Flash Communication: Pd2Zn2 Clusters from the Reduction of Palladium(II) Dichloride Precursors with Metallic Zinc

We report the synthesis and solid-state characterization of two unusual Pd2Zn2 clusters formed from the partial reduction of [PdL2Cl2] precursors (L2 = dcpe or dppe) with metallic zinc. The new clusters have been characterized by single crystal X-ray diffraction and contain a Pd2Zn2Cl3 core capped by two chelating phosphine ligands with Zn in the formal +1.5 oxidation state. While they possess a near tetrahedral arrangement of metal ions, calculations and bonding analysis (NBO, AIM) suggest that there is limited Zn- - -Zn bonding in these species. Characterization in the solution state is suggestive of dynamic behavior on dissolution, with both diamagnetic and paramagnetic species observed by NMR and EPR spectroscopy. One of these Pd2Zn2 clusters was shown to be an effective precursor for the homocoupling of an aryl bromide.