Linker Engineering of High-Nuclearity {V₁₂@P₈W₄₈}-Based Metal-Organic Frameworks for Green-Light-Driven Oxidative...

The development of long-wavelength visible-light-responsive and reusable photocatalysts for organic transformation is of significant interest. Herein, we report the design and synthesis of high-nuclearity {V₁₂@P₈W₄₈}-based metal-organic frameworks, POMOF1 and POMOF2, as heterogeneous photocatalysts for long-wavelength light-triggered oxidation. Linker engineering, by tuning from visible-light-inactive triazole (L1) to a photosensitive anthraquinone-derived ligand (L2), not only leads to the generation of porous 1D open channels within POMOF2 but also imparts a strong peak absorption centered at 500 nm. Moreover, the integration of {V₁₂@P₈W₄₈} and Cu²⁺ ions together with L2 into POMOF2 enables the continued and broad absorption ranging from the ultraviolet to near-infrared region. Consequently, POMOF2 exhibited excellent activity in the green-light-driven oxidative coupling of benzylamines, affording a series of imines with high conversions of up to 99% under mild conditions. In contrast, POMOF1 could barely promote the reaction under the same conditions, further confirming the advantage of linker modulation. POMOF2 is stable and can be reused for three cycles with little loss of catalytic activity and structural integrity. This work highlights the potential of linker engineering as an efficient approach for designing long-wavelength photocatalysts, which can further push forward photoredox catalysis.