Clusters ligand protected

The next smaller ligand-protected nanocluster that was investigated by scanning tunneling spectroscopy (STS) was the four-shell cluster Pt309phen 36O20 [20,21]. The diameter of the Pt core is 1.8 nm, about a tenth of the former example. However, even here a Coulomb blockade could only be observed at 4.2 K, i.e. at room temperature the particle still has metallic behaviour. Since... 

Walter M, Akola J, Lopez-Acevedo O, Jadzinsky PD, Calero G, Ackerson CJ, Whetten RL, Gronbeck H, Hakkinen H (2008) A unified view of ligand-protected gold clusters as superatom complexes. Proc Natl Acad Sci USA 105 9157-9162... 

Fig. 2 Crystal structure of a Au25(SR)i8 cluster (R is phenylethyl group) (a) the icosahedral Au13 core (b) the Aui3 core covered by 12 Au atoms (c) the whole Au25 cluster is protected by 18 thiolate ligands (for clarity, only S was shown, magenta, Au yellow, S)[19]...

Fig. 33 Optical activity of a chiral ligand-protected gold nanocluster [Au25(SRcys)18]. (a) Optimized geometry, (b) Calculated CD spectrum of the cysteine-protected cluster black), and experimental spectrum for a glutathione-protected cluster (red). Reprinted with permission from [299]. Copyright 2010 American Chemical Society...

The advantage of a uniform size must be qualified for colloids, having a size distribution per se which, however, can be relatively narrow in some cases. In principle the solubility of ligand-protected clusters and colloids makes their use as homogeneous catalysts possible. But as it has turned out, cluster solutions tend to decompose during catalytic processes. The isolation of an unchanged cluster material after a homogeneously catalyzed reaction is indicated in only a very... 

Besides the aforementioned progresses, ab initio BH can be applied to many other systems, like ligand-protected clusters, cluster-molecule complexes, and even some chemical reaction. Figure 14 gives the lowest-energy structures of (CO) Au7 clusters with n = 0-4 from the BH search coupled with DFT. Compared to pure Au7 cluster, AU7 clusters adsorbed with different numbers of CO units presented diverse configurations, as shown in Fig. 14. The flexible geometrical variation makes... 

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