Article
Thermodynamics
Hanfeng Jin, Lili Xing, Dapeng Liu, Junyu Hao, Jiuzhong Yang, Aamir Farooq
Summary: Recent investigations have shown that the clustering of hydrocarbons by radical-chain reaction (CHRCR) mechanism is crucial for the rapid synthesis of polycyclic aromatic hydrocarbons (PAHs) and soot. Resonance-stabilized radicals (RSRs) are essential in this mechanism, with non-benzene first-ring species being significant as precursors of larger aromatic hydrocarbons. Stable C7H7 RSRs, such as benzyl, tropyl, and vinyl-cyclopentadienyl, are key in the growth of PAHs.
COMBUSTION AND FLAME
(2021)
Article
Chemistry, Physical
Akant Vats, Satyam Srivastav, Anshika Pandey, Amit Pathak
Summary: The discovery of cyano-substituted polycyclic aromatic hydrocarbon (CN-PAH) form of naphthalene (C10H8) in the Taurus molecular cloud (TMC-1) has sparked interest in searching for other nitrogen-containing naphthalenes in similar interstellar environments. This study reports theoretical microwave spectra of naphthalene in various N-substituted forms, using density functional theory (DFT) calculations to determine spectroscopic constants and simulate rotational spectra. The N-naphthalene species considered show strong transitions at centimetre wavelengths, which is typical for PAH-related species in cold, dark molecular clouds such as TMC-1. The accurate rotational data provided can guide laboratory experiments and astronomical searches.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Lisa Monluc, Anatoliy A. Nikolayev, Iakov A. Medvedkov, Valeriy N. Azyazov, Alexander N. Morozov, Alexander M. Mebel
Summary: The reaction between ortho-benzyne and vinylacetylene predominantly proceeds by the biradical acetylenic mechanism under combustion conditions, forming naphthalene or naphthyl radicals, with the relative yields controlled by temperature and pressure.
Article
Engineering, Chemical
Yu-Hui Wang, Li-Tao Wang, Zhi-Zhen Yao, Jun-Jian Yin, Zi-Bin Huang, Pei-Qing Yuan, Wei-Kang Yuan
Summary: This study investigated the formation of aromatic carbon radicals during heavy oil thermal processing, finding that increasing reaction temperature or radical concentration promotes the reaction. The main contribution to aromatic carbon radicals comes from (CH3)• in PAHs, and the activation entropy of H-abstraction affects the difference in reaction rate constants. The uniqueness of H-abstraction in hetero-PAHs leads to distinct reaction behaviors.
CHEMICAL ENGINEERING SCIENCE
(2021)
Article
Chemistry, Physical
Anita Schneiker, Gopi Ragupathy, Gabor Bazso, Gyorgy Tarczay
Summary: It is well-accepted that the formation of interstellar H-2 is catalyzed by small heterocycles on the surface of interstellar grains. This study investigated the reaction of H atoms with different heterocycles in solid para-H-2. The results revealed the formation of various radicals and suggested the important role of small heterocycles in interstellar H-2 formation. Additionally, it was found that the ratios of different c-C4HxO (x = 4-8) species in an astrophysical object are determined by the rate of H atom addition and abstraction reactions.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Multidisciplinary Sciences
Yusuke Nakakuki, Takashi Hirose, Hikaru Sotome, Min Gao, Daiki Shimizu, Ruiji Li, Jun-Ya Hasegawa, Hiroshi Miyasaka, Kenji Matsuda
Summary: Helically twisted conductive nanocarbon materials are suitable for optoelectronic and electromagnetic molecular devices on the nanometer scale, showing a large effective conjugation length and ultrafast decay dynamics. The extended π-helicenes achieved a large effective conjugation length through helical fusion, leading to an absorption edge in the near-infrared region.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Xiushang Xu, Amy L. Vonder Haar, Rengo Yoshioka, Qizheng Zhang, Serhii Vasylevskyi, Andrew J. Musser, Akimitsu Narita
Summary: A benzo[rst]pentaphene derivative, BPP-MeOPA, was synthesized and characterized by NMR and single-crystal X-ray analysis. Investigation of its photophysical properties, including transient absorption spectroscopy, revealed improved absorption and emission features from an S-1 state with excitonic and charge-transfer character by introducing MeOPA groups.
