1
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Philipp MSM, Krahfuss MJ, Radacki K, Radius U. N‐Heterocyclic Carbene and Cyclic (Alkyl)(amino)carbene Adducts of Antimony(III). Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100632] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Michael S. M. Philipp
- Institute of Inorganic Chemistry Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Mirjam J. Krahfuss
- Institute of Inorganic Chemistry Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Krzysztof Radacki
- Institute of Inorganic Chemistry Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Udo Radius
- Institute of Inorganic Chemistry Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
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2
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Li Y, Chen W, Zhu L, Wang H, Guan J, Shan X, Liu F, Wang Z. Intramolecular CH 3-migration-controlled cation reactions in the VUV photochemistry of 2-methyl-3-buten-2-ol investigated by synchrotron photoionization mass spectrometry and theoretical calculations. Phys Chem Chem Phys 2021; 23:10456-10467. [PMID: 33890587 DOI: 10.1039/d1cp00490e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
2-Methyl-3-buten-2-ol (MBO232) is a biogenic volatile organic compound (BVOC), and has a large percentage of emission into the atmosphere. The vacuum ultraviolet (VUV) photochemistry of BVOCs is of great importance for atmospheric chemistry. Studies have been carried out on several BVOCs but have not extended to MBO232. In the present report, the photoionization and dissociation processes of MBO232 in the energy range of 8.0-15.0 eV have been studied by tunable VUV synchrotron radiation coupled with a time-of-flight mass spectrometer. By measuring the photoionization spectra, the adiabatic ionization energy (AIE) of MBO232 and the appearance energies (AEs) of the eight identified fragment ions (i.e., C4H7O+, C3H7O+, C5H9+, C3H6O+, CH3CO+, CH3O+, C4H5+, and C3H5+) were determined. High-level quantum chemistry calculations suggest that there are 3 direct channels and 5 indirect channels via transition states and intermediates accountable for these fragments. Among the reaction channels, the direct elimination of CH3 is the most dominant channel and produces the resonance-stabilized radical cation. Most interestingly, our results show that the CH3 selectively migrates towards the cation, which leads to the different indirect channels. The CH3 migration is a rare process in the dissociative photoionization of metal-free organic molecules. We explain the process by molecular orbital calculations and electron localization function analysis and explore the non-conventional dissociation channels via the CH3 roaming mechanism. We further perform kinetics analysis using RRKM theory for the channels of interest. The activation barrier, and rate constants are analyzed for the branching fractions of the products. These results provide important implications for the VUV photochemistry of BVOCs in the atmosphere.
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Affiliation(s)
- Yanbo Li
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China.
| | - Weiye Chen
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China.
| | - Long Zhu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China.
| | - Huanhuan Wang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China.
| | - Jiwen Guan
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China.
| | - Xiaobin Shan
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China.
| | - Fuyi Liu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China.
| | - Zhandong Wang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China.
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3
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Bodi A, Hemberger P, Tuckett RP. From Energetics to Intracluster Chemistry: Valence Photoionization of Trifluoromethylsulfur Pentafluoride (CF 3SF 5) by Double Velocity Map Imaging. J Phys Chem A 2021; 125:2601-2611. [PMID: 33729793 DOI: 10.1021/acs.jpca.1c00918] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Trifluoromethylsulfur pentafluoride (CF3SF5) was valence threshold photoionized in a double imaging photoelectron photoion coincidence spectrometer using vacuum ultraviolet synchrotron radiation. In the 12.5-16.4 eV photon energy range, CF3+, SF5+, and SF3+ cations were observed in both room temperature (RT) and molecular beam (MB) experiments. Their fractional abundances exhibited differences beyond the sample temperature. Kinetic energy analysis of the fragment ions confirmed the difference in the dissociative photoionization mechanism. In the RT experiment, the CF3+ kinetic energies were extrapolated to a 11.84 ± 0.15 eV threshold, which was used in an ion cycle to determine the enthalpy of formation of CF3SF5 as ΔfH°298K(CF3SF5) = -1593 ± 16 kJ mol-1. We also updated the enthalpy of formation of the sulfur pentafluoride radical as ΔfH°298K(SF5) = -854 ± 7 kJ mol-1 and discuss the discrepancy between the CF3 ionization energy based on the Active Thermochemical Tables and the value anchored to the CF ionization energy. A computed reaction enthalpy network optimization resulted in ΔfH°298K(CF3SF5) = -1608 ± 20 kJ mol-1. Both values for ΔfH°298K(CF3SF5) agree with previous ab initio ones in contrast to the original, experimental determination. SF3+ is formed by F-transfer processes both in the RT and MB experiments. Although the same peaks were observed in both experiments, the lower SF3+ onset energy and the more slowly rising CF3+ kinetic energy release in the MB experiment revealed clustering and intracluster F-transfer reactions upon ionization. The monomer and dimer cation potential energy surfaces were explored to rationalize the observations. In the dimer cation, the observer CF3SF5 catalyzes fluorine transfer and promotes CF4 formation, which ultimately leads to the SF3+ fragment ion.
