N,N′-((5,5′-(Quinoxaline-2,3-diyl)bis(1H-pyrrole-5,2-diyl))bis(methanylylidene))bis(4-methoxyaniline) 4 and N,N′-((5,5′-(quinoxaline-2,3-diyl)-bis(1H-pyrrole-5,2-diyl))bis(methanylylidene))dianiline 5 have been prepared and structurally characterized. The X-ray crystal structures of compounds 4 and 4a have been determined. These compounds displayed good sensitivity toward transition metal ions with Cd(II), Zn(II) turn-on and Cu(II), Hg(II) turn-off in fluorescence. It is an elegant example of on/off behavior like a lamp. When Cd(II) or Zn(II) is added into compounds 4 or 5, the lamp will switch on, and then when Cu(II) or Hg(II) is added into the mixture, the lamp will switch off. The binding properties of 4 and 5 for cations were examined by fluorescence spectroscopy. The fluorescence data and crystal structure indicate that a 1 : 1 stoichiometry complex is formed between compound 4 (or 5) and metal ions, and the binding affinity is very high. The recognition mechanism between compound 4 (or 5) and metal ion was discussed based on the their chemical constructions and the CHEF/CHEQ effect when they interacted with each other.

中文翻译：

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新型的Cd（ii），Hg（ii）导通和Cu（ii），Zn（ii）导通的Schiff基础荧光探针†

N，N '-（（（5,5'-（喹喔啉-2,3-二基）双（1 H-吡咯-5,2-二基））双（甲叉基））双（4-甲氧基苯胺） 4和N，N '-（（（5,5'-（quinoxaline-2,3- diyl）-bis （1 H -pyrrole-5,2-diyl））bis（methanylylidene））dianiline 已经制备了5种并且在结构上进行了表征。已经确定了化合物4和4a的X射线晶体结构。这些化合物对过渡金属离子具有良好的敏感性。镉（II）， 锌（II） 开启并 铜（II）， 汞（II）关闭荧光。这是开/关行为（例如灯）的一个很好的例子。什么时候镉（II） 或者 锌（II）添加到化合物4或5中时，灯将打开，然后在铜（II） 或者 汞（II）添加到混合物中后，灯泡将熄灭。通过荧光光谱检查4和5对阳离子的结合特性。荧光数据和晶体结构表明，化合物4（或5）与金属离子之间形成了1：1的化学计量配合物，结合亲和力非常高。根据化合物4（或5）与金属离子的化学结构及CHEF /，探讨了它们的识别机理。CHEQ 他们彼此互动时的效果。