香豆素取代之三唑芳杯之合成及金屬離子錯合研究

Abstract

先前本實驗室蔡明宗學長的研究發現具有單取代或雙取代 3-三唑-7-二乙基胺香豆素芳杯化合物 47 ~ 50 與銅二價及汞二價離子錯合效果最好，因此在本論文中分別進行紫外-可見光光譜、螢光光譜的滴定實驗並利用 Stern-Volmer equation 計算 3-三唑-7-二乙基胺香豆素化合物 47 ~ 50 與銅二價及汞二價離子之錯合常數介於 104 ~ 105 M-1之間，且由氫核磁共振光譜滴定實驗推測化合物 47 ~ 50 與金屬離子錯合的位置是在三唑與香豆素上的羰基部分。 另外為了釐清發光基團香豆素上取代基的推電子性之強弱，對於金屬離子選擇性的差異，因此合成了化合物 42 與 43，經由螢光及紫外-可見光光譜發現它們對銅二價離子有明顯的效應，但由紫外-可見光光譜發現，在 430 nm 附近有新的帶 (band) 產生，這可能為芳杯上的酚和銅二價離子發生氧化還原反應後，銅一價離子和三唑上的氮原子及香豆素上羰基的氧原子產生 metal-to-ligand charge transfer (MLCT)，而導致螢光的淬熄，而化合物 45 與 46 則對金屬離子沒有明顯的抓取能力。

The previous research of M.-T. Tsai in our laboratory showed that compounds 47 ~ 50 which contain mono- or bis-3-triazoline-7-N,N- diethyl amino coumarin substituted calix[4]arenas were very selective towared Cu2+ and Hg2+ ions. In this thesis, we carried out UV-Vis and fluorescence titrations analys of each complex and the binding constant of each complex was obtained by Stern-Volmer equation. The binding constants (Ka) are about 104 ~ 105 M-1 for 1 : 1 binding mode. Besides, NMR titration of each complex indicated that coumarin carbonyl and triazoline on 47 ~ 50 act as binding sites for metal ions.

In addition, we synthesized compounds 42 and 43 were synthesized to probe into the relationship between electron-donating ability of substituents on cumarine and selectivity of metal ions. Fluorescence of 42 and 43 was quenched when they complexed with Cu2+, and new absorption band with λmax around 430 nm was also observed in UV-Vis spectra. These phenomena were probably resulted from the calixarene phenol-Cu2+ redox reaction which generated calix-quinone motif and Cu+. The Cu+ was subsequently complexed with triazoline N atoms and coumarin carbonyl O atoms on 42 and 43 leading to metal to ligand charge transfer (MLCT). Nevertheless, 45 and 46 weren’t observed to chelate with metal ions.