Beryllium(II) Recognition by Allosteric Effects in 1,2-Ethylenedioxybenzene Based Ditopic Receptors
作者:Dong-Wan Kim、Jung-Hwan Kim、Jae-Young Hwang、Myong-Yong Choi、Jae-Sang Kim
DOI:10.5012/bkcs.2011.32.8.2643
日期:2011.8.20
Efficient ditopic receptor, uranyl(II) N,N'-(ethylenedioxy)benzenebis(salicylideneimine) (3) for beryllium ion has been obtained upon functionalization of 1,2-ethylenedioxybenzene (1) with a uranyl-salphen (salphen = N,N'-phenylenebis(salicylideneimine)) unit. Binding affinities of the receptor, 3 in AN-DMSO (v/v 95:5) solution have been measured for alkali and alkaline earth metal ions by conductometry comparing 1. The results showed that both monotopic 1 and ditopic receptor 3 were selective for $Be^2+}$ ions over other cations, while especially 3 that can complex both with cations (coordinated to basic oxygen of ethylenedioxybenzene) and anions (coordinated to the Lewis acidic uranyl center) results in an increase of the stability constants by a factor of $10^2.42}$ with respect to 1. Furthermore, the $Be^2+}$-3 interactions are demonstrated by $^1H$ NMR experiments in highly polar solvent medium, DMSO-$d_6$. Higher selectivities were also observed for $Be^2+}$ when the ditopic receptor, 3 was incorporated into PVC membranes and tested as ion selective electrodes at neutral pH.
通过将 1,2-亚乙二氧基苯(1)与一个铀酰-苯酚(salphen = N,N'-亚苯基双水杨醛亚胺)单元官能化,获得了铍离子的高效二位受体铀酰(II)N,N'-(亚乙二氧基)苯双水杨醛亚胺(3)。受体 3 在 AN-DMSO(v/v 95:5)溶液中与碱金属和碱土金属离子的结合亲和力是通过电导测定法比较 1 测得的。结果表明,单位受体 1 和二位受体 3 对 $Be^2+}$ 离子的选择性高于其他阳离子,尤其是 3,它既能与阳离子(与亚乙基二氧苯的碱性氧配位)复合,也能与阴离子(与路易斯酸性铀酰中心配位)复合,其稳定性常数比 1 增加了 $10^2.42}$ 倍。此外,在高极性溶剂介质 DMSO-$d_6$ 中进行的$Be^2+}$-3 相互作用的核磁共振实验也证明了这一点。当将二位受体 3 加入 PVC 膜并在中性 pH 值下作为离子选择性电极进行测试时,还观察到 $Be^2+}$ 具有更高的选择性。