Eclipsed- and Staggered-[Ge₁₈Pd₃{EⁱPr₃}₆]^2– (E = Si, Sn): Positional Isomerism in Deltahedral Zintl Clusters

Abstract

We report the synthesis and characterization of the cluster anions [GePd{SiPr}] (1) with a core of face-fused twinned icosahedra, GePd, and two sets of three PrSi-substituents positioned in "eclipsed" geometry. The new anion is a positional isomer of the recently reported "staggered" stannyl-ligated counterpart [GePd{SnPr}] (2), showing the possibility to find such positional isomerism in Zintl clusters. Both anions are characterized by single-crystal X-ray diffraction, H andC NMR, and negative-ion ESI-MS. Using relativistic DFT calculations, we elucidate and discuss the reasons for the different positioning of the ligands in the stannyl- and silyl-functionalized species.

On the Variable Reactivity of Phosphine‐Functionalized [Ge9] Clusters: Zintl Cluster‐Substituted Phosphines or Phosphine‐Substituted Zintl Clusters

“…[6] The applicability of [Ge 9 {Si(TMS) 3 } 3 ] À as al igand for transition metals has led to subsequents tudies, in whichaseries of different silyl groups were attachedt ot he clusteru nits, leading to an ew group of potentialt ransition-metal ligands, with various shielding of the [Ge 9 ]c ore unit. [10,11] However,i nt hese silyl-and stannyl-substituted [Ge 9 ]c luster compoundso nly the [Ge 9 ]u nit can interact with transition metal complexes,w hereas ac luster substitution with exo-bonded phosphine groups [PR 2 ] + opens alternative reactionp athways due to the electron lone pair located at the phosphorus atom. [8] The bis-silylated clusters peciesa lso react directly with organometallic Cu I compounds,y ielding compounds of the type [(CuPiPr 3 ) 4 {Ge 9 (SiPh 3 ) 2 } 2 ] [5b] or (NHC-M) 2 [h 3 -Ge 9 {Si(TMS) 3 } 2 ]( M: Cu, Ag, and Au;NHC:NHC Dipp or NHC Mes ).…”

(Multi‐)Metallic Cluster Growth

“…These were proven to be excellent starting materials for subsequent reactions with (phosphine‐stabilized) metal halides and metal NHC ( N ‐heterocyclic carbene) complexes . Some cases, in which such reactions came along with cluster re‐organization, were already mentioned above . Here, the reactivity of the silylated cages decreases, as one would expect, with the size of the silyl‐groups, making this parameter a tunable property in the directed synthesis of multi‐metallic clusters.…”

“…Without additional stabilization by tri‐isopropyltin ligands, the reaction of [Pd(PPh 3 ) 4 ] with Ge 9 4− results in the formation of [Pd 2 @Ge 18 ] 4− , a cluster incorporating a Pd 2 dumbbell between two Ge 9 half‐cups . As shown by studies with other substituents, the organometallic ligands do not only decorate the cluster, but they have a notable influence on the reaction mechanism itself, which is made plain by the observation of either an eclipsed (Tt=Si) or a staggered cluster anion (Tt=Sn), [Pd 3 Ge 18 {Tt i Pr 3 } 6 ] 2− , as the product . This is explained by steric reasons, but also by lone pair repulsion at the closest Ge atoms of the two cluster halves.…”

Intermetalloid Clusters: Molecules and Solids in a Dialogue

“…[87] Theresulting products adopt similar structural motifs,a sa ccessible through the earlier presented top-down approaches starting from intermetallic compounds.T his is nicely illustrated by the nine-atomic Ge 9 cluster in K 4 Ge 9 which is isolated through an ionic matrix, and its counterpart [Ge 9 (Hyp) 3 ] À (Hyp = Si(SiMe 3 ) 3 )s tabilized through as hielding ligand sphere.T he same silylated cluster anion is accessible from the appropriate Zintl phase by exchanging the ionic matrix by ligands. [90] Through its stabilizing Fe organyles,[ Ge 12 {FeCp(CO) 2 } 8 {FeCp(CO)} 2 ]c ould likewise be interpreted as an intermetalloid coordination compound; however, even more remarkable is its Ge 12 core resembling an excerpt of the Ge II high-pressure modification ( Figure 12). [90] Through its stabilizing Fe organyles,[ Ge 12 {FeCp(CO) 2 } 8 {FeCp(CO)} 2 ]c ould likewise be interpreted as an intermetalloid coordination compound; however, even more remarkable is its Ge 12 core resembling an excerpt of the Ge II high-pressure modification ( Figure 12).…”