1
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Lai YF, Leung L, Timm MJ, Walker GC, Polanyi JC. Abortive reaction leads to selective adsorbate rotation. Faraday Discuss 2024. [PMID: 38808590 DOI: 10.1039/d3fd00167a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
Electron-induced dissociation of a fluorocarbon adsorbate CF3 (ad) at 4.6 K is shown by Scanning Tunnelling Microscopy (STM) to form directed energetic F-atom 'projectiles' on Cu(110). The outcome of a collision between these directed projectiles and stationary co-adsorbed allyl 'target' molecules was found through STM to give rotational excitation of the target allyl, clockwise or anti-clockwise, depending on the chosen collision geometry. Molecular dynamics computation linked the collisional excitation of the allyl target to an 'abortive chemical reaction', in which the approach of the F-projectile stretched an H-C bond lifting the allyl above the surface, facilitating isomerization from 'Across' to 'Along' a Cu row.
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Affiliation(s)
- Yi-Fang Lai
- Lash Miller Chemical Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada.
| | - Lydie Leung
- Lash Miller Chemical Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada.
| | - Matthew J Timm
- Department of Physical Chemistry, University of Graz, Heinrichstrasse 28, 8010 Graz, Austria
| | - Gilbert C Walker
- Lash Miller Chemical Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada.
| | - John C Polanyi
- Lash Miller Chemical Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada.
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2
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Cheng C, Prezhdo OV, Long R, Fang WH. Photolysis versus Photothermolysis of N 2O on a Semiconductor Surface Revealed by Nonadiabatic Molecular Dynamics. J Am Chem Soc 2023; 145:476-486. [PMID: 36541604 DOI: 10.1021/jacs.2c10643] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Identifying photolysis and photothermolysis during a photochemical reaction has remained challenging because of the highly non-equilibrium and ultrafast nature of the processes. Using state-of-the-art ab initio adiabatic and nonadiabatic molecular dynamics, we investigate N2O photodissociation on the reduced rutile TiO2(110) surface and establish its detailed mechanism. The photodecomposition is initiated by electron injection, leading to the formation of a N2O- ion-radical, and activation of the N2O bending and symmetric stretching vibrations. Photothermolysis governs the N2O dissociation when N2O- is short-lived. The dissociation is activated by a combination of the anionic excited state evolution and local heating. A thermal fluctuation drives the molecular acceptor level below the TiO2 band edge, stabilizes the N2O- anion radical, and causes dissociation on a 1 ps timescale. As the N2O- resonance lifetime increases, photolysis becomes dominant since evolution in the anionic excited state activates the bending and symmetric stretching of N2O, inducing the dissociation. The photodecomposition occurs more easily when N2O is bonded to TiO2 through the O rather than N atom. We demonstrate further that a thermal dissociation of N2O can be realized by a rational choice of metal dopants, which enhance p-d orbital hybridization, facilitate electron transfer, and break N2O spontaneously. By investigating the charge dynamics and lifetime, we provide a fundamental atomistic understanding of the competition and synergy between the photocatalytic and photothermocatalytic dissociation of N2O and demonstrate how N2O reduction can be controlled by light irradiation, adsorption configuration, and dopants, enabling the design of high-performance transition-metal oxide catalysts.
