Oppositely-charged coordination cages form a type I porous ionic liquid with two pore sizes.

Abstract

Here we introduce a new type of porous liquid that combines two coordination cages in a single salt. This material is prepared through the ion metathesis of two oppositely-charged cages: one charged +20, and the other with a -16 charge. This ionic liquid has higher porosity than previously reported systems, because both of its components are hollow cages. The enhanced porosity holds promise for improving performance in chemical separations or storage, reflecting the guest-binding selectivity of the two cages, and the applications accessible due to its liquid nature.