Hydride Doping Effects on the Structure and Properties of Eight-Electron Rh/Ag Superatoms: The [RhH x @Ag 21- x {S 2 P(O n Pr) 2 } 12 ] ( x = 0-2) Series.

Three hitherto unknown eight-electron rhodium/silver alloy nanoclusters, [RhAg 21 {S 2 P(O n Pr) 2 } 12 ] ( 1 ), [RhHAg 20 {S 2 P(O n Pr) 2 } 12 ] ( 2 ), and [RhH 2 Ag 19 {S 2 P(O n Pr) 2 } 12 ] ( 3 ), have been isolated and fully characterized. Cluster 1 contains a regular Rh@Ag 12 icosahedral core, whereas 2 and 3 exhibit distorted RhH@Ag 12 and RhH 2 @Ag 12 icosahedral cores. The single-crystal neutron structure of 2 located the encapsulated hydride at the center of an enlarged RhAg 3 tetrahedron. A similar position was found by neutron diffraction for one of the hydrides in 3 , whereas the other hydride is trigonally coordinated to Rh and an elongated Ag-Ag edge. The solid-state structures of 1 - 3 possess C 1 symmetry due to the asymmetric arrangement of the surrounding capping Ag atoms. Our investigation shows that the insertion of one hydride dopant provokes the elimination of one capping silver atom on the cluster surface, resulting in the general formula [RhH x @Ag 21- x {S 2 P(O n Pr) 2 } 12 ] ( x = 0-2), which maintains the same number of cluster electrons as well as neutral charge. Clusters 1 - 3 exhibit an intense emission band in the NIR region. Contrarily to their PdAg 21 and PdHAg 20 relatives, the 4d orbitals of the encapsulated heterometal are somewhat involved in the optical processes.