Cyclometallated compounds. XV. A tetranuclear acetate-bridged cyclopalladated molecular box

The title complex, tetra-mu -acetato-O:O'-bis{[mu -1,4-bis(2-pyridyloxy)phenylene-N,C-2:N',C-6]dipalladium(II)} bis(trichloromethane) dihydrate, [Pd-4(C16H10N2O2)(2)(C2H3O2)(4)]. 2CHCl(3). 2H(2)O, the product of the reaction of 1,4-bis(2-pyridyloxy)benzene with palladium acetate, is shown to be a tetranuclear, rather than a polymeric, species. It crystallizes about a centre of inversion and has two doubly cyclopalladated ligands bridged by four acetate groups. The cyclopalladated ligand is far from planar in the complex and has the central benzene rings pi -stacked. The chelate rings exist in shallow boat conformations.