Do Anionic π Molecules Aggregate in Solution? A Case Study with Multi-interactive Ligands and Network Formation.

Area of Science:

• Supramolecular chemistry
• Materials science
• Coordination chemistry

Background:

• Anionic molecules typically resist aggregation due to charge repulsion.
• Multi-interactive ligands offer unique opportunities for self-assembly and material design.

Purpose of the Study:

• To investigate the aggregation behavior of a novel multi-interactive anionic ligand, 2,5,8-tri(4 étaire)-1,3,4,6,7,9-hexaazaphenalenate (TPHAP^-).
• To explore the formation of coordination networks using TPHAP^- and cadmium ions.
• To correlate solution aggregation states with solid-state structures.

Main Methods:

• Steady-state spectroscopy and fluorescence lifetime measurements to study solution aggregation.
• Single-crystal X-ray diffraction to determine solid-state structures.
• Coordination of TPHAP^- with cadmium ions to form crystalline materials.

Main Results:

• TPHAP^- exhibits a large Stokes shift and intramolecular charge transfer sensitive to hydrogen bonding.
• Concentration-dependent aggregation states of TPHAP^- potassium salt in methanol were observed.
• Self-assembly with cadmium ions yielded various crystal morphologies, including three new structures.
• X-ray structures revealed porous coordination networks.

Conclusions:

• The multi-interactive nature of TPHAP^- enables aggregation, overcoming typical anionic repulsion.
• Solution aggregation behavior directly influences the formation and structure of solid-state coordination networks.
• TPHAP^- is a versatile ligand for constructing functional porous materials.