Copper Chalcogenide Clusters Stabilized with Ferrocene-Based Diphosphine Ligands

The redox-active diphosphine ligand 1,1′-bis­(diphenylphosphino)­ferrocene (dppf) has been used to stabilize the copper­(I) chalcogenide clusters [Cu12(μ4-S)6(μ-dppf)4] (1), [Cu8(μ4-Se)4(μ-dppf)3] (2), [Cu4(μ4-Te)­(μ4-η2-Te2)­(μ-dppf)2] (3), and [Cu12(μ5-Te)4(μ8-η2-Te2)2(μ-dppf)4] (4), prepared by the reaction of the copper­(I) acetate coordination complex (dppf)­CuOAc (5) with 0.5 equiv of E­(SiMe3)2 (E = S, Se, Te). Single-crystal X-ray analyses of complexes 1–4 confirm the presence of {Cu2xEx} cores stabilized by dppf ligands on their surfaces, where the bidentate ligands adopt bridging coordination modes. The redox chemistry of cluster 1 was examined using cyclic voltammetry and compared to the electrochemistry of the free ligand dppf and the corresponding copper­(I) acetate coordination complex 5. Cluster 1 shows the expected consecutive oxidations of the ferrocene moieties, CuI centers, and phosphine of the dppf ligand.