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Polášek M, Zins EL, Alcaraz C, Žabka J, Křížová V, Giacomozzi L, Tosi P, Ascenzi D. Selective Generation of the Radical Cation Isomers [CH3CN](•+) and [CH2CNH](•+) via VUV Photoionization of Different Neutral Precursors and Their Reactivity with C2H4. J Phys Chem A 2016; 120:5041-52. [PMID: 26890990 DOI: 10.1021/acs.jpca.5b12757] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Experimental and theoretical studies have been carried out to demonstrate the selective generation of two different C2H3N(+) isomers, namely, the acetonitrile [CH3CN](•+) and the ketenimine [CH2CNH](•+) radical cations. Photoionization and dissociative photoionization experiments from different neutral precursors (acetonitrile and butanenitrile) have been performed using vacuum ultraviolet (VUV) synchrotron radiation in the 10-15 eV energy range, delivered by the DESIRS beamline at the SOLEIL storage ring. For butanenitrile (CH3CH2CH2CN) an experimental ionization threshold of 11.29 ± 0.05 eV is obtained, whereas the appearance energy for the formation of [CH2CNH](•+) fragments is 11.52 ± 0.05 eV. Experimental findings are fully supported by theoretical calculations at the G4 level of theory (ZPVE corrected energies at 0 K), giving a value of 11.33 eV for the adiabatic ionization energy of butanenitrile and an exothermicity of 0.49 for fragmentation into [CH2CNH](•+) plus C2H4, hampered by an energy barrier of 0.29 eV. The energy difference between [CH3CN](•+) and [CH2CNH](•+) is 2.28 eV (with the latter being the lowest energy isomer), and the isomerization barrier is 0.84 eV. Reactive monitoring experiments of the [CH3CN](•+) and [CH2CNH](•+) isomers with C2H4 have been performed using the CERISES guided ion beam tandem mass spectrometer and exploiting the selectivity of ethylene that gives exothermic charge exchange and proton transfer reactions with [CH3CN](•+) but not with [CH2CNH](•+) isomers. In addition, minor reactive channels are observed leading to the formation of new C-C bonds upon reaction of [CH3CN](•+) with C2H4, and their astrochemical implications are briefly discussed.
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Affiliation(s)
- Miroslav Polášek
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic , Dolejškova 2155/3, 18223 Prague 8, Czech Republic
| | - Emilie-Laure Zins
- Sorbonne Universités, UPMC Univ. Paris 06, MONARIS, UMR 8233, Université Pierre et Marie Curie , 4 Place Jussieu, case courrier 49, F-75252 Paris Cedex 05, France
| | - Christian Alcaraz
- Laboratoire de Chimie Physique, Bât. 350, UMR 8000, CNRS-Univ. Paris-Sud & Paris-Saclay , Centre Universitaire Paris-Sud, 91405 Orsay Cedex, France.,Synchrotron SOLEIL , L'Orme des Merisiers, Saint-Aubin - BP 48, 91192 Gif-sur-Yvette, France
| | - Ján Žabka
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic , Dolejškova 2155/3, 18223 Prague 8, Czech Republic
| | - Věra Křížová
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic , Dolejškova 2155/3, 18223 Prague 8, Czech Republic
| | - Linda Giacomozzi
- Department of Physics, University of Trento , Via Sommarive 14, 38123 Povo, Italy
| | - Paolo Tosi
- Department of Physics, University of Trento , Via Sommarive 14, 38123 Povo, Italy
| | - Daniela Ascenzi
- Department of Physics, University of Trento , Via Sommarive 14, 38123 Povo, Italy
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Shaffer CJ, Schröder D, Alcaraz C, Žabka J, Zins EL. Reactions of Doubly Ionized Benzene with Nitrogen and Water: A Nitrogen-Mediated Entry into Superacid Chemistry. Chemphyschem 2012; 13:2688-98. [DOI: 10.1002/cphc.201200313] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Indexed: 11/10/2022]
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Unimolecular dissociation of doubly ionized toluene and electron transfer between neutral toluene and its dication. Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2012.03.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Zins EL, Milko P, Schröder D, Aysina J, Ascenzi D, Žabka J, Alcaraz C, Price SD, Roithová J. Formation of Organoxenon Dications in the Reactions of Xenon with Dications Derived from Toluene. Chemistry 2011; 17:4012-20. [DOI: 10.1002/chem.201002556] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Indexed: 11/11/2022]
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Ascenzi D, Aysina J, Zins EL, Schröder D, Žabka J, Alcaraz C, Price SD, Roithová J. Double ionization of cycloheptatriene and the reactions of the resulting C7Hn2+ dications (n = 6, 8) with xenon. Phys Chem Chem Phys 2011; 13:18330-8. [DOI: 10.1039/c1cp21634a] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Ascenzi D, Roithová J, Schröder D, Zins EL, Alcaraz C. Growth Of Doubly Ionized C,H,N Compounds in the Presence of Methane. J Phys Chem A 2009; 113:11204-10. [DOI: 10.1021/jp904859g] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Daniela Ascenzi
