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Pérez-Soto R, Vázquez SA, Martínez-Núñez E. Photodissociation of acryloyl chloride at 193 nm: interpretation of the product energy distributions, and new elimination pathways. Phys Chem Chem Phys 2016; 18:5019-26. [DOI: 10.1039/c5cp07759a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The use of an automated TS search method leads to the finding of novel HCl elimination pathways.
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Affiliation(s)
- Raúl Pérez-Soto
- Departamento de Química Física and Centro Singular de Investigación en Química Biológica y Materiales Moleculares (CIQUS)
- Campus Vida
- Universidade de Santiago de Compostela
- Santiago de Compostela
- Spain
| | - Saulo A. Vázquez
- Departamento de Química Física and Centro Singular de Investigación en Química Biológica y Materiales Moleculares (CIQUS)
- Campus Vida
- Universidade de Santiago de Compostela
- Santiago de Compostela
- Spain
| | - Emilio Martínez-Núñez
- Departamento de Química Física and Centro Singular de Investigación en Química Biológica y Materiales Moleculares (CIQUS)
- Campus Vida
- Universidade de Santiago de Compostela
- Santiago de Compostela
- Spain
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2
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Vázquez SA, Martínez-Núñez E. HCN elimination from vinyl cyanide: product energy partitioning, the role of hydrogen–deuterium exchange reactions and a new pathway. Phys Chem Chem Phys 2015; 17:6948-55. [DOI: 10.1039/c4cp05626d] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A schematic diagram of HCN elimination channels from vinyl cyanide including a new CCdiss pathway.
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Affiliation(s)
- Saulo A. Vázquez
- Departamento de Química Física and Centro Singular de Investigación en Química Biológica y Materiales Moleculares
- Campus Vida
- Universidade de Santiago de Compostela
- Santiago de Compostela
- Spain
| | - Emilio Martínez-Núñez
- Departamento de Química Física and Centro Singular de Investigación en Química Biológica y Materiales Moleculares
- Campus Vida
- Universidade de Santiago de Compostela
- Santiago de Compostela
- Spain
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3
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Kinzel D, González-Vázquez J, González L. H-abstraction is more efficient than cis–trans isomerization in (4-methylcyclohexylidene) fluoromethane. An ab initio molecular dynamics study. Phys Chem Chem Phys 2012; 14:6241-9. [DOI: 10.1039/c1cp22646k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Thompson MGK, Linford BD, Parnis JM. Electron-bombardment matrix isolation and PEPICO studies as complementary techniques in ion chemistry: an FTIR study of the decomposition of the vinyl fluoride cation. JOURNAL OF MASS SPECTROMETRY : JMS 2011; 46:344-351. [PMID: 21438083 DOI: 10.1002/jms.1898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
FTIR spectra have been obtained for matrices formed following electron bombardment of gas mixtures containing varying amounts of vinyl fluoride (VF) in Ar (1:400 to 1:25,600; VF/Ar). The major matrix-isolated products are a π-complex of HF/C(2)H(2) , fluoroacetylene (HC≡CF) and two isomers of C(2)H(2)F(•). These products correspond well with the products of photoionization of VF near 15.8 eV. These observations support the dominant mechanism of ionization in the EB-MI environment as charge transfer of the substrate molecule to Ar(•+). Some differences are noted between the observed EB-MI products and the results from PEPICO studies, primarily in that the EB-MI products are observed as neutralized forms. The close correlation in EB-MI and photoionization results allows the EB-MI technique to be utilized as an ion structural analysis tool in complement to PEPICO studies, and allows the use of PEPICO studies to help predict and elucidate high-pressure chemistry mechanisms through EB-MI studies. The differences in the EB-MI results and ions observed using the PEPICO technique are rationalized in terms of the differences in the experimental techniques. Using VF as the test system, reagent partial pressure conditions that best complement PEPICO studies are determined. Although the major results are observed for all VF partial pressures, dilute samples give rise to further ionization of the primary products, and more concentrated samples give rise to radical-radical reaction chemistry. As a result, a nominal range of 1:3200 (VF/Ar) is demonstrated to provide the best correlation with the gas-phase PEPICO measurements.
