Syntheses and structures of four new copper(I)–selenium clusters: size dependence of the cluster on the reaction conditions

Reactions of copper(I) acetate with bis(trimethylsilyl)selenium in the presence of phosphine ligands produce a wide variety of cluster compounds. The formation of these compounds depends very much upon the phosphine used, the solvent and reaction conditions. The following products have been isolated and characterised by X-ray crystallography: [Cu26Se13(PEt2Ph)14] 1, [Cu12Se6(PCy3)6] 2 (Cy = cyclohexyl, C6H11), [Cu26Se13(PCy3)10] 3 and [Cu59Se30(PCy3)15] 4. The selenium atoms in 1 form a body-centred icosahedron, with an overall spherical cluster framework. Compound 2 also has a spherical framework with the selenium atoms forming a slightly distorted octahedron. Compounds 3 and 4 are both unsymmetrical and 4 possesses a layered structure of selenium and copper atoms.