Zhao Long, Doddipatla Srinivas, Kaiser Ralf I, Lu Wenchao, Kostko Oleg, Ahmed Musahid, Tuli Lotefa Binta, Morozov Alexander N, Howlader A Hasan, Wnuk Stanislaw F, Mebel Alexander M, Azyazov Valeriy N, Mohamed Rana K, Fischer Felix R
Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA.
Phys Chem Chem Phys. 2021 Mar 14;23(10):5740-5749. doi: 10.1039/d0cp06537d. Epub 2021 Feb 17.
Fullerenes (C, C) detected in planetary nebulae and carbonaceous chondrites have been implicated to play a key role in the astrochemical evolution of the interstellar medium. However, the formation mechanism of even their simplest molecular building block-the corannulene molecule (CH)-has remained elusive. Here we demonstrate via a combined molecular beams and ab initio investigation that corannulene can be synthesized in the gas phase through the reactions of 7-fluoranthenyl (CH˙) and benzo[ghi]fluoranthen-5-yl (CH˙) radicals with acetylene (CH) mimicking conditions in carbon-rich circumstellar envelopes. This reaction sequence reveals a reaction class in which a polycyclic aromatic hydrocarbon (PAH) radical undergoes ring expansion while simultaneously forming an out-of-plane carbon backbone central to 3D nanostructures such as buckybowls and buckyballs. These fundamental reaction mechanisms are critical in facilitating an intimate understanding of the origin and evolution of the molecular universe and, in particular, of carbon in our galaxy.
在行星状星云和碳质球粒陨石中检测到的富勒烯（C、C）被认为在星际介质的天体化学演化中起关键作用。然而，即使是它们最简单的分子构建块——碗烯分子（CH）的形成机制仍然难以捉摸。在这里，我们通过分子束和从头算相结合的研究表明，在富含碳的恒星包层模拟条件下，碗烯可以通过7-荧蒽基（CH˙）和苯并[ghi]荧蒽-5-基（CH˙）自由基与乙炔（CH）的反应在气相中合成。这个反应序列揭示了一类反应，其中多环芳烃（PAH）自由基发生环扩展，同时形成对三维纳米结构（如巴基碗和巴基球）至关重要的面外碳骨架。这些基本反应机制对于深入理解分子宇宙的起源和演化，特别是我们星系中碳的起源和演化至关重要。
