1
|
Bird MJ, Cook AR, Zamadar M, Asaoka S, Miller JR. Pushing the limits of the electrochemical window with pulse radiolysis in chloroform. Phys Chem Chem Phys 2020; 22:14660-14670. [PMID: 32573579 DOI: 10.1039/d0cp01948h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Pulse radiolysis (PR) enables the full redox window of a solvent to be accessed, as it does not require electrodes or electrolyte which limit the potentials accessible in voltammetry measurements. PR in chloroform has the additional possibility to enable reaching highly positive potentials because of its large ionization potential (IP). PR experiments demonstrated the formation of the (deuterated) chloroform radical cation CDCl3+˙, identifying it as the source of the broad absorption in the visible part of the spectrum. Results indicated that solutes with a redox potential up to +3.7 V vs. Fc/Fc+ can be oxidized by CDCl3+˙, which is far beyond what is possible with electrochemical techniques. Oxidation is not efficient because of rapid geminate recombination with chloride counterions, but also due to rapid decomposition of CDCl3+˙ which limits the yield of otherwise longer-lived free ions. The rapid, 6 ± 3 ns, decomposition, confirmed by two independent experiments, means that a solute must be present at a concentration >100 mM to capture >90% of the free holes formed. Addition of ethene removes the broad, overlapping absorptions from ubiquitous (chlorine atom, solute) complexes created by PR in halogenated solvents enabling clear observation of solute cations. The results also unravel the complex radiation chemistry of chloroform including the large reported value G(-CHCl3) = 12 molecules/100 eV for the decomposition of chloroform molecules.
Collapse
Affiliation(s)
- Matthew J Bird
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11793, USA.
| | - Andrew R Cook
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11793, USA.
| | - Matibur Zamadar
- Department of Chemistry and Biochemistry, Stephen F. Austin State University, Nacogdoches, Texas 75962-3006, USA
| | - Sadayuki Asaoka
- Department of Biomolecular Engineering, Kyoto Institute of Technology, Matsugaskaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - John R Miller
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11793, USA.
| |
Collapse
|
2
|
Pavliuk MV, Gutiérrez Álvarez S, Hattori Y, Messing ME, Czapla-Masztafiak J, Szlachetko J, Silva JL, Araujo CM, A Fernandes DL, Lu L, Kiely CJ, Abdellah M, Nordlander P, Sá J. Hydrated Electron Generation by Excitation of Copper Localized Surface Plasmon Resonance. J Phys Chem Lett 2019; 10:1743-1749. [PMID: 30920838 DOI: 10.1021/acs.jpclett.9b00792] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Hydrated electrons are important in radiation chemistry and charge-transfer reactions, with applications that include chemical damage of DNA, catalysis, and signaling. Conventionally, hydrated electrons are produced by pulsed radiolysis, sonolysis, two-ultraviolet-photon laser excitation of liquid water, or photodetachment of suitable electron donors. Here we report a method for the generation of hydrated electrons via single-visible-photon excitation of localized surface plasmon resonances (LSPRs) of supported sub-3 nm copper nanoparticles in contact with water. Only excitations at the LSPR maximum resulted in the formation of hydrated electrons, suggesting that plasmon excitation plays a crucial role in promoting electron transfer from the nanoparticle into the solution. The reactivity of the hydrated electrons was confirmed via proton reduction and concomitant H2 evolution in the presence of a Ru/TiO2 catalyst.
Collapse
Affiliation(s)
- Mariia V Pavliuk
- Physical Chemistry Division, Department of Chemistry, Ångström Laboratory , Uppsala University , 75120 Uppsala , Sweden
| | - Sol Gutiérrez Álvarez
- Physical Chemistry Division, Department of Chemistry, Ångström Laboratory , Uppsala University , 75120 Uppsala , Sweden
| | - Yocefu Hattori
- Physical Chemistry Division, Department of Chemistry, Ångström Laboratory , Uppsala University , 75120 Uppsala , Sweden
| | - Maria E Messing
- Solid State Physics and NanoLund , Lund University , Box 118, 22100 Lund , Sweden
| | | | - Jakub Szlachetko
- Institute of Nuclear Physics , Polish Academy of Sciences , PL-31342 Krakow , Poland
- Institute of Physical Chemistry , Polish Academy of Sciences , 01-224 Warsaw , Poland
| | - Jose L Silva
- Materials Theory Division, Department of Physics and Astronomy , Uppsala University , 75120 Uppsala , Sweden
| | - Carlos Moyses Araujo
- Materials Theory Division, Department of Physics and Astronomy , Uppsala University , 75120 Uppsala , Sweden
| | - Daniel L A Fernandes
- Physical Chemistry Division, Department of Chemistry, Ångström Laboratory , Uppsala University , 75120 Uppsala , Sweden
| | - Li Lu
- Department of Materials Science and Engineering , Lehigh University , 5 East Packer Avenue , Bethlehem , Pennsylvania 18015 , United States
| | - Christopher J Kiely
- Department of Materials Science and Engineering , Lehigh University , 5 East Packer Avenue , Bethlehem , Pennsylvania 18015 , United States
| | - Mohamed Abdellah
- Physical Chemistry Division, Department of Chemistry, Ångström Laboratory , Uppsala University , 75120 Uppsala , Sweden
- Department of Chemistry, Qena Faculty of Science , South Valley University , 83523 Qena , Egypt
| | - Peter Nordlander
- Department of Physics , Rice University , 6100 South Main Street , Houston , Texas 77251-1892 , United States
| | - Jacinto Sá
- Physical Chemistry Division, Department of Chemistry, Ångström Laboratory , Uppsala University , 75120 Uppsala , Sweden
- Institute of Physical Chemistry , Polish Academy of Sciences , 01-224 Warsaw , Poland
| |
Collapse
|
3
|
Rivas N, Sciaini G, Marceca E. Static and dynamic scavenging of ammoniated electrons by nitromethane. Phys Chem Chem Phys 2019; 21:21972-21978. [DOI: 10.1039/c9cp03342d] [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
We studied the time-resolved scavenging efficiency of nitromethane for transient electron species in liquid ammonia, at a temperature of 298 K.
