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Krechkivska O, Wilcox CM, Troy TP, Nauta K, Chan B, Jacob R, Reid SA, Radom L, Schmidt TW, Kable SH. Hydrogen-atom attack on phenol and toluene is ortho-directed. Phys Chem Chem Phys 2016; 18:8625-36. [PMID: 26948897 DOI: 10.1039/c5cp07619f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction of H + phenol and H/D + toluene has been studied in a supersonic expansion after electric discharge. The (1 + 1') resonance-enhanced multiphoton ionization (REMPI) spectra of the reaction products, at m/z = parent + 1, or parent + 2 amu, were measured by scanning the first (resonance) laser. The resulting spectra are highly structured. Ionization energies were measured by scanning the second (ionization) laser, while the first laser was tuned to a specific transition. Theoretical calculations, benchmarked to the well-studied H + benzene → cyclohexadienyl radical reaction, were performed. The spectrum arising from the reaction of H + phenol is attributed solely to the ortho-hydroxy-cyclohexadienyl radical, which was found in two conformers (syn and anti). Similarly, the reaction of H/D + toluene formed solely the ortho isomer. The preference for the ortho isomer at 100-200 K in the molecular beam is attributed to kinetic, not thermodynamic effects, caused by an entrance channel barrier that is ∼5 kJ mol(-1) lower for ortho than for other isomers. Based on these results, we predict that the reaction of H + phenol and H + toluene should still favour the ortho isomer under elevated temperature conditions in the early stages of combustion (200-400 °C).
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Affiliation(s)
- Olha Krechkivska
- School of Chemistry, University of New South Wales, Kensington, NSW 2052, Australia.
| | - Callan M Wilcox
- School of Chemistry, University of New South Wales, Kensington, NSW 2052, Australia.
| | - Tyler P Troy
- School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia
| | - Klaas Nauta
- School of Chemistry, University of New South Wales, Kensington, NSW 2052, Australia.
| | - Bun Chan
- School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia
| | - Rebecca Jacob
- School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia
| | - Scott A Reid
- Department of Chemistry, Marquette University, Milwaukee, WI 53201, USA
| | - Leo Radom
- School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia
| | - Timothy W Schmidt
- School of Chemistry, University of New South Wales, Kensington, NSW 2052, Australia.
| | - Scott H Kable
- School of Chemistry, University of New South Wales, Kensington, NSW 2052, Australia.
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Isomer-specific vibronic structure of the 9-, 1-, and 2-anthracenyl radicals via slow photoelectron velocity-map imaging. Proc Natl Acad Sci U S A 2016; 113:1698-705. [PMID: 26792521 DOI: 10.1073/pnas.1520862113] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Polycyclic aromatic hydrocarbons, in various charge and protonation states, are key compounds relevant to combustion chemistry and astrochemistry. Here, we probe the vibrational and electronic spectroscopy of gas-phase 9-, 1-, and 2-anthracenyl radicals (C14H9) by photodetachment of the corresponding cryogenically cooled anions via slow photoelectron velocity-map imaging (cryo-SEVI). The use of a newly designed velocity-map imaging lens in combination with ion cooling yields photoelectron spectra with <2 cm(-1) resolution. Isomer selection of the anions is achieved using gas-phase synthesis techniques, resulting in observation and interpretation of detailed vibronic structure of the ground and lowest excited states for the three anthracenyl radical isomers. The ground-state bands yield electron affinities and vibrational frequencies for several Franck-Condon active modes of the 9-, 1-, and 2-anthracenyl radicals; term energies of the first excited states of these species are also measured. Spectra are interpreted through comparison with ab initio quantum chemistry calculations, Franck-Condon simulations, and calculations of threshold photodetachment cross sections and anisotropies. Experimental measures of the subtle differences in energetics and relative stabilities of these radical isomers are of interest from the perspective of fundamental physical organic chemistry and aid in understanding their behavior and reactivity in interstellar and combustion environments. Additionally, spectroscopic characterization of these species in the laboratory is essential for their potential identification in astrochemical data.
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Weichman ML, Kim JB, DeVine JA, Levine DS, Neumark DM. Vibrational and Electronic Structure of the α- and β-Naphthyl Radicals via Slow Photoelectron Velocity-Map Imaging. J Am Chem Soc 2015; 137:1420-3. [DOI: 10.1021/ja5124896] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marissa L. Weichman
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
| | - Jongjin B. Kim
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
| | - Jessalyn A. DeVine
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
| | - Daniel S. Levine
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
| | - Daniel M. Neumark
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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Roll MF, Kampf JW, Laine RM. Crystalline Hybrid Polyphenylene Macromolecules from Octaalkynylsilsesquioxanes, Crystal Structures, and a Potential Route to 3-D Graphenes. Macromolecules 2011. [DOI: 10.1021/ma200081q] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mark F. Roll
- Macromolecular Science and Engineering, ‡Department of Chemistry, and §Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136, United States
| | - Jeffrey W. Kampf
- Macromolecular Science and Engineering, ‡Department of Chemistry, and §Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136, United States
| | - Richard M. Laine
- Macromolecular Science and Engineering, ‡Department of Chemistry, and §Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136, United States
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Onchoke KK. DFT/TD-DFT investigation of optical absorption spectra, electron affinities, and ionization potentials of mono-nitrated benzanthrones. COMPUT THEOR CHEM 2011. [DOI: 10.1016/j.comptc.2010.09.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Elliott P, Furche F, Burke K. Excited States from Time-Dependent Density Functional Theory. REVIEWS IN COMPUTATIONAL CHEMISTRY 2009. [DOI: 10.1002/9780470399545.ch3] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Hammonds M, Pathak A, Sarre PJ. TD-DFT calculations of electronic spectra of hydrogenated protonated polycyclic aromatic hydrocarbon (PAH) molecules: implications for the origin of the diffuse interstellar bands? Phys Chem Chem Phys 2009; 11:4458-64. [DOI: 10.1039/b903237a] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Troy TP, Schmidt TW. A theoretical treatment of the absorption spectra of all-benzenoid hydrocarbons. ACTA ACUST UNITED AC 2006. [DOI: 10.1111/j.1745-3933.2006.00204.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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