Calixarene-based mol-ecular capsule from olefin metathesis.

Area of Science:

• Supramolecular Chemistry
• Organic Synthesis
• Crystal Engineering

Background:

• Calix[4]arenes are versatile macrocyclic compounds with a well-defined cavity.
• The development of novel cage molecules is crucial for host-guest chemistry and materials science.
• Metathesis reactions offer powerful tools for constructing complex molecular architectures.

Purpose of the Study:

• To synthesize a novel bis-calixarene cage molecule.
• To characterize the structure and conformation of the synthesized cage.
• To explore the self-assembly and structural properties of calixarene-based supramolecular structures.

Main Methods:

• Synthesis of tetra-kis-(all-yloxy)calix[4]arene.
• Olefin metathesis using the first-generation Grubbs catalyst.
• Catalytic hydrogenation for structural modification.
• Single-crystal X-ray diffraction for structural determination.

Main Results:

• Successful synthesis of a novel bis-calixarene cage molecule, C72H72O8·C6H6.
• The cage structure comprises two calix[4]arene units linked by four-carbon chains.
• Calix[4]arene units adopt a flattened cone conformation with specific dihedral angles.
• The crystal lattice contains a benzene solvent molecule, while the cage cavity is empty.
• Disorder in two alkyl linking arms was observed and modeled.

Conclusions:

• The study reports the successful synthesis and structural elucidation of a unique bis-calixarene cage.
• The flattened cone conformation of the calix[4]arene units influences the overall cage architecture.
• The findings contribute to the understanding of calixarene-based supramolecular chemistry and the design of novel molecular cages.