Generation and Characterization of Cyclocarbons

The family of carbon allotropes was expanded by tip-induced synthesis and on-surface characterization of cyclo[N]carbons, molecular rings composed of N carbon atoms [1-3]. Cyclocarbons possess two orthogonal delocalized pi-systems and can undergo different Jahn-Teller distortions rendering them excellent systems for benchmarking theory [4-6]. Even-N cyclocarbons can be doubly aromatic [1,3] or doubly anti-aromatic [2], and can exhibit polyynic [1,2] or cumulenic [3] structures. Odd-N cyclocarbons [5,7] do not allow a symmetric polyynic structure, might be open-shell systems, and will be discussed in the talk.

References: [1] K. Kaiser et al. Science 365, 1299-1301 (2019). [2] Y. Gao et al. Nature (2023) 10.1038/s41586-023-06566-8. [3] L. Sun et al. Nature (2023) 10.1038/s41586-023-06741-x. [4] G. V. Baryshnikov et al. J. Phys. Chem. A 124, 10849–10855 (2020). [5] G. V. Baryshnikov et al. J. Phys. Chem. A 126, 2445–2452 (2022). [6] I. Rončevic et al. (2023) 10.26434/chemrxiv-2023-8kc5t-v2. [7] F. Albrecht et al. (2023) 10.26434/chemrxiv-2023-ddrh7.