Vertex-Shared Linear Superatomic Molecules: Stepping Stones to Novel Materials Composed of Noble Metal Clusters.

Extremely small metal clusters composed of noble metal atoms (M) have orbitals similar to those of atoms and therefore can be thought of as artificial atoms or superatoms. If these superatoms can be assembled into molecular analogs, it might be possible to create materials with new characteristics and properties that are different from those of existing substances. Therefore, the concept of superatomic molecules has attracted significant attention. The present review focuses on vertex-shared linear M superatomic molecules formed via the sharing of a single metal atom between M superatoms having icosahedral cores and summarizes the knowledge obtained to date in this regard. This summary discusses the most suitable ligand combinations for the synthesis of M superatomic molecules along with the valence electron numbers, stability, optical absorption characteristics, and luminescence properties of the M superatomic molecules fabricated to date. This information is expected to assist in the production of many M superatomic molecules with novel structures and physicochemical properties in the future.