聯吡啶釕錯合物在銅離子感測器上的應用

藺以文

指導教授 ： 張一知

國立臺灣師範大學/理學院/化學系/碩士(2011年)

摘要

本研究將兩個聯吡啶釕錯合物修飾在含氮大環 cyclam 上， [{(bpy)2Ru}2 (1,8-bis(4-methyl-2,2’-bipyridime- 4’-ylmethyl)-1,4,8,11,- tetraazacyclotetradecane)](PF6)4 (c-2Ru)，並研究其光物理性質。
從吸收及放光光譜實驗中得知 c-2Ru 對於 Cu2+ 有相當良好的選擇性。利用 Job’s plot可知 c-2Ru 和 Cu2+ 離子的錯合方式為 1 : 1，由 Cu2+ 離子滴定實驗，偵測放光強度的變化，可得它們的結合常數為 1.19 x 109 M-1。
在螢光強度實驗中，Cu2+ 對於 c-2Ru 的淬息常數為 1.6 x 1011 M-1 s-1，大於溶液中的擴散速率常數 (~1010 M-1 s-1)，可能不是一個典型的雙分子碰撞淬息關係。相同的實驗測量生命期結果，發現其變化量不大，可能為靜態淬息。單獨以cyclam加入 Cu2+ 後，在 505 nm有吸收收峰，但 c-2Ru 的放光位置為 615 nm，經由能量傳遞之淬息原因也不太可能發生，更增加靜態淬息的可能性。
在電子順磁光譜上得知， Cu2+ 進入 c-2Ru 中心後，會使得結構中的大環扭曲，推論淬息的原因為中心 cyclam 結構因 Cu2+ 的配位而扭曲，使得兩個釕金屬中心靠近而有產生交互作用，進而使 c-2Ru 的螢光被淬息。

關鍵字

釕錯合物 ； 感測器

並列摘要

Complex with two units of ruthenium(II) polypyridine complexes connected on cyclam, c-2Ru, [{(bpy)2Ru}2(1,8-bis(4-methyl -2,2’-bipyridime-4’-ylmethyl) -1,4,8,11,-tetraazacyclo-tetradecane)](PF6)4 has been synthesis. Absorption and emission spectroscopy and ion reactivity were investigated for this complex.
Complex, c-2Ru, exhibits extremely high selectivity toward Cu(II) ion. Emission was significantly quenched by copper ion. The emission changes in mole fraction plot (Job’s plot) shows that the binding of c-2Ru and Cu2+ is 1:1 faction. Calculating from the copper ion titration curve gives the binding constant of Kb = 1.6 x 109 M-1.
Emission quenching rate was calculated from the quasi-linear quenching region at low copper concentration to be 1.6 x 1011 M-1 s-1. The rate constant is unusually large, even greater than the diffusion rate constant (~ 1010 M-1 s-1). Classical bimolecular collided reaction cannot account for this quenching reaction. At the similar reaction condition, lifetime of ruthenium does not change much. Adding Cu(II) into cyclam solution results a weak absorbed peak at 505 nm (e = 64 M-1, cm-1). Given the emission maximum of c-2Ru complex at 615 nm, the quenching process can not be the energy transfer. Static quenching is highly possible.
In the ERP spectra, copper ion, d9, signal has small Az value of 110 G indicating a distorted square pyramidal coordination of copper ion. Quenching of ruthenium complex may result from the structure change during incorporation of Cu2+ into cyclam core. Two ruthenium polypyridine complexes close to each other may enhance self-quenching.

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