以3-溴代-N-丁基咔唑和4-苯基-3-氨基硫脲为原料,合成了一种新型含咔唑基的硫脲席夫碱L,使用紫外-可见光谱、荧光光谱、核磁氢谱以及质谱等对其成分结构、离子识别性能、识别模式进行了研究。结果表明: L对Hg2+和Ag+具有快速响应的可视化选择性识别。当Hg2+或Ag+加入后,L溶液的颜色由无色立刻变为黄色;同时,L溶液中加入Hg2+和Ag+后,荧光光谱有不同变化,且其他离子的存在并不干扰L对Hg2+和Ag+的选择性识别。研究还发现,L对Hg2+和Ag+的荧光识别模式不同: 加入Ag+后,L与Ag+生成了配合物,发生荧光猝灭;加入Hg2+后,L先与Hg2+络合发生荧光猝灭,然后脱去HgS。

A thiourea Schiff base (L) containing carbazole was synthesized from carbazole derivative and 4-phenyl-3-amino thiourea as reagents. The structure of compound L was characterized by 1H NMR and MS. The recognition performance and the binding mode of L and metal ions were investigated by UV-Vis and fluorescence spectroscopies. The results show that L has a quick visual selective recognition response to Hg2+ and Ag+. The addition of metal ions caused the color of L changed from colorless to yellow,and it can be identified by the naked eyes. The fluorescence spectrum of L has different changes with the adding of Hg2+ or Ag+ to the solution. The presence of other ions does not interfere with the selective recognition of L for Hg2+ and Ag+. It is also found that the binding model of L and Hg2+/Ag+ for fluorescent recognition is different: L coordinates with Ag+ to form complex which causes fluorescence quenching effect;L coordinates with Hg2+ to form complex which causes fluorescence quenching effect,then the complex removes HgS to produce a new compound.