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(TQDACH)和N,N,N',N'-四(1-异喹啉基甲基) )-反式-1,2-环己烷二胺(1-isoTQDACH)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,TQDACH 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-isoTQDACH 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。 TQDACH 和 1-isoTQDACH 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。