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Affiliation(s)
- Cheng Cheng
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing100875, P. R. China
| | - Oleg V Prezhdo
- Departments of Chemistry, and Physics, and Astronomy, University of Southern California, Los Angeles, California90089, United States
| | - Run Long
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing100875, P. R. China
| | - Wei-Hai Fang
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, Beijing Normal University, Beijing100875, P. R. China
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3
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Tang Y, Ejlli B, Niu K, Li X, Hao Z, Xu C, Zhang H, Rominger F, Freudenberg J, Bunz UHF, Muellen K, Chi L. On‐Surface Debromination of 2,3‐Bis(dibromomethyl)‐ and 2,3‐Bis(bromomethyl)naphthalene: Dimerization or Polymerization? Angew Chem Int Ed Engl 2022; 61:e202204123. [PMID: 35474405 PMCID: PMC9401070 DOI: 10.1002/anie.202204123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Indexed: 11/11/2022]
Affiliation(s)
- Yanning Tang
- Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices Joint International Research Laboratory of Carbon-Based Functional Materials and Devices Soochow University Ren'ai road No. 199 Suzhou Jiangsu 215123 China
| | - Barbara Ejlli
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
- Organisch Chemisches Institut Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Kaifeng Niu
- Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices Joint International Research Laboratory of Carbon-Based Functional Materials and Devices Soochow University Ren'ai road No. 199 Suzhou Jiangsu 215123 China
| | - Xuechao Li
- Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices Joint International Research Laboratory of Carbon-Based Functional Materials and Devices Soochow University Ren'ai road No. 199 Suzhou Jiangsu 215123 China
| | - Zhengming Hao
- Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices Joint International Research Laboratory of Carbon-Based Functional Materials and Devices Soochow University Ren'ai road No. 199 Suzhou Jiangsu 215123 China
| | - Chaojie Xu
- Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices Joint International Research Laboratory of Carbon-Based Functional Materials and Devices Soochow University Ren'ai road No. 199 Suzhou Jiangsu 215123 China
| | - Haiming Zhang
- Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices Joint International Research Laboratory of Carbon-Based Functional Materials and Devices Soochow University Ren'ai road No. 199 Suzhou Jiangsu 215123 China
| | - Frank Rominger
- Organisch Chemisches Institut Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Jan Freudenberg
- Organisch Chemisches Institut Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Uwe H. F. Bunz
- Organisch Chemisches Institut Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Klaus Muellen
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
| | - Lifeng Chi
- Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices Joint International Research Laboratory of Carbon-Based Functional Materials and Devices Soochow University Ren'ai road No. 199 Suzhou Jiangsu 215123 China
- Macao Institute of Materials Science and Engineering (MIMSE) MUST-SUDA Joint Research Center for Advanced Functional Materials Macau University of Science and Technology Taipa 999078 Macao China
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4
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Tang Y, Ejlli B, Niu K, Li X, Hao Z, Xu C, Zhang H, Rominger F, Freudenberg J, Bunz UHF, Muellen K, Chi L. On‐Surface Debromination of 2,3‐Bis(dibromomethyl)‐ and 2,3‐Bis(bromomethyl)naphthalene: Dimerization or Polymerization? Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202204123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Yanning Tang
- Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices Joint International Research Laboratory of Carbon-Based Functional Materials and Devices Soochow University Ren'ai road No. 199 Suzhou Jiangsu 215123 China
| | - Barbara Ejlli
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
- Organisch Chemisches Institut Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Kaifeng Niu
- Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices Joint International Research Laboratory of Carbon-Based Functional Materials and Devices Soochow University Ren'ai road No. 199 Suzhou Jiangsu 215123 China
| | - Xuechao Li
- Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices Joint International Research Laboratory of Carbon-Based Functional Materials and Devices Soochow University Ren'ai road No. 199 Suzhou Jiangsu 215123 China
| | - Zhengming Hao
- Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices Joint International Research Laboratory of Carbon-Based Functional Materials and Devices Soochow University Ren'ai road No. 199 Suzhou Jiangsu 215123 China
| | - Chaojie Xu
- Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices Joint International Research Laboratory of Carbon-Based Functional Materials and Devices Soochow University Ren'ai road No. 199 Suzhou Jiangsu 215123 China
| | - Haiming Zhang
- Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices Joint International Research Laboratory of Carbon-Based Functional Materials and Devices Soochow University Ren'ai road No. 199 Suzhou Jiangsu 215123 China
| | - Frank Rominger
- Organisch Chemisches Institut Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Jan Freudenberg
- Organisch Chemisches Institut Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Uwe H. F. Bunz
- Organisch Chemisches Institut Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Klaus Muellen
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
| | - Lifeng Chi
- Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices Joint International Research Laboratory of Carbon-Based Functional Materials and Devices Soochow University Ren'ai road No. 199 Suzhou Jiangsu 215123 China
- Macao Institute of Materials Science and Engineering (MIMSE) MUST-SUDA Joint Research Center for Advanced Functional Materials Macau University of Science and Technology Taipa 999078 Macao China
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5
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Liu C, Zheng Y, Sanche L. Damage Induced to DNA and Its Constituents by 0-3 eV UV Photoelectrons †. Photochem Photobiol 2021; 98:546-563. [PMID: 34767635 DOI: 10.1111/php.13559] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 11/07/2021] [Indexed: 11/28/2022]
Abstract
The complex physical and chemical interactions between DNA and 0-3 eV electrons released by UV photoionization can lead to the formation of various lesions such as base modifications and cleavage, crosslinks and single strand breaks. Furthermore, in the presence of platinum chemotherapeutic agents, these electrons can cause clustered lesions, including double strand breaks. We explain the mechanisms responsible for these damages via the production 0-3 eV electrons by UVC radiation, and by UV photons of any wavelengths, when they are produced by photoemission from nanoparticles lying within about 10 nm from DNA. We review experimental evidence showing that a single 0-3 eV electron can produce these damages. The foreseen benefits UV-irradiation of nanoparticles targeted to the cell nucleus are mentioned in the context of cancer therapy, as well as the potential hazards to human health when they are present in cells.
