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

The structurally precise Cu-rich hydride nanoclusters [PdCu14 H2 (dtc/dtp)6 (C≡CPh)6 ] (dtc: di-butyldithiocarbamate (1); dtp: di-isopropyl dithiophosphate (2)) were synthesized from the reaction of polyhydrido copper clusters [Cu28 H15 (S2 CNn Bu2 )12 ]+ or [Cu20 H11 {S2 P(Oi Pr)2 }9 ] with phenyl acetylene in the presence of Pd(PPh3 )2 Cl2 . 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.