Tetrarubidium Nonagermanide(4-) Ethylenediamine, Rb4[Ge9][en]

Abstract

Orange crystals of Rb4[Ge9][en] are obtained after the exchange reaction of a solution of ‘NaGe2.25' (precursor) in ethylenediamine (en) with solid RbI at 363 K, followed by slow cooling. The compound is very sensitive to oxidation and hydrolysis. The thermal decomposition in dynamic vacuum starts at 350 K with the complete loss of en followed by the sublimation of Rb in four steps (Rb8Ge25, Rb8Ge44, RbxGe136 with x ≤ 16, Ge). The Raman spectrum shows the characteristic bands of the [Ge9]4– anion (151, 163, 185 and 222 cm–1). Rb4[Ge9][en] crystallizes in a new structure type (space group P21/m; a = 15.353 Å, b = 16.434 Å, c = 15.539 Å, β = 113.75°; Z = 6; Pearson code mP198‐40), which can be described as a hierarchical derivative of the structures of Al4YbMo2 and CrB4 (initiators) formed by partial atom‐to‐aggregate replacement: B4[□][Cr] ≙ Al4[Yb][Mo]2 ≙ Rb4[Ge9][en]1–2. Three crystallographic independent [Ge9]4– clusters with different orientations are embedded in a 4‐connected 465 net formed by the Rb atoms, a network of condensed tetraasteranes. The clusters are distorted monocapped tetragonal antiprisms with D1(Ge–Ge) = 2.57 Å (16 Ç ) and D2(Ge–Ge) = 2.84 Å (4 Ç ). The atoms of clusters with D1 and D2 lie at the surface of a rotational ellipsoid (a = b = 2.136 Å, c = 2.431 Å). The en molecules are located in open channels along [1¯ 0 1]. The coordinations [Ge9] Rb12/4 and Rb [Ge9]4/12 en2/8 show that the first step of solvation do not separate the cations from the cluster anions.

On the Mechanism of Connecting Deltahedral Zintl Clusters via Conjugated Buta‐1,3‐dien‐1,4‐diyl Functionalities: Synthesis and Structure of [Ge9−CH=CH−CH=CH−Ge9]6−

“…The intensive signals at 142 and 221 cm −1 are indicative of the Ge 9 clusters. Similar Raman signals in this region are observed for isolated [Ge 9 ] 4− clusters, and thus we assign the signals to the Ge 9 units in 1 a . The covalent connection of the Ge 9 units to carbon atoms are displayed by the signal at 506 cm −1 , which is typical of Ge−C valence vibrations .…”

Homoatomic Polyhedra as Structural Modules in Chemistry: What Binds Fullerenes and Homonuclear Zintl Ions?

“…[27] The expected structure type can be rationalized using the electron counting rules developed by Wade for boranes and carboranes, provided that the BÀH and CÀH exo bonds of homoatomic clusters are substituted by free electron pairs. According to Wades rules, anions [E 9 ] 2À and [E 9 ] 4À with 38 and 40 valence electrons should possess structures of the closo type I and nido type II, respectively.…”

Polyanionische Cluster und Netzwerke der frühen p-Metalle im Festkörper: jenseits der Zintl-Grenze

“…Es konnte auûerdem gezeigt werden, dass Rb 4 Ge 9 Ethylendiamin aufnimmt, wobei eine Rb 4 Ge 9´e n-Struktur entsteht, in der die Kationen teilweise solvatisiert, aber nicht von der Anionenumgebung getrennt sind. [60] An dieser Stelle sei angemerkt, dass durch die Arbeitsgruppe von von Schnering weitere Belege für Ge 9 4À -und Sn 9 4À -Spezies, einschlieûlich solvensfreier Natriumsalze, durch Synthese, Röntgenpulverdiffraktometrie und schwingungsspektroskopische Untersuchungen geliefert wurden. Dabei war jedoch wegen der schlechten Kristallqualität keine eindeutige Lösung der beiden Strukturtypen durch Röntgenbeugung möglich (Zwillingsbildung, vorgetäuschte höhere Symmetrie).…”