Synthesis and Crystal Structure of [Ph₄As]₄[Au₁₂S₈], a Distorted Cubane‐Like Thioaurate(I)

Abstract

Extinction measurements indicate that EDTA, even when present in 1000 fold excess (pH 1 l), cannot compete with the Fell'-complexes of l b and 2d, although the formation constant Kf for the Fe"'-EDTA complex is 102s[91. Finally, the superiority of the ligand l b becomes clear from competition experiments with 2d, in which ca. 70% of the iron(ir1) ions are complexed by l b ; however, in order to establish equilibria, the solutions require to be heated for several hours at 100°C.Our synthetic methodology allows construction of even roomier cavities by using spacers larger than the two 1,3,5-substituted benzene nuclei, e.g. 1,3,5-triphenylbenzene building blocks, as we have previously employed in another connection (cyclophanes)["I. In this respect, these macrooligocycles are also of interest for chemical reactions in cavity interiors as well as for model studies of receptors with larger guests ['].

Quantum‐Sized Gold Nanoclusters: Bridging the Gap between Organometallics and Nanocrystals

“…Therefore, both the radial and peripheral bonds are of importance in stabilizing the icosahedral structure. This structure was first found in the phosphane-capped [Au 13 A C H T U N G T R E N N U N G (PPhMe 2 ) 10 Cl 2 ] 3 + cluster. [8] Later, a Pd-centered Au 12 icosahedron was also found in the neutral complex [Pd 1 Au 12 -…”

“…[9] Moreover, a cuboctahedral Au 12 cage was found in [Au 12 S 8 ] 4 + complexes with a linear S-Au-S motif. [10] For ligand-protected Au 13 clusters, Nature indeed prefers an icosahedral structure, rather than the cuboctahedron. To transform a cuboctahedron into an icosahedron is quite easy.…”

“…[14] Note that these electron numbers are only formal counts by assuming that PR 3 ligands make zero contribution, each halogen localizes one electron, and Au 5d 10 are not counted as valence electrons, though the d electrons can be valence electrons in some circumstances (e.g., in forming Au III complexes). As the nuclearity increases, the cluster starts to adopt a centered polyhedral structure, for example, from tetrahedral Au 4 to octahedral Au 6 and finally to the centered icosahedral Au 13 (ligands omitted).…”

Gold Sulfide Nanoclusters: A Unique Core‐In‐Cage Structure

“…This decreased coordination number for S but not Au in the cage indicates that the Au/S ratio on the cage is close to 1.5, similarly to the thioaruate(I) anion [Au 12 S 8 ] 4À . [14] Therefore, more Au atoms are needed inside the cage to achieve the desired stoichiometry of 2, and the resultant additional Au-Au interaction between the core and the cage also stabilizes the cluster. Our charge analysis shows that the Au 6 core has a total charge of + 0.6 e, which indicates that the electrostatic attraction between the core and the cage also plays a role.…”

Gold: Inorganic & Coordination Chemistry

“…The structure of [Au 9 (Ptol 3 ) 8 ] 3+ can be derived from a centered icosahedron, but it is more simply pictured as a bicapped centered chair as shown in (25). The cluster [Au 9 (Ptol 3 ) 9 ](NO 3 ) 3 has been prepared by NaBH 4 reduction of [Au(Ptol) 3 (26) Another Au 9 cluster, [Au 9 (PCy 3 ) 5 (SCN) 3 ], was prepared by NaBH 4 reduction of [Au(PCy 3 )SCN], and this structure can also be described in terms of a centered icosahedron with different gold atoms missing or as bicapped centered chair as shown in (27).…”