Supported Au25 clusters were prepared through the calcination of Au25(SC12H25)18 on hierarchically porous carbon nanosheets under vacuum at temperatures in the range of 400–500 °C for 2–4 h. TEM and EXAFS analyses revealed that the thiolate coverage on Au25 gradually decreased with increasing calcination temperature and period and became negligibly small when the calcination temperature exceeded 500 °C. The catalysis of these Au25 clusters was studied for the aerobic oxidation of benzyl alcohol. Interestingly, the selectivity for benzaldehyde formation was remarkably improved with the increase in the amount of residual thiolates on Au25, while the activity was reduced. This observation is attributed to the dual roles of the thiolates: the reduction of the oxidation ability of Au25 by electron withdrawal and the inhibition of the esterification reaction on the cluster surface by site isolation.

Clusters of gold atoms can be viewed as superatoms, in which valence electrons confined in the particles occupy atomic-like, discrete electronic levels. Chemical modification of the gold superatoms and their aggregated molecules (superatomic molecules) with organic ligands is a promising approach for their application as the building units of new functional materials. This account surveys the present status of the rapidly growing field of gold superatoms and superatomic molecules protected by thiolates and phosphines. The major aim of this article is to provide a simple picture for the structure, stability and bonding scheme of chemically modified superatoms and superatomic molecules for the development of a new class of hierarchical materials.

Ligation of 2,6-diphenylbenzenethiol (DppSH) onto Au clusters stabilized by poly(N-vinyl-2-pyrrolidone) and subsequent core etching yielded a single cluster Au25(SDpp)11. High-energy X-ray diffraction measurement showed that Au25 constitutes a core in Au25(SDpp)11. We propose a bi-icosahedral Au25 core whose 22 Au surface atoms are capped directly by 11 bulky arenethiolates.

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Dislocations in SrTiO3 deformed plastically by indentation at 900 and 1100 °C are studied by comprehensive transmission electron microscopy. At both 900 and 1100°C all the dislocations studied have Burgers vectors of either 〈100〉 or 〈110〉 type. At 900 °C both types of dislocation are in the glide configuration. On the other hand, at 1100°C 〈001〉 dislocations are in the climb configuration, although most of 〈110〉 dislocations are in the glide configuration. Small dislocation loops, both of 〈100〉 and 〈110〉 types, are observed, and most of them are identified as vacancy type.