Photocatalysis: A Green Tool for Redox Reactions

Abstract Reduction-and-oxidation (redox) reactions are one of the most utilized approaches for the synthesis of value-added compounds. With the growing awareness of green chemistry, researchers have searched for new and sustainable pathways for performing redox reactions. From this, a new field has gained tremendous attention, namely photoredox catalysis. Here, molecules can be easily oxidized or reduced with the use of one of Nature’s biggest resources: visible light. This tutorial paper gives the basics of photoredox catalysis along with limited examples to encourage further research in this blooming research area. 1 Introduction 2 Redox Chemistry 3 Photochemistry 3.1 Laws of Photochemistry 3.2 Principles 3.3 Examples 4 Photoredox Catalysis 4.1 General Principles 4.2 Classification of Redox Processes 4.3 Other Mechanistic Considerations 4.4 Stern–Volmer Plots 4.5 Photophysical Properties 4.6 Redox Potentials 5 Photocatalysts 5.1 Metal-Based Photocatalysts 5.2 Organic Dyes 5.3 Semiconductors 6 Dual Catalysis 7 Conclusions