Quinoline-based fluorescent zinc sensors with enhanced fluorescence intensity, Zn/Cd selectivity and metal binding affinity by conformational restriction
作者:Yuji Mikata、Yumi Sato、Saaya Takeuchi、Yasuko Kuroda、Hideo Konno、Satoshi Iwatsuki
DOI:10.1039/c3dt50719j
日期:——
Two cyclohexanediamine-based tetrakisquinoline derivatives, N,N,N′,N′-tetrakis(2-quinolylmethyl)-trans-1,2-cyclohexanediamine (TQDACH) and N,N,N′,N′-tetrakis(1-isoquinolylmethyl)-trans-1,2-cyclohexanediamine (1-isoTQDACH), have been prepared and their zinc-induced fluorescent response was investigated. In DMF–H2O (1 : 1) solution, TQDACH exhibits increase of fluorescence at 455 nm in the presence of 1 eq. of zinc ion (λex = 317 nm, ϕ = 0.010). Similarly, 1-isoTQDACH exhibited fluorescence enhancement upon binding with zinc (λex = 325 nm, λem = 352 and 475 nm, ϕ = 0.032). The fluorescence intensity ratio induced by cadmium relative to zinc (ICd/IZn) for these 1,2-cyclohexanediamine probes is lower than those for the corresponding ethylenediamine derivatives, TQEN and 1-isoTQEN. Crystal structures of the zinc and cadmium complexes of TQDACH and 1-isoTQDACH reveal the superior metal binding ability of the 1,2-cyclohexanediamine and isoquinoline moieties in comparison to ethylenediamine and quinoline. The conformational restriction afforded by the 1,2-cyclohexanediamine skeleton upon zinc binding leads to enhanced fluorescence intensity and strong metal binding affinity.
两种基于
环己二胺的四
喹啉衍
生物,N,N,N',N'-四(2-
喹啉基甲基)-
反式-1,2-环己二胺(TQ
DACH)和N,N,N',N'-四(1-
异喹啉基甲基) )-反式-1,2-
环己烷二胺(1-isoTQ
DACH)已被制备并研究了它们的
锌诱导荧光响应。在
DMF–
H2O (1 : 1) 溶液中,TQ
DACH 在 1 eq. 存在的情况下在 455 nm 处表现出荧光增强。
锌离子 (λex = 317 nm, phi = 0.010)。同样,1-isoTQ
DACH 在与
锌结合后表现出荧光增强(λex = 325 nm,λem = 352 和 475 nm,φ = 0.032)。这些
1,2-环己二胺探针的
镉相对于
锌诱导的荧光强度比 (ICd/IZn) 低于相应的
乙二胺衍
生物 TQEN 和 1-isoTQEN 的荧光强度比。 TQ
DACH 和 1-isoTQ
DACH 的
锌镉配合物的晶体结构表明,与
乙二胺和
喹啉相比,
1,2-环己二胺和
异喹啉部分具有优异的
金属结合能力。
1,2-环己二胺骨架在
锌结合时所提供的构象限制导致荧光强度增强和
金属结合亲和力增强。