Redox-Switchable Poly-Lewis Acids Allow the Controlled Release of Guests

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Catalysis

Background:

• Poly-Lewis acids (PLAs) are of significant interest for host-guest chemistry and catalysis.
• Redox-active units offer potential for dynamic control over material properties.

Purpose of the Study:

• To synthesize and characterize novel PLAs incorporating redox-active dibenzo[a,e]cyclooctatetraene (dbCOT) units.
• To investigate the impact of reduction/oxidation on the electronic structure and Lewis acidity of these PLAs.
• To explore the potential of these materials for switchable catalysis and functional applications.

Main Methods:

• Synthesis of dbCOT-based PLAs.
• Two-electron reduction of PLAs.
• Single-crystal X-ray diffraction (sc-XRD) for structural analysis.
• Density Functional Theory (DFT) calculations.
• Redox cycling applied to an Al-P coordination polymer.

Main Results:

• Reduced PLAs exhibit planarization and formation of extended π-systems.
• Extended π-systems reduce Lewis acidity, enabling controlled guest release.
• Oxidation regenerates Lewis acidity.
• Coordination polymers remain structurally stable through redox cycles.
• Switchable electronic and structural properties were demonstrated.

Conclusions:

• dbCOT-based PLAs offer tunable Lewis acidity through reversible redox switching.
• These materials are promising for developing switchable catalysts and functional materials in electronics, optics, and magnetism.
• The stability of the coordination polymer backbone during redox cycling is advantageous for material design.