Design and Synthesis of a Thermally Stable Organic Electride

An electride has been synthesized that is stable to auto-decomposition at room temperature.
The key was the theoretically directed synthesis of a per-aza analogue of cryptand[2.2.2] in which each of
the linking arms contains a piperazine ring. This complexant was designed to provide strong complexation
of Na+ via pre-organization of a “crypt” that contains eight nonreducible tertiary amine nitrogens. The structure
and properties indicate that, as with other electrides, the “anions” are electrons trapped in the cavities
formed by close-packing of the complexed cations. The isostructural sodide, with Na- anions in the cavities,
is also stable at and above room temperature.

本研究成功合成了一种可在室温下免于自分解的电子化物（electride）。其合成关键在于通过理论导向设计，制备了穴醚[2.2.2]（cryptand[2.2.2]）的全氮取代类似物，该类似物的每条连接臂均含有一个哌嗪环（piperazine ring）。该络合剂（complexant）通过预组织构建出包含八个不可还原叔胺氮原子的"穴腔"，实现对钠离子（Na+）的强效络合。其结构与性能表征结果显示，与其他电子化物一致，该体系中的"阴离子"为被困于络合阳离子紧密堆积形成的空腔内的电子。该体系的同结构类似物——空腔内填充负钠离子（Na-）的钠化物（sodide），同样可在室温及更高温度下保持稳定。