A cyclopentadienide analogue containing divalent germanium and a heavy cyclobutadiene-like dianion with an unusual Ge4 core
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Updated: Jul 4, 2026

Synthesis of Nine-atom Deltahedral Zintl Ions of Germanium and their Functionalization with Organic Groups
Published on: February 11, 2012
Wenyuan Wang1, Shenglai Yao, Christoph van Wüllen
1Institute of Chemistry, Metalorganics and Inorganic Materials, Technische Universität Berlin, D-10623 Berlin, Germany.
Abstract:
The first isolable cyclogermylidenide salt 2 has been synthesized and isolated by facile dehalogenation of the N-heterocyclic chlorogermylene 1 with elemental potassium in ether and isolated in the form of yellow crystals in 33% yield. Single-crystal X-ray diffraction analysis revealed that 2 crystallizes as a dimeric half-sandwich complex of aromatic C3NGe rings interconnected via intermolecular Ge(II)-->K dative bonds. Its yield can be improved up to 42% by gentle reduction of 1 (or its related GeCl3 complex 8) using potassium graphite. Additionally, the remarkable K2Ge4 cluster compound 9 has been isolated as a side product which consists of an unusual dianionic Ge4 core with parallelogram configuration and pronounced aromaticity as indicated by highly negative NICS values.
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