Supramolecular Ladder Assemblies as a Model for Probing Electronic Interactions between Multiple Stacked π-Conjugated...

Area of Science:

• Supramolecular Chemistry
• Organic Electronics
• Materials Science

Background:

• Barbituric acid (BA) derivatives are known for their hydrogen-bonding capabilities.
• Triphenylenevinylene (TPE-V) units are electroactive moieties with interesting photophysical properties.

Purpose of the Study:

• To create supramolecular architectures that self-assemble into ordered structures.
• To investigate the electronic properties and charge delocalization in these assemblies.

Main Methods:

• Synthesis of mono-, di-, and tri-topic receptors with BA-complementary H-bonding sites.
• Induction of supramolecular assembly into n×m ladders with TPE-V units.
• Electrochemical analysis (cyclic voltammetry) to study oxidation events.
• Spectroscopic analysis (UV-Vis absorption and emission) to probe electronic interactions.

Main Results:

• Successfully formed supramolecular ladders with 1, 2, or 3 TPE-V units.
• Observed through-space electronic interactions between TPE-V units within the assembled structures.
• Demonstrated two single-electron oxidation events in specific architectures (n=2, m=2 or m=3), forming radical cations.
• Quantified comproportionation constants (340 and 70) for radical cation formation.
• Electrochemical data indicated significant charge delocalization over the TPE-V units in the assembly.

Conclusions:

• The designed receptors effectively induce supramolecular assembly into ordered ladders.
• Topological constraints within the assemblies promote through-space electronic coupling.
• The observed electrochemical behavior confirms charge delocalization, suggesting potential for novel electronic materials.