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Affiliation(s)
- Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Richard P Tuckett
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K
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4
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Weidner P, Voronova K, Bodi A, Sztáray B. Dissociative photoionization of 1,3-dioxolane: We need six channels to fit the elephant. JOURNAL OF MASS SPECTROMETRY : JMS 2020; 55:e4522. [PMID: 32510769 DOI: 10.1002/jms.4522] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 03/29/2020] [Accepted: 04/01/2020] [Indexed: 06/11/2023]
Abstract
The dissociative photoionization of 1,3-dioxolane was studied by photoelectron photoion coincidence (PEPICO) spectroscopy in the photon energy range of 9.5-13.5 eV. Our statistical thermodynamics model shows that a total of six dissociation channels are involved in the formation of three fragment ions, namely, C3 H5 O2 + (m/z 73), C2 H5 O+ (m/z 45), and C2 H4 O+ (m/z 44), with two channels contributing to the formation of each. By comparing the results of ab initio quantum chemical calculations to the experimentally derived appearance energies of the fragment ions, the most likely mechanisms for these unimolecular dissociation reactions are proposed, including a description of the relevant parts of the potential energy surface.
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Affiliation(s)
- Peter Weidner
- Department of Chemistry, University of the Pacific, Stockton, California, 95211, USA
| | - Krisztina Voronova
- Department of Chemistry, University of Nevada, Reno, Reno, Nevada, 89557, USA
| | - Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, 5232, Villigen, Switzerland
| | - Bálint Sztáray
- Department of Chemistry, University of the Pacific, Stockton, California, 95211, USA
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5
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Wu X, Yu T, Chen Y, Zhou X, Liu S, Dai X, Liu F, Sheng L. Dissociative photoionization of CF3Cl via the C2E and D2E states: competition of the C–F and C–Cl bond cleavages. Phys Chem Chem Phys 2019; 21:4998-5005. [DOI: 10.1039/c8cp07332e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Competition between C–F and C–Cl ruptures in the dissociative photoionization of CF3Cl via C2E and D2E ionic states
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Affiliation(s)
- Xiangkun Wu
- Hefei National Laboratory for Physical Sciences at the Microscale
- iChEM (Collaborative Innovation Center of Chemistry for Energy Materials)
- Department of Chemical Physics
- University of Science and Technology of China
- Hefei 230026
| | - Tongpo Yu
- Hefei National Laboratory for Physical Sciences at the Microscale
- iChEM (Collaborative Innovation Center of Chemistry for Energy Materials)
- Department of Chemical Physics
- University of Science and Technology of China
- Hefei 230026
| | - Yan Chen
- National Institute of Metrology
- Beijing 100013
- China
| | - Xiaoguo Zhou
- Hefei National Laboratory for Physical Sciences at the Microscale
- iChEM (Collaborative Innovation Center of Chemistry for Energy Materials)
- Department of Chemical Physics
- University of Science and Technology of China
- Hefei 230026
| | - Shilin Liu
- Hefei National Laboratory for Physical Sciences at the Microscale
- iChEM (Collaborative Innovation Center of Chemistry for Energy Materials)
- Department of Chemical Physics
- University of Science and Technology of China
- Hefei 230026
| | - Xinhua Dai
- National Institute of Metrology
- Beijing 100013
- China
| | - Fuyi Liu
- National Synchrotron Radiation Laboratory
- University of Science and Technology of China
- Hefei 230029
- China
| | - Liusi Sheng
- National Synchrotron Radiation Laboratory
- University of Science and Technology of China
- Hefei 230029
- China
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6
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Bodi A, Hemberger P. Low-Energy Photoelectron Spectrum and Dissociative Photoionization of the Smallest Amides: Formamide and Acetamide. J Phys Chem A 2018; 123:272-283. [DOI: 10.1021/acs.jpca.8b10373] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
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7
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Hock A, Schneider H, Krahfuß MJ, Radius U. Hydride Amide and Hydride Phenolate Complexes of NHC Coordinated Aluminum. Z Anorg Allg Chem 2018. [DOI: 10.1002/zaac.201800251] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Andreas Hock
- Institut für Anorganische Chemie; Julius-Maximilians-Universität Würzburg; Am Hubland 97074 Würzburg Germany
