含蒽、芘基三唑取代硫冠醚芳杯螢光感測器之合成及其離子辨識

Abstract

本論文合成一系列螢光感測分子20-24，化合物20-22採用蒽基當作螢光基團，化合物24修飾上芘基螢光基團，然後運用硫冠醚和三唑基團作為金屬離子辨識單位，分別修飾在cone構形和1,3- alternate構形的芳杯上，利用光譜儀器測量這些化合物在乙腈溶液中的光物理性質，證實其化合物的負向異質變構性效應(negative heterotropic allosteric effect)。 首先我們從化合物20-23了解對銀和鉛離子的錯合能力，利用Stern-Volmer plot和Job plot計算出化合物22下緣的三唑基團對Pb2+離子為1:1的錯合，而其錯合常數為3.96×104 M-1。藉由銀離子對化合物22的NMR滴定實驗，以訊號的位移量(ppm)和銀離子濃度做Benesi-Hildebrand plot，算出錯合常數為1.76×103 M-1。從控制實驗化合物23得知，1,3-alternate芳杯上的硫冠醚基團皆會對銀和鉛離子有錯合能力。針對化合物22，我們以紫外可見光譜及螢光光譜的滴定，並搭配氫核磁共振光譜實驗，加入不同當量數的銀和鉛離子來調配螢光基團的放射強度，證明化合物22的負向異質變構性效應。 最後，我們將化合物24對15種金屬離子和9種陰離子進行初步篩選，篩選結果發現銅和汞離子對化合物24有強烈的螢光淬熄，而在陰離子方面，F-離子會造成化合物24 紫外可見光的紅位移，使芘基形成最大螢光放射約在472 nm的靜態激態雙體。AcO-離子也會形成靜態激態雙體的螢光放射，而H2PO4-離子造成動態激態雙體螢光強度減弱而單體螢光強度增加。

In this work, a series of novel fluoroionophores 20-24 were synthesized. The structure of 20-22 featured anthrance moiety and 24 featured pyrene moiety as the fluorophore. The thiacrown and triazole groups as metal ion recongnition sites were modyfied and incorporated into the cone and 1,3-alternate conformations of calix[4]arene. The photo-physical properties of compounds 20-24 in acetonitrile were measured which provided evidence for the allosteric effect of compounds. The binding ability of compounds 20-23 toward Ag+ and Pb2+ were studied first. Stern-Volmer plot and Job plot were used to determine the binding constant of 22 with Pb2+ to be 3.96×104 M-1. From NMR titration experiment of compound 22 with Ag+ ion, we obtain its binding constant to be 1.76×103 M-1 using Benesi-Hildebrand plot of □□□vs [Ag+]. By control compound 23, we found that 1,3-alternate calix[4]thiacrown can bind both Ag+ and Pb2+. Negative allosteric effect of compound 22 with variable amount of Ag+ and Pb2+ ion were proven by UV-vis, fluorescece and 1H NMR spectroscope. Finally, compound 24 was screened with 15 metal ions and 9 anions. We found that the fluorescence of compound 24 was selectively quenched by Cu2+ and Hg2+. The complexation of 24 with F- caused a bathochromic shift of its UV-vis absorption, furthermore, it showed a emission max at around 470 nm consistent with a static excimer formation. The complexation of 24 with acetate also showed emission spectra with λmax 472 nm, but it showed only marginal UV-vis shift. The complexation of 24 with H2PO-4 caused a selective quenched of the dynamic excimer emission but an enhancement of the monomer emission of the pyrenyl groups.