- Department of Physics, University of Trento, Via Sommarive 14, 38050 Povo, Trento, Italy, Department of Organic Chemistry, Charles University in Prague, Hlavova 8, 12843 Prague 2, Czech Republic, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 16610 Prague 6, Czech Republic, Laboratoire de Dynamique, Interactions et Réactivité, UMR 7075 CNRS/UPMC, Université Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris 5, France, Laboratoire de
| | - Jana Roithová
- Department of Physics, University of Trento, Via Sommarive 14, 38050 Povo, Trento, Italy, Department of Organic Chemistry, Charles University in Prague, Hlavova 8, 12843 Prague 2, Czech Republic, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 16610 Prague 6, Czech Republic, Laboratoire de Dynamique, Interactions et Réactivité, UMR 7075 CNRS/UPMC, Université Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris 5, France, Laboratoire de
| | - Detlef Schröder
- Department of Physics, University of Trento, Via Sommarive 14, 38050 Povo, Trento, Italy, Department of Organic Chemistry, Charles University in Prague, Hlavova 8, 12843 Prague 2, Czech Republic, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 16610 Prague 6, Czech Republic, Laboratoire de Dynamique, Interactions et Réactivité, UMR 7075 CNRS/UPMC, Université Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris 5, France, Laboratoire de
| | - Emilie-Laure Zins
- Department of Physics, University of Trento, Via Sommarive 14, 38050 Povo, Trento, Italy, Department of Organic Chemistry, Charles University in Prague, Hlavova 8, 12843 Prague 2, Czech Republic, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 16610 Prague 6, Czech Republic, Laboratoire de Dynamique, Interactions et Réactivité, UMR 7075 CNRS/UPMC, Université Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris 5, France, Laboratoire de
| | - Christian Alcaraz
- Department of Physics, University of Trento, Via Sommarive 14, 38050 Povo, Trento, Italy, Department of Organic Chemistry, Charles University in Prague, Hlavova 8, 12843 Prague 2, Czech Republic, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 16610 Prague 6, Czech Republic, Laboratoire de Dynamique, Interactions et Réactivité, UMR 7075 CNRS/UPMC, Université Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris 5, France, Laboratoire de
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Milko P, Schröder D, Lemr K, Žabka J, Alcaraz C, Roithová J. First and second ionization energies of 1,3,5-trimethylbenzene and 2,4,6-trimethylpyridine. ACTA ACUST UNITED AC 2009. [DOI: 10.1135/cccc2008166] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The first and second ionization energies of trimethyl substituted analogs of benzene and pyridine are determined by means of mass spectrometry in conjunction with synchrotron radiation. The first ionization energy of 1,3,5-trimethylbenzene amounts to (8.38 ± 0.05) eV and the second ionization energy to (22.8 ± 0.1) eV. The first ionization energy of 2,4,6-trimethylpyridine is determined as (8.65 ± 0.05) eV and the second ionization energy as (23.0 ± 0.1) eV. The ionization energies are compared with those of unsubstituted benzene and pyridine and the effects of the methyl groups are evaluated by means of isodesmic reactions. As expected, it is found that the electron-donating effect of the methyl groups stabilizes neutral pyridine and doubly charged pyridine more than neutral benzene and doubly charged benzene, respectively. Surprisingly, the opposite effect is found for the radical cations, which is ascribed to the unfavorable degenerate electronic structure of benzene radical-cation, which disappears upon the methyl substitution.
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Ricketts CL, Schröder D, Roithová J, Schwarz H, Thissen R, Dutuit O, Zabka J, Herman Z, Price SD. Competition of electron transfer, dissociation, and bond-forming processes in the reaction of the CO(2)(2+) dication with neutral CO(2). Phys Chem Chem Phys 2008; 10:5135-43. [PMID: 18701963 DOI: 10.1039/b800865e] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The bimolecular reactivity of the CO(2)(2+) dication with neutral CO(2) is investigated using triple quadrupole and ion-ion coincidence mass spectrometry. Crucial for product analysis is the use of appropriate isotope labelling in the quadrupole experiments in order to distinguish the different reactive pathways. The main reaction corresponds to single-electron transfer from the neutral reagent to the dication, i.e. CO(2)(2+) + CO(2) --> 2CO(2)(+); this process is exothermic by almost 10 eV, if ground state monocations are formed. Interestingly, the results indicate that the CO(2)(+) ion formed when the dication accepts an electron dissociates far more readily than the CO(2)(+) ion formed from the neutral CO(2) molecule. This differentiation of the two CO(2)(+) products is rationalized by showing that the population of the key dissociative states of the CO(2)(+) monocation will be favoured from the CO(2)(2+) dication rather than from neutral CO(2). In addition, two bond-forming reactions are observed as minor channels, one of which leads to CO(+) and O(2)(+) as ionic products and the other affords a long-lived C(2)O(3)(2+) dication.
