Orthogonal, modular anion-cation and cation-anion self-assembly using pre-programmed anion binding sites.

Area of Science:

• Supramolecular Chemistry
• Coordination Chemistry
• Materials Science

Background:

• Anion roles in self-assembly are often reactive and emerge during the process.
• Pre-programming anion binding sites offers potential for predictable and modular structure building.
• Subcomponent self-assembly typically relies on cation coordination.

Purpose of the Study:

• To explore the orthogonal and modular construction of multi-ion assemblies by combining pre-programmed cation and anion binding sites.
• To demonstrate the controlled synthesis of complex architectures using a combination of metal-imine chemistry and macrocyclic host-guest interactions.
• To investigate the use of gold(I) in subcomponent self-assembly for the first time.

Main Methods:

• Integration of cation (M ⁺ ) and anion (X ^- ) binding sites into a single molecular framework.
• Utilizing subcomponent metal-imine chemistry for cation binding (Cu ⁺ , Au ⁺ ) and cyanostar macrocycles for anion binding (BF ₄ ^- , ClO ₄ ^- ).
• Employing imine condensation to link pyridyl-aldehyde and aniline-modified cyanostar components, forming target assemblies like [LM-CS-X-CS-ML] ⁺ .

Main Results:

• Demonstrated orthogonal and modular build-up of structure in multi-ion assemblies.
• Successfully isolated cation-directed (Cu ⁺ ) or anion-bridged (BF ₄ ^- ) intermediates, showcasing pathway control.
• Achieved modular synthesis of different products using Au ⁺ and ClO ₄ ^- , highlighting versatility and the first use of gold(I) in this context.

Conclusions:

• Pre-programmed cation and anion binding sites enable modular noncovalent synthesis of multi-component architectures.
• Judicious selection of spectator ions allows for controlled assembly pathways and isolation of intermediates.
• This approach provides a predictable and versatile platform for constructing complex supramolecular structures.