The self-assembly of giant polyoxovanadates (POVs) is highly attractive yet extremely challenging, hampered by protonation complexity and structural instability. Here, we obtain the largest POV cluster 1 via self-assembly in aqueous solution, in which tartaric acid serves as a structure-directing agent via synergistic coordination interactions between the metal linkers and the POV motifs. This aesthetically appealing giant compound 1 contains 128 vanadium ions and represents the highest‑nuclear V cluster known in POV chemistry to date. Compound 1 is a tetramer of manganese‐bridged [V^V₂₀V^IV₁₂(C₄H₂O₆)₈(OH)₁₀O₆₆(Cl)]²⁷⁻ units that are unique configurations and potential building blocks. Meanwhile, 1 exhibits excellent catalytic performance in the epoxidation reaction of cyclooctene, achieving 98% conversion and 99% selectivity under oxygen atmosphere. This work not only provides a new topology structure to POM chemistry but also establishes a synthesis strategy for constructing high-nuclear POVs.

Fully closed molybdenum blue cages remain difficult to prepare because long-range shell closure needs to be balanced with the stability of a mixed-valence Mo^VI/Mo^V framework. Retaining accessible surface metal sites adds a further challenge when such cages are considered for catalysis. Here we report a sulfate-guided fragment/anion co-assembly strategy for the synthesis of a capsule-shaped {Mo192} molybdenum blue cage, formulated as K₆Na₂₀[H₄₄Mo^VI₁₃₀Mo^V₆₂O₅₄₈(H₂O)₁₀₂(OH)₄₄(SO₄)₁₀]·238H₂O. The cluster is obtained from a Waugh-type K₆MnMo₉O₃₂·6H₂O precursor and molybdate under acidic, reducing, and hydrothermal conditions. Single-crystal X-ray diffraction reveals two fused {Mo96} half-shells, inward sulfate-bound {S-Mo6} units, equatorial {Mo2}-based connections, and continuous windows. The inward-facing sulfate ligands help support shell curvature without blocking the outer surface of the cage. Redox titration, bond-valence-sum analysis, and XPS indicate a mixed Mo^VI/Mo^V framework with an overall reduction degree of ca. 32%. The accessible mixed-valence cage was further evaluated in the tert-butyl hydroperoxide (TBHP) oxidation of 2-tert-butylphenol, giving 99% conversion and 99% selectivity for 2-tert-butyl-p-benzoquinone at 70 °C in 6 h. Hot-filtration, ICP-OES, recycling, FT-IR, and PXRD results support {Mo192} as the major recoverable catalytic phase. These results suggest that internal anion support is a useful way to assist the closure of giant POM cages while retaining surface accessibility for catalytic function. 

In the field of polyoxometalate (POM) chemistry, organophosphonate covalently modified polyoxometalates (OCMPs) have recently emerged as a promising frontier. These hybrid materials not only broaden the structural diversity of conventional POM derivatives and address the inherent stability limitations of POMs, but also allow for the design of improved properties tailored to diverse applications. Despite this growing interest, a systematic review dedicated to OCMPs is still lacking. This review provides a comprehensive summary of recent advances in OCMP research, with a particular focus on their structural features, functional properties, and prospective research directions.