Synthesis, chemical characterization, and molecular structure of Au-8{Fe(CO)(4)}(4)(dppe)(2) and Au6Cu2{Fe(CO)(4)}(4)(dppe)(2)

The new Au-8(Fe(CO)(4))(4)(P<^>P), and Au6Cu2(Fe(CO)(4))(4)(P<^>P)(2) (P<^>P= dppm, dppe) neutral cluster compounds were isolated in good yields by condensation of the [Au-3(Fr(CO)(4))(2)(P<^>D)](-) anions with Au(SEt2)Cl and CuCl, respectively, and have been characterized by IR, NMR and microanalyses. The molecular structures of Au-8( Fe(CO)(4))(4)(dppe)(2) and Au6Cu2( Fe(CO)(4))(4)(dppe)(2) have been determined by X-ray diffraction studies. Both molecules adopt a stereogeometry of the heavy atoms consisting of a triangulated and corrugated ribbon twisted around the elongation direction. Contrary to the expectations the latter displays the two copper atoms in the sites of highest connectivity. This implies that site exchange between copper and gold occurs during the synthesis.