羅丹明及螢光素染料具有出色的光物理特性，例如高螢光量子產率、大的摩耳消光係數、可見光區域的吸收和放射波長以及可以直接用肉眼觀察到螺內醯胺環打開的螢光強度變化檢測過程，以至於被廣泛地用於構建螢光感測探針。在這項研究工作中，我們設計具有羅丹明或螢光素為主要架構的化合物，引入含有硫醚基團修飾的胺類化合物及相關胺基酸衍生物合成出一系列螢光化學感測器Rho6G-1-8、Rho6G-1-8及Fluor-1-4，藉由紫外光-可見光吸收及螢光放射光譜變化探討化學感測器對不同金屬離子的偵測感應能力。經由快速高通量篩選技術，我們發現了連接半胱胺酸的羅丹明螢光感測分子(Rho6G-6)對汞離子表現出「開啟」的螢光響應，並且具有顯著的靈敏度、高選擇性及抗干擾性，並且在進一步的研究中闡述，Rho6G-6和Hg(II)形成其金屬配位化合物的金屬-配體比為2：1。另一方面，我們將合成的螢光探針Rho6G-6在測試紙及活細胞的偵測系統中，成功地展現測定汞離子的能力，經由上述的結果都說明Rho6G-6在螢光感測汞離子的應用上具有很大的潛力。;For the development of fluorescent chemosensors, xanthenes, including rhodamines and fluoresceins, are highly favorable due to their excellent photophysical properties, such as high fluorescence quantum yield, large molar extinction coefficient, absorption and emission wavelength in the visible region. In general, Rhodamine- and fluorescein-based spirolactam or spirolactone derivatives are nonfluorescent and colorless, whereas ring-opening of the corresponding spirolactam/lactone gives rise to strong fluorescence emission and a pink color. In this work, we report the synthesis of a series of Hg(II)-sensitive rhodamine- and fluorescin-based derivatives (Rho6G-1-8, RhoB-1-8, and Fluor-1-4) from rhodamine 6G, rhoamine B, and fluorescein with methyl-S-bearing amines and amino acid esters. N-(Rhodamine-6G) thiolactam–methyl cysteine methyl ester (Rho6G-6) displayed selective colorimetric and fluorescence “turn-on” changes at 537 nm via a rhodamine ring-opening approach toward Hg(II) among other metal ions examined in 1% DMSO aqueous solution. The results demonstrated that Rho6G-6 forms in a 2:1 complex with Hg(II) binding mode and shown a remarkable ratiometric fluorescence enhancement. On the other hand, Rho6G-6 also successfully used in test strips and living cells systems for detection of Hg(II) ions. These results showed that Rho6G-6 will provide a potential chemosensor for Hg(II) in the future.
