Integrating Photoactive Ligands into Dimension-Reduced Metal–Organic Frameworks: Harnessing the Power of Organic Photocatalysts

ConspectusThis Account aims to concisely summarize recent advancements in the field of photocatalysis, with a particular focus on dimension-reduced metal–organic nanomaterials, including coordination cages and 2D structures. Metal–organic frameworks (MOFs), known for their high crystallinity, porosity, and well-determined structures, are at the forefront of this research. They offer a unique confined environment that is optimal for enhancing host–guest interactions. This, in turn, leads to highly selective and efficient catalytic reactions. The ability of MOFs to provide a structured and controlled environment has revolutionized the way we approach catalytic processes, especially in terms of efficiency and selectivity. However, a significant challenge that has emerged in the use of traditional 3-dimensional bulk MOFs is their limitation in mass transport. This limitation often results in reduced catalytic efficiency, hindering their practical applicability in industrial scenarios. To address these challenges, researchers have taken a novel turn toward exploring 0-dimensional (0D) porous coordination cages and 2-dimensional (2D) MOF-derived nanosheets. These structures exhibit improved mass transport capabilities and more exposed catalytic centers, thereby circumventing the issues faced by their 3D counterparts. These structures have shown great promise in overcoming the limitations of pore clogging, a common issue in 3D MOFs, thus paving the way for more efficient and scalable catalytic processes.Section 2 of our paper delves deeper into the design and functionalities of cages and 2D MOF nanosheets. This section is particularly focused on the theoretical and technical approaches necessary to understand and utilize these materials effectively. We discuss various methods, including studying redox cycles through electrochemical and photochemical methods, and exploring the intricate dynamics of host–guest chemistry. Additionally, this section highlights the latest spectroscopic and computational techniques that have been instrumental in recent research efforts. These techniques have enabled scientists to investigate active sites within MOFs, thereby providing deeper insights into their catalytic mechanisms and potential applications. In section 3 of this Account, we provide a discussion on the design and availability of these photoactive ligands and framework materials. In addition to structural innovations, this account also delves into the realm of introducing small-molecule organic photocatalysts. This section is pivotal in understanding the underlying chemistry and the innovative approaches employed in the development of these materials. We elaborate on the synthetic methodologies, the choice of functional groups, and the potential applications of these novel materials. Despite their inherent challenges, such as short excited-state lifespans and difficulties in recycling, these photocatalysts have shown a vast potential for effective photochemical transformations. By integrating these small molecules into the 0D and 2D frameworks, chemists have been able to significantly enhance their efficiency and stability.In conclusion, this Account aims to elucidate the design principles of 0D and 2D MOF nanomaterials, explore reliable characterization techniques, and inspire the development of novel catalysts. The goal is to achieve catalysts with heightened selectivity and activity, which can revolutionize various industrial processes and contribute to sustainable development. Through this comprehensive overview, we hope to provide a foundational understanding for future research in this rapidly evolving field, guiding new discoveries and innovations.