Stabilization and Extraction of Fluoride Anion Using a Tetralactam Receptor
Stabilization and Extraction of Fluoride Anion Using a Tetralactam Receptor
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DOI：
10.1021/acs.joc.9b00042
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发表时间：
2019-04-05
影响因子：
3.6
通讯作者：
Smith, Bradley D.
中科院分区：
文献类型：
--
作者：
Liu, Wenqi;Oliver, Allen G.;Smith, Bradley D.
使用市售原料在几分钟内在一锅中以高浓度制备中性四内酰胺大环。在DMSO中的NMR滴定研究表明，阴离子亲和力的顺序为F- > Ac 0- > Cl- > Br-。受体对F-的亲和力非常高，部分原因是形成了由两个“鞍形”复合物组成的自互补二聚体。X射线晶体结构表明，二聚体中的两个F-离子相隔3.39埃。这种紧密接近的静电惩罚由周围的四内酰胺分子提供的吸引力相互作用补偿。反应性实验表明，稳定的F-作为一个超分子复合物废除其能力，诱导消除和取代化学。这一发现提出了使用四内酰胺大环来稳定氧化还原装置如室温氟离子电池内的含氟液体电解质的想法。制备了亲脂性的四内酰胺大环化合物，并用于高效地将水中的F-萃取到氯仿层中。有利的提取是由于提取的二聚体复合物的结构，所有极性位于自缔合二聚体的核心内，所有非极性官能团位于外表面上。
A neutral tetralactam macrocycle was prepared in a few minutes in one pot and at high concentration using commercially available starting materials. NMR titration studies in DMSO revealed an anion affinity order of F- > Ac0- > Cl- > Br-. The receptor affinity for F- is very high due in part to formation of a self-complementary dimer comprised of two "saddle shaped" complexes. An X-ray crystal structure showed that the two F- ions within the dimer are separated by 3.39 A. The electrostatic penalty for this close proximity is compensated by attractive interactions provided by the surrounding tetralactam molecules. Reactivity experiments showed that stabilization of F- as a supramolecular complex abrogated its capacity to induce elimination and substitution chemistry. This finding raises the idea of using tetralactam macrocycles to stabilize fluoride-containing liquid electrolytes within redox devices such as room-temperature fluoride-ion batteries. A lipophilic version of the tetralactam macrocycle was prepared and used to extract F- from water into a chloroform layer with high efficiency. The favorable extraction is due to the architecture of the extracted dimeric complex, with all the polarity located within the core of the self associated dimer and all the nonpolar functionality on the exterior surface.