A Cationic Metal Glue Strategy for Expanding Paramagnetic Hetero‐Multinuclear Metal‐Oxo Clusters within Polyoxometalate Ligands

Abstract

AbstractPrecise structural design of large hetero‐multinuclear metal‐oxo clusters is crucial for controlling their large spin ground states and multielectron redox properties for application as a single‐molecule magnet (SMM), molecular magnetic refrigeration, and efficient redox catalyst. However, it is difficult to synthesize large hetero‐multinuclear metal oxo clusters as designed because the final structures are unpredictable when employing conventional one‐step condensation reaction of metal cations and ligands. Herein, we report a “cationic metal glue strategy” for increasing the size and nuclearity of hetero‐multinuclear metal‐oxo clusters by using lacunary‐type anionic molecular metal oxides (polyoxometalates, POMs) as rigid multidentate ligands. The employed method enabled the synthesis of {(FeMn4)Mn2Ln2(FeMn4)} oxo clusters (Ln=Gd, Tb, Dy, and Lu), which are the largest among previously reported paramagnetic hetero‐multinuclear metal‐oxo clusters in POMs and showed unique SMM properties. These clusters were synthesized by conjugating {FeMn4} oxo clusters with Mn and Ln cations as glues in a predictable way, indicating that the “cationic metal glue strategy” would be a powerful tool to construct desired large hetero‐multinuclear metal clusters precisely and effectively.