Solution-phase synthesis of Al13- using a dendrimer template

Superatoms, clusters that mimic the properties of elements different to those of which they are composed, have the potential to serve as building blocks for unprecedented materials with tunable properties. The development of a method for the solution-phase synthesis of superatoms would be an indispensable achievement for the future progress of this research field. Here we report the fabrication of aluminum clusters in solution using a dendrimer template, producing Al13 −, which is the most well-known superatom. The Al13 − cluster is identified using mass spectrometry and scanning transmission electron microscopy, and X-ray photoelectron spectroscopy is used to measure the binding energies. The superatomic stability of Al13 − is demonstrated by evaluating its tendency toward oxidation. In addition, the synthesis of Al13 − in solution enables electrochemical measurements, the results of which suggest oxidation of Al13 −. This solution-phase synthesis of Al13 − superatoms has a significant role for the experimental development of cluster science. Superatoms—clusters that exhibit some of the properties of elemental atoms—could serve as building blocks for functional materials, but their synthesis outside of the gas phase is highly challenging. Here, the authors use a dendrimer template to successfully produce Al13 − in solution.