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de Azevedo Santos L, Trujillo-González DE, Jiménez-Halla JOC, Bickelhaupt FM, Solà M. Stabilization of Diborynes versus Destabilization of Diborenes by Coordination of Lewis Bases: Unravelling the Dichotomy. Chemistry 2024; 30:e202303185. [PMID: 37870211 DOI: 10.1002/chem.202303185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/23/2023] [Accepted: 10/23/2023] [Indexed: 10/24/2023]
Abstract
We have quantum chemically investigated the boron-boron bonds in B2 , diborynes B2 L2 , and diborenes B2 H2 L2 (L=none, OH2 , NH3 ) using dispersion-corrected relativistic density functional theory at ZORA-BLYP-D3(BJ)/TZ2P. B2 has effectively a single B-B bond provided by two half π bonds, whereas B2 H2 has effectively a double B=B bond provided by two half π bonds and one σ 2p-2p bond. This different electronic structure causes B2 and B2 H2 to react differently to the addition of ligands. Thus, in B2 L2 , electron-donating ligands shorten and strengthen the boron-boron bond whereas, in B2 H2 L2 , they lengthen and weaken the boron-boron bond. The aforementioned variations in boron-boron bond length and strength become more pronounced as the Lewis basicity of the ligands L increases.
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Affiliation(s)
- Lucas de Azevedo Santos
- Department of Chemistry and Pharmaceutical Sciences, AIMMS, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Daniel E Trujillo-González
- Departamento de Química, División de Ciencias Naturales y Exactas, Unversidad de Guanajuato, Noria Alta S/N Col. Noria Alta, Guanajuato, C.P. 36050, Gto., Mexico
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/ Maria Aurèlia Capmany, 69, 17003, Girona, Catalonia, Spain
| | - J Oscar C Jiménez-Halla
- Departamento de Química, División de Ciencias Naturales y Exactas, Unversidad de Guanajuato, Noria Alta S/N Col. Noria Alta, Guanajuato, C.P. 36050, Gto., Mexico
| | - F Matthias Bickelhaupt
- Department of Chemistry and Pharmaceutical Sciences, AIMMS, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
- Department of Chemical Sciences, University of Johannesburg Auckland Park, Johannesburg, 2006, South Africa
| | - Miquel Solà
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/ Maria Aurèlia Capmany, 69, 17003, Girona, Catalonia, Spain
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Fischer I, Hemberger P. Photoelectron Photoion Coincidence Spectroscopy of Biradicals. Chemphyschem 2023; 24:e202300334. [PMID: 37325876 DOI: 10.1002/cphc.202300334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 06/15/2023] [Accepted: 06/15/2023] [Indexed: 06/17/2023]
Abstract
The electronic structure of biradicals is characterized by the presence of two unpaired electrons in degenerate or near-degenerate molecular orbitals. In particular, some of the most relevant species are highly reactive, difficult to generate cleanly and can only be studied in the gas phase or in matrices. Unveiling their electronic structure is, however, of paramount interest to understand their chemistry. Photoelectron photoion coincidence (PEPICO) spectroscopy is an excellent approach to explore the electronic states of biradicals, because it enables a direct correlation between the detected ions and electrons. This permits to extract unique vibrationally resolved photoion mass-selected threshold photoelectron spectra (ms-TPES) to obtain insight in the electronic structure of both the neutral and the cation. In this review we highlight most recent advances on the spectroscopy of biradicals and biradicaloids, utilizing PEPICO spectroscopy and vacuum ultraviolet (VUV) synchrotron radiation.
