性溶剂中，绿色辐射增强，导致相当大的斯托克斯位移。此外，合成了由咪唑吡啶环体系构成的相应荧光团代替苯并恶唑环体系，并公开了其识别能力。2-（3,4,5,6-四氟-2-羟基苯基）咪唑吡啶(2)被证明具有作为金属阳离子荧光化学传感器的高潜力，它可以发出与每个捕获的金属阳离子对应的不同波长发射信号。当2在乙腈溶液中感应Zn^<2+>阳离子时，产生430 nm左右波长的蓝色发射；当2感知到Al^<3+>和Hg^<2+>时，它发出370 nm波长左右的天蓝色发射信号。这种能力是由于配合物中附着的羟基和金属阳离子上的配位水分子通过氢键连接到2的1-氮原子和2-氟原子。

项目成果

Novel Fluorescent 2-(2-Aminofluorophenyl)benzoxazoles: Syntheses and Photophysical Properties.

新型荧光 2-(2-氨基氟苯基)苯并恶唑：合成和光物理性质。

• DOI: 10.1002/chin.200321120
• 发表时间: 2003
• 期刊: ChemInform
• 作者: Kiyoshi Tanaka;T. Komiya
• 通讯作者: T. Komiya