A Free‐Radical Prompted Barrierless Gas‐Phase Synthesis of Pentacene. Issue 28 (11th May 2020)

• Record Type: Journal Article
• Authors: Zhao, Long; Kaiser, Ralf I.; Lu, Wenchao; Ahmed, Musahid; Evseev, Mikhail M.; Bashkirov, Eugene K.; Azyazov, Valeriy N.; Tönshoff, Christina; Reicherter, Florian; Bettinger, Holger F.; Mebel, Alexander M.
• Is Part Of: Angewandte Chemie international edition. Volume 59:Issue 28(2020)
• Page Start: 11334
• Page End: 11338
• Publication Date: 2020-05-11
• Subjects: gas-phase chemistry -- hydrogen abstraction/vinylacetylene addition (HAVA) -- interstellar medium -- mass spectrometry -- polycyclic aromatic hydrocarbons (PAHs); Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.202003402
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: A representative, low‐temperature gas‐phase reaction mechanism synthesizing polyacenes via ring annulation exemplified by the formation of pentacene (C22 H14 ) along with its benzo[ a ]tetracene isomer (C22 H14 ) is unraveled by probing the elementary reaction of the 2‐tetracenyl radical (C18 H11 . ) with vinylacetylene (C4 H4 ). The pathway to pentacene—a prototype polyacene and a fundamental molecular building block in graphenes, fullerenes, and carbon nanotubes—is facilitated by a barrierless, vinylacetylene mediated gas‐phase process thus disputing conventional hypotheses that synthesis of polycyclic aromatic hydrocarbons (PAHs) solely proceeds at elevated temperatures. This low‐temperature pathway can launch isomer‐selective routes to aromatic structures through submerged reaction barriers, resonantly stabilized free‐radical intermediates, and methodical ring annulation in deep space eventually changing our perception about the chemistry of carbon in our universe. Abstract : PAH for the course : Pentacene, a polycyclic aromatic hydrocarbon (PAH), can be formed through molecular mass growth processes via ring annulation at low temperatures via the reaction of 2‐tetracenyl radicals with vinylacetylene. It thus disputes the conventional hypotheses that synthesis of PAHs solely proceeds at elevated temperatures.