Isolation and Structural Elucidation of 15–Nuclear Copper Dihydride Clusters: An Intermediate in the Formation of a Two–Electron Copper Superatom

Highly reactive copper-dihydride clusters, [Cu15(H)2(S2CNR2)6(C2Ph)6](PF6) {R = nBu (1H), nPr (2H), iBu (3H)}, are isolated during the reaction of [Cu28H15{S2CNnBu2}12](PF6) with ten equivalents of phenylacetylene. They are found to be intermediates in the formation of the earlier reported two-electron superatom [Cu13(S2CNR2)6(C2Ph)4]+. Better yields are obtained by reacting dithiocarbamate sodium salts, [Cu(CH3CN)4](PF6), BH4– and phenylacetylene. The presence of two hydrides in the isolated clusters is confirmed by the synthesis and characterization of its deuteride analogue [Cu15(D)2(S2CNR2)6(C2Ph)6]+, and a single-crystal neutron structure of 2H. Structural characterization of 1H reveals a new bicapped icosahedral copper(I) cage encapsulating a linear copper dihydride (CuH2)– unit. In conclusion, reaction of 3H with Au(I) salts yields a highly luminescent [AuCu12(S2CNiBu2)6(C2Ph)4]+ cluster.