Stacking Interactions Drive Selective Self-Assembly and Self-Sorting of Pyrene-Based M(II)4L6 Architectures

Area of Science:

• Coordination Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Metal-organic self-assembly offers pathways to complex architectures.
• Pyrene-based ligands provide unique photophysical and structural properties.
• Controlling assembly through ligand design is crucial for functional materials.

Purpose of the Study:

• To investigate the self-assembly of isomeric bis(3-aminophenyl)pyrenes with metal ions.
• To explore the formation of novel supramolecular structures and their guest-binding capabilities.
• To understand the role of ligand structure and donor-acceptor interactions in selective self-assembly.

Main Methods:

• Subcomponent self-assembly using pyrene-based diamines, 2-formylpyridine, and Fe(II), Co(II), Zn(II) ions.
• X-ray crystallography to determine the structures of the resulting assemblies.
• Guest binding studies to assess selectivity of the M(II)2L2 box.
• Comparative studies of homoleptic and heteroleptic assemblies.

Main Results:

• Formation of two new M(II)4L6 assemblies with distinct coordination modes (meridional and facial).
• Discovery of a M(II)2L2 box selectively binding electron-deficient guests via pi-stacking.
• Selective self-assembly of a heteroleptic M(II)4L4L'2 architecture favored thermodynamically.
• Observation of narcissistic self-sorting with an isomeric pyrene-based diamine.

Conclusions:

• Meta linkages in ligands facilitate pi-stacking for guest recognition and assembly control.
• Donor-acceptor interactions drive the formation of thermodynamically favored heteroleptic architectures.
• Self-assembly offers precise control over complex supramolecular structures with tunable properties.