Cavity Constriction and Chiralization of Polyaromatic Subnanotubes via Post-assembly Ligand/Metal Modification

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Organic Chemistry

Background:

• Late-stage modification of coordination-driven structures is challenging due to metal-ligand bond instability.
• Tuning cavity functions of nanostructures requires robust and adaptable frameworks.

Purpose of the Study:

• To develop polyaromatic subnanotubes with modifiable components (metal hinges and ligands).
• To demonstrate post-assembly modification for tuning cavity properties and creating multi-functional host-guest systems.

Main Methods:

• Synthesis of polyaromatic subnanotubes from PtCl2 and anthracene-embedded bispyridine ligands.
• Reversible symmetrical modification of ligands using O2 to create constricted subnanotubes.
• Asymmetrical modification of metal hinges with chiral ammonium groups to generate cryptochiral subnanotubes.

Main Results:

• Achieved reversible conversion to constricted subnanotubes via ligand modification.
• Demonstrated significant enhancement (up to 4-fold) of coumarin dye emission within the subnanocavity.
• Generated cryptochiral subnanotubes inducing strong chiroptical properties (CD and CPL) in bound dyes.
• Successfully performed two-directional post-assembly multi-modifications.

Conclusions:

• Polyaromatic subnanotubes offer a versatile platform for post-assembly modification.
• These modifications enable precise control over cavity functions and host-guest interactions.
• The developed subnanotubes are promising for creating advanced multi-functional host-guest systems and chiroptical materials.