Mixed Gold(I)−Gold(III) Complexes with Bridging Selenido Ligands. Theoretical Studies of the Gold(I)−Gold(III) Interactions

The gold(I) compounds [Se(AuPPh 3 ) 2 ] and [Se{Au 2 (μ-dppf)}] (dppf = 1,1‘-bis(diphenylphosphino)ferrocene) react with 1 and 2 equiv of [Au(C 6 F 5 ) 3 OEt 2 ] to give the mixed gold(I)−gold(III) derivatives [Se(AuPPh 3 ) 2 {Au(C 6 F 5 ) 3 } n ] and [Se{Au 2 (μ-dppf)}{Au(C 6 F 5 ) 3 } n ] ( n = 1, 2). The reaction of [Se(AuPPh 3 ) 2 ] with [Au(C 6 F 5 ) 2 Cl] 2 affords the complex [{Se(AuPPh 3 )} 2 {μ-Au(C 6 F 5 ) 2 } 2 ]. The crystal structures of [Se{Au 2 (μ-dppf)}{Au(C 6 F 5 ) 3 }] and [{Se(AuPPh 3 )} 2 {μ-Au(C 6 F 5 ) 2 } 2 ] have been characterized by X-ray diffraction studies. They show dissimilar Au(I)···Au(III) distances, indicating the presence of weak interactions. Quasi-relativistic pseudopotential calculations on [Se(AuPH 3 ) 2 (AuR 3 )], [Se(AuPH 3 )(AuR 3 ) 2 ] - (R = −H, −CH 3 ), and [{Se(AuPH 3 )} 2 {Au(CH 3 ) 2 } 2 ] models have been performed at Hartree−Fock and second-order Møller−Plesset perturbation theory levels. There is a good agreement between experimental and theoretical geometries at the MP2 level.