Template and Solid-State-Assisted Assembly of an M₉L₆ Expanded Coordination Cage for Medium-Sized Molecule...

Area of Science:

• Supramolecular Chemistry
• Coordination Chemistry
• Materials Science

Background:

• The M6L4 cage, assembled from metal blocks and triangular ligands, possesses a hydrophobic cavity suitable for small molecule encapsulation.
• This cage exhibits molecular recognition capabilities.

Purpose of the Study:

• To construct a larger supramolecular cage with an expanded internal volume from existing components.
• To investigate the guest recognition properties of the newly synthesized larger cage.

Main Methods:

• Self-assembly of palladium(II) or platinum(II) blocks and triazine-cored triangular ligands.
• Utilizing pillar[5]arene as a template to guide the formation of an M8L6 precursor.
• Formation of the M9L6 cage from the M8L6 precursor.

Main Results:

• Successfully synthesized an M9L6 cage with an internal volume of 1540 Å3, significantly larger than the M6L4 cage's 450 Å3.
• The M9L6 cage maintains the molecular recognition abilities of its predecessor.
• The new cage can recognize medium-sized guest molecules up to approximately 1600 molecular weight.

Conclusions:

• The M9L6 cage represents a successful expansion of supramolecular cage volume while preserving molecular recognition functions.
• This work demonstrates a templated self-assembly approach for creating larger, functional supramolecular structures.
• The M9L6 cage offers new possibilities for encapsulating and recognizing larger guest molecules.