Isolation of a Silver(0) Dimer with a Direct Ag-Ag Bond

Despite decades of efforts, molecule featuring a direct Ag(0)-Ag(0) bond has never been isolated─a fundamental challenge that stands in contrast to the established chemistry of gold. Here we report the synthesis, characterization, and reactivity of the first molecular Ag(0)-Ag(0) bonded complex, which was stabilized by a tridentate P-Mg-P pincer ligand. Computational studies indicate that the Ag(0)-Ag(0) σ-bond acts as a two-electron donor to the Mg centers. This Ag(0)2 complex reacts with a range of substrates─including selenium, diphenyl diselenide, azobenzene, phenylacetylene, and an isocyanide─to afford a series of heterometallic Mg/Ag products through two-electron reduction processes. These transformations highlight the reducing character of the Ag(0)2 unit and help fill a gap in the periodic trend of coinage-metal chemistry.