名称:
8-TQEN (N,N,N′,N′-tetrakis(8-quinolylmethyl)ethylenediamine) analogs as fluorescent cadmium sensors: strategies to enhance Cd2+-induced fluorescence and Cd2+/Zn2+ selectivity
摘要:
为了挖掘TQEN(N,N,N′,N′-四(2-喹啉甲基)乙二胺)系列荧光探针未开发的传感潜力,设计并表征了8-TQEN(N,N,N′,N′-四(8-喹啉甲基)乙二胺)类似物。尽管8-TQEN由于在水介质和有机溶剂中溶解性差而缺乏实用性,但6-MeO-8-TQEN(N,N,N′,N′-四(6-甲氧基-8-喹啉甲基)乙二胺,1b)在DMF-HEPES缓冲液(1:1)中表现出对Cd2+的选择性荧光增强,波长为395 nm(ICd/I0 = 25,λex = 332 nm,φCd = 0.025)。Zn2+引起的荧光增强较弱(IZn/I0 = 9,IZn/ICd = 0.35)。相比之下,母体探针TQEN(IZn/I0 = 23,ICd/IZn = 0.64)和6-MeOTQEN(IZn/I0 = 11,ICd/IZn = 1.29)对Zn2+表现出更高的敏感性。当喹啉基团被8-羟基喹啉取代时,观察到不同的响应。丙二胺衍生物,8-TQOEPN(N,N,N′,N′-四(8-喹啉氧乙烯)丙二胺,2c)在Cd2+结合时在423 nm处表现出显著的荧光增强(λex = 325 nm,ICd/I0 = 19,φCd = 0.31)。荧光增强是Cd2+特异性的,因为Zn2+仅引起更温和的发射增加(IZn/I0 = 8.8,IZn/ICd = 0.45)。