| | - Heidi Schneider
- Institut für Anorganische Chemie; Julius-Maximilians-Universität Würzburg; Am Hubland 97074 Würzburg Germany
| | - Mirjam J. Krahfuß
- Institut für Anorganische Chemie; Julius-Maximilians-Universität Würzburg; Am Hubland 97074 Würzburg Germany
| | - Udo Radius
- Institut für Anorganische Chemie; Julius-Maximilians-Universität Würzburg; Am Hubland 97074 Würzburg Germany
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8
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West B, Rodriguez Castillo S, Sit A, Mohamad S, Lowe B, Joblin C, Bodi A, Mayer PM. Unimolecular reaction energies for polycyclic aromatic hydrocarbon ions. Phys Chem Chem Phys 2018; 20:7195-7205. [PMID: 29480289 PMCID: PMC6031295 DOI: 10.1039/c7cp07369k] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Imaging photoelectron photoion coincidence spectroscopy was employed to explore the unimolecular dissociation of the ionized polycyclic aromatic hydrocarbons (PAHs) acenaphthylene, fluorene, cyclopenta[d,e,f]phenanthrene, pyrene, perylene, fluoranthene, dibenzo[a,e]pyrene, dibenzo[a,l]pyrene, coronene and corannulene. The primary reaction is always hydrogen atom loss, with the smaller species also exhibiting loss of C2H2 to varying extents. Combined with previous work on smaller PAH ions, trends in the reaction energies (E0) for loss of H from sp2-C and sp3-C centres, along with hydrocarbon molecule loss were found as a function of the number of carbon atoms in the ionized PAHs ranging in size from naphthalene to coronene. In the case of molecules which possessed at least one sp3-C centre, the activation energy for the loss of an H atom from this site was 2.34 eV, with the exception of cyclopenta[d,e,f]phenanthrene (CPP) ions, for which the E0 was 3.44 ± 0.86 eV due to steric constraints. The hydrogen loss from PAH cations and from their H-loss fragments exhibits two trends, depending on the number of unpaired electrons. For the loss of the first hydrogen atom, the energy is consistently ca. 4.40 eV, while the threshold to lose the second hydrogen atom is much lower at ca. 3.16 eV. The only exception was for the dibenzo[a,l]pyrene cation, which has a unique structure due to steric constraints, resulting in a low H loss reaction energy of 2.85 eV. If C2H2 is lost directly from the precursor cation, the energy required for this dissociation is 4.16 eV. No other fragmentation channels were observed over a large enough sample set for trends to be extrapolated, though data on CH3 and C4H2 loss obtained in previous studies is included for completeness. The dissociation reactions were also studied by collision induced dissociation after ionization by atmospheric pressure chemical ionization. When modeled with a simple temperature-based theory for the post-collision internal energy distribution, there was reasonable agreement between the two sets of data.
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Affiliation(s)
- Brandi West
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa K1N 6N5, Canada.
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9
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Candian A, Bouwman J, Hemberger P, Bodi A, Tielens AGGM. Dissociative ionisation of adamantane: a combined theoretical and experimental study. Phys Chem Chem Phys 2018; 20:5399-5406. [PMID: 29155909 DOI: 10.1039/c7cp05957d] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Diamond nanoparticles, or nanodiamonds, are intriguing carbon-based materials which, maybe surprisingly, are the most abundant constituent of presolar grains. While the spectroscopic properties of even quite large diamondoids have already been explored, little is known about their unimolecular fragmentation processes. In this paper we characterise the dissociative ionisation of adamantane (C10H16) - the smallest member of the diamondoid family - utilising imaging Photoelectron Photoion Coincidence (iPEPICO) spectroscopy and Density Functional Theory (DFT) calculations. We have found adamantane to dissociatively photoionise via several parallel channels of which H, C3H7 and C4H8 losses are the most important ones. Calculations confirm the existence of a rate-limiting transition state for the multiple C-loss channels, which is located at 10.55 eV with respect to neutral adamantane. In addition, we found dissociation channels leading to small cationic hydrocarbons, which may be relevant in the interstellar medium.
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Affiliation(s)
- Alessandra Candian
- Leiden Observatory, Leiden University, P.O. Box 9513, 2300-RA Leiden, The Netherlands.
