Hierarchical Assembly of an Interlocked M₈ L₁₆ Container

Area of Science:

• Supramolecular Chemistry
• Coordination Chemistry
• Materials Science

Background:

• Metals and organic ligands can self-assemble into complex architectures.
• Templating by anions is a known strategy in supramolecular chemistry.
• Catenanes are mechanically interlocked molecules with unique properties.

Purpose of the Study:

• To synthesize and characterize a novel metallosupramolecular architecture.
• To investigate the role of anions in templating the self-assembly process.
• To explore the potential applications of the resulting structure.

Main Methods:

• Self-assembly of palladium(II) cations and phenanthrene-derived ligands.
• Structural characterization using mass spectrometry, NMR spectroscopy, and X-ray diffraction.
• Investigation of anion-templated structural rearrangements.

Main Results:

• Formation of a M8L16 metallosupramolecular architecture, a D4h-symmetric "Hopf link" catenane.
• Identification of nitrate anions within channel-like cavities, acting as templates.
• Demonstration of nitrate-triggered rearrangement of precursor assemblies into the catenane.
• Preparation of a functionalized analogue that self-assembles into reversible vesicle-like structures.

Conclusions:

• Nitrate anions are crucial templates for the formation of the M8L16 "Hopf link" catenane.
• The metallosupramolecular architecture can be further functionalized for self-assembly into higher-order structures.
• This work expands the scope of anion-templated synthesis in supramolecular chemistry.