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Affiliation(s)
- Chaochao Liu
- State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou, China
| | - Yi Zheng
- State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou, China
| | - Léon Sanche
- Département de Médecine Nucléaire et Radiobiologie et Centre de Recherche Clinique, Faculté de Médecine, Université de Sherbrooke, Sherbrooke, QC, Canada
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6
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Dong Y, Wang Y, Zhuang P, Fu X, Zheng Y, Sanche L. Role of Transient Anions in Chemoradiation Therapy: Base Modifications, Cross-Links, and Cluster Damages Induced to Cisplatin-DNA Complexes by 1–20 eV Electrons. J Phys Chem B 2020; 124:3315-3325. [DOI: 10.1021/acs.jpcb.0c00946] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Yanfang Dong
- State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350116, P.R. China
| | - Yaxiao Wang
- State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350116, P.R. China
| | - Puxiang Zhuang
- State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350116, P.R. China
| | - Xianzhi Fu
- State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350116, P.R. China
| | - Yi Zheng
- State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350116, P.R. China
| | - Léon Sanche
- Department of Nuclear Medicine and Radiobiology and Clinical Research Center, Faculty of Medicine, Université de Sherbrooke, Sherbrooke, QC, Canada J1H 5N4
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7
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Chu W, Zheng Q, Prezhdo OV, Zhao J. CO2 Photoreduction on Metal Oxide Surface Is Driven by Transient Capture of Hot Electrons: Ab Initio Quantum Dynamics Simulation. J Am Chem Soc 2020; 142:3214-3221. [DOI: 10.1021/jacs.9b13280] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Weibin Chu
- ICQD/Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Department of Chemistry and Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States
| | - Qijing Zheng
- ICQD/Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Oleg V. Prezhdo
- Department of Chemistry and Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States
| | - Jin Zhao
- ICQD/Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
- Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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8
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Anggara K, Leung L, Timm MJ, Hu Z, Polanyi JC. Electron-induced molecular dissociation at a surface leads to reactive collisions at selected impact parameters. Faraday Discuss 2019; 214:89-103. [DOI: 10.1039/c8fd00137e] [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
A collimated beam of ‘projectiles’ strikes a chemisorbed ‘target’ thereby selecting the impact parameter, achieving an elusive goal of reaction dynamics.
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Affiliation(s)
- Kelvin Anggara
- Lash Miller Chemical Laboratories
- Department of Chemistry and Institute of Optical Sciences
- University of Toronto
- Toronto
- Canada
| | - Lydie Leung
- Lash Miller Chemical Laboratories
- Department of Chemistry and Institute of Optical Sciences
- University of Toronto
- Toronto
- Canada
| | - Matthew J. Timm
- Lash Miller Chemical Laboratories
- Department of Chemistry and Institute of Optical Sciences
- University of Toronto
- Toronto
- Canada
| | - Zhixin Hu
- Center for Joint Quantum Studies and Department of Physics
- Tianjin University
- Tianjin
- China
| | - John C. Polanyi
- Lash Miller Chemical Laboratories
- Department of Chemistry and Institute of Optical Sciences
- University of Toronto
- Toronto
- Canada
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9
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Anggara K, Leung L, Timm MJ, Hu Z, Polanyi JC. Approaching the forbidden fruit of reaction dynamics: Aiming reagent at selected impact parameters. SCIENCE ADVANCES 2018; 4:eaau2821. [PMID: 30310869 PMCID: PMC6173530 DOI: 10.1126/sciadv.aau2821] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 08/30/2018] [Indexed: 06/08/2023]
Abstract
Collision geometry is central to reaction dynamics. An important variable in collision geometry is the miss-distance between molecules, known as the "impact parameter." This is averaged in gas-phase molecular beam studies. By aligning molecules on a surface prior to electron-induced dissociation, we select impact parameters in subsequent inelastic collisions. Surface-collimated "projectile" molecules, difluorocarbene (CF2), were aimed at stationary "target" molecules characterized by scanning tunneling microscopy (STM), with the observed scattering interpreted by computational molecular dynamics. Selection of impact parameters showed that head-on collisions favored bimolecular reaction, whereas glancing collisions led only to momentum transfer. These collimated projectiles could be aimed at the wide variety of adsorbed targets identifiable by STM, with the selected impact parameter assisting in the identification of the collision geometry required for reaction.
