Development of polymeric materials for heterogeneous (photo)catalytic applications

Abstract

Demand for both renewable energy and sustainable chemical processes as a result of anthropogenic climate change in our society has never been greater. As we attempt to understand and develop new materials to address this need, the principles of ‘green’ chemistry help shape this journey. One method that has shown great promise to meet this demand is the utilisation of (photo)catalytic processes, which has been a driving force behind the development of many new materials. Among these materials, conjugated porous polymers (CPPs) have received much attention as (photo)catalytic materials due to their high specific surface area, extended π-conjugation and ability to act as light harvesters. This thesis presents a series of published works highlighting the research performed, including synthetic design and a wide scope of applications, and ideas towards how these materials will shape the way forward. Chapter 2 presents two CPPs with a broad range of absorbances from 520-550 nm which were utilised as efficient heterogeneous photosensitisers under visible light irradiation for singlet oxygen generation. Chapter 3 expands the scope of applications by introducing a CPP with both broad visible light absorbance and active bipyridyl groups within the polymer framework. This allowed for its use as both a (photo)catalysts for Knoevenagel reactions and photooxidation of benzylamines as well as a chelating agent for Pb uptake. Chapter 4 focuses on polymer-supported photosensitisers based on a repeat unit found in other CPPs. These polystyrene-based photosensitisers were used to generate reactive oxygen species under irradiation at 420 nm and helped demonstrate the significance of continuous flow chemistry compared to traditional batch procedures. Chapter 5 completes the story with a post-synthetically modified CPP used for Ag uptake. The silver-loaded polymers were then employed as heterogeneous catalysts for the heterocyclisation of 4-pentynoic acid. Overall, the results presented demonstrate a potential way forward to help meet the energy and sustainability demands in society.