Design and Structural Transformations of Zinc(II) Knotted Cage Frameworks

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Organic Synthesis

Background:

• Interwoven architectures are prevalent in biomolecules like proteins, DNA, and RNA.
• Synthesizing artificial interwoven structures with complex topologies remains a significant challenge.
• Controlled structural transformations of these artificial systems are not well-established.

Purpose of the Study:

• To develop a rational design strategy for synthesizing artificial interwoven structures.
• To enable controlled self-assembly of covalently linked knotted cage frameworks.
• To investigate the role of structural rigidity in framework transformations and guest binding.

Main Methods:

• Utilized tailored ligands and zinc coordination to direct self-assembly.
• Employed a rational design strategy focusing on ligand rigidity.
• Investigated the impact of peripheral crosslinkers and subcomponent addition sequence.

Main Results:

• Successfully synthesized covalently linked trefoil perplexane and trefoil tetrahedral knotted cage frameworks.
• Demonstrated two-way interconversion between interwoven and non-interwoven architectures.
• Showcased tunable guest encapsulation and release, regulated by cage conformation and crosslinkers.

Conclusions:

• Structural rigidity is key to governing framework transformations in self-assembled systems.
• The sequence of subcomponent addition critically influences product outcomes by stabilizing intermediates.
• This work provides a pathway for designing complex, transformable molecular architectures with tunable properties.