一种裸眼识别Cu^2＋和Hg^2＋传感器的合成与性质研究

Synthesis and Spectroscopic Study of a Chemosensor for Naked Eye Recognition of Cu^(2+) and Hg^(2+)

设计合成了一种香豆素修饰的罗丹明类衍生物L,用作程序型Cu2+与Hg2+检测传感器。采用核磁共振谱、高分辨质谱、红外光谱对其结构进行了表征。利用紫外光谱考察L对不同金属离子的识别作用,研究发现L可以高选择性和高灵敏度识别Cu2+。向L溶液中加入不同的金属离子时(Zn2+,Hg2+,Cu2+,Fe3+,Cd2+,Co2+,Ni 2+,Mg2+,Ca2+,Al 3+,La3+,K+,Na+,Mn2+,Pb2+和Ag+),只有Cu2+的加入会使溶液由无色变为粉色,并且在534nm出现一个新的吸收峰,说明传感器L可以裸眼识别Cu2+。通过紫外滴定得到L可以识别Cu2+的最低检测限为1.9×10-8 mol·L-1。制备了基于L的Cu2+检测试纸,该试纸可以方便快捷的检测水中的Cu2+。通过Job’s曲线和高分辨质谱确定了配合物L-Cu2+之间的结合比为1∶1。另外,若向L-Cu2+的DMSO溶液中加入1equiv.EDTA,溶液瞬间由粉色变为无色,说明EDTA可以取代L并与Cu2+结合,因此传感器L识别Cu2+是可逆的。另外,向L-Cu2+的配合物中加入Hg2+,溶液会由粉色变为无色(而加入其他阳离子没有明显变化),这可顺序实现对Hg2+的裸眼识别。通过紫外滴定计算出L-Cu2+识别Hg2+的最低检测限为2.9×10-7 mol·L-1。因此该程序型传感器L可以有序的裸眼识别Cu2+和Hg2+。

Compound L,as the procedural sensor for the detection of Cu2＋and Hg2＋,was designed and synthesized based on the coumarin-modified rhodamine derivative.The structure of compound L was characterized by NMR,high resolution mass spectrometry and infrared method.Its sensing behavior toward various metal ions was investigated with absorbance methods.The study found that L had good selectivity and sensitivity for Cu2＋.When addition of various metal ions（Zn2＋,Hg2＋,Cu2＋,Fe3＋,Cd2＋,Co2＋,Ni 2＋,Mg2＋,Ca2＋,Al 3＋,La3＋,K＋,Na＋,Mn2＋,Pb2＋and Ag＋）,only Cu2＋could induce a visible change of solution from colourless to pink and a new absorption band centered at 534 nm appear,which indicated that compound L could be used for the naked eye detection of Cu2＋.From UV titration,the detection limit was about 1.9×10-8 mol·L-1.Test strips based on L were fabricated,and this test strips could act as a convenient and efficient Cu2＋test kit.The binding ratio of the complex of L-Cu2＋was 1∶1according to the Job＇s plot and high resolution mass spectrometer（HRMS）experiments.Moreover,Upon addition of 1equiv.EDTA to the mixture of L and Cu2＋in DMSO solution,colour changed from pink to almost colourless,indicating that the EDTA replaced the receptor L to coordinate with Cu2＋.Therefore,L could be classified as a reversible sensor for Cu2＋.In addition,when adding Hg2＋to L-Cu2＋complexes,a visible change of solution from pink to colourless was observed,while other metal ions didn＇t cause this change.Thus,L-Cu2＋complex also could be used for the naked eye recognition of Hg2＋,and the detection limit was calculated about 2.9×10-7 mol·L-1 according to the UV titration.Consequently,this procedural sensor L could be use for the orderly naked eye recognition of Cu2＋and Hg2＋.