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Affiliation(s)
- Ingo Fischer
- Julius-Maximilians-Universität Würzburg, Institut für Physikalische und Theoretische Chemie, Am Hubland, D-97074, Würzburg, Germany
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institut (PSI), CH-5232, Villigen, Switzerland
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Schleier D, Gerlach M, Schaffner D, Mukhopadhyay DP, Hemberger P, Fischer I. Threshold photoelectron spectroscopy of trimethylborane and its pyrolysis products. Phys Chem Chem Phys 2023; 25:4511-4518. [PMID: 36445209 DOI: 10.1039/d2cp04513c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Trimethylborane (TMB) and its chemistry upon pyrolysis have been investigated by threshold photoelectron spectroscopy. TMB shows an unstructured spectrum and its adiabatic ionization energy (IEad) has been determined to be 9.93 ± 0.1 eV. Dissociative photoionization induces a methyl radical loss in TMB and the barrier to dissociation in the cation is measured to be 0.65 ± 0.1 eV. Upon pyrolysis methane loss dominates, leading to C2H5B, which can exist in five different isomeric structures. Quantum chemical calculations were used to investigate possible methane loss mechanisms as well as the isomerization pathways on the C2H5B potential energy surface. Through isomer-selective photoion mass-selected threshold photoelectron spectroscopy (ms-TPES) the two isomers CH3BCH2 and CH3CHBH were identified by their ms-TPE spectra and IEad values of 8.55 ± 0.02 eV and 8.73 ± 0.02 eV were determined, respectively. A second channel leading to the loss of ethene from TMB forms CH2BH, which exhibits an IEad value of 9.37 ± 0.03 eV. The reaction mechanism in the literature needs to be expanded by an additional methane loss from the intermediately formed ethyl methyl borane.
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Affiliation(s)
- Domenik Schleier
- Institute for Physical and Theoretical Chemistry, University of Würzburg, 97074, Würzburg, Germany.
| | - Marius Gerlach
- Institute for Physical and Theoretical Chemistry, University of Würzburg, 97074, Würzburg, Germany.
| | - Dorothee Schaffner
- Institute for Physical and Theoretical Chemistry, University of Würzburg, 97074, Würzburg, Germany.
| | - Deb Pratim Mukhopadhyay
- Institute for Physical and Theoretical Chemistry, University of Würzburg, 97074, Würzburg, Germany.
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute (PSI), 5232, Villigen, Switzerland.
| | - Ingo Fischer
- Institute for Physical and Theoretical Chemistry, University of Würzburg, 97074, Würzburg, Germany.
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Schleier D, Gerlach M, Pratim Mukhopadhyay D, Karaev E, Schaffner D, Hemberger P, Fischer I. Ammonia Borane, NH 3 BH 3 : A Threshold Photoelectron-Photoion Coincidence Study of a Potential Hydrogen-Storage Material. Chemistry 2022; 28:e202201378. [PMID: 35622451 PMCID: PMC9401591 DOI: 10.1002/chem.202201378] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Indexed: 12/17/2022]
Abstract
We have investigated the photoionization of ammonia borane (AB) and determined adiabatic ionization energy to be 9.26±0.03 eV for the X+ 2E←X 1A1 transition. Although the threshold photoelectron spectrum appears at first glance to be similar to the one of the isosteric ethane, the electronic situation differs markedly, due to different orbital energies. In addition, an appearance energy AE0K(NH3BH3, NH3BH2+)= 10.00±0.03 eV has been determined, corresponding to the loss of a hydrogen atom at the BH3‐site. From the data, a 0 K bond dissociation energy for the B−H bond in the cation of 71.5±3 kJ mol−1 was derived, whereas the one in the neutral compound has been estimated to be 419±10 kJ mol−1.
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Affiliation(s)
- Domenik Schleier
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany.,Present Address: Laboratory for Astrophysics, Leiden Observatory, Leiden University, 2300 RA, Leiden (The, Netherlands
| | - Marius Gerlach
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Deb Pratim Mukhopadhyay
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany.,Present address: Department of Dynamics of Molecules and Clusters, J. Heyrovský Institute of Physical Chemistry, Dolejškova 2155/3, 182 23, Praha 8, Czech Republic
| | - Emil Karaev
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Dorothee Schaffner
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institut (PSI), 5232, Villigen, Switzerland
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
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Mukhopadhyay DP, Gerlach M, Hartweg S, Fischer I, Loison JC. Photoelectron spectroscopy of low valent organophosphorus compounds, P-CH 3, H-PCH 2 and PCH 2. Phys Chem Chem Phys 2022; 24:10993-10999. [PMID: 35467677 DOI: 10.1039/d2cp01082h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the mass-selected slow photoelectron spectra of three reactive organophosphorus species, PCH2, and the two isomers, methylenephosphine or phosphaethylene, HPCH2 and methylphosphinidine, P-CH3. All spectra were recorded by double imaging photoelectron-photoion coincidence spectroscopy (i2PEPICO) using synchrotron radiation and all species were generated in a flow reactor by the reaction of trimethyl phosphine with fluorine atoms. Adiabatic ionisation energies of 8.80 ± 0.02 eV (PCH2), 10.07 ± 0.03 eV (H-PCH2) and 8.91 ± 0.04 eV (P-CH3) were determined and the vibronic structure was simulated by calculating Franck-Condon factors from optimised structures based on quantum chemical methods. Observation of biradicalic P-CH3 isomer with its triplet ground state is surprising because it is less stable than H-PCH2.
