Atom Exchange Versus Reconstruction: (Ge_xAs_4−x)^x− (x=2, 3) as Building Blocks for the Supertetrahedral Zintl Cluster [Au₆(Ge₃As)(Ge₂As₂)₃]³⁻

Abstract

The Zintl anion (Ge2As2)2− represents an isostructural and isoelectronic binary counterpart of yellow arsenic, yet without being studied with the same intensity so far. Upon introducing [(PPh3)AuMe] into the 1,2‐diaminoethane (en) solution of (Ge2As2)2−, the heterometallic cluster anion [Au6(Ge3As)(Ge2As2)3]3− is obtained as its salt [K(crypt‐222)]3[Au6(Ge3As)(Ge2As2)3]⋅en⋅2 tol (1). The anion represents a rare example of a superpolyhedral Zintl cluster, and it comprises the largest number of Au atoms relative to main group (semi)metal atoms in such clusters. The overall supertetrahedral structure is based on a (non‐bonding) octahedron of six Au atoms that is face‐capped by four (GexAs4−x)x− (x=2, 3) units. The Au atoms bind to four main group atoms in a rectangular manner, and this way hold the four units together to form this unprecedented architecture. The presence of one (Ge3As)3− unit besides three (Ge2As2)2− units as a consequence of an exchange reaction in solution was verified by detailed quantum chemical (DFT) calculations, which ruled out all other compositions besides [Au6(Ge3As)(Ge2As2)3]3−. Reactions of the heavier homologues (Tt2Pn2)2− (Tt=Sn, Pb; Pn=Sb, Bi) did not yield clusters corresponding to that in 1, but dimers of ternary nine‐vertex clusters, {[AuTt5Pn3]2}4− (in 2–4; Tt/Pn=Sn/Sb, Sn/Bi, Pb/Sb), since the underlying pseudo‐tetrahedral units comprising heavier atoms do not tend to undergo the said exchange reactions as readily as (Ge2As2)2−, according to the DFT calculations.

New Noncentrosymmetric Tetrel Pnictides Composed of Square‐Planar Gold(I) with Peculiar Bonding

“…A rare example of the pnictide square‐planar unit is the flat Au 3 As 8 layer composed of [AuAs 4 ] units connected through As−As bonds in the structure of Nd 10 Au 3 As 8 O 10 [30] . Among the reported Au tetrel pnictide fragments, to the best of our knowledge, AuTtPn compounds of 1:1:1 composition are the first example of a solid‐state network composed of square‐planar AuTt 2 Pn 2 units [31] . The layers are connected in the stacking direction through additional Ge−P bonds (Figure 1).…”

Ternary aromatic and anti-aromatic clusters derived from the hypho species [Sn2Sb5]3−

“…The first structural determination of a Zintl anion was made by Kummer and Diehl in the 1970s, when they revealed the presence of [Sn 9 ] 4− cluster, which was subsequently used as a precursor for the synthesis of many polystannides 1 . Afterward, many more homo- and heteroatomic polyanions were discovered including [E 9 ] 4− (E = Si-Pb), [Pn 7 ] 3− (Pn = P-Bi) and [Tt 2 Pn 2 ] 2- (Tt = Ge-Pb) 2 – 11 , and a number of new clusters were produced using them as precursors 12 – 15 . In the majority of these clusters, the relationship between structure, bonding, and valence electron count can be understood in terms of either the Zintl-Klemm concept addressing electron-precise structures composed of formal two-center two-electron (2c-2e)bonds 16 , 17 or the Wade-Mingos rules 18 – 20 , which were originally applied to electron-deficient boranes with delocalized bonding, and later introduced into Zintl clusters.…”

Atom Exchange Versus Reconstruction: (GexAs4−x)x− (x=2, 3) as Building Blocks for the Supertetrahedral Zintl Cluster [Au6(Ge3As)(Ge2As2)3]3−

“…Compound 1 was characterized by means of single-crystal X-ray diffraction (SC-XRD) [18] and energy-dispersive X-ray spectroscopy (EDS, Figure S9). Electrospray-ionization mass spectrometry (ESI-MS) revealed fragmentation of the large cluster anion (M w = 2360.01 g mol À1 ) under ESI-MS conditions.…”

“…Compounds 2-4 were also characterized by means of SC-XRD [18] and m-XFS. Additionally, ESI mass spectra were recorded on fresh solutions of single-crystals, which indicated different degrees of fragmentation under ESI-MS conditions for the three different species, notably also producing (SnBi 3 ) À upon redissolving the single-crystals in the case of 2.…”