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.