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10
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Wu X, Tang G, Zhang H, Zhou X, Liu S, Liu F, Sheng L, Yan B. Cl-Loss dynamics in the dissociative photoionization of CF3Cl with threshold photoelectron–photoion coincidence imaging. Phys Chem Chem Phys 2018; 20:4917-4925. [DOI: 10.1039/c7cp07502b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cl-loss dynamics in the dissociative photoionization of CF3Cl was investigated in the photon energy range of 12.30–18.50 eV.
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Affiliation(s)
- Xiangkun Wu
- Hefei National Laboratory for Physical Sciences at the Microscale
- iChEM (Collaborative Innovation Center of Chemistry for Energy Materials)
- Department of Chemical Physics
- University of Science and Technology of China
- Hefei
| | - Guoqiang Tang
- Hefei National Laboratory for Physical Sciences at the Microscale
- iChEM (Collaborative Innovation Center of Chemistry for Energy Materials)
- Department of Chemical Physics
- University of Science and Technology of China
- Hefei
| | - Hanhui Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale
- iChEM (Collaborative Innovation Center of Chemistry for Energy Materials)
- Department of Chemical Physics
- University of Science and Technology of China
- Hefei
| | - Xiaoguo Zhou
- Hefei National Laboratory for Physical Sciences at the Microscale
- iChEM (Collaborative Innovation Center of Chemistry for Energy Materials)
- Department of Chemical Physics
- University of Science and Technology of China
- Hefei
| | - Shilin Liu
- Hefei National Laboratory for Physical Sciences at the Microscale
- iChEM (Collaborative Innovation Center of Chemistry for Energy Materials)
- Department of Chemical Physics
- University of Science and Technology of China
- Hefei
| | - Fuyi Liu
- National Synchrotron Radiation Laboratory
- University of Science and Technology of China
- Hefei
- China
| | - Liusi Sheng
- National Synchrotron Radiation Laboratory
- University of Science and Technology of China
- Hefei
- China
| | - Bing Yan
- Institute of Atomic and Molecular Physics
- Jilin University
- Changchun 130012
- China
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11
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Pastoors JIM, Bodi A, Hemberger P, Bouwman J. Dissociative Ionization and Thermal Decomposition of Cyclopentanone. Chemistry 2017; 23:13131-13140. [PMID: 28692134 PMCID: PMC5639375 DOI: 10.1002/chem.201702376] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Indexed: 11/24/2022]
Abstract
Despite the growing use of renewable and sustainable biofuels in transportation, their combustion chemistry is poorly understood, limiting our efforts to reduce harmful emissions. Here we report on the (dissociative) ionization and the thermal decomposition mechanism of cyclopentanone, studied using imaging photoelectron photoion coincidence spectroscopy. The fragmentation of the ions is dominated by loss of CO, C2H4, and C2H5, leading to daughter ions at m/z 56 and 55. Exploring the C5H8O.+ potential energy surface reveals hydrogen tunneling to play an important role in low‐energy decarbonylation and probably also in the ethene‐loss processes, yielding 1‐butene and methylketene cations, respectively. At higher energies, pathways without a reverse barrier open up to oxopropenyl and cyclopropanone cations by ethyl‐radical loss and a second ethene‐loss channel, respectively. A statistical Rice–Ramsperger–Kassel–Marcus model is employed to test the viability of this mechanism. The pyrolysis of cyclopentanone is studied at temperatures ranging from about 800 to 1100 K. Closed‐shell pyrolysis products, namely 1,3‐butadiene, ketene, propyne, allene, and ethene, are identified based on their photoion mass‐selected threshold photoelectron spectrum. Furthermore, reactive radical species such as allyl, propargyl, and methyl are found. A reaction mechanism is derived incorporating both stable and reactive species, which were not predicted in prior computational studies.