CHEMICAL COMMUNICATIONS
(2023)
Review
Environmental Sciences
Meng Qiao, Weixiao Qi, Huijuan Liu, Jiuhui Qu
Summary: Oxygenated polycyclic aromatic hydrocarbons (OPAHs) have higher concentrations and toxicity in water environments, posing significant ecological risks to surface water ecosystems.
ENVIRONMENT INTERNATIONAL
(2022)
Article
Engineering, Environmental
Paulina Godlewska, Patryk Oleszczuk
Summary: The study found that biochar derived from a mixture of SL and biomass (SLW) had a better effect on the persistence and bioavailability of PAHs in soil compared to biochar derived solely from sewage sludge (SL).
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Chemistry, Organic
Yushi Ohno, Shogo Ando, Daisuke Furusho, Ryoyu Hifumi, Yuuya Nagata, Ikuyoshi Tomita, Shinsuke Inagi
Summary: Here, a facile and selective synthesis of cationic azatriphenylene derivatives was achieved through electrochemical intramolecular cyclization, where the key step involves atom-economical C-H pyridination without a transition-metal catalyst or an oxidant. This proposed strategy provides a practical approach for introducing cationic nitrogen (N (+)) into pi-electron systems, thus expanding the molecular design of N (+)-doped polycyclic aromatic hydrocarbons.
Article
Chemistry, Inorganic & Nuclear
Huimin Zhong, Cong Jiang, Jiahui Zou, Guancheng Zhu, Yanyan Huang
Summary: In this study, CeO2-based porous carbonaceous frameworks (CeO2 PCFs) were used as antioxidant nanozymes to scavenge reactive oxygen species and absorb benzo[a]pyrene. CeO2 PCFs exhibited excellent superoxide dismutase-like and catalase-like activity, effectively eliminating superoxide radical, hydroxyl radical, and hydrogen peroxide. The 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) free radical scavenging assay confirmed the free radical scavenging ability of CeO2 PCFs. Furthermore, CeO2 PCFs with large surface area and porous structure efficiently adsorbed benzo[a]pyrene. The designed CeO2 PCFs can serve as new antioxidant nanozymes for scavenging reactive oxygen species and adsorbing polycyclic aromatic hydrocarbons (PAHs).
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Michael Frenklach, Alexander S. Semenikhin, Alexander M. Mebel
Summary: Rotationally excited dimerization of aromatic moieties is proposed as a mechanism for soot particle inception, where the formed E-bridge can rapidly transform from an angled to a planar structure through bridge H atom abstraction. This process effectively speeds up the growth of polycyclic aromatic hydrocarbons by combining aromatic moieties collisionally, leading to physical dimerization.
