The first atomically and structurally precise silver-nanoclusters stabilized by Se-donor ligands, [Ag {Se P(O Pr) } ] (3) and [Ag {Se P(OEt) } ] (4), were isolated by ligand replacement reaction of [Ag {S P(O Pr) } ] (1) and [Ag {S P(O Pr) } ] (2), respectively. Furthermore, doping reactions of 4 with Au(PPh )Cl resulted in the formation of [AuAg {Se P(OEt) } ] (5). Structures of 3, 4, and 5 were determined by single-crystal X-ray diffraction. The anatomy of cluster 3 with an Ag core having C symmetry is very similar to that of its dithiophosphate analogue 1. Clusters 4 and 5 exhibit an Ag and Au@Ag core of O symmetry composed of eight silver capping atoms in a cubic arrangement and encapsulating an Ag and Au@Ag centered icosahedron, respectively. Both ligand exchange and heteroatom doping result in significant changes in optical and emissive properties for chalcogen-passivated silver nanoparticles, which have been theoretically confirmed as 8-electron superatoms.

A templated galvanic exchange performed on [Ag20{Se2P(OiPr)2}12] of C3 symmetry with three equiv AuI yields a mixture of [Au1+xAg20−x{Se2P(OiPr)2}12]+ (x=0–2) from which [Au@Ag20{Se2P(OiPr)2}12]+ and [Au@Au2Ag18{Se2P(OiPr)2}12]+ are successfully characterized to have T and C1 symmetry, respectively. Crystal structural analyses combined with DFT calculations on the model compounds explicitly demonstrate that the central Ag0 of Ag20 being oxidized by AuI migrates to the protecting atomic shell as a new capping AgI, and both second and third Au dopants prefer occupying non‐adjacent icosahedron vertices. The differences in symmetry, T and C1, are manifested in the spatial orientation of their protecting atomic shell composed of eight capping Ag atoms as well as re‐construction upon the replacement of Ag atoms on the vertices of AuAg12 icosahedral core with second and third Au dopants. As a result, a unique pathway for substitutional‐doped clusters with increased nuclearity is proposed.

Theauthors declare no conflict of interest. Figure 4. UV/Vis absorption (left) and normalized emission spectra (right) of 4 and 5 in chloroform.

5Pd nanoparticles supported on nitrogen-doped graphene (NG) were prepared as hydrogenation catalysts. Different nitrogen sources (ethylenediamine, ammonia, and urea) were employed to synthesise NG by hydrothermal treatment at a mild condition. The as-made samples were characterized by transmission electron microscopy, scanning electron microscopy, Raman spectroscopy, elemental analysis, nitrogen adsorption-desorption, X-ray diffraction, and X-ray photoelectron spectroscopy. Remarkably improved 10 dispersion of Pd nanoparticles were observed when nitrogen was introduced into the graphene structure. These NG-supported Pd catalysts showed enhanced catalytic hydrogenation activities owing to the superior dispersion of Pd. In the hydrogenation of different olefins, perfect turnover frequencys were obtained over NG-supported Pd catalyst with urea as the nitrogen source.

No abstract