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Rodrigues R, Bou Debes D, Mendes M, Guerra P, Mestre G, Eden S, Cornetta LM, Ingólfsson O, da Silva FF. Experimental and Theoretical Study on Electron Ionization and Fragmentation of Propylene Oxide─the First Chiral Molecule Detected in the Interstellar Medium. J Phys Chem A 2024; 128:4795-4805. [PMID: 38860325 DOI: 10.1021/acs.jpca.4c02116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2024]
Abstract
Propylene oxide, CH3CHOCH2, is the first chiral molecule detected in space and the third C3 oxide detected toward the Sagittarius B2 (Sgr B2 (N)) molecular cloud, the others being propanal, CH3CH2CHO, and acetone, (CH3)2CO. With homochirality being ubiquitous in the building blocks of living matter, the formation and decay paths of propylene oxide in space are of specific interest. Motivated by the significant role of photo- and secondary electrons in astrochemistry, we have studied electron ionization and fragmentation of propylene oxide. Ion appearance energies are determined and compared to threshold values for the respective processes calculated at the G4MP2 level of theory, and potential reaction pathways are computed at the DFT level of theory. Electron ionization is found to destabilize propylene oxide, leading to barrierless opening of the C1-C2 bond of the epoxy ring, hydrogen transfer, and fragmentation over the methyl vinyl ether or rupture of the C2-O bond of the epoxy ring and fragmentation of the allyl alcohol cation as an intermediate, rather than direct bond ruptures.
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Affiliation(s)
- Rodrigo Rodrigues
- CEFITEC, Departamento de Física, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica 2829-516, Portugal
| | - Daniel Bou Debes
- School of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, U.K
| | - Mónica Mendes
- CEFITEC, Departamento de Física, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica 2829-516, Portugal
| | - Pedro Guerra
- CEFITEC, Departamento de Física, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica 2829-516, Portugal
| | - Gonçalo Mestre
- CEFITEC, Departamento de Física, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica 2829-516, Portugal
| | - Samuel Eden
- School of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, U.K
| | - Lucas M Cornetta
- Instituto de Física da Universidade de São Paulo, Universidade de São Paulo, São Paulo 05508-900, Brazil
| | - Oddur Ingólfsson
- Department of Chemistry and Science Institute, University of Iceland, Dunhagi 3, Reykjavik IS-107, Iceland
| | - F Ferreira da Silva
- CEFITEC, Departamento de Física, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica 2829-516, Portugal
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Potential Energy Surfaces for Noble Gas (Ar, Kr, Xe, Rn)–Propylene Oxide Systems: Analytical Formulation and Binding. Symmetry (Basel) 2022. [DOI: 10.3390/sym14020249] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Multidimensional potential energy surfaces for heavy noble gas–propylene oxide systems are obtained by applying the phenomenological method successfully used to describe homologous systems involving He and Ne atoms. Such potential energy surfaces, where the interaction exclusively arises from the anisotropic van der Waals interaction components, are given in an analytical form. Therefore, they can be easily used as force fields to carry out molecular simulations to evaluate spectroscopic features and the dynamical selectivity of weakly bound complexes formed by propylene oxide (a prototype chiral species) with a noble gas atom (a prototype isotropic partner) by two-body collisions under a variety of conditions. Several potential energy minima are identified on the surfaces, which are confirmed and characterized by high level ab initio calculations. The next step to further generalize this methodology is its extension to systems involving propylene oxide-diatomic molecules (as H2, O2 and N2), as well as to propylene oxide dimers.
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Palazzetti F, Cappelletti D, Coletti C, Falcinelli S, Pirani F. Molecular beam scattering experiments on noble gas-propylene oxide: Total integral cross sections and potential energy surfaces of He- and Ne-C 3H 6O. J Chem Phys 2021; 155:234301. [PMID: 34937350 DOI: 10.1063/5.0073737] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The interactions of He and Ne with propylene oxide have been investigated with the molecular beam technique by measuring the total (elastic + inelastic) integral cross section as a function of collision velocity. Starting from the analysis of these experimental data, potential energy surfaces, formulated as a function of the separation distance and orientation of propylene oxide with respect to the interacting partners, have been built: The average depth of potential wells (located at intermediate separation distances) has been characterized by analyzing the observed "glory" quantum effects, and the strength of long-range attractions has been obtained from the magnitude and the velocity dependence of the smooth component of measured cross sections. The surfaces, tested and improved against new ab initio calculations of minima interaction energies at the complete basis set level of theory, are defined in the full space of relative configurations. This represents a crucial condition to provide force fields useful to carry out, in general, important molecular property simulations and to evaluate, in the present case, the spectroscopic features and the dynamical selectivity of weakly bound complexes formed by propylene oxide, a prototype chiral species, during collisions in interstellar clouds and winds, in the space and planetary atmospheres. The adopted formulation of the interaction can be readily extended to similar systems, involving heavier noble gases or diatomic molecules (H2, O2, and N2) as well as to propylene oxide dimers.
