GOLD(I)-GOLD(III) INTERACTIONS IN POLYNUCLEAR SULFUR-CENTERED COMPLEXES - SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF [S(AU(2)DPPF)(AU(C6F5)(3))] AND [(S(AU(2)DPPF))(2)(AU(C6F5)(2))]OTF (DPPF EQUALS 1,1'-BIS(DIPHENYLPHOSPHINO)FERROCENE)

The reactions of [S(Au(2)dppf)] (dppf = 1,1'-bis(diphenylphosphino)fer rocene) with the gold(III) precursors [Au(C6F5)(3)(OEt2)] and [Au(C6F5 )(2)(OEt2)(2)]OTf afford the mixed-valence complexes [S(Au(2)dppf)(Au( C6F5)(3))] (1) and [{S(Au(2)dppf)}(2)(Au(C6F5)(2)}]OTf (2). The crysta l structures of these derivatives have been determined and show short gold(I)-gold(III) contacts of 3.404(1) Angstrom in 1 and 3.2195(8) and 3.3661(10) Angstrom in 2. DFT calculations, including correlation and relativistic corrections, show that in these compounds where sulfur b ridges three gold atoms it prefers to become pyramidal rather than pla nar, and Au(I)-Au(III) distances are indicative of a possible weak int eraction. EH calculations suggest that such interaction is similar in origin to the well-studied Au(I)-Au(I) weak interactions and that it m ay occur in some real compounds.