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Feldman VI. Astrochemically Relevant Radicals and Radical-Molecule Complexes: A New Insight from Matrix Isolation. Int J Mol Sci 2023; 24:14510. [PMID: 37833965 PMCID: PMC10572415 DOI: 10.3390/ijms241914510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 09/15/2023] [Accepted: 09/16/2023] [Indexed: 10/15/2023] Open
Abstract
The reactive open-shell species play a very important role in the radiation-induced molecular evolution occurring in the cold areas of space and presumably leading to the formation of biologically relevant molecules. This review presents an insight into the mechanism of such processes coming from matrix isolation studies with a main focus on the experimental and theoretical studies performed in the author's laboratory during the past decade. The radicals and radical cations produced from astrochemically relevant molecules were characterized by Fourier transform infrared (FTIR) and electron paramagnetic resonance (EPR) spectroscopy. Small organic radicals containing C, O, and N atoms are considered in view of their possible role in the formation of complex organic molecules (COMs) in space, and a comparison with earlier results is given. In addition, the radical-molecule complexes generated from isolated intermolecular complexes in matrices are discussed in connection with their model significance as the building blocks for COMs formed under the conditions of extremely restricted molecular mobility at cryogenic temperatures.
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Affiliation(s)
- Vladimir I Feldman
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
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2
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Sheka EF. A Neoteric View of sp2 Amorphous Carbon. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:nano13101648. [PMID: 37242064 DOI: 10.3390/nano13101648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 02/22/2023] [Accepted: 02/24/2023] [Indexed: 05/28/2023]
Abstract
Presented is a concentrated synopsis of facilities of empirical and virtual analytics that, once applied, have provided a fully new vision of sp2 amorphous carbons. This study proved that the solids are multilevel structures, started with the first-level basic structural units (BSUs) and accomplished as macroscopic agglomerates of globular structures, consisting, in its turn, of stacked BSUs. BSUs present necklaced graphene molecules, size, and shape of which are governed by the relevant graphene domains while chemical composition in addition to basic carbon is controlled with heteroatoms of the necklaces. This study shows that BSUs and stacks of BSUs determine the short-range order of the solids and are the main subject of the applied analytics. The synopsis consists of two parts related to empirical and virtual analytics. The former is composed of sections related to structural determination, total and atomic chemical content evaluation and elicitation of the covalent bond composition. The second presents new analytic approaches based on the Digital Twins concept and virtual vibrational spectrometry. The synopsis is configured as an atlas composed of generalized pictures accompanied with necessary explanations to be discussed in detail in the extended references.
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Affiliation(s)
- Elena F Sheka
- Institute of Physical Researches and Technology, Peoples' Friendship University of Russia (RUDN University), 117198 Moscow, Russia
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3
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Sheka EF. Virtual Vibrational Spectrometry of Stable Radicals-Necklaced Graphene Molecules. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:597. [PMID: 35214926 PMCID: PMC8877590 DOI: 10.3390/nano12040597] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 02/02/2022] [Accepted: 02/05/2022] [Indexed: 02/04/2023]
Abstract
The article presents results of an extended virtual experiment on graphene molecules performed using the virtual vibrational spectrometer HF Spectrodyn that exploits semiempirical Hartree-Fock approximation. The molecules are composed of flat graphene domains surrounded with heteroatom necklaces. Not existing individually, these molecules are met in practice as basic structure units of complex multilevel structure of all sp2 amorphous carbons. This circumstance deprives the solids' in vitro spectroscopy of revealing the individual character of basic structural elements, and in silico spectrometry fills this shortcoming. The obtained virtual vibrational spectra allow for drawing first conclusions about the specific features of the vibrational dynamics of the necklaced graphene molecules, caused by spatial structure and packing of their graphene domains as well as by chemical composition of the relevant necklaces. As shown, IR absorption spectra of the molecules are strongly necklace dependent, once becoming a distinct spectral signature of the amorphous body origin. Otherwise, Raman spectra are a spectral mark of the graphene domain's size and packing, thus disclosing the mystery of their universal D-G-band standard related to graphene-containing materials of various origins.
