Owing to the unique lone-pair effect and pronounced hydrolytic tendency, the controllable synthesis of Sb^III-containing polyoxometalates (POMs) remains a significant challenge. Rather than being confined as internal heterogroup, the employment of Sb^III as an accessible metal center that cooperates with the POM framework represents an emerging research frontier. In this work, a series of Sb^III-containing polyoxotungstates were successfully prepared, displaying a systematic structural evolution from dimeric to trimeric assemblies with tunable Sb content. Benefiting from the introduction of strongly Lewis acidic Sb^III centers, the obtained POMs, serving as Lewis acid-base catalysts, exhibited significantly enhanced catalytic activity, broad substrate scope, and excellent recyclability in the Knoevenagel condensation reaction. Based on the structure-activity relationship analysis, it is believed that modulation of the coordination environment around the Sb^III centers might serve as a promising strategy for the optimization of catalytic performance.

Precise control over metal-organic polyhedra (MOPs) architectures via metal and organic linker engineering presents a critical challenge for advancing functional porous materials with specific properties. The rational design of organic linkers and secondary building units (SBUs) with programmable configurational features facilitates the assembly of novel MOPs, wherein structural complexity is enhanced through the integration of low-symmetry linkers and expandable SBUs. Herein, a series of polyoxovanadate-based metal-organic polyhedra (VMOPs) with modulated structures were systematically engineered through linker desymmetrization and SBU expansion approach. Two types of tritopic triazine (D_3h)- or imidazole (C_s/C₁)-functionalized carboxylate ligands assemble with 3-connected prototype {V₆S} or expansional {V₆P} clusters, yielding VMOPs that exhibit structural evolution from T_d-symmetric regular tetrahedrons to D_2d-symmetric isosceles variants. Expansion of vertex clusters leads to structural fine-tuning of VMOPs, giving rise to diverse ligand conformations. Interestingly, these VMOPs exhibit significant differences during the iodine adsorption in both n-hexane solution and gaseous phases, which can be explained by the comprehensive influence of their cavity volume, the functional groups included, and the stacking arrangement. These findings demonstrate an effective structure-designing strategy via regulation of ligand symmetry and SBU architectural features, providing a powerful approach for the customized synthesis of MOPs with tailored structures and functionalities.

Novel structures of polyoxometalates can be obtained by confining the synthons within specific nanospaces. This capability is what the confined synthetic method excels at. Within the cavity of {P₈W₄₈}, a novel multicomponent cluster comprising cationic Fe^III and Ce^III heterometals and PO₄³⁻ oxyanions was successfully nucleated for the first time. Alongside examining the structure and composition of this host–guest assembly, thorough investigations were conducted into the enhanced peroxidase-like activity induced by the Fenton-active metallic species. Preliminary studies on a colorimetric sensor based on [{Fe^III₈Ce^III₄O₂(OH)₁₂(H₂O)₈(PO₄)₂}(P₈W₄₈O₁₈₄)]²⁶⁻ yielded promising results, demonstrating its ability to detect ascorbic acid with high sensitivity and specificity.