Discovery and Supramolecular Interactions of Neutral Palladium‐Oxo Clusters Pd(16) and Pd(24)

We report on the synthesis, structure, and physicochemical characterization of the first three examples of neutral palladium‐oxo clusters (POCs). The 16‐palladium(II)‐oxo cluster [Pd(16)O(24)(OH)(8)((CH(3))(2)As)(8)] (Pd(16)) comprises a cyclic palladium‐oxo unit capped by eight dimethylarsinate groups. The chloro‐derivative [Pd(16)Na(2)O(26)(OH)(3) Cl(3) ((CH(3))(2) As)(8)] (Pd(16)Cl) was also prepared, which forms a highly stable 3D supramolecular lattice via strong intermolecular interactions. The 24‐palladium(II)‐oxo cluster [Pd(24)O(44)(OH)(8)((CH(3))(2)As)(16)] (Pd(24)) can be considered as a bicapped derivative of Pd(16) with a tetra‐palladium‐oxo unit grafted on either side. The three compounds were fully characterized 1) in the solid state by single‐crystal and powder XRD, IR, TGA, and solid‐state (1)H and (13)C NMR spectroscopy, 2) in solution by (1)H, (13)C NMR and (1)H DOSY spectroscopic methods, and 3) in the gas phase by electrospray ionization mass spectrometry (ESI‐MS).