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Affiliation(s)
- Claire L Ricketts
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, Prague 6, Czech Republic
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Franceschi P, Ascenzi D, Tosi P, Thissen R, Zabka J, Roithová J, Ricketts CL, De Simone M, Coreno M. Dissociative double photoionization of N2 using synchrotron radiation: Appearance energy of the N2+ dication. J Chem Phys 2007; 126:134310. [PMID: 17430035 DOI: 10.1063/1.2714521] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Photoionization cross sections for the production of the doubly charged ion N2+ from N2 have been measured by means of synchrotron radiation in the photon energy range from 50 to 110 eV. The appearance energy for N2+ has been determined as 55.2+/-0.2 eV, i.e., about 1.3 eV higher than the spectroscopic dissociation limit leading to the charge asymmetric dissociation channel N2+(2P)+N(4S) at 53.9 eV. The onset of a second threshold at 59.9+/-0.2 eV is detected and the energy dependence of photoion intensities near the threshold regions is interpreted in terms of the Wannier theory. The production of the N2+ dication is discussed in terms of direct and indirect mechanisms for dissociative charge asymmetric photoionization and by comparison with the potential energy curves of the intermediate N(2)2+ dication. Experimental evidences for the opening of the Coulomb explosion channel N2++N+ at high photon energies are provided by measuring the kinetic energy release spectra of N2+ fragments at selected photon energies.
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Affiliation(s)
- Pietro Franceschi
- Dipartimento di Fisica, Università di Trento, via Sommarive 14, 38050 Povo (TN), Italy.
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Roithová J, Schröder D. On a Possible Growth Mechanism for Polycyclic Aromatic Hydrocarbon Dications: C7H62++C2H2. Chemistry 2007; 13:2893-902. [PMID: 17200932 DOI: 10.1002/chem.200600913] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The mechanism of the bond-forming reaction between C(7)H(6) (2+) and C(2)H(2) to yield C(9) entities has been investigated by density functional theory calculations with close comparison with experimental data. It is shown that the reaction produces the C(9)H(6) (2+) and C(9)H(7) (2+) di-cations with geometries most probably derived from the indene skeleton. In comparison, the formation of linear structures of di-cations is much more energy-demanding and therefore appears improbable.
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Affiliation(s)
- Jana Roithová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 16610 Praha, Czech Republic.
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Roithová J, Schröder D. Bond-formation versuselectron transfer: C–C-coupling reactions of hydrocarbon dications with benzene. Phys Chem Chem Phys 2007; 9:731-8. [PMID: 17268685 DOI: 10.1039/b615648g] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The bimolecular reactions of several hydrocarbon dications C(m)H(n)(2+) (m = 6-10, n = 4-9) with neutral benzene are investigated by tandem mass spectrometry using a multipole instrument. Not surprisingly, the major reaction of C(m)H(n)(2+) with benzene corresponds to electron transfer from the neutral arene to the dication resulting in the pair of monocationic products C(m)H(n)(+) + C(6)H(6)(+). In addition, also dissociative electron transfer takes place, whereas proton transfer from the C(m)H(n)(2+) dication to neutral benzene is almost negligible. Interestingly, the excess energy liberated upon electron transfer from the neutral arene to the C(m)H(n)(2+) dication is not equally partitioned in the monocationic products in that the cations arising from the dicationic precursor have a higher internal energy content than the monocations formed from the neutral reaction partner. In addition to the reactions leading to monocationic product ions, bond-forming reactions with maintenance of the two-fold charge are observed, which lead to a condensation of the C(m)H(n)(2+) dications with neutral benzene under formation of intermediate C(m+6)H(n+6)(2+) species and then undergo subsequent losses of molecular hydrogen or neutral acetylene. This reaction complements a recently proposed dicationic route for the formation of polycyclic aromatic hydrocarbons under extreme conditions such as they exist in interstellar environments.
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Affiliation(s)
- Jana Roithová
- Institute of Organic Chemistry and Biochemistry, Flemingovo nám 2, 16610, Prague 6, Czech Republic
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Roithová J, Schröder D. Bimolecular reactions of molecular dications: reactivity paradigms and bond-forming processes. Phys Chem Chem Phys 2007; 9:2341-9. [PMID: 17492096 DOI: 10.1039/b617681j] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The bimolecular reactivity of molecular dications in the gas phase is reviewed from an experimental point of view. Recent research has demonstrated that in addition to the ubiquitous occurrence of electron transfer in the reactions of gaseous dications with neutral molecules, bond-forming reactions play a much larger role than anticipated before. Thus, quite a number of hydrogen-containing dications show proton transfer to neutral reagents as an abundant or even as the major pathway, and also the nature of the neutral reagent itself is decisive for the amount of proton transfer which takes place. Further, several hydrocarbon dications C(m)H(n)(2+) of medium size (m = 6-14, n = 6-10) undergo bond-forming reactions with unsaturated hydrocarbons such as acetylene or benzene, thereby offering new routes for the formation of larger aromatic compounds under extreme conditions such as interstellar environments. Likewise, recent results on the bimolecular reactivity of multiply charged metal ions have revealed the occurrence of a number of new bond-forming reactions which open promising prospects for further research.
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Affiliation(s)
- Jana Roithová
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Praha 6, Czech Republic
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