Department of Chemistry, University of Miami, Coral Gables, Florida 33146, United States.
Department of Chemistry, Ball State University, Muncie, Indiana 47306, United States.
Anal Chem. 2021 Apr 6;93(13):5412-5419. doi: 10.1021/acs.analchem.0c04801. Epub 2021 Mar 26.
CH-hydrogen bonding provides access to new building blocks for making macrocyclic ionophores with high degrees of preorganization and selective anion recognition. In this study, an anion-binding ionophore in the shape of a clamshell (ClS) was employed that is composed of two cyanostar (CNstar) macrocycles with preorganized cavities linked with a 12-carbon chain. This ionophore allows for anion complexation by CH-hydrogen bonding. The potentiometric performance of membrane-based ion-selective electrodes incorporating this ionophore was evaluated. Different membrane compositions were prepared to determine the optimum concentrations of the ionophore and lipophilic additive in the membrane. The optimized electrode had a slope of -58.2 mV/decade and demonstrated an -Hofmeister selectivity pattern toward iodide with a nanomolar detection limit. Electrospray ionization mass spectrometry was employed to study the relative association strengths of ClS with various anions. The observed mass peaks of the ion-ionophore complexes were found to be consistent with the potentiometric selectivity pattern of the corresponding electrodes. Overall, the selectivity of the electrode could be altered by using an ionophore in which the two CNstar macrocycles are linked together with a flexible 12-carbon chain to control the molecularity of the binding event.
CH 氢键为构建具有高预组织度和选择性阴离子识别能力的大环离子载体提供了新的构建模块。在这项研究中，采用了一种蛤壳形状的阴离子结合离子载体 (ClS)，它由两个具有预组织空腔的氰星 (CNstar) 大环通过 12 个碳原子链连接而成。该离子载体允许通过 CH 氢键进行阴离子络合。评估了包含这种离子载体的基于膜的离子选择性电极的电位性能。制备了不同的膜组合物，以确定膜中离子载体和疏水性添加剂的最佳浓度。优化后的电极斜率为-58.2 mV/decade，对碘化物表现出 -Hofmeister 选择性模式，检测限低至纳摩尔。采用电喷雾电离质谱研究了 ClS 与各种阴离子的相对缔合强度。观察到的离子-离子载体复合物的质谱峰与相应电极的电位选择性模式一致。总的来说，通过使用将两个 CNstar 大环通过柔性 12 个碳原子链连接在一起的离子载体，可以改变电极的选择性，以控制结合事件的分子数。
