Ferrocene-Functionalized Zirconocene-Oxo Assemblies: {Zr3Fc3} and {Zr12Fc4} Clusters with Excellent Photo-Fenton Catalytic Activities

We present two bimetallic architectures cooperatively assembled from trinuclear zirconocene units (Cp3Zr3, Cp = η5-C5H5) and redox-active ferrocene-based ligands (ferrocene carboxylic acid (HFcA) or 1,1-ferrocene dicarboxylic acid (H2FcDA)). Interestingly, single-crystal analysis revealed that Cp3Zr3 units exhibited diverse coordination behaviors upon combination with ferrocene derivatives, ultimately leading to two heterometallic clusters: {Zr3Fc3} with a metallocavitand structure and {Zr12Fc4} with a molecular ring architecture. Notably, the incorporation of ferrocene units provides a photosensitizing center, enabling excellent photocatalytic Fenton-like degradation of methylene blue with efficiencies of 88.86% {Zr3Fc3} and 99.85% {Zr12Fc4}. Furthermore, the DFT calculation results suggest that the HOMO → LUMO transition mainly involves metal-to-core charge transfer (MCCT) from the iron center of the ferrocenyl groups to the Zr-oxo cluster core. This work not only advances the structural diversity of ferrocene-functionalized zirconium-oxo clusters but also offers valuable insights into high-performance Fenton-like photocatalysts.