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Affiliation(s)
- Johan I M Pastoors
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7c, 6525 ED, Nijmegen, The Netherlands
| | - Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, 5232, Villigen, Switzerland
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, 5232, Villigen, Switzerland
| | - Jordy Bouwman
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7c, 6525 ED, Nijmegen, The Netherlands.,Present address: Sackler Laboratory for Astrophysics, Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA, Leiden, The Netherlands
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12
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Wu X, Zhou X, Hemberger P, Bodi A. Dissociative Photoionization of Dimethyl Carbonate: The More It Is Cut, the Bigger the Fragment Ion. J Phys Chem A 2017; 121:2748-2759. [DOI: 10.1021/acs.jpca.7b00544] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xiangkun Wu
- Hefei
National Laboratory for Physical Sciences at the Microscale and Department
of Chemical Physics, National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026, China
| | - Xiaoguo Zhou
- Hefei
National Laboratory for Physical Sciences at the Microscale and Department
of Chemical Physics, National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026, China
| | - Patrick Hemberger
- Laboratory
for Femtochemistry and Synchrotron Radiation, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Andras Bodi
- Laboratory
for Femtochemistry and Synchrotron Radiation, Paul Scherrer Institute, 5232 Villigen, Switzerland
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13
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Schmitt HC, Flock M, Welz E, Engels B, Schneider H, Radius U, Fischer I. Electronic Structure and Excited-State Dynamics of an Arduengo-Type Carbene and its Imidazolone Oxidation Product. Chemistry 2017; 23:3084-3090. [PMID: 28071828 DOI: 10.1002/chem.201605027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Indexed: 11/06/2022]
Abstract
We describe an investigation of the excited-state dynamics of isolated 1,3-di-tert-butyl-imidazoline-2-ylidene (tBu2 Im, C11 H20 N2 , m/z=180), an Arduengo-type carbene, by time- and frequency-resolved photoionization using a picosecond laser system. The energies of several singlet and triplet excited states were calculated by time-dependent density functional theory (TD-DFT). The S1 state of the carbene deactivates on a 100 ps time scale possibly by intersystem crossing. In the experiments we observed an additional signal at m/z=196, that was assigned to the oxidation product 1,3-di-tert-butyl-imidazolone, tBu2 ImO. It shows a well-resolved resonance-enhanced multiphoton ionization (REMPI) spectrum with an origin located at 36951 cm-1 . Several low-lying vibrational bands could be assigned, with a lifetime that depends strongly on the excitation energy. At the origin the lifetime is longer than 3 ns, but drops to 49 ps at higher excess energies. To confirm formation of the imidazolone we also performed experiments on benzimidazolone (BzImO) for comparison. Apart from a redshift for BzImO the spectra of the two compounds are very similar. The TD-DFT values display a very good agreement with the experimental data.
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Affiliation(s)
- Hans-Christian Schmitt
- Institute of Physical und Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Marco Flock
- Institute of Physical und Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Eileen Welz
- Institute of Physical und Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Bernd Engels
- Institute of Physical und Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Heidi Schneider
- Institute of Inorganic Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Udo Radius
- Institute of Inorganic Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Ingo Fischer
- Institute of Physical und Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
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14
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Bodi A, Hemberger P, Tuckett RP. Coincident velocity map image reconstruction illustrated by the single-photon valence photoionisation of CF3SF5. Phys Chem Chem Phys 2017; 19:30173-30180. [DOI: 10.1039/c7cp05576e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photoion–photoelectron kinetic energy and angular anisotropy correlation maps reveal new details about the ionization mechanism.
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Affiliation(s)
- Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute
- Villigen 5232
- Switzerland
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute
- Villigen 5232
- Switzerland
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15
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Bodi A, Sigurdardottir KL, Kvaran Á, Bjornsson R, Arnason I. Dissociative Photoionization of 1-Halogenated Silacyclohexanes: Silicon Traps the Halogen. J Phys Chem A 2016; 120:9188-9197. [DOI: 10.1021/acs.jpca.6b09195] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Andras Bodi
- Laboratory
for Femtochemistry and Synchrotron Radiation, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | | | - Ágúst Kvaran
- Science
Institute, University of Iceland, Dunhaga 3, 107 Reykjavík, Iceland
| | - Ragnar Bjornsson
- Science
Institute, University of Iceland, Dunhaga 3, 107 Reykjavík, Iceland
| | - Ingvar Arnason
- Science
Institute, University of Iceland, Dunhaga 3, 107 Reykjavík, Iceland
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16
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Schneider H, Krahfuß MJ, Radius U. To Rearrange or not to Rearrange: Reactivity of NHCs towards Chloro- and HydrostannanesR2SnCl2(R= Me, Ph) and Ph3SnH. Z Anorg Allg Chem 2016. [DOI: 10.1002/zaac.201600271] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Heidi Schneider
- Institut für Anorganische Chemie; Julius-Maximilians-Universität Würzburg; Am Hubland 97074 Würzburg Germany
| | - Mirjam J. Krahfuß
- Institut für Anorganische Chemie; Julius-Maximilians-Universität Würzburg; Am Hubland 97074 Würzburg Germany
| | - Udo Radius
- Institut für Anorganische Chemie; Julius-Maximilians-Universität Würzburg; Am Hubland 97074 Würzburg Germany
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17
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Würtemberger-Pietsch S, Schneider H, Marder TB, Radius U. Adduct Formation, B-H Activation and Ring Expansion at Room Temperature from Reactions of HBcat with NHCs. Chemistry 2016; 22:13032-6. [PMID: 27428465 DOI: 10.1002/chem.201603328] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Indexed: 11/07/2022]
Abstract
We report the reactions of catecholborane (HBcat; 1) with unsaturated and saturated NHCs as well as CAAC(Me) . Mono-NHC adducts of the type HBcat⋅NHC (NHC=nPr2 Im, iPr2 Im, iPr2 Im(Me) , and Dipp2 Im) were obtained by stoichiometric reactions of HBcat with the unsaturated NHCs. The reaction of CAAC(Me) with HBcat yielded the B-H activated product CAAC(Me) (H)Bcat via insertion of the carbine-carbon atom into the B-H bond. The saturated NHC Dipp2 SIm reacted in a 2:2 ratio yielding an NHC ring-expanded product at room temperature forming a six-membered -B-C=N-C=C-N- ring via C-N bond cleavage and further migration of the hydrides from two HBcat molecules to the former carbene-carbon atom.
