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Title: A Free-Radical Pathway to Hydrogenated Phenanthrene in Molecular Clouds-Low Temperature Growth of Polycyclic Aromatic Hydrocarbons

Journal Article · · ChemPhysChem

The hydrogen-abstraction/acetylene-addition mechanism has been fundamental to unravelling the synthesis of polycyclic aromatic hydrocarbons (PAHs) detected in combustion flames and carbonaceous meteorites like Orgueil and Murchison. However, the fundamental reaction pathways accounting for the synthesis of complex PAHs, such as the tricyclic anthracene and phenanthrene along with their dihydrogenated counterparts, remain elusive to date. By investigating the hitherto unknown chemistry of the 1-naphthyl radical with 1,3-butadiene, we reveal a facile barrierless synthesis of dihydrophenanthrene adaptable to low temperatures. Finally, these aryl-type radical additions to conjugated hydrocarbons via resonantly stabilized free-radical intermediates defy conventional wisdom that PAH growth is predominantly a high-temperature phenomenon and thus may represent an overlooked path to PAHs as complex as coronene and corannulene in cold regions of the interstellar medium like in the Taurus Molecular Cloud.

Research Organization:
Univ. of Hawaii at Manoa, Honolulu, HI (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
FG02-03ER15411; FG02-04ER15570
OSTI ID:
1602964
Alternate ID(s):
OSTI ID: 1373978
Journal Information:
ChemPhysChem, Vol. 18, Issue 15; ISSN 1439-4235
Publisher:
ChemPubSoc EuropeCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 11 works
Citation information provided by
Web of Science

References (45)

Formation history of polycyclic aromatic hydrocarbons in galaxies journal February 2014
Calculations of Rate Coefficients for the Chemically Activated Reactions of Acetylene with Vinylic and Aromatic Radicals journal November 1994
Electronic Spectroscopy of Medium-Sized Polycyclic Aromatic Hydrocarbons: Implications for the Carriers of the 2175 Å uv bump journal February 2010
Untangling the chemical evolution of Titan's atmosphere and surface–from homogeneous to heterogeneous chemistry journal January 2010
Formation of benzene in the interstellar medium journal December 2010
Indigenous Polycyclic Aromatic Hydrocarbons in Circumstellar Graphite Grains from Primitive Meteorites journal July 1998
PAH Formation under Single Collision Conditions: Reaction of Phenyl Radical and 1,3-Butadiene to Form 1,4-Dihydronaphthalene journal April 2012
Can Neutral and Ionized Polycyclic Aromatic Hydrocarbons be Carriers of the Ultraviolet Extinction bump and the Diffuse Interstellar Bands? journal October 2011
Reaction mechanism of soot formation in flames journal February 2002
Isotopic evidence from an Antarctic carbonaceous chondrite for two reaction pathways of extraterrestrial PAH formation journal December 2000
Hydrogen Abstraction/Acetylene Addition Revealed journal June 2014
Hydrogen Abstraction Acetylene Addition and Diels−Alder Mechanisms of PAH Formation:  A Detailed Study Using First Principles Calculations journal September 2005
Reaction of Phenyl Radicals with Acetylene:  Quantum Chemical Investigation of the Mechanism and Master Equation Analysis of the Kinetics journal September 2003
The inner wind of IRC+10216 revisited: new exotic chemistry and diagnostic for dust condensation in carbon stars journal August 2012
Dust destruction in the ISM: a re-evaluation of dust lifetimes journal May 2011
A Plasmon Resonance in Dehydrogenated Coronene (C 24 H x ) and Its Cations and the Origin of the Interstellar Extinction Band at 217.5 Nanometers journal February 2006
Hydrogen-Abstraction/Acetylene-Addition Exposed journal October 2016
The reactivity of ground-state carbon atoms with unsaturated hydrocarbons in combustion flames and in the interstellar medium journal April 2002
The Infrared Spectrum of Protonated Naphthalene and its Relevance for the Unidentified Infrared Bands journal August 2009
Detailed modeling of soot particle nucleation and growth journal January 1991
Unexpected Chemistry from the Reaction of Naphthyl and Acetylene at Combustion-Like Temperatures journal March 2015
Formation of polycyclic aromatic hydrocarbons and their growth to soot—a review of chemical reaction pathways journal August 2000
Low temperature formation of naphthalene and its role in the synthesis of PAHs (Polycyclic Aromatic Hydrocarbons) in the interstellar medium journal December 2011
HACA's Heritage: A Free-Radical Pathway to Phenanthrene in Circumstellar Envelopes of Asymptotic Giant Branch Stars journal March 2017
Detailed kinetic modeling of soot formation in shock-tube pyrolysis of acetylene journal January 1985
Formation Mechanism of Polycyclic Aromatic Hydrocarbons beyond the Second Aromatic Ring journal May 2013
Hydrogen Abstraction/Acetylene Addition Revealed journal June 2014
Formation pathways of ethynyl-substituted and cyclopenta-fused polycyclic aromatic hydrocarbons journal January 2000
HACA's Heritage: A Free-Radical Pathway to Phenanthrene in Circumstellar Envelopes of Asymptotic Giant Branch Stars journal March 2017
Polycyclic aromatic hydrocarbon processing in interstellar shocks journal February 2010
Formation Mechanisms of Naphthalene and Indene: From the Interstellar Medium to Combustion Flames journal January 2017
Interstellar polycyclic aromatic hydrocarbons - The infrared emission bands, the excitation/emission mechanism, and the astrophysical implications journal September 1989
Hydrogen-Abstraction/Acetylene-Addition Exposed journal October 2016
Formation of buckminsterfullerene (C60) in interstellar space journal December 2011
Charged polycyclic aromatic hydrocarbon clusters and the galactic extended red emission journal March 2007
A detailed kinetic modeling study of aromatics formation in laminar premixed acetylene and ethylene flames journal July 1997
Shattering by turbulence as a production source of very small grains: Shattering as a source of very small grains journal July 2010
Spectroscopic properties of polycyclic aromatic hydrocarbons (PAHs) and astrophysical implications journal January 1997
Hydrogen and carbon isotopic ratios of polycyclic aromatic compounds in two CM2 carbonaceous chondrites and implications for prebiotic organic synthesis journal September 2015
Unexpected Chemistry from the Reaction of Naphthyl and Acetylene at Combustion-Like Temperatures journal March 2015
Identification of Complex Aromatic Molecules in Individual Interplanetary Dust Particles journal October 1993
Formation of Polycyclic Aromatic Hydrocarbons and Carbonaceous Solids in Gas-Phase Condensation Experiments journal April 2009
Formation of polycyclic aromatic hydrocarbons in circumstellar envelopes journal June 1989
Composition profiles and reaction mechanisms in a near-sooting premixed benzene/oxygen/argon flame journal January 1981
The Structure, Origin, and Evolution of Interstellar Hydrocarbon Grains journal May 2013

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