1,4‐Digermacyclopenta‐1,3‐diene: Continuous Cyclic σ*–π Delocalization Enables Aromatic Stabilization in a Heavy‐Element 4π System

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Authors: Daichi Uchida, Hiroko Yamada, Yoshiyuki Mizuhata
Cited by: 1
References: 45

Abstract

ABSTRACT Aromaticity in heavy‐element systems can arise from unconventional modes of cyclic electron delocalization that are not accessible in lighter‐element frameworks. Herein, we report 1,4‐digermacyclopenta‐1,3‐diene as an unusual aromatic system in which a formally 4π electron framework is stabilized through cooperative σ*–π interactions. X‐ray crystallography reveals a nearly planar [Ge 2 C 3 ] ring, while magnetic and electronic analyses (NICS, GIMIC, ACID, and EDDB) consistently indicate significant aromatic stabilization. In particular, GIMIC calculations show a pronounced diatropic ring current with an average strength of +8.38 nA T −1 . Natural bond orbital analysis reveals that this stabilization originates from σ*–π delocalization involving the Ge–Ge bond and adjacent π orbitals. Despite a low‐lying open‐shell contribution (y ≈ 0.11), the system remains predominantly closed‐shell. Notably, this system represents a rare case in which σ*–π interactions form a continuous cyclic delocalization pathway, resulting in a distinct form of aromatic stabilization.

Fields of Study & Subjects

Synthesis and Properties of Aromatic Compounds Synthesis and characterization of novel inorganic/organometallic compounds Magnetism in coordination complexes

Publication details

Journal / source
Angewandte Chemie International Edition
Publisher
Wiley
Volume
65
Issue
24
Pages
e7558823–e7558823
Publication date
24 April 2026
Language
EN