Metallonanobelt: A Kinetically Stable Shape-Persistent Molecular Belt Prepared by Reversible Self-Assembly Processes

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Coordination Chemistry

Background:

• Shape-persistent macrocycles are crucial for developing novel molecular architectures.
• Triptycene units offer rigidity for constructing complex supramolecular structures.
• Metallamacrocycles combine the properties of organic macrocycles with metal coordination.

Purpose of the Study:

• To synthesize a novel triptycene-based metallonanobelt.
• To investigate the templating effect of pillar[6]arene on macrocycle formation.
• To evaluate the stability and handling properties of the metallonanobelt.

Main Methods:

• Self-assembly of 2,3,6,7-tetraaminotriptycene (L) with square planar Pd2+.
• Utilizing a pillar[6]arene derivative (P6) as a template for selective pentamer formation.
• Isolation of the metallonanobelt based on solubility differences.

Main Results:

• Selective formation of a pentameric metallonanobelt was achieved using a P6 template.
• A mixture of oligomers was obtained in the absence of the template.
• The isolated pentamer exhibited remarkable stability in solution due to the robust [Pd(o-phenylenediamine)2] unit.

Conclusions:

• The metallonanobelt can be synthesized with high selectivity using a templating strategy.
• The resulting metallonanobelt is highly stable, akin to covalently synthesized nanobelts.
• This work provides a pathway for creating well-defined, robust metallomacrocyclic nanostructures.