A Novel Tetrameric Polyoxotantalate Aggregate: {Co8Ta24} Featuring a High-Nuclearity Co-8 Cluster

The first Co-containing polyoxotantalate cluster, [H5Co8Ta24O80](15-), has been obtained. The tetramer has by far the highest degree of polymerization of any polyoxotantalate based on {Ta6O19} and is the largest high-nuclearity Co-cluster-containing polyoxotantalate obtained thus far. The synthesis of new polyoxotantalates has long been a challenging subject in polyoxotantalate chemistry. The findings of this study show the possibility of using Ta-based polyoxometalates as ligands to construct large aggregated structures analogous to the related Nb compounds. Therefore, the work demonstrates exciting progress in the synthesis of new polyoxotantalates.