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Affiliation(s)
- Deb Pratim Mukhopadhyay
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Marius Gerlach
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Sebastian Hartweg
- Synchrotron SOLEIL, L'Orme des Merisiers, St Aubin, B. P. 48, F-91192 Gif sur Yvette, France
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
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Rösch D, Almeida R, Sztáray B, Osborn DL. High-Resolution Double Velocity Map Imaging Photoelectron Photoion Coincidence Spectrometer for Gas-Phase Reaction Kinetics. J Phys Chem A 2022; 126:1761-1774. [PMID: 35258948 DOI: 10.1021/acs.jpca.1c10293] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We present a new photoelectron photoion coincidence (PEPICO) spectrometer that combines high mass resolution of cations with independently adjustable velocity map imaging of both cations and electrons. We photoionize atoms and molecules using fixed-frequency vacuum ultraviolet radiation. Mass-resolved photoelectron spectra associated with each cation's mass-to-charge ratio can be obtained by inversion of the photoelectron image. The mass-resolved photoelectron spectra enable kinetic time-resolved probing of chemical reactions with isomeric resolution using fixed-frequency radiation sources amenable to small laboratory settings. The instrument accommodates a variety of sample delivery sources to explore a broad range of physical chemistry. To demonstrate the time-resolved capabilities of the instrument, we study the 193 nm photodissociation of SO2 via the C̃(1B2) ← X̃(1A1) transition. In addition to the well-documented O(3Pj) + SO(3Σ-) channel, we observe direct evidence for a small yield of S(3Pj) + O2(3Σg-) as a primary photodissociation product channel, which may impact sulfur mass-independent fractionation chemistry.
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Affiliation(s)
- Daniel Rösch
- Combustion Research Facility, Sandia National Laboratories, Mail Stop 9055, Livermore, California 94551-0969, United States
| | - Raybel Almeida
- Combustion Research Facility, Sandia National Laboratories, Mail Stop 9055, Livermore, California 94551-0969, United States
| | - Bálint Sztáray
- Department of Chemistry, University of the Pacific, Stockton, California 95211, United States
| | - David L Osborn
- Combustion Research Facility, Sandia National Laboratories, Mail Stop 9055, Livermore, California 94551-0969, United States.,Department of Chemical Engineering, University of California, Davis, Davis, California 95616, United States
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7
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Fischer I, Pratt ST. Photoelectron spectroscopy in molecular physical chemistry. Phys Chem Chem Phys 2022; 24:1944-1959. [PMID: 35023533 DOI: 10.1039/d1cp04984d] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Photoelectron spectroscopy has long been a powerful method in the toolbox of experimental physical chemistry and molecular physics. Recent improvements in coincidence methods, charged-particle imaging, and electron energy resolution have greatly expanded the variety of environments in which photoelectron spectroscopy can be applied, as well as the range of questions that can now be addressed. In this Perspectives Article, we focus on selected recent studies that highlight these advances and research areas. The topics include reactive intermediates and new thermochemical data, high-resolution comparisons of experiment and theory using methods based on pulsed-field ionisation (PFI), and the application of photoelectron spectroscopy as an analytical tool to monitor chemical reactions in complex environments, like model flames, catalytic or high-temperature reactors.
