[Au₃Ge₄₅]⁹⁻—A Binary Anion Containing a {Ge₄₅} Cluster

Abstract

The golden era of germanium: The largest known germanium cluster [Au3Ge45]9− consists of 45 Ge atoms coordinated to three Au atoms and is obtained by the reaction of K4Ge9 and [AuCl(PPh3)]. DFT calculations reveal the large variety of chemical‐bond character in the {Ge45} moiety; localized two‐center, two‐electron bonds coexist with delocalized polyhedral and three‐center, two‐electron bonds.

At the Border of Intermetallic Compounds and Transition‐Metal Oxides: Crystal Intergrowth of the Zintl Phase Cs4Ge9 and Cs2WO4 or Cs3VO4 as well as Nine‐Atom Cluster Relocation in the Solid State

“…n oligomers and polymers (n = 2, 3, 4, and 1, respectively). [5] A [Ge 45 ] 12À anion has been found to complex Au atoms, [6] and full oxidation leads to the crystalline modification of clathrate-II-type germanium. [2,7] Further stable Ge modifications based on Ge 9 clusters as building blocks are predicted from theoretical calculations.…”

Metalloid Cluster Compounds of Germanium: Synthesis – Properties – Subsequent Reactions

“…Hence, here exists for the first time a topological approach to the structure of elemental germanium, which is much more pronounced in the case of the anionic compound 6, as the average oxidation state of the germanium atoms is 0.4 here, which is much closer to the value 0 for the element. The structural features of 5 and 6 were additionally observed in the cluster anion Au 3 Ge 45 9-, which was synthesized from the Zintl anion Ge 9 4-, [34] showing that this arrangement of germanium atoms is important in the borderland between the molecular and the solid state. However, other arrangements are also possible when ten germanium atoms are present in the cluster core of a metalloid cluster compound, as discussed in the following chapter.…”

“…Thus, a coupling of individual metalloid cluster compounds can lead to larger compounds or aggregates. Such a synthetic route has already led to larger compounds with the Zintl anions; for example, the reaction of the Zintl anion Ge 9 4-with Ni, Pd or Au reagents yields anionic cluster compounds with 13 [Ge 13 Ni 6 (CO) 5 4-], [39] 18 (Ge 18 Pd 2 4-) [40] and 45 (Au 3 Ge 45 9-) [34] germanium atoms in the cluster core. To perform subsequent reactions with metalloid germanium cluster compounds, the shielding of the cluster core by the ligand shell, necessary for the synthesis and isolation, is counterproductive as the naked germanium atoms are not available for reagents such as transition-metal compounds (Figure 8).…”

Polyhedral nine-atom clusters of tetrel elements and intermetalloid derivatives

“…A combination of the oxidative coupling reaction described in §3(a) and the complexation of the resulting polyanion reported in §3(b) leads to larger clusters reaching the nanometre scale. [Au 3 Ge 45 ] 9− was found as a by-product of the reaction of ethylenediamine solutions of K 4 Ge 9 and Ph 3 PAu(I)Cl (figure 6d; Spiekermann et al 2007a). By changing the reaction conditions, the yield of this fascinating large cluster can be raised.…”

“…Ge-Au contacts in [Au 3 Ge 45 ] 9− confine the cluster to a more or less spherical shape. Interestingly, [Au 3 Ge 45 ] 9− exhibits no Au-Au contacts, despite the presence of a largely negative cluster charge (Spiekermann et al 2007a). …”