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Affiliation(s)
- Elena F Sheka
- Institute of Physical Research and Technologies, Peoples' Friendship University of Russia (RUDN University), 117198 Moscow, Russia
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4
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Carbenes, related intermediates, and small-sized cycles: contribution from Professor Nefedov’s laboratory. MENDELEEV COMMUNICATIONS 2021. [DOI: 10.1016/j.mencom.2021.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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5
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Kortyna A, Samin AJ, Miller TA, Nesbitt DJ. Sub-Doppler infrared spectroscopy of resonance-stabilized hydrocarbon intermediates: ν 3/ν 4 CH stretch modes and CH 2 internal rotor dynamics of benzyl radical. Phys Chem Chem Phys 2017; 19:29812-29821. [PMID: 29099133 DOI: 10.1039/c7cp05776h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Highly reactive benzyl radicals are generated by electron dissociative attachment to benzyl chloride doped into a neon-hydrogen-helium discharge and immediately cooled to Trot = 15 K in a high density, supersonic slit expansion environment. The sub-Doppler spectra are fit to an asymmetric-top rotational Hamiltonian, thereby yielding spectroscopic constants for the ground (v = 0) and first excited (v = 1, ν3, ν4) vibrational levels of the ground electronic state. The rotational constants obtained for the ground state are in good agreement with previous laser induced fluorescence measurements (LIF), with vibrational band origins (ν3 = 3073.2350 ± 0.0006 cm-1, ν4 = 3067.0576 ± 0.0006 cm-1) in agreement with anharmonically corrected density functional theory calculations. To assist in detection of benzyl radical in the interstellar medium, we have also significantly improved the precision of the ground state rotational constants through combined analysis of the ground state IR and LIF combination differences. Of dynamical interest, there is no evidence in the sub-Doppler spectra for tunneling splittings due to internal rotation of the CH2 methylene subunit, which implies a significant rotational barrier consistent with partial double bond character in the CC bond. This is further confirmed with high level ab initio calculations at the CCSD(T)-f12b/ccpVdZ-f12 level, which predict a zero-point energy corrected barrier to internal rotation of ΔEtun ≈ 11.45 kcal mol-1 or 4005 cm-1. In summary, the high-resolution infrared spectra are in excellent agreement with simple physical organic chemistry pictures of a strongly resonance-stabilized benzyl radical with a nearly rigid planar structure due to electron delocalization around the aromatic ring.
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Affiliation(s)
- A Kortyna
- JILA, National Institute of Standards and Technology, University of Colorado, Boulder, Colorado 80309, USA
| | - A J Samin
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA
| | - T A Miller
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA
| | - D J Nesbitt
- JILA, National Institute of Standards and Technology, University of Colorado, Boulder, Colorado 80309, USA and Department of Physics, University of Colorado Boulder, Boulder, CO 80309, USA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
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Asatryan R, Bennadji H, Bozzelli JW, Ruckenstein E, Khachatryan L. Molecular Products and Fundamentally Based Reaction Pathways in the Gas-Phase Pyrolysis of the Lignin Model Compound p-Coumaryl Alcohol. J Phys Chem A 2017; 121:3352-3371. [PMID: 28406634 DOI: 10.1021/acs.jpca.7b01656] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The fractional pyrolysis of lignin model compound para-coumaryl alcohol (p-CMA) containing a propanoid side chain and a phenolic OH group was studied using the System for Thermal Diagnostic Studies at temperatures from 200 to 900 °C, in order to gain mechanistic insight into the role of large substituents in high-lignin feedstocks pyrolysis. Phenol and its simple derivatives p-cresol, ethyl-, propenyl-, and propyl-phenols were found to be the major products predominantly formed at low pyrolysis temperatures (<500 °C). A cryogenic trapping technique was employed combined with EPR spectroscopy to identify the open-shell intermediates registered at pyrolysis temperatures above 500 °C. These were characterized as radical mixtures primarily consisting of oxygen-linked conjugated radicals. A comprehensive potential energy surface analysis of p-CMA and p-CMA + H atom systems was performed using various DFT protocols to examine the possible role of concerted molecular eliminations and free-radical mechanisms in the formation of major products. Other significant unimolecular concerted reactions along with formation and decomposition of primary radicals are also described and evaluated. The calculations suggest that a set of the chemically activated secondary radical channels is relevant to the low temperature product formation under fractional pyrolysis conditions.
