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

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Surface Chemistry

Background:

• Cucurbit[8]urils are macrocyclic hosts capable of forming inclusion complexes.
• Azopyridine molecules can act as guests within cucurbit[8]uril cavities.
• Controlling molecular assembly at surfaces is crucial for advanced materials development.

Purpose of the Study:

• To describe the spatial confinement of multivalent azopyridine guest molecules mediated by cucurbit[8]urils.
• To investigate the formation and properties of heteroternary host-guest complexes in solution and on surfaces.
• To explore the creation of patterned surfaces using supramolecular interactions.

Main Methods:

• Attachment of fluorescent dye-labelled multivalent azopyridine molecules to methyl viologen/cucurbit[8]uril inclusion complexes.
• Verification of heteroternary complex formation in solution and on gold substrates.
• Deposition and modification of polymer surfaces using grafting and supramolecular techniques.
• Creation of micrometer-sized patterns via soft lithography.
• Supramolecular exchange experiments on surface-bound heterocomplexes.

Main Results:

• Heteroternary host-guest complexes were successfully formed in solution and on gold substrates.
• Surface binding constants for multivalent ligands were significantly higher (two orders of magnitude) than for monovalent ligands.
• Defined micrometer-sized patterns were created on cyclic olefin polymer surfaces.
• Supramolecular exchange experiments demonstrated selective substitution based on molecular valency, enabling cross-pattern formation.

Conclusions:

• Multivalent azopyridine molecules can be spatially confined by cucurbit[8]urils at surfaces.
• This supramolecular strategy allows for enhanced surface binding and the creation of precisely patterned materials.
• The valency-dependent exchange provides a mechanism for controlled molecular assembly and pattern generation.