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Affiliation(s)
| | - Heidi Schneider
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Todd B Marder
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.
| | - Udo Radius
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.
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18
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Kostko O, Bandyopadhyay B, Ahmed M. Vacuum Ultraviolet Photoionization of Complex Chemical Systems. Annu Rev Phys Chem 2016; 67:19-40. [DOI: 10.1146/annurev-physchem-040215-112553] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Oleg Kostko
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720;
| | - Biswajit Bandyopadhyay
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720;
| | - Musahid Ahmed
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720;
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19
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Heringa MF, Slowik JG, Prévôt ASH, Baltensperger U, Hemberger P, Bodi A. Dissociative Ionization Mechanism and Appearance Energies in Adipic Acid Revealed by Imaging Photoelectron Photoion Coincidence, Selective Deuteration, and Calculations. J Phys Chem A 2016; 120:3397-405. [DOI: 10.1021/acs.jpca.6b00908] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Maarten F. Heringa
- Laboratory
of Atmospheric Chemistry, Paul Scherrer Institute, Villigen PSI, Switzerland
- Laboratory
for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, Villigen
PSI, Switzerland
| | - Jay G. Slowik
- Laboratory
of Atmospheric Chemistry, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - André S. H. Prévôt
- Laboratory
of Atmospheric Chemistry, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Urs Baltensperger
- Laboratory
of Atmospheric Chemistry, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Patrick Hemberger
- Laboratory
for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, Villigen
PSI, Switzerland
| | - Andras Bodi
- Laboratory
for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, Villigen
PSI, Switzerland
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20
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Voronova K, Mozaffari Easter CM, Torma KG, Bodi A, Hemberger P, Sztáray B. Bifurcated dissociative photoionization mechanism of acetic acid anhydride revealed by imaging photoelectron photoion coincidence spectroscopy. Phys Chem Chem Phys 2016; 18:25161-25168. [DOI: 10.1039/c6cp05370j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
PEPICO allows us a peek beyond the transition state to identify bifurcated reaction pathways.
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Affiliation(s)
| | | | | | - Andras Bodi
- Laboratory for Femtochemistry and Synchrotron Radiation
- Paul Scherrer Institute
- Villigen 5232
- Switzerland
| | - Patrick Hemberger
- Laboratory for Femtochemistry and Synchrotron Radiation
- Paul Scherrer Institute
- Villigen 5232
- Switzerland
| | - Bálint Sztáray
- Department of Chemistry
- University of the Pacific
- Stockton
- USA
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21
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Würtemberger-Pietsch S, Radius U, Marder TB. 25 years of N-heterocyclic carbenes: activation of both main-group element-element bonds and NHCs themselves. Dalton Trans 2015; 45:5880-95. [PMID: 26675582 DOI: 10.1039/c5dt04106f] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
N-Heterocyclic carbenes (NHCs) are widely used ligands and reagents in modern inorganic synthesis as well as in homogeneous catalysis and organocatalysis. However, NHCs are not always innocent bystanders. In the last few years, more and more examples were reported of reactions of NHCs with main-group elements which resulted in modification of the NHC. Many of these reactions lead to ring expansion and the formation of six-membered heterocyclic rings involving insertion of the heteroatom into the C-N bond and migration of hydrides, phenyl groups or boron-containing fragments. Furthermore, a few related NHC rearrangements were observed some decades ago. In this Perspective, we summarise the history of NHC ring expansion reactions from the 1960s till the present.
