Polycationic-Shelled Capsular and Tubular Nanostructures and Their Anionic-Guest Binding Properties

Area of Science:

• Supramolecular chemistry
• Nanotechnology
• Materials science

Background:

• Development of novel nanostructures with tailored properties is crucial for advanced applications.
• Cationic nanostructures offer unique electrostatic interactions for molecular recognition and encapsulation.
• Bisacridinium ligands provide a versatile platform for constructing polyaromatic nanospaces.

Purpose of the Study:

• To synthesize new capsular and tubular nanostructures with unique electrostatic characteristics.
• To explore the self-assembly of metal ions and bent bisacridinium ligands for nanospace creation.
• To investigate the water solubility and selective encapsulation capabilities of the synthesized nanostructures.

Main Methods:

• Quantitative assembly of metal ions and bent bisacridinium ligands.
• Synthesis of spherical and tubular nanostructures with diameters around 1 nm.
• Preparation of a polycationic capsule with an elliptical nanocavity using an elongated ligand.
• Assessment of water solubility and selective encapsulation of anionic organic compounds.

Main Results:

• Successfully prepared capsular and tubular nanostructures with closed spherical and open cylindrical cavities, respectively.
• Achieved facile three-step synthesis for these nanostructures.
• Developed a polycationic capsule with an elliptical nanocavity.
• Demonstrated sufficient water solubility for the spherical polyaromatic capsule despite the absence of hydrophilic groups.
• Showcased selective encapsulation of anionic organic compounds within the highly cationic cavity (12+).

Conclusions:

• Novel cationic nanostructures (capsules and tubes) with unique electrostatic properties were successfully synthesized.
• The facile synthetic protocol allows for the creation of diverse nanostructures, including those with elliptical nanocavities.
• The polycationic nature of the nanostructures imparts water solubility and enables selective encapsulation of anionic species in aqueous media.