Clippane: A Mechanically Interlocked Molecule (MIM) Based on Molecular Tweezers

Area of Science:

• Supramolecular Chemistry
• Organometallic Chemistry
• Materials Science

Background:

• Mechanically interlocked molecules (MIMs) are complex architectures with unique properties.
• Metallotweezers offer versatile platforms for constructing sophisticated molecular structures.
• Controlling self-assembly and preventing dissociation are key challenges in MIM synthesis.

Purpose of the Study:

• To synthesize and characterize a new mechanically interlocked molecule.
• To investigate the role of bulky substituents in stabilizing MIMs.
• To confirm the mechanically interlocked nature in various phases.

Main Methods:

• Synthesis of pyrene-imidazolylidene gold(I) metallotweezers and pyridine-centered linkers.
• Self-aggregation of metallotweezers to form a dimeric structure.
• Characterization using experimental techniques (e.g., NMR, Mass Spectrometry, X-ray crystallography) in solution, gas phase, and solid state.

Main Results:

• Successful preparation of a novel mechanically interlocked molecule via self-aggregation.
• Demonstration that tert-butyl groups act as stoppers, preventing dimer dissociation.
• Confirmation of the mechanically interlocked structure in solution, gas phase, and solid state.
• Comparison with non-substituted tweezers, highlighting the importance of bulky groups for mechanical coercion.

Conclusions:

• The study successfully demonstrates the formation of a stable mechanically interlocked molecule.
• Bulky tert-butyl groups are crucial for achieving mechanical interlocking by preventing dissociation.
• The findings provide insights into the design principles for stable MIMs with controlled self-assembly.