Cuboctahedral Pd as a spherical aromatic noble metal core: insights from a ligand-protected [Pd(Tr)] cluster.

Low-valent palladium nanoparticles are efficient species promoting catalytic activity and selectivity in a number of chemical reactions. Recently, an atom-centered cuboctahedral Pd motif has been characterized as a ligand-protected [Pd(Tr)] cluster featuring a 1s superatomic shell structure. In this report, we describe the ligand-cluster of and endohedral-cage interaction in [Pd(Tr)], which accounts for a favorable situation in the overall cluster. In addition, the spherical aromatic properties of the cluster were evaluated to understand the behavior of the ligand-protected Pd cluster core. Our results indicate a sizable interaction towards carbon-based ligands in an overall spherical aromatic cluster featuring a long-range shielding cone. Thus, [Pd(Tr)] is rationalized as the first ligand-protected palladium cluster to date exhibiting spherical aromatic properties, serving as a stable building block for molecule-based materials or as a dopant in porous carbon materials.