Synthesis of Bimetallic Copper‐Rich Nanoclusters Encapsulating a Linear Palladium Dihydride Unit.

The structurally precise Cu‐rich hydride nanoclusters [PdCu14H2(dtc/dtp)6(C≡CPh)6] (dtc: di‐butyldithiocarbamate (1); dtp: di‐isopropyl dithiophosphate (2)) were synthesized from the reaction of polyhydrido copper clusters [Cu28H15(S2CNnBu2)12]+ or [Cu20H11{S2P(OiPr)2}9] with phenyl acetylene in the presence of Pd(PPh3)2Cl2. Their structures and compositions were determined by single‐crystal X‐ray diffraction and the results supported by ESI‐mass spectrometry. Hydride positions in 1 were confirmed by single‐crystal neutron diffraction. Each hydride is connected to one Pd0 and four CuI atoms in slightly distorted trigonalbipyramidal geometry. The anatomies of clusters 1 and 2 are very similar and DFT calculations allow rationalizing the interactions between the encapsulated [PdH2]2− unit and its Cu14 bicapped icosahedral cage. As a result, Pd has the highest coordination number (14) so far recorded. Come in number 14: A unique methodology was used to synthesize atomically precise palladium‐alloyed copper hydride clusters. X‐ray and neutron diffraction revealed that a 14‐electron [PdH2]2− unit is iono‐covalently encapsulated within a bicapped icosahedral [Cu14]14+ cage and, as a result, the central Pd0 adopts the coordination number of 14. [ABSTRACT FROM AUTHOR]