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 {Mo 2 VP 2 }-stabilized decamer {Mo 110 V 10 P 20 } and a {Mo 2 VP 2 }-mediated elliptical tetradecamer {Mo 154 V 4 P 8 }. The former constitutes the long-sought archetypal decameric prototype, while the latter gives rise to a rare giant structural variant alongside classical {Mo 154 }. Furthermore, employing anion-guided strategies enabled in situ site-specific molecular growth at {Mo 2 } active sites of these wheels: sulfate-induced symmetrical capping of {Mo 110 V 10 P 20 } with two {Mo 11 } units yields Mo green {Mo 132 V 10 P 20 } whereas a hierarchical growth mediated by PhPO 3 2– /SO 4 2– anions on {Mo 154 V 4 P 8 } generates Mo blue {Mo 188 V 11 P 20 } through the incorporation of {Mo 1 }, arch-shaped {Mo 4 }, and {ε-Mo V 24 V V 7 } 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.