Anion-Guided Controlled Molecular Growth of Multi-Component Giant Mo Wheel Family for Enhanced Oxidation Catalysis

Understanding the self-assembly of multicomponent giant polyoxometalates and their subsequent controlled molecular growth is crucial for addressing the challenges of building multicomponent structural motifs and elucidating structure-property relationships in complex cluster chemistry, yet it presents a significant challenge. Herein, we report two unprecedented giant Mo wheels featuring unique multicomponent building blocks, which are a {Mo₂VP₂}-stabilized decamer {Mo₁₁₀V₁₀P₂₀} and a {Mo₂VP₂}-mediated elliptical tetradecamer {Mo₁₅₄V₄P₈}. The former constitutes the long-sought archetypal decameric prototype, while the latter gives rise to a rare giant structural variant alongside classical {Mo₁₅₄}. Furthermore, employing anion-guided strategies enabled <i>in situ</i> site-specific molecular growth at {Mo₂} active sites of these wheels: sulfate-induced symmetrical capping of {Mo₁₁₀V₁₀P₂₀} with two {Mo₁₁} units yields Mo green {Mo₁₃₂V₁₀P₂₀} whereas a hierarchical growth mediated by PhPO₃^2-/SO₄^2- anions on {Mo₁₅₄V₄P₈} generates Mo blue {Mo₁₈₈V₁₁P₂₀} through the incorporation of {Mo₁}, arch-shaped {Mo₄}, and {ε-Mo^V₂₄V^V₇} guests. Molecular-growth products exhibit enhanced broad-spectrum light absorption and improved charge separation efficiency, leading to superior photocatalytic aerobic oxidation performance over both their precursors and undoped analogues. This study pioneers the use of multicomponent moieties in the design of giant Mo wheels and establishes an anion-guided strategy for precisely regulating molecular growth, which opens pathways to functional giant clusters with tailored properties.