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10
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Davis D, Kundu S, Prabhudesai VS, Sajeev Y, Krishnakumar E. Formation of CO2 from formic acid through catalytic electron channel. J Chem Phys 2018; 149:064308. [DOI: 10.1063/1.5032172] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Affiliation(s)
- Daly Davis
- Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Mumbai 400005, India
| | - Sramana Kundu
- Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Mumbai 400005, India
| | - Vaibhav S. Prabhudesai
- Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Mumbai 400005, India
| | - Y. Sajeev
- Theoretical Chemistry, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - E. Krishnakumar
- Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Mumbai 400005, India
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11
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Anggara K, Huang K, Leung L, Chatterjee A, Cheng F, Polanyi JC. Bond selectivity in electron-induced reaction due to directed recoil on an anisotropic substrate. Nat Commun 2016; 7:13690. [PMID: 27934861 PMCID: PMC5476794 DOI: 10.1038/ncomms13690] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 10/25/2016] [Indexed: 11/09/2022] Open
Abstract
Bond-selective reaction is central to heterogeneous catalysis. In heterogeneous catalysis, selectivity is found to depend on the chemical nature and morphology of the substrate. Here, however, we show a high degree of bond selectivity dependent only on adsorbate bond alignment. The system studied is the electron-induced reaction of meta-diiodobenzene physisorbed on Cu(110). Of the adsorbate's C-I bonds, C-I aligned 'Along' the copper row dissociates in 99.3% of the cases giving surface reaction, whereas C-I bond aligned 'Across' the rows dissociates in only 0.7% of the cases. A two-electronic-state molecular dynamics model attributes reaction to an initial transition to a repulsive state of an Along C-I, followed by directed recoil of C towards a Cu atom of the same row, forming C-Cu. A similar impulse on an Across C-I gives directed C that, moving across rows, does not encounter a Cu atom and hence exhibits markedly less reaction.
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Affiliation(s)
- Kelvin Anggara
- Lash Miller Chemical Laboratories, Department of Chemistry and Institute of Optical Sciences, University of Toronto, 80 St George Street, Toronto, Ontario M5S 3H6, Canada
| | - Kai Huang
- Lash Miller Chemical Laboratories, Department of Chemistry and Institute of Optical Sciences, University of Toronto, 80 St George Street, Toronto, Ontario M5S 3H6, Canada
| | - Lydie Leung
- Lash Miller Chemical Laboratories, Department of Chemistry and Institute of Optical Sciences, University of Toronto, 80 St George Street, Toronto, Ontario M5S 3H6, Canada
| | - Avisek Chatterjee
- Lash Miller Chemical Laboratories, Department of Chemistry and Institute of Optical Sciences, University of Toronto, 80 St George Street, Toronto, Ontario M5S 3H6, Canada
| | - Fang Cheng
- Lash Miller Chemical Laboratories, Department of Chemistry and Institute of Optical Sciences, University of Toronto, 80 St George Street, Toronto, Ontario M5S 3H6, Canada
| | - John C Polanyi
- Lash Miller Chemical Laboratories, Department of Chemistry and Institute of Optical Sciences, University of Toronto, 80 St George Street, Toronto, Ontario M5S 3H6, Canada
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12
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Cheng F, Leung L, Wang CG, Ji W, Polanyi JC. Retention of chirality in electron-induced reactions. Chem Commun (Camb) 2016; 52:6115-8. [PMID: 27073075 DOI: 10.1039/c6cc00849f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two enantiomers were observed by Scanning Tunneling Microscopy (STM) when meta-iodopyridine was physisorbed on a 4.6 K Cu(110) surface. The chirality of the reagent was retained in the products of the electron-induced reaction. Dynamical calculations showed this to be a consequence of the reaction occurring on one side of the mirror plane.
