两种臂式荧光氮杂冠醚化学传感器

Two Chemosensors Based on the Fluorescent Group Armed-Azacrown Ether

合成了萘基臂式苯并氮杂15-冠-5(3)和5-氯喹啉基臂式苯并氮杂15-冠-5(4)两种荧光化学传感器,由元素分析、NMR等进行了结构表征;在乙醇溶剂中采用紫外光谱和荧光光谱法分别研究了冠醚3和4对金属离子K+,Ca2+,Mg2+,Pb2+,Co2+,Ni2+,Mn2+,Cu2+,Zn2+,Cd2+和Hg2+的选择性传感性能.结果表明,冠醚3仅对Cu2+离子有显著的传感作用,是一种典型的辐射能量转移过程.冠醚4对Ni2+,Co2+,Cu2+和Mn2+离子有特殊的敏感性,金属离子浓度逐渐增大使冠醚4产生先增强后猝灭的荧光现象,荧光增强归因于阻断了从冠环氮原子到喹啉荧光体的弱光诱导电子转移(PET)过程,而选择性猝灭源于冠醚环与喹啉基团对金属离子协同螯合的机制.冠醚3和4的构性关系表明,发光体基团对传感器的选择性能够产生重要的影响.

In this paper,two novel fluorescent chemosensors,naphthalene-armed benzoaza-15-crown-5（3） and 5-chloroquinoline-armed benzoaza-15-crown-5（4）,were synthesized,and their structures were con-firmed by 1H NMR and elementary analysis.The selective sensibility of crown ether 3 and 4 for K＋,Ca2＋,Mg2＋,Pb2＋,Co2＋,Ni2＋,Mn2＋,Cu2＋,Zn2＋,Cd2＋and Hg2＋ were examined respectively by ultraviolet spec-troscopy and fluorescence spectrum method in ethanol.The obtained results indicate that crown ether 3 ex-hibits significant sensitivity only to Cu2＋ ion,which may be due to a typical radiation energy transfer process.Crown ether 4 shows special sensitivity for Ni2＋,Co2＋,Cu2＋ and Mn2＋ ions,and the gradual in-creasing amount of the metal ions leads to the changes of the fluorescence of 4 in the quenching after the enhancement.That fluorescence enhancement may be due to the suppression of the weak photo-induced electron transfer（PET） operating from the nearby nitrogen atom of the crown ether ring to the quinoline fluorophore;and fluorescence quenching may be due to the mechanism of the crown ether ring cooperated with the quinoline group chelating to the metal ion.The contrast between the structure-property relationship of crown ether 3 and that of crown ether 4 indicates that the luminophor group of the sensor has great effect on the metal ion-selectivity.