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Updated: Apr 21, 2026

Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
Tetraazaacenes containing four-membered rings in different oxidation states. Are they aromatic? A computational study
Manuel Schaffroth1, Renana Gershoni-Poranne, Amnon Stanger
1Organisch-Chemisches Institut, Universität Heidelberg , Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
Abstract:
A symmetrical tetraazaacene incorporating a central cyclobutadiene ring was calculated in different oxidation (hydrogenation) states, displaying different tautomers and conformers. Geometries, thermodynamics, and electronic properties were computed, and the aromaticity of all these species was calculated on a per ring basis by NICS-scans and NICS-X-scans. The results unveil unexpected and fascinating insights into the complex aromaticity of those compounds, including a formally aromatic (!) cyclobutadiene ring.
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