Guest Encapsulation Within Surface-Adsorbed Self-Assembled Cages

Coordination cages encapsulate a wide variety of guests in the solution state. This ability renders them useful for applications such as catalysis and the sequestration of precious materials. Here we report a simple and general method for the immobilisation of coordination cages on alumina. Cage loadings were quantified via adsorption isotherms and guest displacement assays demonstrated that the adsorbed cages retained the ability to encapsulate and separate guest and non-guest molecules. Finally, we used a system of two cages adsorbed on to different regions of alumina to stabilise and separate a pair of Diels-Alder reagents. The addition of a single competitive guest resulted in the controlled release of the reagents, thus triggering their reaction. We envisage this method of coordination cage immobilisation on solid phases to be applicable to the extensive library of reported cages, enabling new applications based upon selective solid-phase molecular encapsulation.