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Hemberger P, Pan Z, Wu X, Zhang Z, Kanayama K, Bodi A. Photoion Mass-Selected Threshold Photoelectron Spectroscopy to Detect Reactive Intermediates in Catalysis: From Instrumentation and Examples to Peculiarities and a Database. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2023; 127:16751-16763. [PMID: 37670794 PMCID: PMC10476201 DOI: 10.1021/acs.jpcc.3c03120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 08/04/2023] [Indexed: 09/07/2023]
Abstract
Photoion mass-selected threshold photoelectron spectroscopy (ms-TPES) is a synchrotron-based, universal, sensitive, and multiplexed detection tool applied in the areas of catalysis, combustion, and gas-phase reactions. Isomer-selective vibrational fingerprints in the ms-TPES of stable and reactive intermediates allow for unequivocal assignment of spectral carriers. Case studies are presented on heterogeneous catalysis, revealing the role of ketenes in the methanol-to-olefins process, the catalytic pyrolysis mechanism of lignin model compounds, and the radical chemistry upon C-H activation in oxyhalogenation. These studies demonstrate the potential of ms-TPES as an analytical technique for elucidating complex reaction mechanisms. We examine the robustness of ms-TPES assignments and address sampling effects, especially the temperature dependence of ms-TPES due to rovibrational broadening. Data acquisition approaches and the Stark shift from the extraction field are also considered to arrive at general recommendations. Finally, the PhotoElectron PhotoIon Spectral Compendium (https://pepisco.psi.ch), a spectral database hosted at Paul Scherrer Institute to support assignment, is introduced.
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Affiliation(s)
| | - Zeyou Pan
- Paul
Scherrer Institute, Villigen 5232, Switzerland
| | - Xiangkun Wu
- Paul
Scherrer Institute, Villigen 5232, Switzerland
| | - Zihao Zhang
- Paul
Scherrer Institute, Villigen 5232, Switzerland
| | - Keisuke Kanayama
- Paul
Scherrer Institute, Villigen 5232, Switzerland
- Institute
of Fluid Science, Tohoku University 2-1-1 Katahira, Aoba, Sendai 980-8577, Miyagi, Japan
- Graduate
School of Engineering, Tohoku University, 6-6 Aramaki Aza Aoba, Aoba, Sendai 980-8579, Miyagi, Japan
| | - Andras Bodi
- Paul
Scherrer Institute, Villigen 5232, Switzerland
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Genossar N, Changala PB, Gans B, Loison JC, Hartweg S, Martin-Drumel MA, Garcia GA, Stanton JF, Ruscic B, Baraban JH. Ring-Opening Dynamics of the Cyclopropyl Radical and Cation: the Transition State Nature of the Cyclopropyl Cation. J Am Chem Soc 2022; 144:18518-18525. [PMID: 36174230 DOI: 10.1021/jacs.2c07740] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We provide compelling experimental and theoretical evidence for the transition state nature of the cyclopropyl cation. Synchrotron photoionization spectroscopy employing coincidence techniques together with a novel simulation based on high-accuracy ab initio calculations reveal that the cation is unstable via its allowed disrotatory ring-opening path. The ring strains of the cation and the radical are similar, but both ring opening paths for the radical are forbidden when the full electronic symmetries are considered. These findings are discussed in light of the early predictions by Longuet-Higgins alongside Woodward and Hoffman; we also propose a simple phase space explanation for the appearance of the cyclopropyl photoionization spectrum. The results of this work allow the refinement of the cyclopropane C-H bond dissociation energy, in addition to the cyclopropyl radical and cation cyclization energies, via the Active Thermochemical Tables approach.
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Affiliation(s)
- Nadav Genossar
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva 8410501, Israel.,Israel Atomic Energy Commission, P.O. Box 7061, Tel Aviv 61070, Israel
| | - P Bryan Changala
- Center for Astrophysics─Harvard & Smithsonian, Cambridge, Massachusetts 02138, United States
| | - Bérenger Gans
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, Orsay 91405, France
| | | | - Sebastian Hartweg
- Synchrotron Soleil, L'Orme des Merisiers, St. Aubin BP48, Gif sur Yvette F-91192, France
| | | | - Gustavo A Garcia
- Synchrotron Soleil, L'Orme des Merisiers, St. Aubin BP48, Gif sur Yvette F-91192, France
| | - John F Stanton
- Quantum Theory Project, Departments of Chemistry and Physics, University of Florida, Gainesville, Florida 32611, United States
| | - Branko Ruscic
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Joshua H Baraban
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva 8410501, Israel
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