5-苯基-2-(3-三氟甲苯)-2H-1,2,3-三氮唑-4-羧酸乙酯的结构性质及其罗丹明B衍生物对Hg^(2+)的显色响应

Structural Properties of Ethyl 5-Phenyl-2-(3-(trifluoromethyl)phenyl)-2H-1,2,3-triazole-4-carboxylate and Chromo Genic Responses of Its Rhodamine B Derivatives to Hg^(2+) Ions

对一种新合成的化合物5-苯基-2-(3-三氟甲苯)-2H-1,2,3-三氮唑-4-羧酸乙酯(EPFC),利用Gauss View5.0量化程序及含时密度泛函TD-DFT方法对其结构性质及理论光谱进行了计算;并将其与罗丹明B反应合成了一种新型含有1,2,3-三氮唑基团的化合物REPFC,通过核磁共振及高分辨质谱对其进行了结构表征;应用紫外吸收和荧光分析法研究了REPFC与15种金属离子的作用.结果表明:EPFC易失去电子,计算光谱与实验光谱的结果较好地吻合;在一定浓度范围内,肉眼可观察到REPFC仅对Hg^(2+)有粉红色的显色反应,使其荧光增强,并且反应时间很快,不受其他金属离子的影响,反应络合比为1∶2,提出了REPFC与Hg^(2+)显色反应的off-on机理模型,研究结果可为进一步开发此类三氮唑化合物在生理条件下的应用提供理论指导.

Ethyl 5-phenyl-2-（3-（trifluoromethyl）phenyl）-2H-1,2,3-triazole-4-carboxylate （EPFC）, a newly synthesized com- pound, is used to study its structural properties and explore as a fluorescent probe for metal ions. EPFC was investigated in terms of structural, fluorescence spectroscopic, UV-Vis spectroscopic and theoretical analysis by using HF/6-31G（d）, CIS/6-31G（d） and B3LYP/6-31G（d） methods, respectively. The corresponding product was characterized by NMR and HRESIMS methods. The interactions of the compound with 15 kinds of metal ions （Pb^2＋, Mn^2＋, K^＋, Na^＋, Ag^＋, Ca2＋, Cd2＋, Co2＋, Cu2＋, Fe3＋, Zn2＋, Ni2＋, Hg2＋, Li＋ and Mg2＋） were investigated by UV absorption spectroscopy and fluo- rescence spectroscopy. The quanama chemical values suggested that it is easy for EPFC to lose electron with weak electron accepting ability by frontier molecular orbital analysis. The calculated spectra were complimented with experimental meas- urements in great degree. In addition, a novel rhodamine B derivative containing 1,2,3-triazole unit, and REPFC was success- fully designed and synthesized by the reaction between rhodamine B and EPFC. REPFC displayed more selectivity response to Hg2＋ ion than other metal ions in N,N-dimethylformamide （DMF）-H20 （V/V= 1/1, pH 7.4） within a REPFC concentration range of 2.67 ×10^-5-4.67×10^-5 moloL-1 with an fluorescent enhancement and a rapid chemical reaction. The triazole ap- pended colorless chemosensor turns to pink upon complex formation only with Hg2＋ ions even in the presence of other com-mon metal ions and enables naked-eye detection. The coordination mechanism and tuna on/off fluorescence for Hg2＋ ions were well proposed by explaining Hg2＋ inducing the ring-opened rhodamine B moiety. This study was an advancement for the application of 1,2,3-triazole compound and provides guidance for using simple and high-selectivity Hg2＋ probes in aqueous solutions under physiological conditions.