利用電化學及螢光方法研究對稱雙苯-十六-冠-五-醚與金屬離子錯合

張明娟(Chang minchuah)

指導教授 ： 劉高家秀

國立臺灣師範大學/理學院/化學系/碩士(2000年)

摘要

本論文合成的一系列碳軸側臂對稱雙苯十六環冠醚中，以索套冠醚LCE-3b和索套冠醚 LCE-3e當作鉛離子和銀離子選擇電極薄膜電極的材料。由實驗結果顯示，以索套冠醚LCE-3b –PVC -NaTPB -NPOE和索套冠醚LCE-3e –PVC -NaTPB-NPOE的比例為5:50:1:100製成的薄膜電極，得到28.9和55.4mV/decade接近於能士特的理論值而感應的時間少於30秒，且電極有超過3個月以上的再現性。
探討對金屬離子之錯合現象及形式，利用13C-NMR金屬誘導變化效應輔以1H-NMR光譜變化，可看出冠醚與金屬離子錯合時構形的改變情形，十六環碳軸冠醚與鈉離子及銀離子形成1：1錯合，錯合主要由冠醚主體決定。
引入不同的發光團側臂可以快速地以螢光光譜在定性上測得金屬離子對冠醚螢光訊號強弱的影響：鈉離子使螢光強度增強，銀離子使螢光強度減弱，並可測知冠醚與金屬的錯合能力大小。
使用鈉離子選擇性電極，來測量冠醚LCE(3a~3h)對Na+的熱力學常數，發現十六碳軸索套冠醚與鈉離子的錯合主要是由焓所控制和形成錯合的穩定性是由熵（△S）所控制。

關鍵字

冠醚 ； 離子選擇性電極 ； 螢光 ； 熱力學常數

並列摘要

A series of sym-dibenzo-16-crown-5 ethers have been synthesized. Lariat crown ethers 3b and 3e were fabricated as the lead and the silver ion selective membrane electrodes, respectively. The best performance observed with the two membrane electrodes are composed with the following composition: (1) LCE-3b –PVC -NaTPB –NPOE and (2) LCE-3e –PVC -NaTPB-NPOE, at a ratio of 5:50:1:100. These two membrane electrodes show Nernstain response toward silver and lead with 55.4 and 28.9 mV per decade, respectively. The response time was less than 30 seconds and a good reproducibility over a period of 3 months was observed.
13C and 1H NMR spectroscopies were used to investigate the formation of complexes between these lariat ethers with alkali metal cations. Results indicated that C-pivot sidearm lariat crown ethers form 1：1 complexes with Na+ and Ag+ ions. In addition, the oxygen atom on the top of the bridged carbon chain plays an important role in the complexing process.
Crown ether-linked different fluorophores are well suited to the recognition of traces of metal ions. The addition of Na+ enhanced the fluorescence emission intensity while the addition of Ag+ quenched the fluorescence intensity. In addition, the complex ability was determined by the fluorescence spectral.
The thermodynamic parameters constantsΔH and ΔS, of these lariat crown ethers (3a~3h) with sodium ion have been determined with a commercial sodium ion selective electrode. Results reveal that the complex formation of these lariat crown ether with sodium ion are mainly controlled by the enthalpy; which is further modified the entropy.

並列關鍵字

crown ether ； ion- selective electrode ； fluorescence ； thermodynamic parameter

參考文獻

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