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Affiliation(s)
- Fang Cheng
- Lash Miller Chemical Laboratories, Department of Chemistry and Institute of Optical Sciences, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
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13
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Lock D, Rusimova KR, Pan TL, Palmer RE, Sloan PA. Atomically resolved real-space imaging of hot electron dynamics. Nat Commun 2015; 6:8365. [PMID: 26387703 PMCID: PMC4595757 DOI: 10.1038/ncomms9365] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 08/10/2015] [Indexed: 11/24/2022] Open
Abstract
The dynamics of hot electrons are central to understanding the properties of many electronic devices. But their ultra-short lifetime, typically 100 fs or less, and correspondingly short transport length-scale in the nanometre range constrain real-space investigations. Here we report variable temperature and voltage measurements of the nonlocal manipulation of adsorbed molecules on the Si(111)-7 × 7 surface in the scanning tunnelling microscope. The range of the nonlocal effect increases with temperature and, at constant temperature, is invariant over a wide range of electron energies. The measurements probe, in real space, the underlying hot electron dynamics on the 10 nm scale and are well described by a two-dimensional diffusive model with a single decay channel, consistent with 2-photon photo-emission (2PPE) measurements of the real time dynamics.
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Affiliation(s)
- D. Lock
- Department of Physics, University of Bath, Bath, BA2 7AY, UK
| | - K. R. Rusimova
- Department of Physics, University of Bath, Bath, BA2 7AY, UK
| | - T. L. Pan
- Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT, UK
| | - R. E. Palmer
- Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT, UK
| | - P. A. Sloan
- Department of Physics, University of Bath, Bath, BA2 7AY, UK
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14
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Huang K, Leung L, Lim T, Ning Z, Polanyi JC. Vibrational excitation induces double reaction. ACS NANO 2014; 8:12468-12475. [PMID: 25489788 DOI: 10.1021/nn5053074] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Electron-induced reaction at metal surfaces is currently the subject of extensive study. Here, we broaden the range of experimentation to a comparison of vibrational excitation with electronic excitation, for reaction of the same molecule at the same clean metal surface. In a previous study of electron-induced reaction by scanning tunneling microscopy (STM), we examined the dynamics of the concurrent breaking of the two C-I bonds of ortho-diiodobenzene physisorbed on Cu(110). The energy of the incident electron was near the electronic excitation threshold of E0=1.0 eV required to induce this single-electron process. STM has been employed in the present work to study the reaction dynamics at the substantially lower incident electron energies of 0.3 eV, well below the electronic excitation threshold. The observed increase in reaction rate with current was found to be fourth-order, indicative of multistep reagent vibrational excitation, in contrast to the first-order rate dependence found earlier for electronic excitation. The change in mode of excitation was accompanied by altered reaction dynamics, evidenced by a different pattern of binding of the chemisorbed products to the copper surface. We have modeled these altered reaction dynamics by exciting normal modes of vibration that distort the C-I bonds of the physisorbed reagent. Using the same ab initio ground potential-energy surface as in the prior work on electronic excitation, but with only vibrational excitation of the physisorbed reagent in the asymmetric stretch mode of C-I bonds, we obtained the observed alteration in reaction dynamics.
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Affiliation(s)
- Kai Huang
- Lash Miller Chemical Laboratories, Department of Chemistry and Institute of Optical Sciences, University of Toronto , 80 St. George Street, Toronto, Ontario M5S SH6, Canada
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15
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Cheng F, Ji W, Leung L, Ning Z, Polanyi JC, Wang CG. How adsorbate alignment leads to selective reaction. ACS NANO 2014; 8:8669-8675. [PMID: 25102432 DOI: 10.1021/nn503721h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
There has been much interest in the effect of adsorbate alignment in a surface reaction. Here we show its significance for an electron-induced reaction occurring along preferred axes of the asymmetric Cu(110) surface, characterized by directional copper rows. By scanning tunneling microscopy (STM), we found that the heterocyclic aromatic reagent, physisorbed meta-iodopyridine, lay with its carbon-iodine either along the rows of Cu(110), "A", or perpendicular, "P". Electron-induced dissociative attachment with the C-I bond initially along "A" gave a chemisorbed I atom and chemisorbed vertical pyridyl, singly surface-bound, whereas that with C-I along "P" gave a chemisorbed I atom and a horizontal pyridyl, doubly bound. An impulsive two-state model, involving a short-lived antibonding state of C-I, accounted for the different product surface binding in terms of closer Cu···Cu atomic spacing along "A" accommodating only one binding site of the pyridyl ring recoiling from I and wider spacing along "P" accommodating simultaneously both binding sites, N-Cu and C-Cu, in the meta-position on the recoiling pyridyl ring. STM studies combined with dynamical modeling can be seen as a way to improve understanding of the role of surface alignment in determining reactive outcomes in induced reaction at asymmetric crystalline surfaces.
