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Karir G, Mendez-Vega E, Portela-Gonzalez A, Saraswat M, Sander W, Hemberger P. The elusive phenylethynyl radical and its cation: synthesis, electronic structure, and reactivity. Phys Chem Chem Phys 2024; 26:18256-18265. [PMID: 38904382 DOI: 10.1039/d4cp02129k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Abstract
Alkynyl radicals and cations are crucial reactive intermediates in chemistry, but often evade direct detection. Herein, we report the direct observation of the phenylethynyl radical (C6H5CC˙) and its cation (C6H5CC+), which are two of the most reactive intermediates in organic chemistry. The radical is generated via pyrolysis of (bromoethynyl)benzene at temperatures above 1500 K and is characterized by photoion mass-selected threshold photoelectron spectroscopy (ms-TPES). Photoionization of the phenylethynyl radical yields the phenylethynyl cation, which has never been synthesized due to its extreme electrophilicity. Vibrationally-resolved ms-TPES assisted by ab initio calculations unveiled the complex electronic structure of the phenylethynyl cation, which appears at an adiabatic ionization energy (AIE) of 8.90 ± 0.05 eV and exhibits an uncommon triplet (3B1) ground state, while the closed-shell singlet (1A1) state lies just 2.8 kcal mol-1 (0.12 eV) higher in energy. The reactive phenylethynyl radical abstracts hydrogen to form ethynylbenzene (C6H5CCH) but also isomerizes via H-shift to the o-, m-, and p-ethynylphenyl isomers (C6H4CCH). These radicals are very reactive and undergo ring-opening followed by H-loss to form a mixture of C8H4 triynes, along with low yields of cyclic 3- and 4-ethynylbenzynes (C6H3CCH). At higher temperatures, dehydrogenation from the unbranched C8H4 triynes forms the linear tetraacetylene (C8H2), an astrochemically relevant polyyne.
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Affiliation(s)
- Ginny Karir
- Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, Bochum 44780, Germany.
| | - Enrique Mendez-Vega
- Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, Bochum 44780, Germany.
| | | | - Mayank Saraswat
- Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, Bochum 44780, Germany.
| | - Wolfram Sander
- Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, Bochum 44780, Germany.
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute (PSI), Villigen CH-5232, Switzerland.
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Báez-Grez R, Pino-Rios R. Exploring the Nature of Chemical Bonding between Noble Gases and Hypercoordinate Group 13 Compounds: Beyond Boron. J Phys Chem A 2024; 128:4950-4955. [PMID: 38864772 DOI: 10.1021/acs.jpca.4c00685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
In this article, we systematically study the stability and chemical bond nature of EH4Ng+ compounds (E = Al-Tl; Ng = He-Rn) at the CCSD(T) and ωB97XD levels of theory. Thermochemical calculations obtained by exploring different dissociation pathways show that these compounds could be stable at low temperatures. In addition, studied compounds have a strong E-Ng bond, which has been characterized using different methodologies such as quantum theory of atoms in molecules (QTAIM), natural bond orbital (NBO) theory, and natural energy decomposition analysis (NEDA). Results indicate that the nature of the chemical bond is predominantly covalent, especially in the case those including the heavier gases (Ar-Rn), occurring through a charge transfer from the noble gas to the group 13 element. However, the electrostatic contribution is also important in the stabilization of this bond. This study extends the universe of group 13 molecules containing noble gas bonds beyond boron and other elements from the second period.
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Affiliation(s)
- Rodrigo Báez-Grez
- Facultad de Ciencias, Universidad Arturo Prat., Casilla 121, Iquique 1100000, Chile
| | - Ricardo Pino-Rios
- Química y Farmacia, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Casilla 121, Iquique 1100000, Chile
- Centro de Investigación Medicina de Altura - CEIMA, Universidad Arturo Prat, Casilla 121, Iquique 1100000, Chile
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Vásquez-Espinal A, Pino-Rios R. Strong carbon - noble gas covalent bond and fluxionality in hypercoordinate compounds. Phys Chem Chem Phys 2023; 25:27468-27474. [PMID: 37800185 DOI: 10.1039/d3cp03576j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/07/2023]
Abstract
Thermodynamic, kinetic, and chemical bonding analysis at the coupled cluster level has been carried out for a series of hypercoordinated carbon compounds with formula CH4Ng2+ (Ng = He-Rn). Results show that these compounds could be stable at room temperature and Born-Oppenheimer molecular dynamics simulations (BOMD) in conjunction with activation energies indicate high kinetic stability. In addition, all chemical bonding descriptors agree with a strong C-Ng covalent bond and a bonding pattern similar to that of CH5+. Finally, BOMD simulations showed that these compounds are fluxional, with a continuous formation/breaking of H-H and C-H bonds. To the best of the authors' knowledge, these results represent the first series of fluxional compounds possessing a covalent bond between a main group element and a noble gas atom.
