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Title: Pyrene synthesis in circumstellar envelopes and its role in the formation of 2D nanostructures

Abstract

For the past decades, the hydrogen-abstraction/acetylene-addition (HACA) mechanism has been instrumental in attempting to untangle the origin of polycyclic aromatic hydrocarbons (PAHs) as identified in carbonaceous meteorites such as Allende and Murchison. However, the fundamental reaction mechanisms leading to the synthesis of PAHs beyond phenanthrene (C 14H 10) are still unknown. By exploring the reaction of the 4-phenanthrenyl radical (C 14H 9•) with acetylene (C 2H 2) under conditions prevalent in carbon-rich circumstellar environments, we show evidence of a facile, isomer-selective formation of pyrene (C 16H 10). Along with the hydrogen-abstraction/vinylacetylene-addition (HAVA) mechanism, molecular mass growth processes from pyrene may lead through systematic ring expansions not only to more complex PAHs, but ultimately to 2D graphene-type structures. Lastly, these fundamental reaction mechanisms are crucial to facilitate an understanding of the origin and evolution of the molecular universe and, in particular, of carbon in our Galaxy.

Authors:
 [1];  [1]; ORCiD logo [2];  [2]; ORCiD logo [2];  [3];  [3];  [3];  [4]
  1. Univ. of Hawaii at Manoa, Honolulu, HI (United States). Dept. of Chemistry
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Chemical Sciences Division
  3. Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Univ. of California, Berkeley, CA (United States). Kavli Energy Nano Sciences Inst.
  4. Florida International Univ., Miami, FL (United States). Dept. of Chemistry and Biochemistry
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division
OSTI Identifier:
1461139
Grant/Contract Number:  
AC02-05CH11231
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Nature Astronomy
Additional Journal Information:
Journal Volume: 2; Journal Issue: 5; Journal ID: ISSN 2397-3366
Publisher:
Springer
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 79 ASTRONOMY AND ASTROPHYSICS

Citation Formats

Zhao, Long, Kaiser, Ralf I., Xu, Bo, Ablikim, Utuq, Ahmed, Musahid, Joshi, Dharati, Veber, Gregory, Fischer, Felix R., and Mebel, Alexander M. Pyrene synthesis in circumstellar envelopes and its role in the formation of 2D nanostructures. United States: N. p., 2018. Web. doi:10.1038/s41550-018-0399-y.
Zhao, Long, Kaiser, Ralf I., Xu, Bo, Ablikim, Utuq, Ahmed, Musahid, Joshi, Dharati, Veber, Gregory, Fischer, Felix R., & Mebel, Alexander M. Pyrene synthesis in circumstellar envelopes and its role in the formation of 2D nanostructures. United States. doi:10.1038/s41550-018-0399-y.
Zhao, Long, Kaiser, Ralf I., Xu, Bo, Ablikim, Utuq, Ahmed, Musahid, Joshi, Dharati, Veber, Gregory, Fischer, Felix R., and Mebel, Alexander M. Mon . "Pyrene synthesis in circumstellar envelopes and its role in the formation of 2D nanostructures". United States. doi:10.1038/s41550-018-0399-y.
@article{osti_1461139,
title = {Pyrene synthesis in circumstellar envelopes and its role in the formation of 2D nanostructures},
author = {Zhao, Long and Kaiser, Ralf I. and Xu, Bo and Ablikim, Utuq and Ahmed, Musahid and Joshi, Dharati and Veber, Gregory and Fischer, Felix R. and Mebel, Alexander M.},
abstractNote = {For the past decades, the hydrogen-abstraction/acetylene-addition (HACA) mechanism has been instrumental in attempting to untangle the origin of polycyclic aromatic hydrocarbons (PAHs) as identified in carbonaceous meteorites such as Allende and Murchison. However, the fundamental reaction mechanisms leading to the synthesis of PAHs beyond phenanthrene (C14H10) are still unknown. By exploring the reaction of the 4-phenanthrenyl radical (C14H9•) with acetylene (C2H2) under conditions prevalent in carbon-rich circumstellar environments, we show evidence of a facile, isomer-selective formation of pyrene (C16H10). Along with the hydrogen-abstraction/vinylacetylene-addition (HAVA) mechanism, molecular mass growth processes from pyrene may lead through systematic ring expansions not only to more complex PAHs, but ultimately to 2D graphene-type structures. Lastly, these fundamental reaction mechanisms are crucial to facilitate an understanding of the origin and evolution of the molecular universe and, in particular, of carbon in our Galaxy.},
doi = {10.1038/s41550-018-0399-y},
journal = {Nature Astronomy},
number = 5,
volume = 2,
place = {United States},
year = {Mon Mar 05 00:00:00 EST 2018},
month = {Mon Mar 05 00:00:00 EST 2018}
}

Journal Article:
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