Isolation and Structures of Polyarene Palladium Nanoclusters

[Image: see text] We report that surrounding coordination of neutral six-membered arene rings affords molecularly well-defined organotransition metal nanoclusters. With the use of [2.2]paracyclophane as the face-capping arene ligand, we have isolated two polyarene palladium nanoclusters, one consisting of a hexakis-arene ligand shell and a hexagonal close-packed Pd(13) anticuboctahedron trichloride core, and the other consisting of an octakis-arene ligand shell and a non-close-packed Pd(17) square gyrobicupola dichloride core, both with Pd–Pd direct bonding. The μ(4)-facial coordination mode of arene was discovered through the structural characterization of the Pd(13) cluster. Their Pd(13) and Pd(17) cores, which are distinct from the previously identified face-centered-cubic Pd(13) core surrounded by seven-membered cycloheptatrienyl, are explained by stereochemical and theoretical analyses.