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Affiliation(s)
- Alejandro Vásquez-Espinal
- Química y Farmacia, Facultad de Ciencias de la Salud, Universidad Arturo Prat. Casilla 121, Iquique 1100000, Chile.
| | - Ricardo Pino-Rios
- Química y Farmacia, Facultad de Ciencias de la Salud, Universidad Arturo Prat. Casilla 121, Iquique 1100000, Chile.
- Instituto de Estudios de la Salud, Universidad Arturo Prat, Iquique, 1100000, Chile
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Zhang G, Su Y, Zou X, Fu L, Song J, Chen D, Sun C. Charge-Shift Bonding in Xenon Hydrides: An NBO/NRT Investigation on HXeY···HX (Y = Cl, Br, I; X = OH, Cl, Br, I, CCH, CN) via H-Xe Blue-Shift Phenomena. Front Chem 2020; 8:277. [PMID: 32391318 PMCID: PMC7191121 DOI: 10.3389/fchem.2020.00277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 03/23/2020] [Indexed: 11/13/2022] Open
Abstract
Noble-gas bonding represents curiosity. Some xenon hydrides, such as HXeY (Y = Cl, Br, I) and their hydrogen-bonded complexes HXeY···HX (Y = Cl, Br, I; X = OH, Cl, Br, I, CN, CCH), have been identified in matrixes by observing H-Xe frequencies or its monomer-to-complex blue shifts. However, the H-Xe bonding in HXeY is not yet completely understood. Previous theoretical studies provide two answers. The first one holds that it is a classical covalent bond, based on a single ionic structure H-Xe+ Y-. The second one holds that it is resonance bonding between H-Xe+ Y- and H- Xe+-Y. This study investigates the H-Xe bonding, via unusual blue-shifted phenomena, combined with some NBO/NRT calculations for chosen hydrogen-bonded complexes HXeY···HX (Y = Cl, Br, I; X = OH, Cl, Br, I, CN, CCH). This study provides new insights into the H-Xe bonding in HXeY. The H-Xe bond in HXeY is not a classical covalent bond. It is a charge-shift (CS) bond, a new class of electron-pair bonds, which is proposed by Shaik and Hiberty et al. The unusual blue shift in studied hydrogen-bonded complexes is its H-Xe CS bonding character in IR spectroscopy. It is expected that these studies on the H-Xe bonding and its IR spectroscopic property might assist the chemical community in accepting this new-class electron-pair bond concept.
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Affiliation(s)
- Guiqiu Zhang
- Key Laboratory of Molecular and Nano Probes, College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging, Ministry of Education, Shandong Normal University, Jinan, China
| | | | | | | | | | | | - Chuanzhi Sun
- Key Laboratory of Molecular and Nano Probes, College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging, Ministry of Education, Shandong Normal University, Jinan, China
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Richter WE, Duarte LJ, da Silva AF, Bruns RE. Revisiting the negative dipole moment derivatives of HNgX molecules. Theor Chem Acc 2020. [DOI: 10.1007/s00214-020-2582-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Tsuge M, Räsänen M, Khriachtchev L. Thermal decomposition of the HXeCl···H2O complex in solid xenon: Experimental characterization of the two-body decomposition channel. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2019.136987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Ryazantsev SV, Tyurin DA, Nuzhdin KB, Feldman VI, Khriachtchev L. The HKrCCH⋯CO2 complex: an ab initio and matrix-isolation study. Phys Chem Chem Phys 2019; 21:3656-3661. [DOI: 10.1039/c8cp04327b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Structure of the HKrCCH⋯CO2 complex prepared in a low-temperature krypton matrix.
