Host-guest capability of a three-dimensional heterometallic macrocycle

Area of Science:

• Supramolecular Chemistry
• Coordination Chemistry
• Materials Science

Background:

• Host-guest chemistry is crucial for molecular recognition and self-assembly.
• Heterometallic coordination macrocycles offer unique structural and functional properties.
• Controlling the assembly of macrocycles with different guest molecules is challenging.

Purpose of the Study:

• To synthesize and characterize a novel three-dimensional heterometallic coordination macrocycle.
• To investigate the host-guest complexation behavior with planar and non-planar polycyclic aromatic hydrocarbons.
• To explore the structural transformations of the macrocycle under different conditions.

Main Methods:

• Synthesis of a three-dimensional heterometallic coordination macrocycle.
• Host-guest complexation studies with pyrene, corannulene, coronene, and naphthalene bisimide.
• Single-crystal X-ray diffraction analysis to determine complex structures.
• Investigation of macrocycle stability and transformation in the presence of a soft base.

Main Results:

• The macrocycle successfully forms 1:1 host-guest complexes with pyrene, coronene, and corannulene.
• The non-planar corannulene guest molecule flattens upon encapsulation.
• Larger cavity macrocycles form infinite sandwich structures with naphthalene bisimide.
• The macrocycles can be disassembled by a soft base to yield hexanuclear triangular prism complexes.

Conclusions:

• The designed heterometallic coordination macrocycle exhibits selective guest encapsulation.
• Macrocycle cavity size dictates the type of host-guest assembly formed.
• The macrocycle's structural integrity can be reversibly controlled, leading to new complex architectures.