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Affiliation(s)
- Rubik Asatryan
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York , Buffalo, New York 14226, United States
| | - Hayat Bennadji
- Department of Environmental Sciences, Louisiana State University , Baton Rouge, Louisiana 70808, United States
| | - Joseph W Bozzelli
- Department of Chemistry and Environmental Science, New Jersey Institute of Technology , Newark, New Jersey 07102, United States
| | - Eli Ruckenstein
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York , Buffalo, New York 14226, United States
| | - Lavrent Khachatryan
- Department of Chemistry, Louisiana State University , Baton Rouge, Louisiana 70803, United States
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Buckingham GT, Porterfield JP, Kostko O, Troy TP, Ahmed M, Robichaud DJ, Nimlos MR, Daily JW, Ellison GB. The thermal decomposition of the benzyl radical in a heated micro-reactor. II. Pyrolysis of the tropyl radical. J Chem Phys 2016; 145:014305. [DOI: 10.1063/1.4954895] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Grant T. Buckingham
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden Colorado 80401, USA
| | - Jessica P. Porterfield
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA
| | - Oleg Kostko
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Tyler P. Troy
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Musahid Ahmed
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - David J. Robichaud
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden Colorado 80401, USA
| | - Mark R. Nimlos
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden Colorado 80401, USA
| | - John W. Daily
- Department of Mechanical Engineering, Center for Combustion and Environmental Research, University of Colorado, Boulder, Colorado 80309-0427, USA
| | - G. Barney Ellison
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA
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Savee JD, Zádor J, Hemberger P, Sztáray B, Bodi A, Osborn DL. Threshold photoelectron spectrum of the benzyl radical. Mol Phys 2015. [DOI: 10.1080/00268976.2015.1021398] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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9
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Buckingham GT, Ormond TK, Porterfield JP, Hemberger P, Kostko O, Ahmed M, Robichaud DJ, Nimlos MR, Daily JW, Ellison GB. The thermal decomposition of the benzyl radical in a heated micro-reactor. I. Experimental findings. J Chem Phys 2015; 142:044307. [DOI: 10.1063/1.4906156] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Grant T. Buckingham
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA
| | - Thomas K. Ormond
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA
| | - Jessica P. Porterfield
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA
| | - Patrick Hemberger
- Molecular Dynamics Group, Paul Scherrer Institut, CH-5232 Villigen-PSI, Switzerland
| | - Oleg Kostko
- Chemical Sciences Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720, USA
| | - Musahid Ahmed
- Chemical Sciences Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720, USA
| | - David J. Robichaud
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA
| | - Mark R. Nimlos
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA
| | - John W. Daily
- Department of Mechanical Engineering, Center for Combustion and Environmental Research,University of Colorado, Boulder, Colorado 80309-0427, USA
| | - G. Barney Ellison
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA
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10
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Sander W, Roy S, Bravo-Rodriguez K, Grote D, Sanchez-Garcia E. The Benzylperoxyl Radical as a Source of Hydroxyl and Phenyl Radicals. Chemistry 2014; 20:12917-23. [DOI: 10.1002/chem.201402459] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Indexed: 11/10/2022]
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11
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Mišić V, Piech K, Bally T. Carbocations Generated under Stable Conditions by Ionization of Matrix-Isolated Radicals: The Allyl and Benzyl Cations. J Am Chem Soc 2013; 135:8625-31. [DOI: 10.1021/ja401890m] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Vladimir Mišić