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Affiliation(s)
- Sabrina Würtemberger-Pietsch
- Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany. u.radius@uni-wuerzburg
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22
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Voronova K, Mozaffari Easter CM, Covert KJ, Bodi A, Hemberger P, Sztáray B. Dissociative Photoionization of Diethyl Ether. J Phys Chem A 2015; 119:10654-63. [DOI: 10.1021/acs.jpca.5b08091] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Krisztina Voronova
- Department
of Chemistry, University of the Pacific, Stockton, California 95211, United States
| | | | - Kyle J. Covert
- Department
of Chemistry, University of the Pacific, Stockton, California 95211, United States
| | - Andras Bodi
- Molecular
Dynamics Group, Paul Scherrer Institut, Villigen 5232, Switzerland
| | - Patrick Hemberger
- Molecular
Dynamics Group, Paul Scherrer Institut, Villigen 5232, Switzerland
| | - Bálint Sztáray
- Department
of Chemistry, University of the Pacific, Stockton, California 95211, United States
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23
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24
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Schneider H, Schmidt D, Radius U. The reductive P–P coupling of primary and secondary phosphines mediated by N-heterocyclic carbenes. Chem Commun (Camb) 2015; 51:10138-41. [DOI: 10.1039/c5cc02517f] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
P–P bond formation! The reaction of an NHC with primary and secondary phosphines leads to dehydrocoupling of the phosphines with the formation of iPr2ImH2 and the corresponding carbene-phosphinidene adducts.
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Affiliation(s)
- Heidi Schneider
- Institut für Anorganische Chemie
- Julius-Maximilians-Universität Würzburg
- D-97074 Würzburg
- Germany
| | - David Schmidt
- Institut für Anorganische Chemie
- Julius-Maximilians-Universität Würzburg
- D-97074 Würzburg
- Germany
| | - Udo Radius
- Institut für Anorganische Chemie
- Julius-Maximilians-Universität Würzburg
- D-97074 Würzburg
- Germany
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25
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Hemberger P, Bodi A, Berthel JHJ, Radius U. Intramolecular CN Bond Activation and Ring-Expansion Reactions of N-Heterocyclic Carbenes. Chemistry 2014; 21:1434-8. [DOI: 10.1002/chem.201406036] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Indexed: 11/11/2022]
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26
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Lang M, Holzmeier F, Fischer I, Hemberger P. Decomposition of diazomeldrum's acid: a threshold photoelectron spectroscopy study. J Phys Chem A 2014; 118:11235-43. [PMID: 25369422 DOI: 10.1021/jp509324w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Derivatives of meldrum's acid are known precursors for a number of reactive intermediates. Therefore, we investigate diazomeldrum's acid (DMA) and its pyrolysis products by photoionization using vacuum ultraviolet (VUV) synchrotron radiation. The threshold photoelectron spectrum of DMA yields an ionization energy (IE) of 9.68 eV. Several channels for dissociative photoionization are observed. The first one is associated with loss of CH3, leading to a daughter ion with m/z = 155. Its appearance energy AE0K was determined to be 10.65 eV by fitting the experimental data using statistical theory. A second parallel channel leads to m/z = 69, corresponding to N2CHCO, with an AE0K of 10.72 eV. Several other channels open up at higher energy, among them the formation of acetone cation, a channel expected to be the result of a Wolff-rearrangement (WR) in the cation. When diazomeldrum's acid is heated in a pyrolysis reactor, three thermal decomposition pathways are observed. The major one is well-known and yields acetone, N2 and CO as consequence of the WR. However, two further channels were identified: The formation of 2-diazoethenone, NNCCO, together with acetone and CO2 as the second channel and E-formylketene (OCCHCHCO), propyne, N2 and O2 as a third one. 2-Diazoethenone and E-formylketene were identified based on their threshold photoelectron spectra and accurate ionization energies could be determined. Ionization energies for several isomers of both molecules were also computed. One of the key findings of this study is that acetone is observed upon decomposition of DMA in the neutral as well as in the ion and both point to a Wolff rearrangement to occur. However, the ion is subject to other decomposition channels favored at lower internal energies.