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Affiliation(s)
- Sergey V. Ryazantsev
- Department of Chemistry
- University of Helsinki
- FI-00014 Helsinki
- Finland
- Department of Chemistry
| | - Daniil A. Tyurin
- Department of Chemistry
- Lomonosov Moscow State University
- 119991 Moscow
- Russia
| | - Kirill B. Nuzhdin
- Department of Chemistry
- Lomonosov Moscow State University
- 119991 Moscow
- Russia
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Ghosh A, Gupta A, Gupta R, Ghanty TK. Noble gas hydrides in the triplet state: HNgCCO + (Ng = He, Ne, Ar, Kr, and Xe). Phys Chem Chem Phys 2018; 20:20270-20279. [PMID: 30039141 DOI: 10.1039/c8cp03516d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Motivated by the very recent investigations of neutral noble gas compounds in the open-shell configuration, we explored a new series of noble gas hydrides in the triplet state. The possible existence of noble gas-inserted ketenyl cations, HNgCCO+ (Ng = He, Ne, Ar, Kr, and Xe), in their triplet electronic state has been predicted by various ab initio quantum chemical techniques. Density functional theory (DFT), second-order Møller-Plesset perturbation theory (MP2), and coupled-cluster theory (CCSD(T)) based methods have been employed to investigate the structures, energetics, harmonic vibrational frequencies, and charge distribution analysis of these ions. The aforementioned ions have been found to be thermodynamically stable with respect to all plausible 2-body and 3-body dissociation channels, except the 2-body dissociation pathway leading to the formation of global minima products (Ng + HCCO+). Nevertheless, each of the predicted HNgCCO+ ions is connected to the global minima products through a transition state with a finite barrier height on the potential energy surface, which confirms the kinetic stability of the metastable species. Detailed analysis of the optimized structural parameters, energetics, and harmonic vibrational frequencies of the predicted species clearly indicated that a strong covalent bond exists between H and Ng atoms, while a comparatively weak interaction is found between Ng and C atoms. Moreover, charge distribution and atoms-in-molecules (AIM) analysis strongly concurred with the above inferences and also suggested that the predicted metastable ions should exist essentially in the form of [HNg]+[CCO] complex. These results ultimately indicate that these predicted species may be prepared and characterized by suitable experimental technique(s) under a cryogenic environment.
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Affiliation(s)
- Ayan Ghosh
- Laser and Plasma Technology Division, Beam Technology Development Group, Bhabha Atomic Research Centre, Mumbai 400 085, India
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Resonance bonding in XNgY (X = F, Cl, Br, I; Ng = Kr or Xe; Y = CN or NC) molecules: an NBO/NRT investigation. J Mol Model 2018; 24:129. [PMID: 29736860 DOI: 10.1007/s00894-018-3665-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Accepted: 04/17/2018] [Indexed: 10/17/2022]
Abstract
Several noble-gas-containing molecules XNgY were observed experimentally. However, the bonding in such systems is still not understood. Using natural bond orbital and natural resonance theory (NBO/NRT) methods, the present work investigated bonding of the title molecules. The results show that each of the studied XNgY molecules should be better described as a resonance hybrid of ω-bonding and [Formula: see text]-type long-bonding structures: X:- Ng+ - Y, X - Ng+: Y-, and X^Y. The ω-bonding and long-bonding make competing contributions to the composite resonance hybrid due to the accurately preserved bond order conservation principle. We find that the resonance bonding is highly tunable for these noble-gas-containing molecules due to its dependence on the nature of the halogen X or the central noble-gas atoms Ng. When the molecule XNgY consists of a relatively lighter Ng atom, a relatively low-electronegative X atom, and the CN fragment rather than NC, the long-bonding structure X^Y tends to be highlighted. In contrast, the heavy Ng atom and high-electronegative X atom will enhance the ω-bonding structure. Overall, the present work provides electronic principles and chemical insights that help understand the bonding in these XNgY species.
