π-Extended Salphen Scaffolds Enable CO₂ Electroreduction and Singlet Oxygen Generation.

Area of Science:

• Materials Science
• Organic Chemistry
• Electrochemistry

Background:

• π-conjugated systems offer tunable redox and photophysical properties.
• Salen ligands are versatile platforms for developing functional materials.
• Developing metal-free catalysts for CO2 reduction is a key challenge.

Purpose of the Study:

• To synthesize and characterize novel π-conjugated salen ligands and their boron difluoride complexes.
• To investigate their performance in electrochemical CO2 reduction.
• To explore their potential as photosensitizers for chemical transformations.

Main Methods:

• Electrochemical synthesis and characterization.
• Spectroscopic analysis (UV-Vis, fluorescence).
• Computational modeling (DFT).

Main Results:

• Synthesized new π-conjugated salen ligands and boron complexes.
• Achieved up to 56% Faradaic efficiency for electrochemical CO2 reduction to CO using organocatalysis.
• Demonstrated efficient singlet-oxygen generation for alkene oxidation under blue light.

Conclusions:

• π-extension of salen frameworks creates redox-active organocatalysts for CO2 reduction.
• Boron complexes exhibit excellent photosensitizing properties.
• This work presents metal-free alternatives for small molecule activation and photoredox catalysis.