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Amsharov KY, Kabdulov MA, Jansen M. Homo-elimination of HF-An Efficient Approach for Intramolecular Aryl-Aryl Coupling. Chemistry 2010; 16:5868-71. [PMID: 20391586 DOI: 10.1002/chem.201000374] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Konstantin Yu Amsharov
- Department Chemistry III, Institution Max Planck, Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart, Germany.
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Alfalah S, Kinzel D, González-Vázquez J, González L. Non-adiabatic photoisomerization versus photodissociation dynamics of the chiral fluoroethylene derivative (4-methylcyclohexylidene) fluoromethane. Chem Phys 2010. [DOI: 10.1016/j.chemphys.2010.03.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Zou P, Strecker KE, Ramirez-Serrano J, Jusinski LE, Taatjes CA, Osborn DL. Ultraviolet photodissociation of vinyl iodide: understanding the halogen dependence of photodissociation mechanisms in vinyl halides. Phys Chem Chem Phys 2009; 10:713-28. [PMID: 19791455 DOI: 10.1039/b712117b] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photodissociation of vinyl iodide has been investigated at several wavelengths between 193 and 266 nm using three techniques: time-resolved Fourier transform emission spectroscopy, multiple pass laser absorption spectroscopy, and velocity-mapped ion imaging. The only dissociation channel observed is C-I bond cleavage to produce C2H3 (nu, N) + I (2P(J)) at all wavelengths investigated. Unlike photodissociation of other vinyl halides (C2H3X, X = F, Cl, Br), in which the HX product channel is significant, no HI elimination is observed. The angular and translational energy distributions of I atoms indicate that atomic products arise solely from dissociation on excited states with negligible contribution from internal conversion to the ground state. We derive an upper limit on the C-I bond strength of D0(C2H3-I) < or = 65 kcal mol(-1). The ground-state potential-energy surface of vinyl iodide is explored by ab initio calculations. We present a model in which the highest occupied molecular orbital in vinyl halides has increasing X(np) non-bonding character with increasing halogen mass. This change leads to reduced torsional force around the C-C bond in the excited state. Because the ground-state energy is highest when the CH2 plane is perpendicular to the CHX plane, a reduced torsional force in the excited state correlates with a lower rate for internal conversion compared to excited-state C-X bond fission. This model explains the gradual change in photodissociation mechanisms of vinyl halides from the dominance of internal conversion in vinyl fluoride to the dominance of excited-state dissociation in vinyl iodide.
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Affiliation(s)
- Peng Zou
- Combustion Research Facility, Sandia National Laboratories, PO Box 969, Livermore, CA 94551-0969, USA
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González-Vázquez J, González L. A CASSCF and CASPT2 study of the photochemistry of 1,1- and 1,2-difluoroethylenes. Chem Phys 2008. [DOI: 10.1016/j.chemphys.2008.01.043] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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9
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Tarrazo-Antelo T, Martínez-Núñez E, Vázquez SA. Ab initio and RRKM study of the elimination of HF and HCl from chlorofluoroethylene. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2006.12.075] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/30/2022]
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Martínez-Núñez E, Vázquez S. Rovibrational distributions of HF in the photodissociation of vinyl fluoride at 193 nm: a direct MP2 quasiclassical trajectory study. J Chem Phys 2006; 121:5179-82. [PMID: 15352810 DOI: 10.1063/1.1782531] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Quasiclassical trajectory calculations were performed to calculate rovibrational distributions of the nascent HF fragment in the photodissociation of vinyl fluoride at 193 nm. The trajectories were initiated at the transition states of the four-center (4C) and three-center (3C) HF elimination channels, using a microcanonical, quasiclassical normal-mode sampling. In general, the calculated distributions are in reasonably good agreement with experiment. In particular, the trajectory distributions show bimodal character, although not as pronounced as that observed experimentally. The calculations predict that the 3C and 4C distributions are rather similar to each other, which suggests that the low-J and high-J components of the rotational distributions cannot be specifically assigned to each of these channels.
