Zn2+離子為人類和其他生物重要的微量元素之一，過量或缺少均易導致疾病，故其簡易、快速及精確的檢測方法有其必要性。螢光感測器應用於對金屬離子的感測，能檢驗在環境中或生物體內的含量顯示其重要性。相對其它檢測儀器有易操作、量測快速、成本低的優點，已可應用於疾病診斷或水質評估等用途。
本研究利用Suzuki-Miyaura coupling反應成功地合成出含水楊亞胺結構的二噻吩一吡咯衍生物(S1)作為金屬離子螢光感測器，利用吸收光譜及螢光放射光譜探討其在溶液中對金屬離子的辨識能力與結合模式，S1本身因光誘導電子轉移(photo-induced electron transfer, PET)的作用，在乙醇水溶液中(EtOH/H2O = 9/1)螢光強度低，但在Zn2+離子存在下螢光強度大幅增強(λem = 465 nm，23倍)，原因是水楊亞胺基辨識基團結合Zn2+離子，抑制亞胺基上氮的孤對電子轉移(PET)，讓激發態電子以放光形式回到基態產生螢光增強。由Job plot實驗得到S1與鋅離子形成錯合物的配位比例是2：1，由濃度滴定實驗得到偵測極限是1.28×10-8 M，在UV燈照射下可用肉眼觀察到S1與Zn2+離子結合產生藍光。在雙離子競爭實驗，確認僅有水楊亞胺結構S0會同時對Zn2+、Al3+、Mg2+離子螢光增強，而S1對於Zn2+離子選擇性較佳，能排除Al3+、Mg2+離子對辨識基團螢光增強的影響。評估在不同有機溶劑系統下，皆能對Zn2+離子保持選擇性。此外，以S1及錯合物S12Zn進行DFT模擬分析，獲得最適化的結構及能階差計算，結果表明錯合物S12Zn的結合模式是穩定的系統。

We have been synthesized a novel salicylimine fluorescent sensor S1 with dithienylpyrrole moiety through Suzuki-Miyaura coupling and imine condensation. In addition, S0 without the dithienylpyrrole moiety was also prepared for comparison. Their structures were characterized by NMR spectroscopy and element analysis. S1 exhibited weak fluorescence due to photoinduced electron transfer (PET). However, upon the addition of Zn2+ the fluorescence intensity was greatly enhanced at 465 nm due to the inhibition of PET. From Job plot, the stoichiometric ratio of S1 to Zn2+ was 2:1. The limit of detection (LOD) towards Zn2+ was 1.28×10-8 M and the binding constants was 4.37×105 M-2. S1 shows good selectivity toward Zn2+ in dual ions competitive experiment and in various solvent systems, respectively. The binding mode of S1 toward Zn2+ using DFT simulation analysis shows that complex S12Zn is a stable system. Our results show that S1 demonstrates good sensitivity and selectivity toward Zn2+ which is applicable as turn-on fluorescent sensor for environmental analysis.

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