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

The structurally precise Cu-rich hydride nanoclusters [PdCu H (dtc/dtp) (C≡CPh) ] (dtc: di-butyldithiocarbamate (1); dtp: di-isopropyl dithiophosphate (2)) were synthesized from the reaction of polyhydrido copper clusters [Cu H (S CN Bu ) ] or [Cu H {S P(O Pr) } ] with phenyl acetylene in the presence of Pd(PPh ) Cl . 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 Pd and four Cu 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 [PdH ] unit and its Cu bicapped icosahedral cage. As a result, Pd has the highest coordination number (14) so far recorded.