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Affiliation(s)
- Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Stephen T Pratt
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, IL 60439, USA.
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Schleier D, Schaffner D, Gerlach M, Hemberger P, Fischer I. Threshold photoelectron spectroscopy of iminoborane, HBNH. Phys Chem Chem Phys 2021; 24:20-24. [PMID: 34889911 DOI: 10.1039/d1cp04899f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the mass-selected threshold photoelectron spectrum (ms-TPES) of iminoborane (HBNH), generated by pyrolysis of borazine. The adiabatic ionization energy (IE) of the X+ 2Π ← X 1Σ+ transition was determined to be 11.31 ± 0.02 eV and the wavenumber of the B-N stretching vibration in the cation was measured to be 1550 cm-1. The Renner-Teller splitting in the X+ 2Π state gives rise to two sets of vibrational progressions, separated by 70 meV.
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Affiliation(s)
- Domenik Schleier
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, Würzburg D-97074, Germany.
| | - Dorothee Schaffner
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, Würzburg D-97074, Germany.
| | - Marius Gerlach
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, Würzburg D-97074, Germany.
| | - Patrick Hemberger
- Laboratory for Femtochemistry and Synchrotron Radiation, Paul Scherrer Institut (PSI), Villigen CH-5232, Switzerland.
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, Würzburg D-97074, Germany.
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Gerlach M, Monninger S, Schleier D, Hemberger P, Goettel JT, Braunschweig H, Fischer I. Photoelectron Photoion Coincidence Spectroscopy of NCl 3 and NCl 2. Chemphyschem 2021; 22:2164-2167. [PMID: 34390518 PMCID: PMC8596423 DOI: 10.1002/cphc.202100537] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/10/2021] [Indexed: 12/02/2022]
Abstract
We investigate NCl3 and the NCl2 radical by photoelectron‐photoion coincidence spectroscopy using synchrotron radiation. The mass selected threshold photoelectron spectrum (ms‐TPES) of NCl3 is broad and unstructured due to the large geometry change. An ionization energy of 9.7±0.1 eV is estimated from the spectrum and supported by computations. NCl2 is generated by photolysis at 213 nm from NCl3 and its ms‐TPES shows an extended vibrational progression with a 90 meV spacing that is assigned to the symmetric N−Cl stretching mode in the cation. An adiabatic ionization energy of 9.94 ± 0.02 eV is determined.
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Affiliation(s)
- Marius Gerlach
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Sophie Monninger
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Domenik Schleier
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institut (PSI), 5232, Villigen, Switzerland
| | - James T Goettel
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry and Catalysis with Boron, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Holger Braunschweig
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry and Catalysis with Boron, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
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Liu S, Légaré MA, Seufert J, Prieschl D, Rempel A, Englert L, Dellermann T, Paprocki V, Stoy A, Braunschweig H. 2,2′-Bipyridyl as a Redox-Active Borylene Abstraction Agent. Inorg Chem 2020; 59:10866-10873. [DOI: 10.1021/acs.inorgchem.0c01383] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Siyuan Liu
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Marc-André Légaré
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Jens Seufert
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Dominic Prieschl
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Anna Rempel
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Lukas Englert
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Theresa Dellermann
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Valerie Paprocki
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Andreas Stoy
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Holger Braunschweig
- Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
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11
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Preparation and regeneration of supported single-Ir-site catalysts by nanoparticle dispersion via CO and nascent I radicals. J Catal 2020. [DOI: 10.1016/j.jcat.2019.12.040] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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12
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Mukhopadhyay DP, Schleier D, Fischer I, Loison JC, Alcaraz C, Garcia GA. Photoelectron spectroscopy of boron-containing reactive intermediates using synchrotron radiation: BH 2, BH, and BF. Phys Chem Chem Phys 2020; 22:1027-1034. [PMID: 31854408 DOI: 10.1039/c9cp06010c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mass selected slow photoelectron spectra (SPES) of three boron-containing reactive species, BH2, BH, and BF were recorded by double imaging photoion-photoelectron coincidence spectroscopy (i2PEPICO) using synchrotron radiation. All species were generated in a flow reactor from the H-abstraction of B2H6 by F atoms created in a F2 microwave discharge. The spectrum of BH2+ exhibits a long bending mode progression with a 970 cm-1 spacing due to the large geometry change from bent to linear upon ionization. Its ionization energy was determined as 8.12 ± 0.02 eV. For BH, photoionisation from both X1Σ+ singlet and a3Π triplet state was observed, permitting the experimental determination of the singlet/triplet gap (ΔEST) from the observed IE's of 9.82 eV and 8.48 eV. In addition, a threshold photoelectron spectrum of BF was recorded, which leads to an IE of 11.11 eV and an improved value for νBF+ of 1690 cm-1. All spectra were simulated by calculating Franck-Condon factors from optimised structures based on quantum chemical calculations.