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Affiliation(s)
- Melanie Lang
- Institute of Physical and Theoretical Chemistry, University of Würzburg , Am Hubland, D-97074 Würzburg, Germany
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27
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Liang S, Hemberger P, Neisius NM, Bodi A, Grützmacher H, Levalois-Grützmacher J, Gaan S. Elucidating the Thermal Decomposition of Dimethyl Methylphosphonate by Vacuum Ultraviolet (VUV) Photoionization: Pathways to the PO Radical, a Key Species in Flame-Retardant Mechanisms. Chemistry 2014; 21:1073-80. [DOI: 10.1002/chem.201404271] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Indexed: 11/09/2022]
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28
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West B, Sit A, Mohamed S, Joblin C, Blanchet V, Bodi A, Mayer PM. Dissociation of the anthracene radical cation: a comparative look at iPEPICO and collision-induced dissociation mass spectrometry results. J Phys Chem A 2014; 118:9870-8. [PMID: 25245634 DOI: 10.1021/jp505438f] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The dissociation of the anthracene radical cation has been studied using two different methods: imaging photoelectron photoion coincidence spectrometry (iPEPCO) and atmospheric pressure chemical ionization-collision induced dissociation mass spectrometry (APCI-CID). Four reactions were investigated: (R1) C14H10(+•) → C14H9(+) + H, (R2) C14H9(+) → C14H8(+•) + H, (R3) C14H10(+•) → C12H8(+•) + C2H2 and (R4) C14H10(+•) → C10H8(+•) + C4H2. An attempt was made to assign structures to each fragment ion, and although there is still room for debate whether for the C12H8(+•) fragment ion is a cyclobuta[b]naphthalene or a biphenylene cation, our modeling results and calculations appear to suggest the more likely structure is cyclobuta[b]naphthalene. The results from the iPEPICO fitting of the dissociation of ionized anthracene are E0 = 4.28 ± 0.30 eV (R1), 2.71 ± 0.20 eV (R2), and 4.20 ± 0.30 eV (average of reaction R3) whereas the Δ(‡)S values (in J K(-1) mol(-1)) are 12 ± 15 (R1), 0 ± 15 (R2), and either 7 ± 10 (using cyclobuta[b]naphthalene ion fragment in reaction R3) or 22 ± 10 (using the biphenylene ion fragment in reaction R3). Modeling of the APCI-CID breakdown diagrams required an estimate of the postcollision internal energy distribution, which was arbitrarily assumed to correspond to a Boltzmann distribution in this study. One goal of this work was to determine if this assumption yields satisfactory energetics in agreement with the more constrained and theoretically vetted iPEPICO results. In the end, it did, with the APCI-CID results being similar.
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Affiliation(s)
- Brandi West
- Chemistry Department, University of Ottawa , Ottawa, Canada K1N 6N5
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29
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Holzmeier F, Lang M, Hemberger P, Bodi A, Schäfer M, Dewhurst RD, Braunschweig H, Fischer I. Photoionization and pyrolysis of a 1,4-azaborinine: retro-hydroboration in the cation and identification of novel organoboron ring systems. Chemistry 2014; 20:9683-92. [PMID: 24976576 DOI: 10.1002/chem.201402884] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Indexed: 12/30/2022]
Abstract
The photoionization and dissociative photoionization of 1,4-di-tert-butyl-1,4-azaborinine by means of synchrotron radiation and threshold photoelectron photoion coincidence spectroscopy is reported. The ionization energy of the compound was determined to be 7.89 eV. Several low-lying electronically excited states in the cation were identified. The various pathways for dissociative photoionization were modeled by statistical theory, and appearance energies AE0K were obtained. The loss of isobutene in a retro-hydroboration reaction is the dominant pathway, which proceeds with a reverse barrier. Pyrolysis of the parent compound in a chemical reactor leads to the generation of several yet unobserved boron compounds. The ionization energies of the C4 H6 BN isomers 1,2- and 1,4-dihydro-1,4-azaborinine and the C3 H6 BN isomer 1,2-dihydro-1,3-azaborole were determined from threshold photoelectron spectra.
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Affiliation(s)
- Fabian Holzmeier
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg (Germany)
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30
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Bodi A, Hemberger P. Imaging breakdown diagrams for bromobutyne isomers with photoelectron–photoion coincidence. Phys Chem Chem Phys 2014; 16:505-15. [DOI: 10.1039/c3cp53212g] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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31
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Russell EM, Cudjoe E, Mastromatteo ME, Kercher JP, Sztáray B, Bodi A. From Iron Pentacarbonyl to the Iron Ion by Imaging Photoelectron Photoion Coincidence. J Phys Chem A 2013; 117:4556-63. [DOI: 10.1021/jp402443e] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Eileen M. Russell
- Department of Chemistry, Hiram College, Hiram, Ohio 44234, United States
| | - Elvis Cudjoe
- Department of Chemistry, Hiram College, Hiram, Ohio 44234, United States
| | | | - James P. Kercher
- Department of Chemistry, Hiram College, Hiram, Ohio 44234, United States
| | - Bálint Sztáray
- Department of Chemistry, University of the Pacific, Stockton, California 95211, United States
| | - Andras Bodi
- Paul Scherrer Institut,
Villigen 5232, Switzerland
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