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Affiliation(s)
- Federico Palazzetti
- Dipartimento di Chimica, Biologia e Biotecnologie - Università degli Studi di Perugia, Perugia, Italy
| | - David Cappelletti
- Dipartimento di Chimica, Biologia e Biotecnologie - Università degli Studi di Perugia, Perugia, Italy
| | - Cecilia Coletti
- Dipartimento di Farmacia, Università degli Studi "G. D'Annunzio" Chieti-Pescara, Chieti, Italy
| | - Stefano Falcinelli
- Dipartimento di Ingegneria Civile ed Ambientale, Università degli Studi di Perugia, Perugia, Italy
| | - Fernando Pirani
- Dipartimento di Chimica, Biologia e Biotecnologie - Università degli Studi di Perugia, Perugia, Italy
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Falcinelli S, Rosi M. Production and Characterization of Molecular Dications: Experimental and Theoretical Efforts. Molecules 2020; 25:molecules25184157. [PMID: 32932839 PMCID: PMC7571021 DOI: 10.3390/molecules25184157] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 09/08/2020] [Accepted: 09/09/2020] [Indexed: 11/16/2022] Open
Abstract
Molecular dications are doubly charged cations of importance in flames, plasma chemistry and physics and in the chemistry of the upper atmosphere of Planets. Furthermore, they are exotic species able to store a considerable amount of energy at a molecular level. This high energy content of several eV can be easily released as translational energy of the two fragment monocations generated by their Coulomb explosion. For such a reason, they were proposed as a new kind of alternative propellant. The present topic review paper reports on an overview of the main contributions made by the authors’ research groups in the generation and characterization of simple molecular dications during the last 40 years of coupling experimental and theoretical efforts.
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Affiliation(s)
- Stefano Falcinelli
- Department of Civil and Environmental Engineering, University of Perugia, Via G. Duranti 93, 06125 Perugia, Italy
- Correspondence: (S.F.); (M.R.); Tel.: +39-075-585-3862 (S.F.); +39-075-585-3858 (M.R.)
| | - Marzio Rosi
- Department of Civil and Environmental Engineering, University of Perugia, Via G. Duranti 93, 06125 Perugia, Italy
- SCITEC, CNR, Via Elce di Sotto 8, 06123 Perugia, Italy
- Correspondence: (S.F.); (M.R.); Tel.: +39-075-585-3862 (S.F.); +39-075-585-3858 (M.R.)
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Falcinelli S, Rosi M, Pirani F, Bassi D, Alagia M, Schio L, Richter R, Stranges S, Balucani N, Lorent V, Vecchiocattivi F. Angular Distribution of Ion Products in the Double Photoionization of Propylene Oxide. Front Chem 2019; 7:621. [PMID: 31572712 PMCID: PMC6749015 DOI: 10.3389/fchem.2019.00621] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 08/29/2019] [Indexed: 11/13/2022] Open
Abstract
A photoelectron-photoion-photoion coincidence technique, using an ion imaging detector and tunable synchrotron radiation in the 18.0–37.0 eV photon energy range, inducing the ejection of molecular valence electrons, has been applied to study the double ionization of the propylene oxide, a simple prototype chiral molecule. The experiment performed at the Elettra Synchrotron Facility (Trieste, Italy) allowed to determine angular distributions for ions produced by the two-body dissociation reactions following the Coulomb explosion of the intermediate (C3H6O)2+ molecular dication. The analysis of the coincidence spectra recorded at different photon energies was done in order to determine the dependence of the β anisotropy parameter on the photon energy for the investigated two-body fragmentation channels. In particular, the reaction leading to CH3+ + C2H3O+ appears to be characterized by an increase of β, from β ≈ 0.00 up to β = 0.59, as the photon energy increases from 29.7 to 37.0 eV, respectively. This new observation confirms that the dissociation channel producing CH3+ and C2H3O+ final ions can occur with two different microscopic mechanisms as already indicated by the bimodality obtained in the kinetic energy released (KER) distributions as a function of the photon energy in a recent study. Energetic considerations suggest that experimental data are compatible with the formation of two different stable isomers of C2H3O+: acetyl and oxiranyl cations. These new experimental data are inherently relevant and are mandatory information for further experimental and theoretical investigations involving oriented chiral molecules and linearly or circularly polarized radiation. This work is in progress in our laboratory.
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Affiliation(s)
- Stefano Falcinelli
- Department of Civil and Environmental Engineering, University of Perugia, Perugia, Italy
| | - Marzio Rosi
- Department of Civil and Environmental Engineering, University of Perugia, Perugia, Italy
| | - Fernando Pirani
- Department of Chemistry, Biology and Biotechnologies, University of Perugia, Perugia, Italy
| | - Davide Bassi
- Department of Physics, University of Trento, Trento, Italy
| | | | - Luca Schio
- IOM-CNR Tasc, Trieste, Italy.,Department of Basic and Applied Sciences for Engineering (SBAI), University of Rome "Sapienza", Rome, Italy
| | | | - Stefano Stranges
- IOM-CNR Tasc, Trieste, Italy.,Department of Chemistry and Drug Technologies, University of Rome "Sapienza", Rome, Italy
| | - Nadia Balucani
- Department of Chemistry, Biology and Biotechnologies, University of Perugia, Perugia, Italy
| | - Vincent Lorent
- Laboratoire de physique des lasers, Université Paris 13 (UP13) - Institut Galilée - CNRS LPL UMR7538, Villetaneuse, France
| | - Franco Vecchiocattivi
- Department of Civil and Environmental Engineering, University of Perugia, Perugia, Italy
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