Discovery of a Neutral 40-Pd<sup>II</sup>-Oxo Molecular Disk, [Pd<sub>40</sub>O<sub>24</sub>(OH)<sub>16</sub>{(CH<sub>3</sub>)<sub>2</sub>AsO<sub>2</sub>}<sub>16</sub>]: Synthesis, Structural Characterization, and Catalytic Studies
Saurav Bhattacharya, Xiang Ma, Ali S. Mougharbel, Mohamed Haouas, Pei Su, Michael F. Espenship, Dereje H. Taffa, Helge Jaensch, Anton‐Jan Bons, Tobias Stuerzer, Michael Wark, Julia Laskin, Emmanuel Cadot, Ulrich Kortz
Abstract
We report on the synthesis and structural characterization of a giant, discrete, and neutral molecular disk, [Pd40O24(OH)16{(CH3)2AsO2}16] (Pd40), comprising a 40-palladium-oxo core that is capped by 16 dimethylarsinate moieties, resulting in a palladium-oxo cluster (POC) with a diameter of ∼2 nm. Pd40, which is the largest known neutral Pd-based oxo cluster, can be isolated either as a discrete species or constituting a 3D H-bonded organic–inorganic framework (HOIF) with a 12-tungstate Keggin ion, [SiW12O40]4– or [GeW12O40]4–. 1H and 13C NMR as well as 1H-DOSY NMR studies indicate that Pd40 is stable in aqueous solution, which is also confirmed by ESI-MS studies. Pd40 was also immobilized on a mesoporous support (SBA15) followed by the generation of size-controlled Pd nanoparticles (diameter ∼2–6 nm, as based on HR-TEM), leading to an effective heterogeneous hydrogenation catalyst for the transformation of various arenes to saturated carbocycles.