Molecular boxes on a molecular printboard: encapsulation of anionic dyes in immobilized dendrimers

Fifth-generation poly(propylene imine) dendrimers, modified with 64 apolar adamantyl groups, have been immobilized on cyclodextrin host monolayers ("molecular printboards") on glass by supramolecular microcontact printing. The immobilized dendrimers retain their guest-binding properties and function as "molecular boxes" that can be filled with fluorescent dye molecules from solution. Alternatively, part of the immobilized dendrimers were filled with dye molecules by cross-microcontact printing while the remaining, empty dendrimers were filled with a different dye from solution, resulting in alternating patterns of dye molecules. In addition, we demonstrate that encapsulation of dyes in immobilized dendrimers is reversible: immobilized molecular boxes can be filled with a dye, emptied, and subsequently refilled with a different dye.