- Department of Chemistry, University of Fribourg, Fribourg CH-1700, Switzerland
| | - Krzysztof Piech
- Department of Chemistry, University of Fribourg, Fribourg CH-1700, Switzerland
| | - Thomas Bally
- Department of Chemistry, University of Fribourg, Fribourg CH-1700, Switzerland
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12
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Arjunan V, Saravanan I, Mythili CV, Balakrishnan K, Mohan S. Vibrational, conformational and electronic structure investigations of α,α'-dibromo-o-xylene, α,α'-dibromo-m-xylene and α,α'-dibromo-p-xylene. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2012; 91:166-177. [PMID: 22381787 DOI: 10.1016/j.saa.2012.02.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 01/31/2012] [Accepted: 02/02/2012] [Indexed: 05/31/2023]
Abstract
The Fourier transform infrared (FTIR) and FT-Raman spectra of α,α'-dibromo-o-xylene (DBOX), α,α'-dibromo-m-xylene (DBMX) and α,α'-dibromo-p-xylene (DBPX) of the configuration BrCH(2)C(6)H(4)CH(2)Br have been recorded in the range 4000-400 and 4000-100 cm(-1), respectively. The conformational analysis of these compounds was performed. The complete vibrational assignment and analysis of the fundamental modes of the most stable conformer of the compounds were carried out using the experimental FTIR and FT-Raman data, and quantum mechanical studies. The observed vibrational frequencies were compared with the wavenumbers derived theoretically for the optimized geometry of the compounds from the DFT-B3LYP gradient calculations employing the standard 6-31G**, high level 6-311++G** and cc-pVTZ basis sets. The structural parameters and vibrational wavenumbers obtained from the DFT method are in good agreement with the experimental data. The potential energy distributions of the fundamental modes were also calculated with DFT force fields utilizing Wilson's FG matrix method. The effect of -CH(2)Br group on the skeletal vibrations has been discussed.
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Affiliation(s)
- V Arjunan
- Department of Chemistry, Kanchi Mamunivar Centre for Post-Graduate Studies, Puducherry 605 008, India.
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13
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Wren SW, Vogelhuber KM, Ichino T, Stanton JF, Lineberger WC. Photoelectron Spectroscopy of Anilinide and Acidity of Aniline. J Phys Chem A 2012; 116:3118-23. [DOI: 10.1021/jp211463r] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Scott W. Wren
- JILA, University of Colorado and National Institute of Standards and Technology, Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
| | - Kristen M. Vogelhuber
- JILA, University of Colorado and National Institute of Standards and Technology, Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
| | - Takatoshi Ichino
- Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712-0165, United States
| | - John F. Stanton
- Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712-0165, United States
| | - W. Carl Lineberger
- JILA, University of Colorado and National Institute of Standards and Technology, Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
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14
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Satink RG, Meijer G, von Helden G. Infrared Spectroscopy of Neutral C7H7 Isomers: Benzyl and Tropyl. J Am Chem Soc 2003; 125:15714-5. [PMID: 14677940 DOI: 10.1021/ja038329i] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The gas-phase infrared absorption spectra of neutral benzyl and tropyl, isomers of formula C7H7, have been measured in the 400-1800 cm-1 spectral region. In addition, a quantum chemical calculation has been performed to model the infrared spectra. For the benzyl radical, the theory shows satisfactory overlap with the experiment, although vibrations involving the CH2 group might be anharmonic. The tropyl radical, which is subject to the Jahn-Teller effect, seems well modeled for the out-of-plane vibrational modes, but less so for the in-plane vibrational modes.
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Affiliation(s)
- Rob G Satink
- FOM-institute for Plasma Physics "Rijnhuizen", Edisonbaan 14, NL-3439 MN, Nieuwegein, The Netherlands.
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