Collapse
Affiliation(s)
- Nicolás Rivas
- The Ultrafast Electron Imaging Lab
- Department of Chemistry and Waterloo Institute for Nanotechnology
- University of Waterloo
- Waterloo
- Canada
| | - Germán Sciaini
- The Ultrafast Electron Imaging Lab
- Department of Chemistry and Waterloo Institute for Nanotechnology
- University of Waterloo
- Waterloo
- Canada
| | - Ernesto Marceca
- Department of Inorganic
- Analytical and Physical Chemistry-FCEN
- Universidad de Buenos Aires and INQUIMAE-CONICET. Cdad. Universitaria
- Buenos Aires C1428EGA
- Argentina
| |
Collapse
|
4
|
Pshenichnyuk SA, Modelli A, Komolov AS. Interconnections between dissociative electron attachment and electron-driven biological processes. INT REV PHYS CHEM 2018. [DOI: 10.1080/0144235x.2018.1461347] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Stanislav A. Pshenichnyuk
- Institute of Molecule and Crystal Physics – Subdivision of the Ufa Research Centre of the Russian Academy of Sciences, Ufa, Russia
| | - Alberto Modelli
- Dipartimento di Chimica ‘G. Ciamician’, Università di Bologna, Bologna, Italy
- Centro Interdipartimentale di Ricerca in Scienze Ambientali, Ravenna, Italy
| | - Alexei S. Komolov
- Department of Solid State Electronics, St. Petersburg State University, St. Petersburg, Russia
| |
Collapse
|
5
|
Li Z, Milosavljević AR, Carmichael I, Ptasinska S. Characterization of Neutral Radicals from a Dissociative Electron Attachment Process. PHYSICAL REVIEW LETTERS 2017; 119:053402. [PMID: 28949760 DOI: 10.1103/physrevlett.119.053402] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Indexed: 05/25/2023]
Abstract
Despite decades of gas-phase studies on dissociative electron attachment (DEA) to various molecules, as yet there has been no direct detection and characterization of the neutral radical species produced by this process. In this study, we performed stepwise electron spectroscopy to directly measure and characterize the neutrals produced upon zero-electron-energy DEA to the model molecule, carbon tetrachloride (CCl_{4}). We observed the direct yield of the trichloromethyl radical (CCl_{3}^{·}) formed by DEA to CCl_{4} and measured the appearance energies of all the other neutral species. By combining these experimental findings with high-level quantum chemical calculations, we performed a complete analysis of both the DEA to CCl_{4} and the subsequent electron-impact ionization of CCl_{3}^{·}. This work paves the way toward a complete experimental characterization of DEA processes, which will lead to a better understanding of the low-energy electron-induced formation of radical species.
Collapse
Affiliation(s)
- Zhou Li
- Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, USA
- Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Aleksandar R Milosavljević
- Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, USA
- SOLEIL, l'Orme des Merisiers, St. Aubin, BP48, 91192 Gif sur Yvette Cedex, France
| | - Ian Carmichael
- Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Sylwia Ptasinska
- Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, USA
- Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA
| |
Collapse
|
6
|
Lengyel J, van der Linde C, Fárník M, Beyer MK. The reaction of CF2Cl2 with gas-phase hydrated electrons. Phys Chem Chem Phys 2016; 18:23910-5. [PMID: 27523883 PMCID: PMC7116337 DOI: 10.1039/c6cp01976e] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The reaction of dichlorodifluoromethane (CF2Cl2) with hydrated electrons (H2O)n(-) (n = 30-86) in the gas phase was studied using Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. The hydrated electron reacts with CF2Cl2, forming (H2O)mCl(-) with a rate constant of (8.6 ± 2.2) × 10(-10) cm(3) s(-1), corresponding to an efficiency of 57 ± 15%. The reaction enthalpy was determined using nanocalorimetry, revealing a strongly exothermic reaction with ΔHr(CF2Cl2, 298 K) = -208 ± 41 kJ mol(-1). The combination of the measured reaction enthalpy with thermochemical data from the condensed phase yields a C-Cl bond dissociation enthalpy (BDE) ΔHC-Cl(CF2Cl2, 298 K) = 355 ± 41 kJ mol(-1) that agrees within error limits with the predicted values from quantum chemical calculations and published BDEs.
