Structural Investigation of a Fully Ordered closo‐Ge₉^2– Cluster in the Compound [K⁺(2,2,2‐crypt)]₂Ge₉^2–

Abstract

Abstract[K+(2,2,2‐crypt)]2Ge92– containing the deltahedral Zintl anion Ge92– has been isolated from a solution of K4Ge9 in ethylenediamine in the presence of 2,2,2‐crypt, intended as an intermediate in mixed‐cluster synthesis. The subsequent crystallographic characterisation shows the closo‐Ge92– cluster unit to be tricapped trigonal‐prismatic with a symmetry very close to D3h. Each Ge92– unit is surrounded by two 2,2,2‐crypt units, each with a chelated K+ cation, viz. [K+(2,2,2‐crypt)]. The structure characterisation of this ordered Ge92– cluster is surprisingly enough the first one reported. A chemical bonding analysis reveals two local minima of D3h symmetry, with that of lowest energy being highly similar to that resulting from the crystallographic analysis of low‐temperature data. The cluster interaction scheme is based on highly delocalised bonding.

Synthesis and characterization of pristine closo-[Ge10]2−

“…Akerstedt et al reinvestigated the same compound (identical unit cell and cell volume) at 100 K, and observed a fully ordered closo-[Ge 9 ] 2À cluster. 33,34 § The formation of 1a is an oxidative process (Scheme S1, ESI †), as the formal number of valence electrons per Ge atom, reduces from 22/9 in case of [Ge 9 ] 4À to 22/10 for 1a. ¶ Layering of such solutions with cryptand[2.2.2] or 18-crown-6 (1,4,7,10,13,16-hexaoxacyclooctadecane) in toluene has yielded a variety of crystals containing (connected) Ge 9 clusters, but none comprising 1a.…”

Synthesis and Crystal Structure of a Salt Containing ∞1{Zn[trans‐μ2(η3:η3‐Ge9)]}2– Anions: A Polymer with Ge9 Zintl Clusters Bridged by Zn Atoms

“…[38] The 22 SE Ge 9 clusters 1a and 1b also possess D 3h -symmetric tricapped trigonal-prismatic structures, although with larger values h mean = 2.94 and 2.93 Å, respectively. This is in agreement with the observation that the D 3h -symmetric structure may appear instead of the expected C 4v -symmetric monocapped square-antiprismatic nido structure in which the LUMO, which is antibonding along the prism heights Table 1.…”

“…Structural parameters of the Ge 9 clusters 1a and 1b in compound 1 and also [Ge 9 ] 2-. [38] h: height of the prism, e: length of the base of the trigonal prism, c: distance to the capping Ge atoms, γ: deviation from coplanarity of opposite triangular faces of the trigonal prism. [39] Cluster [23,25,44] In contrast, the reaction of elemental mercury leads to the polymeric anion ϱ 1 [Hg(Ge 9 )] 2-with Hg linking the Ge 9 clusters, [37,45,46] Figures S3 and S4), whereas crystalline Zn powder could not be detected.…”

Evidence for the Existence of (SiP6H2)2– and its Homologs as Examples of Binary Nortricyclane‐Type Zintl Anions

“…As we cannot completely exclude the presence of 0.7 equiv. of OH – instead of H 2 O in the solid‐state structure (the SCXRD data does not allow to determine the number of protons), we first considered the formation of the known anion (P 7 H) 2– [or a mixture of (P 7 H 2 ) – and P 7 3– ], but dropped this option based on the EDX results (Table S6, Supporting Information). Hence, if (P 7 H) 2– , (P 7 H 2 ) – , or P 7 3– were present, they would only represent minor components.…”

“…The X‐ray diffraction experiment and structure analysis revealed a compound that may be summarized as “[K(crypt‐222)] 2 (Ge x P 7– x H 2– x ) 1– n (Ge 9– y P y H 2– y ) n “ ( 2 ) and obviously contains the named anions, yet beside 9‐atom cages. The structure is additionally afflicted by a high degree of rotational disorder, which is not untypical for these spherical anions . For this, we refrain from a more detailed discussion of the crystal structure data here.…”