Molecular Donuts and Donut Holes

摘要

The molecular host-guest complex reported by Miras et al. on page 72 of this issue (7) provides insight into a remarkable system in which a template molecule forms, builds a host around itself, and then exits once its job is done. By using a flow reactor system, the authors capture an early stage in this process, where a molecular donut has its "hole" still inside (see the figure, panel A). In this complex, the two metal oxide anions are held together by a ring of Na~+ ions and hydrogen bonds. The success of this approach suggests possibilities for finding other transient host-guest complexes and designing new open framework structures.