Oral Presentation Royal Australian Chemical Institute National Congress 2026

Redox active butafulvene-based macrocycles (137028)

Ingrid Y Dell 1 , Seyed M.B.H Ghazvini 1 , Yikun Zhu 2 , Zheng Wei 2 , Muhammad Y Mahboob 3 , Minu Sheeja 3 , Cina Foroutan-Nejad 3 , Marina A Petrukhina 2 , Marcus Korb 1
  1. University of Western Australia, Crawley, WA, Australia
  2. Department of Chemistry, State University of New York - Albany, Albany, NY, United States of America
  3. Institute of Organic Chemistry, Polish Academy of Sciences, Warsaw, Poland

Redox-active, π-conjugated macrocycles have been highly researched since the mid-20th century, as they offer a powerful platform to switch electronic structure by changing electron count, enabling access to otherwise elusive aromatic/antiaromatic states.[1] Recently, there has been renewed interest in highly unsaturated carbon scaffolds, particularly cyclo[n]carbons, which are unstable and cannot be isolated unless protecting groups are used, most commonly based on dehydro[n]annulene frameworks.[2] Recently, aromatic and anti-aromatic dehydroannulenes were isolated, and their electronic properties determined. It was found that heteroatoms peripheral to the main macrocycle core can significantly affect its electronics.[3] We report the synthesis and purification of aromatic purely hydrocarbon butafulvene based dehydro[18]annulene macrocycles assembled from 1,2-dibromocyclobutene precursors. Rb+ mediated 2e− reductions in the presence of both [2.2.2]cryptand, and 18-crown-6 were conducted in collaboration with Petrukhina group (SUNY Albany), and both products were isolated. Variation of the Rb‑chelating ligand led to either the solvent separated ion product ([2.2.2]cryptand), or the contact-ion product (18‑crown‑6). In both cases, reduction of the macrocycle led to topographical changes, as well as systemic bond length alteration, indicative of a difference in π-conjugation when compared to the neutral cycle. The continuation of this work involves the synthesis of larger butafulvene based dehydro[24]annulenes, and investigations into how variations in ring size affect structural and electrochemical properties.

  1. F. Sondheimer, “The Annulenes” Acc. Chem. Res. 1972, 84, 33.
  2. Y. Gao, P. Gupta, I. Rončević, C. Mycroft, P. J. Gates, A. W. Parker, H. L. Anderson, “Solution-phase stabilization of a cyclocarbon by catenane formation” Science (1979). 2025, 389, 708–710.
  3. Y. Lie, G. Baryshnikov, M. Pittelkow, “Aromatic and Antiaromatic Dehydroannulenes” J. Am. Chem. Soc. 2026, 148, 1096–1105.