Polybismuthide Anions as Ligands: The Homoleptic Complex [(Bi7)Cd(Bi7)]4− and the Ternary Cluster [(Bi6)Zn3(TlBi5)]4−

A coordination compound with intact Bi₇³⁻ ligands, namely the homoleptic complex [(Bi₇)Cd(Bi₇)]⁴⁻, and the ternary cluster [(Bi₆)Zn₃(TlBi₅)]⁴⁻ were prepared through in situ degradation of the binary Zintl anion (TlBi₃)²⁻. The compounds provide a glimpse into a possible formation pathway of the polycyclic polybismuthide, the follow‐up chemistry of which has been unprecedented to date. Both title compounds were further studied by means of DFT methods.

Abstract

We present the results from a reactivity study of the binary anion (TlBi₃)²⁻ towards Group 12 metal compounds MPh₂ (M=Zn, Cd, Hg) to gain access to coordination compounds of polycyclic polypnictide molecules such as Bi₇³⁻ or Bi₁₁³⁻. The coordination chemistry of these polybismuthide cages has been unprecedented to date, while it has been known for a long time for the lighter Group 15 anions Pn₇³⁻ (Pn=P, As, Sb). The use of (TlBi₃)²⁻, previously shown to release Tl under certain conditions in situ, resulted in the formation of the first heterometallic polyanion in which a nortricyclane‐type polybismuthide coordinates a transition‐metal atom, [(Bi₇)Cd(Bi₇)]⁴⁻. Reactions with the lighter Group 12 metal precursor yielded the uncommon ternary cluster [(Bi₆)Zn₃(TlBi₅)]⁴⁻, most likely representing a reaction intermediate, and at the same time hinting at the formation of the nortricyclane‐shaped cage. Quantum‐chemical studies provide deeper insight into the stability trends of the [(E₇)M(E₇)]⁴⁻ anion family and reveal a complex bonding situation in [(Bi₆)Zn₃(TlBi₅)]⁴⁻, which features both localized and multi‐center bonding.

from A via a.sfakia on Inoreader http://bit.ly/2C135ZR