JOURNAL OF PHYSICAL CHEMISTRY A
(2021)
Article
Chemistry, Physical
Thomas Liu, Baptiste Carles, Christine Elias, Claire Tonnele, Daniel Medina-Lopez, Akimitsu Narita, Yannick Chassagneux, Christophe Voisin, David Beljonne, Stephane Campidelli, Loic Rondin, Jean-Sebastien Lauret
Summary: In this study, we conducted single-molecule spectroscopy at cryogenic temperatures to investigate the optical properties of graphene quantum dots (GQDs). We found that temperature has an effect on the spectral characteristics of GQDs, and we used density functional theory calculations to explain these observations. Additionally, we discovered that the vibrational features can serve as a unique fingerprint for identifying GQDs.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Astronomy & Astrophysics
Thomas S-Y Lai, Lee Armus, U. Vivian, Tanio Diaz-Santos, Kirsten L. Larson, Aaron Evans, Matthew A. Malkan, Philip Appleton, Jeff Rich, Francisco Muller-Sanchez, Hanae Inami, Thomas Bohn, Jed McKinney, Luke Finnerty, David R. Law, Sean T. Linden, Anne M. Medling, George C. Privon, Yiqing Song, Sabrina Stierwalt, Paul P. van der Werf, Loreto Barcos-Munoz, J. D. T. Smith, Aditya Togi, Susanne Aalto, Torsten Boker, Vassilis Charmandaris, Justin Howell, Kazushi Iwasawa, Francisca Kemper, Joseph M. Mazzarella, Eric J. Murphy, Michael J. Brown, Christopher C. Hayward, Jason Marshall, David Sanders, Jason Surace
Summary: This study presents the JWST/MIRI integral-field spectroscopy of the nearby merging, luminous infrared galaxy NGC 7469, revealing the presence of a Seyfert type-1.5 nucleus, highly ionized outflow, and a bright circumnuclear star-forming ring. The observations also show prominent polycyclic aromatic hydrocarbon emission and warm molecular gas in the starburst ring.
ASTROPHYSICAL JOURNAL LETTERS
(2022)
Review
Environmental Sciences
Jamie M. Dearnley, Charles Killeen, Rebecca L. Davis, Vince P. Palace, Gregg T. Tomy
Summary: This article reviews the metabolism and toxicity of polycyclic aromatic compounds (PACs) in fish and presents various methods for analyzing metabolite-containing bile. Recent environmental monitoring studies demonstrate the utility of this technique in assessing oil spill pollution, establishing baseline exposure, and evaluating pollution in urban waterways.
CRITICAL REVIEWS IN ENVIRONMENTAL SCIENCE AND TECHNOLOGY
(2022)
Article
Chemistry, Multidisciplinary
Chao He, Ralf I. Kaiser, Wenchao Lu, Musahid Ahmed, Pavel S. Pivovarov, Oleg V. Kuznetsov, Marsel V. Zagidullin, Alexander M. Mebel
Summary: Researchers have discovered a unconventional mechanism of reaction in which benzyl and phenyl radicals react to produce a specific isomer of the simplest polycyclic aromatic hydrocarbon (PAH), called 9H-fluorene, in the gas phase. The structure of 9H-fluorene provides fundamental insights into the evolution of hydrocarbons in high temperature settings and its potential use as a molecular building block for complex curved nanostructures.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Astronomy & Astrophysics
Joshua H. Marks, Jia Wang, Mikhail M. Evseev, Oleg V. Kuznetsov, Ivan O. Antonov, Ralf I. Kaiser
Summary: The study explores the formation of complex organic molecules in interstellar ice analogs composed of methanol and carbon dioxide using simulated secondary electrons generated in the track of galactic cosmic rays. Detecting the reaction products as they sublime, the researchers identify carbonic acid monomethyl ester (CH3OCOOH) and glycolic acid (HOCH2COOH) in the processed ices. The abundance of these molecules in analog interstellar ices and the low irradiation dose needed for their formation makes them excellent candidates for interstellar detection, unlike tautomers dihydroxyacetaldehyde ((OH)(2)CCHO) and enol ethenetriol (HOCHC(OH)(2)), which were not found to form under the applied conditions.
