Mixed gold(II)-gold(III) complexes with bridging selenido ligands. Theoretical studies of the gold(I)-gold(III) interactions

摘要

The gold(I) compounds [Se(AuPPh_3)_2] and [Se{Au_2(#mu#_dppf)}] (dppf = 1,1'-bis(diphenylphosphino) ferrocene) react with 1 and 2 equiv of [Au(C_6F_5)_3OEt_2] to give the mixed gold(I)-gold(III) derivatives [Se(AuPPh_3)_2 {Au(C_6F_5)_3}_n] and [Se{Au_2(#mu#-dppf)} {Au(C_6F_5)_3}_n] (n = 1,2). The reaction of [Se(AuPPh_3)_2] with [Au(C_6F_5)_3Cl]_2 affords the complex [{Se(AuPPh_3)}_2{#mu#-Au(C_6F_5)_2}_2]. The crystal structures of [Se{Au_2(#mu#-dppf)} {Au(C_6F_5)_3}] and [{Se(AuPPh_3)}_2{#mu#-Au(C_6F_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 of [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 secondorder Moller-Plesset perturbation theory levels. There is a good agreement between experimental and theoretical geometries at the MP2 level.