One-step Macrocycle-to-Macrocycle Conversion Towards Two New Macrocyclic Arenes with Different Structures and Properties.

Two new macrocyclic arenes H1 and H2 were conveniently synthesized by the one-step reaction of carboxylic acid substituted octopus[3]arene. It was found that H1 was composed of three ethenoanthracene subunits with a rigid hexagonal structure and H2 contained two ethenoanthracene subunits and one anthracene subunit with a rigid house-shaped structure. Among them, H2 exhibited strong blue fluorescence due to the existence of an anthracene subunit. Moreover, both H1 and H2 showed large and electron-rich cavities, which enable them to effectively complex different nitrogen-containing heterocyclic salt guests in solution and the solid state. It was further found that H2 exhibited stronger complexation towards the tested guests than H1 probably due to the stronger charge-transfer interactions between H2 and the guests.