Multivalency in Heteroternary Complexes on Cucurbit[8]uril-Functionalized Surfaces: Self-assembly, Patterning, and Exchange Processes

The spatial confinement of multivalent azopyridine guest molecules mediated by cucurbit[8]urils is described. Fluorescent dye-labelled multivalent azopyridine molecules were attached to preformed methyl viologen/cucurbit[8]uril inclusion complexes in solution and at surfaces. The formation of the resulting heteroternary host–guest complexes was verified in solution and on gold substrates. Surface binding constants of the multivalent ligands were two orders of magnitude higher than that of the monovalent one. Poly-l-lysine grafted with oligo(ethylene glycol) and maleimide moieties was deposited on cyclic olefin polymer surfaces and further modified with thiolated methyl viologen and cucurbit[8]uril. Defined micrometer-sized patterns were created by soft lithographic techniques. Supramolecular exchange experiments were performed on these surface-bound heterocomplexes, which allowed the creation of cross-patterns by taking advantage of the molecular valency, which led to the substitution of the monovalent guest by the multivalent guests but not vice versa.