The successful isolation of cyclo-C18 in the experiment means the ground-breaking epoch of carbon rings. Herein, we studied the thermodynamic stabilities of cyclo-Cn (4 ≤ n ≤ 34) with density functional theory. When n = 4N + 2 (N is integer), cyclo-Cn (10 ≤ n ≤ 34) were thermodynamically stable. Especially, cyclo-C10 and cyclo-C14 were thermodynamically, kinetically, dynamically, and optically preferred to cyclo-C18, and were the candidates of zero-dimension carbon rings. The carbon atoms were sp hybridization in cyclo-C10, cyclo-C14 and cyclo-C18. Cyclo-C14 and cyclo-C18 had alternating abnormal single and triple bonds, but cyclo-C10 had equal bonds. Cyclo-C10, cyclo-C14, and cyclo-C18 with large aromaticities had out-plane and in-plane pi systems, which were perpendicular to each other. The number of pi electrons in out-plane and in-plane pi systems followed the Huckel rule. Simulated UV-vis-NIR spectra indicated the similar electronic structures of cyclo-C14 and cyclo-C18.
@article{arxiv.2002.04765,
title = {Potential molecular semiconductor devices: cyclo-Cn (n = 10 and 14) with higher stabilities and aromaticities than acknowledged cyclo-C18},
author = {Meng-Yang Li and Zhibin Gao and Yan-Bo Han and Yao-Xiao Zhao and Kun Yuan and Shigeru Nagase and Masahiro Ehara and Xiang Zhao},
journal= {arXiv preprint arXiv:2002.04765},
year = {2020}
}