Dinuclear Au(I), Au(II) and Au(III) Complexes with (CF2 )n Chains: Insights into The Role of Aurophilic Interactions in the Au(I) Oxidation.

New dinuclear Au(I), Au(II) and Au(III) complexes containing (CF2 )n bridging chains were obtained. Metallomacrocycles [Au2 {μ-(CF2 )4 }{μ-diphosphine}] show an uncommon figure-eight structure, the helicity inversion barrier of which is influenced by aurophilic interactions and steric constraints imposed by the diphosphine. Halogenation of LAu(CF2 )4 AuL (L=PPh3 , PMe3 , (dppf)1/2 , (binap)1/2 ) gave [Au(II)]2 species, some of which display unprecedented folded structures with Au-Au bonds. Aurophilic interactions facilitate this oxidation process by preorganizing the starting [Au(I)]2 complexes and lowering its redox potential. The obtained [Au(II)]2 complexes undergo thermal or photochemical elimination of R3 PAuX to give Au(III) perfluorinated auracycles. Evidence of a radical mechanism for these decomposition reactions was obtained.