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Affiliation(s)
- Emilio Martínez-Núñez
- Departamento de Quimica Fisica, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
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Martínez-Núñez E, Vázquez S. Rotational distributions of HBr in the photodissociation of vinyl bromide at 193nm: An investigation by direct quasiclassical trajectory calculations. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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12
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Martínez-Núñez E, Vázquez S. Quasiclassical trajectory calculations on the photodissociation of CF2CHCl at 193 nm: product energy distributions for the HF and HCl eliminations. J Chem Phys 2006; 122:104316. [PMID: 15836324 DOI: 10.1063/1.1859276] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Quasiclassical trajectory calculations were carried out to determine product energy distributions for the HCl and HF eliminations that take place in the photodissociation of 2-chloro-1,1-difluoroethylene at 193 nm. The trajectories were initiated at the transition states of the HCl and HF elimination channels under microcanonical, quasiclassical conditions, and were propagated with the energies and gradients taken directly from density functional theory calculations. Good agreement with experiment is found, except for the translational energy distribution of the HF elimination channel and the average vibrational energy of the HCl fragment. Possible sources of disagreement are discussed.
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Affiliation(s)
- Emilio Martínez-Núñez
- Departamento de Química Física, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
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Barbatti M, Aquino AJA, Lischka H. A Multireference Configuration Interaction Investigation of the Excited-State Energy Surfaces of Fluoroethylene (C2H3F). J Phys Chem A 2005; 109:5168-75. [PMID: 16833872 DOI: 10.1021/jp050834+] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Multireference configuration interaction with singles and doubles (MR-CISD) calculations has been performed for the optimization of conical intersections and stationary points on the fluoroethylene excited-state energy surfaces. For the planar ground state geometry, the vertical spectrum including 3s and 3p Rydberg states was calculated. From this geometry, a rigid torsion around the CC bond strongly reduces the energy gap between S0 and S1 states. Furthermore, a search for the minimum of the crossing seam shows that there exists a conical intersection close to the twisted structure and two additional ones for cis and trans pyramidalized structures. These three intersections are connected by the same seam. We have shown that the Hula-Twist process is an alternative way to the direct CC twisting in order to reach this part of the seam. Other conical intersections were also located in the CH3CF and CH2FCH, H-migration, and C(3v) structures. The photodynamics of the system is discussed based on topological features of these intersections.
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Affiliation(s)
- Mario Barbatti
- Institute for Theoretical Chemistry, University of Vienna, Währingerstrasse 17, A-1090 Vienna, Austria.
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Vázquez SA, Aoiz FJ, Bañares L, Santamarı́a J, Martı́nez-Núñez E, Fernández-Ramos A. Quasi-classical trajectory study of H2 elimination in the photodissociation of difluoroethylenes at 193 nm. J Chem Phys 2003. [DOI: 10.1063/1.1559678] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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González-Vázquez J, Fernández-Ramos A, Martínez-Núñez E, Vázquez SA. Dissociation of Difluoroethylenes. I. Global Potential Energy Surface, RRKM, and VTST Calculations. J Phys Chem A 2003. [DOI: 10.1021/jp021901s] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jesús González-Vázquez
- Departamento de Química Física, Universidad de Santiago de Compostela, Santiago de Compostela, E-15706, Spain
| | - Antonio Fernández-Ramos
- Departamento de Química Física, Universidad de Santiago de Compostela, Santiago de Compostela, E-15706, Spain
| | - Emilio Martínez-Núñez
- Departamento de Química Física, Universidad de Santiago de Compostela, Santiago de Compostela, E-15706, Spain
| | - Saulo A. Vázquez
- Departamento de Química Física, Universidad de Santiago de Compostela, Santiago de Compostela, E-15706, Spain
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