Visible-light-driven reversible shuttle vicinal dihalogenation using lead halide perovskite quantum dot catalysts

Area of Science:

• Synthetic Chemistry
• Materials Science
• Photocatalysis

Background:

• Vicinal dihalides are valuable synthetic intermediates.
• Current dihalogenation methods often rely on expensive, hazardous reagents or significant energy input.
• Developing sustainable and efficient dihalogenation techniques is crucial.

Purpose of the Study:

• To develop a novel, sustainable method for vicinal dihalogenation.
• To utilize photocatalysis with low-cost materials for redox-neutral transformations.
• To explore the use of metal-halide perovskite quantum dots (QDs) in photocatalytic shuttle systems.

Main Methods:

• A photocatalytically assisted shuttle (p-shuttle) strategy was employed.
• 1,2-dihaloethanes were used as halogen sources under visible light.
• Metal-halide perovskite quantum dots served as photocatalysts.
• Ultrafast laser transient absorption spectroscopy was used to study reaction mechanisms.

Main Results:

• The p-shuttle strategy enabled redox-neutral and reversible vicinal dihalogenation.
• Perovskite QDs efficiently utilized hot electrons for the challenging photocatalytic reactions.
• The system demonstrated high tolerance for a wide range of alkenes at room temperature.
• Exceptional turnover numbers exceeding 120,000 were achieved for dibromination, dichlorination, and hetero-dihalogenation.

Conclusions:

• Metal-halide perovskite QDs offer superior performance in photoredox shuttle vicinal dihalogenation compared to other catalysts.
• This work presents a sustainable, visible-light-driven heterogeneous catalysis approach for novel chemical transformations.
• The findings open new avenues for utilizing perovskite QDs in green synthetic chemistry.