Abstract

In recent decades, visible-light photoredox chemistry has experienced unprecedented development, enabling the discovery of new reactivities and opportunities in natural product synthesis. Catalysts comprising polypyridyl complexes of ruthenium and iridium predominantly used in photochemical reactions due to their remarkable properties. However, the scarcity and toxicity of transition metals render their use unsustainable and expensive. Therefore, I present an interdisciplinary approach for the development of metal-free photocatalytically active compounds, based on polymers of intrinsic microporosity (PIMs), which have gained attention due to their high surface area arising from their contorted molecular features. Through the synthesis of novel monomers and polymers coupled with their extensive characterization allowed the establishment of structure–property relationships within this catalytic platform, focusing on solubility, redox potentials, catalytic performance, and recyclability. The synthetic utility of PIMs was assessed through Minisci-type reactions with a broad range of substrates, showing remarkable performance compared to a variety of organic and transition metal photocatalysts, demonstrating their viability as metal-free alternatives in photocatalysis. Leveraging on the macromolecular features of the synthesized PIMs, they demonstrated complete retention in the nanofiltration setup, considerably outperforming commercial catalysts, achieving rejection selectivity 23 times greater than that of Ru or Ir complexes. Furthermore, I developed a continuous-flow system for photoredox reactions with in-line catalyst recycling, coupled with real-time reaction monitoring, to achieve turnover number as high as 504. The findings in my PhD thesis aim to bridge the gap between molecular design and process engineering, by providing a useful methodological framework to advance sustainable and cost-effective fine-chemical manufacturing.