Research Projects

The intrinsic functional groups of supramolecular metal-organic cages, along with their distinctive host-guest interactions, can be harnessed as effective photoreductants by utilizing in situ-generated radical anion intermediates. The three-dimensional cavity of metal-organic cages functions like an enzymatic pocket, offering a confined environment that elevates the local concentration of reactants and stabilizes reactive intermediates and transition states. This confinement can enhance reaction rates, improve selectivity, and enable pathways that are otherwise inaccessible in bulk solution. However, the design and development of strongly reducing metal-organic cages remain challenging due to the instability of in situ-generated radical anions. To overcome this bottleneck, we propose targeted design strategies that involve selecting suitable radical anion-generating groups as functional ligands for constructing stable and efficient metal-organic cage-based reductants. The emphasis will be on selecting appropriate redox-active ligands for the cage’s building blocks, enabling the formation of a strongly reducing radical anion upon light irradiation. The in situ-generated radical anions of metal-organic cages will be explored for various photoredox catalytic transformations in aqueous medium, including the reduction of aryl chlorides to produce value-added chemical products that are typically inaccessible with conventional photocatalysts. Photoreduction of aryl chlorides holds significant scientific and practical importance, especially in the realms of sustainable organic synthesis, green chemistry, and the production of value-added compounds. A key advantage of the proposed materials is their reusability, while maintaining high yield and selectivity in catalytic transformations. Additionally, redox-active guest molecules such as perylene diimide will be encapsulated within redox-inactive cages, and their photoredox activity will be investigated in the confined environment of the host cavity. Specific work plan and novel aspects: • Exploration of the potential of metal-organic cage-based radical anions for photoredox catalysis within their cavities • Incorporation of a functional guest capable of in situ radical anion generation within the cage cavity and investigation of its guest-induced photoredox activity • Elucidation of the catalytic mechanism through an integrated approach involving spectroscopy, computational modeling, and electrochemical analysis We believe that the development of redox-active metal-organic cages, as outlined in the proposed objectives, for the reductive activation of organic molecules in aqueous medium via single-electron transfer (SET), a fundamental step underpinning a wide range of powerful synthetic transformations, holds significant potential for translational research with broad societal impact.