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Affiliation(s)
- Fang Cheng
- Lash Miller Chemical Laboratories, Department of Chemistry and Institute of Optical Sciences, University of Toronto , Toronto, Ontario M5S 3H6, Canada
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Bao Q, Chen Y, Zheng Y, Sanche L. Cisplatin Radiosensitization of DNA Irradiated with 2-20 eV Electrons: Role of Transient Anions. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2014; 118:15516-15524. [PMID: 26793285 PMCID: PMC4716812 DOI: 10.1021/jp503706h] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Platinum chemotherapeutic agents, such as cisplatin (cis-diamminedichloroplatinum(II)), can act as radiosensitizers when bound covalently to nuclear DNA in cancer cells. This radiosensitization is largely due to an increase in DNA damage induced by low-energy secondary electrons, produced in large quantities by high-energy radiation. We report the yields of single- and double-strand breaks (SSB and DSB) and interduplex cross-links (CL) induced by electrons of 1.6-19.6 eV (i.e., the yield functions) incident on 5 monolayer (ML) films of cisplatin-DNA complexes. These yield functions are compared with those previously recorded with 5 ML films of unmodified plasmid DNA. Binding of five cisplatin molecules to plasmid DNA (3197 base pairs) enhances SSB, DSB, and CL by factors varying, from 1.2 to 2.8, 1.4 to 3.5, and 1.2 to 2.7, respectively, depending on electron energy. All yield functions exhibit structures around 5 and 10 eV that can be attributed to enhancement of bond scission, via the initial formation of core-excited resonances associated with π → π* transitions of the bases. This increase in damage is interpreted as arising from a modification of the parameters of the corresponding transient anions already present in nonmodified DNA, particularly those influencing molecular dissociation. Two additional resonances, specific to cisplatin-modified DNA, are formed at 13.6 and 17.6 eV in the yield function of SSB. Furthermore, cisplatin binding causes the induction of DSB by electrons of 1.6-3.6 eV, i.e., in an energy region where a DSB cannot be produced by a single electron in pure DNA. Breaking two bonds with a subexcitation-energy electron is tentatively explained by a charge delocalization mechanism, where a single electron occupies simultaneously two σ* bonds linking the Pt atom to guanine bases on opposite strands.
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Affiliation(s)
- Qianhong Bao
- Research Institute of Photocatalysis, State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350002, P. R. China
| | - Yunfeng Chen
- Research Institute of Photocatalysis, State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350002, P. R. China
| | - Yi Zheng
- Research Institute of Photocatalysis, State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350002, P. R. China
| | - Léon Sanche
- Group in the Radiation Sciences, Faculty of Medicine, Université de Sherbrooke, Sherbrooke, QC, Canada J1H 5N4
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Rezaee M, Alizadeh E, Cloutier P, Hunting DJ, Sanche L. A single subexcitation-energy electron can induce a double-strand break in DNA modified by platinum chemotherapeutic drugs. ChemMedChem 2013; 9:1145-9. [PMID: 24376113 DOI: 10.1002/cmdc.201300462] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Indexed: 11/08/2022]
Abstract
The sensitization of malignant cells to ionizing radiation is the clinical rationale for the use of platinum-drug-based concurrent chemoradiotherapy (CCRT) for cancer treatment; however, the specific mechanisms of radiosensitization and their respective contributions still remain unknown. Biological mechanisms such as inhibition of DNA repair may contribute to the efficacy of CCRT; nevertheless, there is a dearth of information on the possible contribution of nanoscopic mechanisms to the generation of lethal DNA lesions, such as double-strand breaks (DSB). The present study demonstrates that the abundant near zero-eV (0.5 eV) electrons, created by ionizing radiation during radiotherapy, induce DSB in supercoiled plasmid DNA modified by platinum-containing anticancer drugs (Pt drugs), but not in unmodified DNA. They do so more efficiently than other types of radiation, including soft X-rays and 10 eV electrons. The formation of DSB by 0.5 eV electrons is found to be a single-hit process. These findings reveal insights into the radiosensitization mechanism of Pt drugs that can have implications for the development of optimal clinical protocols for platinum-based CCRT and the deployment of in situ sources of subexcitation-energy electrons (e.g., Auger electron-emitting radionuclides) to efficiently enhance DSB formation in DNA modified by Pt drugs in malignant cells.
