雙三唑螢光離子感應器的合成與金屬離子感應性質研究

Abstract

我們應用即合化學合成出一系列「芘-三唑-碳鏈-三唑-芘」化合物17□22、「芘-三唑-縮二醇醚-三唑-芘」化合物23□26及控制化合物27，當作金屬離子的螢光感應器並利用1H-NMR滴定推測其錯合模式。藉由螢光光譜的量測，發現化合物17-18和27一樣只對Cu2+、Hg2+、Cr3+有效應。化合物19□22除了可以和Cu2+、Hg2+及Cr3+錯合之外，也都會和Pb2+錯合造成芘的單體及雙體的螢光淬熄，而20和22可與Zn2+、Cd2+錯合，使得單體螢光變強而激態雙體螢光變弱。進而推測化合物19□22和Pb2+錯合在靠近芘的位置，20和22與Zn2+、Cd2+則錯合在靠近碳鏈架橋位置。在一系列改變縮二醇醚架橋鏈長的化合物23□26中，對Pb2+錯合的現象是最有趣的，其中化合物23□25會和Pb2+錯合造成芘的單體及雙體的螢光淬熄，而化合物26和Pb2+錯合，卻使得單體螢光變強而激態雙體螢光變弱。推測化合物23□25和Pb2+錯合在靠近芘的位置，鏈長最長的化合物26和Pb2+則錯合在靠近冠醚狀架橋的位置。

Under Click Chemistry condition, we synthesized a series of “pyrene-triazole-methylene chain-triazole-pyrene” compounds 17□22, “pyrene-triazole-polyoxyethylene-triazole-pyrene” compounds 23□26, and control compound 27 as fluoroionophores. Possible complexation modes of these metal complexes were proposed based on the results from 1H-NMR and fluorescence titration studies. Based on fluorescence spectroscopy studies, we found that compounds 17□□18, and 27 all showed similar quenching effects towards metal ions such as Cu2+, Hg2+, and Cr3+. By contrast, compounds 19□22 not only complexed with Cu2+, Hg2+, and Cr3+ but also with Pb2+ to show fluorescence quenching in both the monomer and excimer emissions of the pyrenes moieties. Compounds 20□and□22 complexed with Zn2+ or Cd2+ to show an enhanced monomer but a decreased excimer emissions. It was proposed that in the complexation of compounds 19□22 with Pb2+, Pb2+ was near the pyrene moieties. However, Zn2+ or Cd2+ was near the methylene chain in corresponding complexs with compounds 20□and□22. Interestingly, in a series of analogue compounds 23□26 with different length of polyoxyethylene spacers (n = 2□5), different phenomena were observed when they bind with Pb2+. For compounds 23□25, monomer and excimer quenching in the presence of Pb2+ disclosed that Pb2+ was located near the pyrene moieties. While for compound 26 with the longest spacer of the series, Pb2+ was found to be near the acyclic crown ether bridge which caused an enhanced monomer but a decreased excimer emission.