ASTROPHYSICAL JOURNAL
(2023)
Article
Chemistry, Physical
Chaya Weeraratna, Xiaochen Tang, Oleg Kostko, Vi H. Rapp, Lara A. Gundel, Hugo Destaillats, Musahid Ahmed
Summary: A new generation of electronic cigarettes with acidifying additives exacerbates the youth vaping epidemic. The behavior of nicotine in vaping aerosols was studied using X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure spectroscopy. It was found that nicotine in the core of aqueous particles is partially protonated and further protonated by acidification. However, the degree of nicotine protonation at the particle surface is significantly lower. The presence of propylene glycol and glycerol completely eliminates nicotine protonation at the surface.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Chao He, Ralf I. Kaiser, Wenchao Lu, Musahid Ahmed, Yahaira Reyes, Stanislaw F. Wnuk, Alexander M. Mebel
Summary: The gas-phase reaction between the 1-indenyl radical and the cyclopentadienyl radical was studied using synchrotron-based mass spectrometry coupled with a pyrolytic reactor. The isomer selective production of phenanthrene, anthracene, and benzofulvalene was identified through soft photoionization with tunable vacuum ultraviolet photons. Our findings challenge the classical theory regarding the combination of radicals and provide insight into the evolution of the cosmic carbon budget.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Ryan Reynolds, Musahid Ahmed, Kevin R. Wilson
Summary: Criegee intermediates (CIs) play a crucial role in the ozonolysis of unsaturated organic compounds, controlling the formation of small fragmentation products and higher molecular weight oligomeric compounds. The reaction of CI with carboxylic acids (RCOOH) to produce oligomeric alpha-acyloxyalkyl hydroperoxides (AAHPs) is of interest to the chemical transformation of organic compounds in the atmosphere. The rate of this reaction in condensed phases, however, is still uncertain.
ACS EARTH AND SPACE CHEMISTRY
(2023)
Article
Chemistry, Physical
Cameron J. J. Mackie, Wenchao Lu, Jiashu Liang, Oleg Kostko, Biswajit Bandyopadhyay, Ishan Gupta, Musahid Ahmed, Martin Head-Gordon
Summary: The stability and distributions of small water clusters generated in a supersonic beam expansion were studied using tunable vacuum ultraviolet (VUV) radiation generated at a synchrotron. Time-of-flight mass spectrometry revealed enhanced population of protonated water clusters (H+(H2O)( n )) based on ionization energy and photoionization distance from source, indicating the presence of magic numbers below n = 21 commonly reported in the literature. The VUV threshold photoionization of neutral water clusters near the nozzle exit resulted in a different nonequilibrium state compared to a skimmed molecular beam, leading to the discovery of a new magic number at 14.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Physical
Souvick Biswas, Dababrata Paul, Chao He, Nureshan Dias, Musahid Ahmed, Michelle L. Pantoya, Ralf I. Kaiser
Summary: Researchers have discovered an active heterogeneous surface chemistry between aluminum nanoparticles (AlNPs) and alumina in hydrocarbon jet fuels, which challenges previous understanding of alumina’s reactivity.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Musahid Ahmed, Wenchao Lu
Summary: Understanding the origins of structure and bonding at the molecular level in complex chemical systems is crucial in physical chemistry. This study utilizes vibrational spectroscopy, X-ray techniques, microreactors, and aerosol beams to investigate intricate interactions such as hydrogen bonding, proton transfer, and noncovalent interactions. Various spectroscopy methods provide insights into the self-assembly and growth processes of different chemical systems. Future directions in studying hydrogen-bond networks in deep eutectic solvents and organic frameworks are also discussed.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Chao He, Ralf I. Kaiser, Wenchao Lu, Musahid Ahmed, Vladislav S. Krasnoukhov, Pavel S. Pivovarov, Marsel V. Zagidullin, Valeriy N. Azyazov, Alexander N. Morozov, Alexander M. Mebel
Summary: Using a microchemical reactor and computational fluid dynamics (CFD) simulations, it is discovered that the reaction between benzyl and propargyl radicals synthesizes the simplest representative of PAHs, naphthalene. This reveals a novel Propargyl Addition-BenzAnnulation (PABA) mechanism and provides important insights into the origin of aromatic substances in the universe.
Article
Chemistry, Physical
Alon Zamir, Estefania Rossich Molina, Musahid Ahmed, Tamar Stein
Summary: This computational study investigates water cluster confinement within small finite polycyclic aromatic hydrocarbons (PAHs). The results serve as a model for understanding confinement in larger systems and provide insights into molecular interactions in confined systems.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