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Affiliation(s)
- D P Mukhopadhyay
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - D Schleier
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - I Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - J-C Loison
- ISM-CNRS, Université de Bordeaux, 351 cours de la Libération, F-, 33405 Talence, France
| | - C Alcaraz
- LCP, UMR 8000, CNRS-Univ. Paris-Sud and Paris Saclay, Bât. 350, Centre Universitaire Paris-Sud, F-91405 Orsay, France
| | - G A Garcia
- Synchrotron SOLEIL, L'Orme des Merisiers, St Aubin, B.P. 48, F-91192 Gif sur Yvette, France
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Feng S, Lin X, Song X, Liu Y, Jiang Z, Hemberger P, Bodi A, Ding Y. The role of H2 on the stability of the single-metal-site Ir1/AC catalyst for heterogeneous methanol carbonylation. J Catal 2020. [DOI: 10.1016/j.jcat.2019.10.032] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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14
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Schleier D, Reusch E, Lummel L, Hemberger P, Fischer I. Threshold Photoelectron Spectroscopy of IO and HOI. Chemphyschem 2019; 20:2413-2416. [PMID: 31508875 PMCID: PMC6790590 DOI: 10.1002/cphc.201900813] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Indexed: 11/08/2022]
Abstract
Iodine oxides appear as reactive intermediates in atmospheric chemistry. Here, we investigate IO and HOI by mass-selective threshold photoelectron spectroscopy (ms-TPES), using synchrotron radiation. IO and HOI are generated by photolyzing iodine in the presence of ozone. For both molecules, accurate ionization energies are determined, 9.71±0.02 eV for IO and 9.79±0.02 eV for HOI. The strong spin-spin interaction in the 3 Σ- ground state of IO+ leads to an energy splitting into the Ω=0 and Ω=±1 sublevels. Upon ionization, the I-O bond shortens significantly in both molecules; thus, a vibrational progression, assigned to the I-O stretch, is apparent in both spectra.
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Affiliation(s)
- Domenik Schleier
- Institute for Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Engelbert Reusch
- Institute for Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Lisa Lummel
- Institute for Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Patrick Hemberger
- Laboratory for Femtochemistry and Synchrotron Radiation, Paul Scherrer Institute (PSI), 5232, Villigen, Switzerland
| | - Ingo Fischer
- Institute for Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
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Antonov I, Voronova K, Chen MW, Sztáray B, Hemberger P, Bodi A, Osborn DL, Sheps L. To Boldly Look Where No One Has Looked Before: Identifying the Primary Photoproducts of Acetylacetone. J Phys Chem A 2019; 123:5472-5490. [DOI: 10.1021/acs.jpca.9b04640] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Ivan Antonov
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Krisztina Voronova
- Department of Chemistry, University of the Pacific, Stockton, California 95211, United States
| | - Ming-Wei Chen
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Bálint Sztáray
- Department of Chemistry, University of the Pacific, Stockton, California 95211, United States
| | | | - Andras Bodi
- Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - David L. Osborn
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Leonid Sheps
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
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16
