Discovery and Supramolecular Interactions of Neutral Palladium-Oxo Clusters Pd and Pd.

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 O (OH) ((CH ) As) ] (Pd ) comprises a cyclic palladium-oxo unit capped by eight dimethylarsinate groups. The chloro-derivative [Pd Na O (OH)  Cl  ((CH )  As) ] (Pd Cl) was also prepared, which forms a highly stable 3D supramolecular lattice via strong intermolecular interactions. The 24-palladium(II)-oxo cluster [Pd O (OH) ((CH ) As) ] (Pd ) can be considered as a bicapped derivative of Pd 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 H and C NMR spectroscopy, 2) in solution by H, C NMR and H DOSY spectroscopic methods, and 3) in the gas phase by electrospray ionization mass spectrometry (ESI-MS).