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Affiliation(s)
- Mohammad Rezaee
- Department of Nuclear Medicine & Radiobiology, Faculty of Medicine & Health Sciences, University of Sherbrooke, 3001, 12e Ave. Nord, Sherbrooke, QC, J1H 5N4 (Canada).
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da Silva FF, Matias C, Almeida D, García G, Ingólfsson O, Flosadóttir HD, Ómarsson B, Ptasinska S, Puschnigg B, Scheier P, Limão-Vieira P, Denifl S. NCO(-), a key fragment upon dissociative electron attachment and electron transfer to pyrimidine bases: site selectivity for a slow decay process. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2013; 24:1787-97. [PMID: 24043519 DOI: 10.1007/s13361-013-0715-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 06/26/2013] [Accepted: 06/27/2013] [Indexed: 05/25/2023]
Abstract
We report gas phase studies on NCO(-) fragment formation from the nucleobases thymine and uracil and their N-site methylated derivatives upon dissociative electron attachment (DEA) and through electron transfer in potassium collisions. For comparison, the NCO(-) production in metastable decay of the nucleobases after deprotonation in matrix assisted laser desorption/ionization (MALDI) is also reported. We show that the delayed fragmentation of the dehydrogenated closed-shell anion into NCO(-) upon DEA proceeds few microseconds after the electron attachment process, indicating a rather slow unimolecular decomposition. Utilizing partially methylated thymine, we demonstrate that the remarkable site selectivity of the initial hydrogen loss as a function of the electron energy is preserved in the prompt as well as the metastable NCO(-) formation in DEA. Site selectivity in the NCO(-) yield is also pronounced after deprotonation in MALDI, though distinctly different from that observed in DEA. This is discussed in terms of the different electronic states subjected to metastable decay in these experiments. In potassium collisions with 1- and 3-methylthymine and 1- and 3-methyluracil, the dominant fragment is the NCO(-) ion and the branching ratios as a function of the collision energy show evidence of extraordinary site-selectivity in the reactions yielding its formation.
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Affiliation(s)
- Filipe Ferreira da Silva
- Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516, Caparica, Portugal
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Ning Z, Polanyi JC. Catalyzed Surface-Aligned Reaction, H(ad) + H2(ad) = H2(g) + H(ad) on Coinage Metals. Z PHYS CHEM 2013. [DOI: 10.1524/zpch.2013.0413] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Huang K, Leung L, Lim T, Ning Z, Polanyi JC. Single-electron induces double-reaction by charge delocalization. J Am Chem Soc 2013; 135:6220-5. [PMID: 23582020 DOI: 10.1021/ja400612c] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Injecting an electron by scanning tunneling microscope into a molecule physisorbed at a surface can induce dissociative reaction of one adsorbate bond. Here we show experimentally that a single low-energy electron incident on ortho-diiodobenzene physisorbed on Cu(110) preferentially induces reaction of both of the C-I bonds in the adsorbate, with an order-of-magnitude greater efficiency than for comparable cases of single bond breaking. A two-electronic-state model was used to follow the dynamics, first on an anionic potential-energy surface (pes*) and subsequently on the ground state pes. The model led to the conclusion that the two-bond reaction was due to the delocalization of added charge between adjacent halogen-atoms of ortho-diiodobenzene through overlapping antibonding orbitals, in contrast to the cases of para-dihalobenzenes, studied earlier, for which electron-induced reaction severed exclusively a single carbon-halogen bond. The finding that charge delocalization within a single molecule can readily cause concerted two-bond breaking suggests the more general possibility of intra- and also intermolecular charge delocalization resulting in multisite reaction. Intermolecular charge delocalization has recently been proposed by this laboratory to account for reaction in physisorbed molecular chains (Ning, Z.; Polanyi, J. C. Angew. Chem., Int. Ed. 2013, 52, 320-324).
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Affiliation(s)
- Kai Huang
- Lash Miller Chemical Laboratories, Department of Chemistry and Institute of Optical Sciences, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6 Canada
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