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Reusch E, Kaiser D, Schleier D, Buschmann R, Krueger A, Hermann T, Engels B, Fischer I, Hemberger P. Pentadiynylidene and Its Methyl-Substituted Derivates: Threshold Photoelectron Spectroscopy of R 1-C 5-R 2 Triplet Carbon Chains. J Phys Chem A 2019; 123:2008-2017. [PMID: 30776230 DOI: 10.1021/acs.jpca.8b12244] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mass-selective threshold photoelectron spectroscopy in the gas phase was employed to characterize the dialkynyl triplet carbenes pentadiynylidene (HC5H), methylpentadiynylidene (MeC5H), and dimethylpentadiynylidene (MeC5Me). Diazo compounds were employed as precursors to generate the carbenes by flash pyrolysis. The R1-C5-R2 carbon chains were photoionized by vacuum ultraviolet (VUV) synchrotron radiation in photoelectron photoion coincidence (PEPICO) experiments. High-level ab initio computations were carried out to support the interpretation of the experiments. For the unsubstituted pentadiynylidene (R1 = R2 = H) the recorded spectrum yields an adiabatic ionization energy (IEad) of 8.36 ± 0.03 eV. In addition, a second carbene isomer, 3-(didehydrovinylidene)cyclopropene, with a singlet electronic ground state, was identified in the spectrum based on the IEad of 8.60 ± 0.03 eV and Franck-Condon simulations. We found that multireference computations are required to reliably calculate the IEad for this molecule. CASPT2 computations predicted an IEad = 8.55 eV, while coupled-cluster computations significantly overestimate the IE. The cyclic isomer is most likely formed from another isomer of the precursor present in the sample. Stepwise methyl-substitution of the carbene leads to a reduction of the IE to 7.77 ± 0.04 eV for methylpentadiynylidene and 7.27 ± 0.06 eV for dimethylpentadiynylidene. The photoionization and dissociative photoionization of the precursors is investigated as well.
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Affiliation(s)
- Engelbert Reusch
- Institute of Physical and Theoretical Chemistry , University of Würzburg , Am Hubland D-97074 , Germany
| | - Dustin Kaiser
- Institute of Physical and Theoretical Chemistry , University of Würzburg , Am Hubland D-97074 , Germany
| | - Domenik Schleier
- Institute of Physical and Theoretical Chemistry , University of Würzburg , Am Hubland D-97074 , Germany
| | - Rachel Buschmann
- Institute of Organic Chemistry , University of Würzburg , Am Hubland D-97074 , Germany
| | - Anke Krueger
- Institute of Organic Chemistry , University of Würzburg , Am Hubland D-97074 , Germany
| | - Thomas Hermann
- Institute of Physical and Theoretical Chemistry , University of Würzburg , Am Hubland D-97074 , Germany
| | - Bernd Engels
- Institute of Physical and Theoretical Chemistry , University of Würzburg , Am Hubland D-97074 , Germany
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry , University of Würzburg , Am Hubland D-97074 , Germany
| | - Patrick Hemberger
- Laboratory for Femtochemistry and Synchrotron Radiation , Paul Scherrer Institut (PSI) , CH-5232 Villigen , Switzerland
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17
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Dyke JM. Photoionization studies of reactive intermediates using synchrotron radiation. Phys Chem Chem Phys 2019; 21:9106-9136. [DOI: 10.1039/c9cp00623k] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photoionization with synchrotron radiation enables sensitive and selective monitoring of reactive intermediates in environments such as flames and plasmas.
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18
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Gerlach M, Bodi A, Hemberger P. Metamorphic meta isomer: carbon dioxide and ketenes are formed via retro-Diels–Alder reactions in the decomposition of meta-benzenediol. Phys Chem Chem Phys 2019; 21:19480-19487. [DOI: 10.1039/c9cp03519b] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Deoxygenation of the lignin model compound resorcinol was investigated using VUV synchrotron radiation: Formation of two reactive ketenes and decarboxylation are the dominating pathways, much different from the other two benzenediol isomers.
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Affiliation(s)
- Marius Gerlach
- Laboratory for Synchrotron Radiation and Femtochemistry
- Paul Scherrer Institute
- CH-5234 Villigen PSI
- Switzerland
| | - Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry
- Paul Scherrer Institute
- CH-5234 Villigen PSI
- Switzerland
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry
- Paul Scherrer Institute
- CH-5234 Villigen PSI
- Switzerland
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