Safe Entry to Ag(I)/Ag(III) Mixed Valence Salts Containing the Homoleptic Ag(III) Anion [Ag(CF3)4]–

The synthesis of Naumann’s AgI/AgIII mixed valence salt [AgI]+[AgIII(CF3)4]– (Ag-1) is revisited.  Ag-1 is now safely available in half gram scale upon 2e– oxidation of AgF in presence of CF3SiMe3 and ambient air.  In addition to its unprecedented crystallographic characterization, the use of Ag-1 to build the novel AgI/AgIII salts [Ag(bpy)2]-1, [Ag(18-crown-6)2]-1, [Ag-crypt-222]-1 and [Ag(PCy3)2]-1 is herein reported, alongside their characterization by NMR, single crystal X-ray diffraction (Sc-XRD) and elemental analysis (EA).  The utility of the currently affordable Ag-1 in gold(I) catalysis was demonstrated by the excellent catalytic activity displayed by [{Au(PPh3)}2(m−Cl)]-1 and [Au(PPh3)]-1 in the 5-exo-dig cyclization of N-propargylbenzamide (2).  These cationic AuI catalysts are accessible from (PPh3)AuCl and Ag-1, and outperform the activity of the well-known benchmark catalyst (PPh3)AuNTf2.