SYNTHESES AND STRUCTURES OF 4 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 compo unds. The formation of these compounds depends very much upon the phos phine used, the solvent and reaction conditions. The following product s have been isolated and characterised by X-ray crystallography: [Cu26 Se13(PEt2Ph)(14)] 1, [Cu12Se6(PCy3)(6)] 2 (Cy = cyclohexyl, C6H11), [C u26Se13(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.