Self-assembly of a giant heterometallic polyoxovanadate with catalytic activity for epoxidation of alkenes

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.