Executive Summary : | Multifunctional catalysts have revolutionized catalytic efficiency and selectivity in modern times. They bridge the gap between heterogeneous and homogeneous catalysis and offer solutions to well-known catalytic problems. However, the synthesis, long-term stability and catalytic efficiency of these catalysts remain significant challenges. The increasing atmospheric CO2 levels have become a major concern for the research industry, and converting this abundant C1 feedstock into value-added chemicals requires efficient and stable catalysts. One important conversion in this domain is the cycloaddition of CO2 to epoxide to form cyclic carbonates. While most of the literature relies on thermal conditions, an efficient catalyst that can perform this task under natural sunlight with high conversion rates is significant. Unfortunately, existing materials and protocols cannot integrate both reactive adsorption sites and photocatalytic moieties in the same material. Thus, a strategic design of multifunctional materials capable of performing both functions simultaneously is necessary. This proposal aims to design a unique porphyrin linker that introduces imidazolium rings and isopthalate carboxylate connectivity at meso-positions. The linker geometry creates unique topological architectures in their respective frameworks where the pore surfaces are decorated with abundant CO2 adsorption sites. The pore size and pore surface's synergistic cooperation are expected to result in remarkable CO2 adsorption capacity, even from the atmosphere directly. The frameworks obtained from the proposed linkers can accommodate Lewis acid sites required to activate epoxides for conversions. The halide counter ion of imidazolium/pyridinium rings at the meso position will be utilized for ring opening of epoxides and restricts the use of cocatalyst for halide ion source. The linker's length creates a huge pore volume in the corresponding frameworks, enabling larger epoxide substrates for cycloaddition of CO2. Most importantly, the photoactive porphyrin component of the linker catalyses the reaction under natural sunlight, owing to its strong absorption behaviour in visible light. Moreover, the variety of porphyrin-based skeletons designed for this study aims to bring cooperative synergy between all the linker/framework functionalities towards photo-assisted cycloaddition of CO2 to epoxides, forming cyclic carbonates. |