Enhanced Photocatalytic Activity in Thorium-Based Metal–Organic Frameworks (MOFs) via Solvent Induced π–π Stacking of Photoactive Ligands

Thorium-based metal-organic frameworks (MOFs) exhibit exceptional stability and hold promise for photocatalytic applications, yet their performance modulation remains challenging. Herein, two novel thorium MOFs (<b>IHEP-32</b> and <b>IHEP-33</b>) were synthesized via a solvent-induced strategy using N,N'-bis(5-isophthalic acid) naphthalene diimide (BINDI) ligands. Both materials demonstrate reversible photochromism and maintain structural integrity in aqueous solutions (pH 2-12). The results of the catalytic oxidation of thioether driven by visible light indicate that the catalytic conversion rate of <b>IHEP-32</b> reached 73.3%, significantly higher than that of <b>IHEP-33</b> at 50.2%. Structural analysis reveals that π-π stacking interactions between BINDI ligands in <b>IHEP-32</b> facilitate efficient charge carrier transport, while the absence of such interactions in <b>IHEP-33</b> limits its activity. This work offers valuable perspectives for designing innovative and efficient photocatalysts.