From Molecular to Polymeric Donors: Prolonged Charge Separation in Modular Photoredox-Active Ru(II) Polypyridyl-Type...

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Organic Synthesis

Background:

• Photoredox-active materials are crucial for energy conversion and catalysis.
• Developing efficient synthetic routes for complex photoredox systems remains a challenge.

Purpose of the Study:

• To present a divergent modular synthesis for photoredox-active dyads, triads, and tetrads.
• To explore late-stage diversification strategies for advanced molecular assemblies.

Main Methods:

• Combining "chemistry-on-the-ligand", stepwise complexation, and "chemistry-on-the-complex".
• Utilizing palladium-catalyzed borylation and Suzuki-Miyaura cross-coupling for functionalization.
• Employing (spectro-)electrochemical, time-resolved transient absorption, and emission spectroscopy.

Main Results:

• Successful synthesis of photoredox-active dyads, triads, and tetrads from a single ligand precursor.
• Preserved redox properties and high-energy charge-separated (CS) states with minimal driving force for quenching.
• Formation of long-lived CS states in polymer-based triads, extending CS lifetime by two orders of magnitude compared to molecular triads.

Conclusions:

• The modular approach enables efficient synthesis of advanced photoredox-active assemblies.
• Late-stage diversification via "chemistry-on-the-complex" is effective for tailoring material properties.
• Long-lived CS states (up to 13.2 μs) were achieved in conjugated polycarbazole multidonors.