2026/01/23 by Manoj Kumar, Henning Remm, Viktoria H. Gessner · 1 voice · 5 citations
Chemistry · #Aromaticity #Cyclobutadiene #Delocalized electron #Electronic structure #Organometallic Complex Synthesis and Catalysis #Planar #Reactivity (psychology) #Steric effects #Synthesis and Properties of Aromatic Compounds #Synthesis and characterization of novel inorganic/organometallic compounds #Ylide
paper · doi:10.1021/jacs.5c19206
published in Journal of the American Chemical Society 148(4), 4496-4506 (American Chemical Society)
openalex publication_date 2026/01/23 · openalex created_date 2026/01/24 · openalex updated_date 2026/08/01
Aromaticity is a fundamental concept traditionally used to explain the structure, stability, and reactivity of cyclic organic compounds. Heavier analogs have also been investigated for their aromatic character, but their electronic structure was shown to differ significantly depending on the substituents. Herein, we report the synthesis and isolation of a germanium analog of cyclobutadiene Y N 2 Ge 4 (Y N = Ph 2 P(NMes)-C-PPh 3 ), featuring two iminophosphinoyl-tethered ylide ligands. The Ge 4 compound is obtained through reduction of either chlorogermylene Y N GeCl or digermylene Y N Ge-GeY N and exhibits a planar Ge 4 core with a perpendicular coordination of the ylide groups. Detailed computational analyses revealed an aromatic character, as evidenced by several aromaticity descriptors. This aromaticity arises exclusively from the delocalization of the σ-electrons, while any π-bonding is lost due to the coordination of the ligands in the π-plane. This electronic structure resembles that of all-metal clusters, thereby extending the concept of σ- and all-metal aromaticity to cyclobutadiene-like systems.