本研究合成出二rhodamine衍生物4-(3-(3',6'-bis(diethylamino)- 3-oxospiro[isoindoline-1,9'-xanthen]-2-yl)thioureido)phenyl methacrylate (RB)與4-(3-(3',6'-bis(diethylamino)-3-oxo-5-(4-(1,2,2-triphenylvinyl)phenyl)spiro[isoindoline-1,9'-xanthen]-2-yl)thioureido)phenyl methacrylate (TR)分別作為turn-on與TBET汞離子螢光感測器，並以自由基聚合法(free radical polymerization)與親水性單體N-isopropylacrylamide (NIPAAm)及N-hydroxymethylacrylamide (NMA)合成出不同螢光單體比例之共聚高分子poly(NIPAAm-co-NMA-co-RB)與poly(NIPAAm-co-NMA-co-TR)，改善螢光單體的親水性，使其更容易與水溶液中的離子作用。
本研究所合成之感測器對於Hg2+具有感測性，能夠誘導硫代胺基脲(thiosemicarbazide)形成噁二唑(oxadiazole)，為不可逆的脫硫環化反應，使螺內醯胺(spirolactam)開環，促使rhodamine螢光強度增加，溶液由無色變為粉紅色，並且具有快速響應性。TR為結合兩螢光基團之分子，以tetraphenylethene作為能量供體，rhodamine作為能量受體，其中tetraphenylethene結構具有聚集誘導發光(aggregation-induced emission, AIE)特性，在弱親和力溶劑中聚集，使分子內旋轉受到限制而放出螢光，添加Hg2+能夠藉由跨鍵能量轉移(trough-bond energy transfer, TBET)的產生觀察到螢光波長的消長與位移，並且具有較大的stokes shift。

In this study, random copolymers poly(NIPAAm-co-NMA-co-RB) and poly(NIPAAm-co-NMA-co-TR) were synthesized by free radical polymerization. Rhodamine derivatives RB and TR were used as the turn-on and TBET fluorescent sensor for the recognition of mercury ions, respectively. NIPAAm and NMA segments were designed to increase hydrophilicity to facilitate the sensing ability of mercury ions in aqueous solution. The system utilized the irreversible Hg2+-promoted reaction of thiosemicarbazides to form 1,3,4-oxadiazoles, which possess the advantage of quick response time. The interaction with mercury ions could trigger the transformation process from ring-closed spirolactam form to ring-opened amide for rhodamine moieties, which can enhance the fluorescence intensity of rhodamine moieties and the color of the solution was changed from colorless to pink. TR is constructed by coupling a tetraphenylethene donor with a rhodamine acceptor. The tetraphenylethene group of TR with aggregation-induced emission phenomenon showed strong emission in a poor solvent is attributed to the restriction of intramolecular rotation. Upon the addition of mercury ions in the poor solvent, the change of the fluorescent wavelength and intensity could be observed due to through-bond energy transfer, and possessed a large pseudo-stokes shift.

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