Electroactive Anion Receptor with High Affinity for Arsenate
Electroactive Anion Receptor with High Affinity for Arsenate
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DOI：
10.1021/acs.joc.0c01206
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发表时间：
2020-08-07
影响因子：
3.6
通讯作者：
Swager, Timothy M.
中科院分区：
文献类型：
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作者：
Etkind, Samuel, I;Vander Griend, Douglas A.;Swager, Timothy M.
在这里，我们提出了一个包含氧化还原活性1,4-二硫胺单元的大环聚酰胺笼的合成和表征。8种阴离子在乙腈中的紫外/可见滴定实验表明，通过选择性形成HG(2)配合物，H2AsO4- (log beta(2) = 10.4（-0.4)(+0.4)）和HCO3- (log beta(2) = 8.3（-0.4)(+0.3)）比其他常见阴离子客体如Cl- (log K-1:1 = 3.20（-0.02)(+0.03)）、HSO4- (log K-1:1 = 3.57（-0.03)(+0.02)）和H2PO4- (log K-1:1 = 4.24（-0.04)(+0.05)）具有更高的亲和力。在蛋白质和合成受体中，砷酸盐对磷酸盐的识别是罕见的，尽管选择性的起源尚不清楚，但利用结合化学计量的差异代表了开发能够区分两种阴离子的受体的未充分探索的途径。在1:3 CD2Cl2/MeCN-d(3)中进行的H-1 NMR分析发现阴离子结合化学计量学与所用溶剂有很强的依赖性。最后，循环伏安法的滴定实验为每个阴离子提供了不同的和复杂的反应，尽管阴离子和受体之间的反应在大多数情况下被观察到。这些结果表明1,4-二硫苷在超分子受体的构建中是一个有趣的识别基团。
Herein, we present the synthesis and characterization of a macrocyclic polyamide cage that incorporates redox-active 1,4-dithiin units. UV/vis titration experiments with eight anions in acetonitrile revealed high affinity for H2AsO4- (log beta(2) = 10.4(-0.4)(+0.4)) and HCO3- (log beta(2) = 8.3(-0.4)(+0.3)) over other common anionic guests, such as Cl- (log K-1:1 = 3.20(-0.02)(+0.03)), HSO4- (log K-1:1 = 3.57(-0.03)(+0.02)), and H2PO4- (log K-1:1 = 4.24(-0.04)(+0.05)), by the selective formation of HG(2) complexes. The recognition of arsenate over phosphate is rare among both proteins and synthetic receptors, and though the origin of selectivity is not known, exploiting the difference in the binding stoichiometry represents an underexplored avenue toward developing receptors that can differentiate between the two anions. Additional analysis by H-1 NMR in 1:3 CD2Cl2/MeCN-d(3) found a strong dependence of anion binding stoichiometry with the solvent employed. Finally, titration experiments with cyclic voltammetry provided varying and complex responses for each anion tested, though reaction between the anion and receptors was observed in most cases. These results implicate 1,4-dithiins as interesting recognition moieties in the construction of supramolecular receptors.