Low-temperature gas-phase formation of cyclopentadiene and its role in the formation of aromatics in the interstellar medium

• 成果类型: Article
• 署名作者: Yang, Zhenghai; Medvedkov, Iakov A.; Goettl, Shane J.; Nikolayev, Anatoliy A.; Mebel, Alexander M.; Li, Xiaohu; Kaiser, Ralf I.
• 署名单位: University of Hawaii System; University of Hawaii Manoa; Samara National Research University; State University System of Florida; Florida International University; Chinese Academy of Sciences; Xinjiang Astronomy Observatory, CAS; Chinese Academy of Sciences; Chinese Academy of Sciences
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-8542
• DOI: 10.1073/pnas.2409933121
• 发表日期: 2024-12-17
• 关键词: active thermochemical tables; molecular-beam; hydrocarbons; energy; identification; isomers; benzene; tmc-1

摘要

The cyclopentadiene (C5H6) molecule has emerged as a molecular building block of nonplanar polycyclic aromatic hydrocarbons (PAHs) and carbonaceous nanostructures such as corannulene (C20H10), nanobowls (C40H10), and fullerenes (C60) in deep space. However, the underlying elementary gas- phase processes synthesizing cyclopentadiene from acyclic hydrocarbon precursors have remained elusive. Here, by merging crossed molecular beam experiments with rate coefficient calculations and comprehensive astrochemical modeling, we afford persuasive testimony on an unconventional low- temperature cyclization pathway to cyclopentadiene from acyclic precursors through the reaction of the simplest diatomic organic radical-methylidyne (CH)- with 1,3- butadiene (C4H6) representing main route to cyclopentadiene observed in TaurusMolecular Cloud. This facile route provides potential solution for the incorporation of the cyclopentadiene moiety in complex aromatic systems via bottom-up molecular mass growth processes and offers an entry point to the low- temperature chemistry in deep space leading eventually to nonplanar PAHs in our carbonaceous Universe.