Unlocking New Potentials of Photoredox Catalysts: Rational Design and Synthetic Applications

The evolution of photochemistry during the 20th century has provided chemistry with new synthetic tools. The advent of modern photoredox catalysis has disclosed how the knowledge of metal complexes as light absorbing redox mediators, i.e. as photoredox catalysts (PCs) was instrumental to the development of new synthetic methods. Recent concerns on the use of precious metals have paved the way for the development of purely organic molecules as PCs, which have often been able to match or outperform the long-standing organometallic complexes. Continuous research in the field has shown how the design of new organic PCs can even disclose reactivities which are not possible with the established PCs. This PhD Dissertation focused on two closely related topics, namely i) the disclosure of new synthetic methods based on organic photoredox catalysts and, ii) the rationally guided design of new catalytic structures. In particular, established organic PCs have first been leveraged to perform straightforward fluorination and cycloaddition reactions. The role and mode of action of the PCs in each reaction has been fully elucidated, providing valuable insight into the reaction mechanisms. The physicochemical and mechanistic knowledge acquired from the development of novel synthetic methods has been used to the design of organic PCs able to outperform previously known catalytic systems and engage in mechanistically varied synthetic settings. The methods and catalysts disclosed in this Dissertation provide new tools for the manipulation of organic substrates, enriching chemistry with new opportunities.