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Zhang G, Song J, Fu L, Tang K, Su Y, Chen D. Understanding and modulating the high-energy properties of noble-gas hydrides from their long-bonding: an NBO/NRT investigation on HNgCO +/CS +/OSi + and HNgCN/NC (Ng = He, Ar, Kr, Xe, Rn) molecules. Phys Chem Chem Phys 2018; 20:10231-10239. [PMID: 29611602 DOI: 10.1039/c8cp00306h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The noble-gas hydrides, HNgX (X is an electronegative atom or fragment), represent potential high-energy materials because their two-body decomposition process, HNgX → Ng + HX, is strongly exoergic. Our previous studies have shown that each member of the HNgX (X = halogen atom or CN/NC fragment) molecules is composed of three leading resonance structures: two ω-bonding structures (H-Ng+ :X- and H:- Ng+-X) and one long-bonding structure (H∧X). The last one paints a novel [small sigma, Greek, circumflex]-type long-bonding picture. The present study focuses on the relationship between this novel bonding motif and the unusual energetic properties. We chose HNgCO+/CS+/OSi+/CN/NC, with the formula HNgAB (Ng = He, Ar, Kr, Xe, Rn; AB = CO+/CS+/OSi+/CN/NC) as the research system. We first investigated the bonding of HNgCO+ and its analogous HNgCS+/OSi+ species using NBO/NRT methods, and quantitatively compared the bonding with that in HNgCN/NC molecules. NBO/NRT results showed that each of the HNgCO+/CS+/OSi+ molecules could be better represented as a resonance hybrid of ω-bonding and long-bonding structures, but the long-bonding is much weaker than that in HNgCN/NC molecules. Furthermore, we introduced the long-bonding concept into the rationalization of the high-energy properties, and found a good correlation between the highly exothermic two-body dissociation channel and the long-bond order, bH-A. We also found that the long-bond order is highly tunable for these noble-gas hydrides due to its dependence on the nature of the electronegative AB fragments or the central noble-gas atoms, Ng. On the basis of these results, we could optimize the energetic properties by changing the long-bonding motif of our studied molecules. Overall, this study shows that the long-bonding model provides an easy way to rationalize and modulate the unusual energy properties of noble-gas hydrides, and that it is helpful to predict some noble-gas hydrides as potential energetic materials.
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Affiliation(s)
- Guiqiu Zhang
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Normal University, Wenhua East Road 88, Jinan, Shandong 250014, P. R. China.
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Ryazantsev SV, Lundell J, Feldman VI, Khriachtchev L. Photochemistry of the H 2O/CO System Revisited: The HXeOH···CO Complex in a Xenon Matrix. J Phys Chem A 2018; 122:159-166. [PMID: 29206459 DOI: 10.1021/acs.jpca.7b10293] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report on the complex of a noble-gas hydride HXeOH with carbon monoxide. This species is prepared via the annealing-induced H + Xe + OH···CO reaction in a xenon matrix, the OH···CO complexes being produced by VUV photolysis of the H2O···CO complexes. The H-Xe stretching mode of the HXeOH···CO complex absorbs at 1590.3 cm-1 and it is blue-shifted by 12.7 cm-1 from the H-Xe stretching band of HXeOH monomer. The observed blue shift indicates the stabilization of the H-Xe bond upon complexation, which is characteristic of complexes of noble-gas hydrides. The HXeOH···CO species is the first complex of a noble-gas hydride with carbon monoxide and the second observed complex of HXeOH. On the basis of the MP2/aug-cc-pVTZ-PP calculations, the experimental complex is assigned to the structure, where the carbon atom of CO interacts with the oxygen atom of HXeOH.
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Affiliation(s)
- Sergey V Ryazantsev
- Department of Chemistry, University of Helsinki , P.O. Box 55, FI-00014 Helsinki, Finland.,Department of Chemistry, Lomonosov Moscow State University , Moscow 119991 Russia
| | - Jan Lundell
- Department of Chemistry, University of Jyväskylä , Jyväskylä, FI-40014, Finland
| | - Vladimir I Feldman
- Department of Chemistry, Lomonosov Moscow State University , Moscow 119991 Russia
| | - Leonid Khriachtchev
- Department of Chemistry, University of Helsinki , P.O. Box 55, FI-00014 Helsinki, Finland
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