芳杯下緣含有(1)對位羧基衍生物之蒽與三唑(2)對位雙芘-酯-三唑之化學感測器的合成及其在金屬離子辨識之研究

Abstract

(1) 芳杯下緣含有對位羧基衍生物之蒽與三唑化學感測器的合成及其在金屬離子辨識之研究 我們運用即合化學在芳杯下緣修飾上三唑(triazole)基當作陽離子的辨識端，並引入蒽(anthryl)基當做螢光基團，接著在其對位引入第二個官能基，得到化合物5a-9a，當作金屬離子的螢光感測器。藉由螢光光譜的量測，我們發現化合物5a、7a和控制化合物10a一樣只對Cu2+，Hg2+及Cr3+有效應。化合物6a、8a、9a除了可以和Cu2+，Hg2+及Cr3+錯合之外，6a也會和Pb2+及Mn2+錯合造成些微的螢光淬熄，而8a可以對Ba2+、Ca2+、Cd2+、Li+、Mg2+、Pb2+及Zn2+錯合造成螢光的增強，9a則可以對Ag+及Cd2+錯合造成螢光的增強。由這些觀測結果我們推測化合物8a和9a在光激發狀態下，因為其修飾的官能基(醯胺基、硫代醯胺基)會提供電子到蒽基，進行PET機制抑制蒽基的螢光，而上述官能基與金屬離子錯合後，抵銷了PET機制，因而使螢光增強。我們利用1H NMR滴定實驗推測化合物與金屬離子的的錯合模式，並發現金屬離子皆錯合在芳杯下緣三唑與所修飾上的第二官能基的位置之間。 (2) 芳杯下緣對位含有雙芘-酯-三唑之化學感測器的合成及其在金屬離子辨識之研究 我們延續上一章所設計的螢光離子感測器，亦在芳杯下緣的對位利用即合化學的方法獲得五員三唑雜環作為金屬離子的辨識端，並引入螢光基團-芘作為訊號傳遞的感應端，在五員三唑雜環與芘之間以增加結構彈性且能幫助金屬離子辨識的酯基作連結，合成出控制化合物14、芳杯單取代合物15、對位雙取代化合物16與羥基以丙基保護之對位雙取代化合物18。化合物14、15只對Cu2+、Hg2+及Cr3+離子有明顯螢光淬熄現象發生，而化合物16雖然也只對Cu2+、Hg2+與Cr3+離子有效應，但16與Cu2+、Cr3+錯合會使單體與激態雙體螢光皆淬熄，與Hg2+離子錯合卻使單體螢光增強，激態雙體螢光減弱。化合物18除了對Cu2+、Hg2+、Cr3+還對Ag+及Zn2+離子錯合有單體螢光增強，激態雙體螢光淬熄的現象，其中較特別的是對Cu2+離子的錯合會產生靜態的激態雙體(static excimer)。我們利用1H NMR滴定實驗推測化合物與金屬離子的的錯合模式，並證明化合物16芳杯下緣的羥基會與Cu2+離子進行氧化還原反應，使Cu2+離子還原成Cu+離子。

(1) The Synthesis of calix[4]arenes with Distal Anthryl-triazoles and Acid Derivatives for Metal ion Sensing Studies. We used the Click Chemistry to modify the lower rim of calix[4]arenes with a triazole cationic binding site, and an anthracene as a fluorophore. After we incorporating a second acid derivatives group into 5a, compounds 6a□9a were obtained as fluoroionophores for metal ions. Compounds 5a□9a and control compound 10a showed fluorescence quenching toward Cu2+, Hg2+, and Cr3+ ions. Besides that, 6a also showed a slight fluorescence quenching toward Pb2+ and Mn2+ ions; 8a showed fluorescence enhancement toward Ba2+, Ca2+, Cd2+, Li+, Mg2+, Pb2+ and Zn2+ ions; 9a showed fluorescence enhancement toward Ag+ and Cd2+. We inferred that the functional groups (amide and thioamide) of 8a and 9a might donate electrons to the anthryl group via PET mechanism, thus the fluorescence of anthryl group was quenched. When the functional groups of 8a and 9a bind with metal ions, the metal ions may inhibit the PET mechanism, and therefore enhance the fluorescence. Possible binding modes of these metal complexes were proposed based on 1H NMR titration experiments. (2) The Synthesis of calix[4]arenes with Distal Pyrenyl-ester-triazoles for Metal ion Sensing Studies. The lower-rim of calix[4]arenes was modified with triazoles as the cationic binding sites, and pyrenes as the fluorophores. Mono-substituted compound 15, bis-substituted compound 16, phenol protected compound 18 and control compound 14 were synthesized. Both 14 and 15 showed fluorescence quenching toward Cu2+, Hg2+ and Cr3+ ions. 16 showed both monomer and excimer fluorescence quenching toward Cu2+and Cr3+, but showed monomer enhancement and excimer quenching toward Hg2+. Compound 18 showed monomer enhancement and excimer quenching toward Ag+ and Zn2+ besides Cu2+, Hg2+ and Cr3+ ions. Note that the complex of 18˙Cu2+ formed a static excimer. We used 1H NMR titration experiment to determine possible binding modes of these metal complexes and proved that the hydroxyl group of 16 proceeded oxidation-reduction with Cu2+.