Collapse
Affiliation(s)
- Jozef Lengyel
- Institut für Ionenphysik und Angewandte Physik, Leopold-Franzens-Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Christian van der Linde
- Institut für Ionenphysik und Angewandte Physik, Leopold-Franzens-Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| | - Michal Fárník
- J. Heyrovský Institute of Physical Chemistry v.v.i., Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech Republic
| | - Martin K. Beyer
- Institut für Ionenphysik und Angewandte Physik, Leopold-Franzens-Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
| |
Collapse
|
7
|
Pshenichnyuk SA, Modelli A. Resonance electron attachment to plant hormones and its likely connection with biochemical processes. J Chem Phys 2015; 140:034313. [PMID: 25669385 DOI: 10.1063/1.4861497] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Gas-phase formation of temporary negative ion states via resonance attachment of low-energy (0-6 eV) electrons into vacant molecular orbitals of salicylic acid (I) and its derivatives 3-hydroxy- (II) and 4-hydroxybenzoic acid (III), 5-cloro salicylic acid (IV) and methyl salicylate (V) was investigated for the first time by electron transmission spectroscopy. The description of their empty-level structures was supported by density functional theory and Hartree-Fock calculations, using empirically calibrated linear equations to scale the calculated virtual orbital energies. Dissociative electron attachment spectroscopy (DEAS) was used to measure the fragment anion yields generated through dissociative decay channels of the parent molecular anions of compounds I-V, detected with a mass filter as a function of the incident electron energy in the 0-14 eV energy range. The most intense negative fragment produced by DEA to isomers I-III is the dehydrogenated molecular anion [M-H](-), mainly formed at incident electron energies around 1 eV. The vertical and adiabatic electron affinities were evaluated at the B3LYP/6-31+G(d) level as the anion/neutral total energy difference. The same theoretical method was also used for evaluation of the thermodynamic energy thresholds for production of the negative fragments observed in the DEA spectra. The gas-phase DEAS data can provide support for biochemical reaction mechanisms in vivo.
Collapse
Affiliation(s)
- Stanislav A Pshenichnyuk
- Institute of Molecule and Crystal Physics, Ufa Research Centre, Russian Academy of Sciences, Prospeκt Oktyabrya 151, 450075 Ufa, Russia
| | - Alberto Modelli
- Dipartimento di Chimica "G. Ciamician", Università di Bologna, via Selmi 2, 40126 Bologna, Italy and Centro Interdipartimentale di Ricerca in Scienze Ambientali, via S. Alberto 163, 48123 Ravenna, Italy
| |
Collapse
|
8
|
Modelli A, Pshenichnyuk SA. Gas-phase dissociative electron attachment to flavonoids and possible similarities to their metabolic pathways. Phys Chem Chem Phys 2013; 15:1588-600. [PMID: 23243660 DOI: 10.1039/c2cp43379f] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The gas-phase empty-level structures and formation of anion states via resonance attachment of low-energy electrons to the flavonoids naringenin (III), quercetin (IV) and myricetin (V) and the smaller reference molecules chromone (I) and flavone (II) are investigated experimentally for the first time. Dissociative electron attachment spectroscopy (DEAS) is used to measure the fragment anion currents generated through dissociative decay channels of the molecular anions of compounds I–V, detected with a mass filter as a function of the incident electron energy in the 0–14 eV energy range. Due to the insufficient volatility of flavonoids III–V, the energies of vertical electron attachment associated with temporary occupation of the lower-lying virtual orbitals are measured with electron transmission spectroscopy (ETS) only in the smaller reference molecules I and II. The experimental findings are interpreted with the support of appropriate density functional theory calculations with the B3LYP functional. The experimental vertical electron attachment energies measured in the ET spectra of I and II are compared with the orbital energies of the neutral molecules scaled using an empirically calibrated linear equation. The vertical and adiabatic electron affinities are evaluated at the B3LYP/6-31+G(d) level as the anion/neutral total energy difference. The latter theoretical method is also used for evaluation of the most stable conformers of the neutral molecules, O–H bond dissociation energies and thermodynamic energy thresholds for production of the anion fragments observed in the DEA spectra. A possible role played by loss of an H(2) molecule from the parent molecular anion in vivo in the mitochondrial respiratory chain is briefly discussed.
Collapse
Affiliation(s)
- Alberto Modelli
- Università di Bologna, Dipartimento di Chimica G. Ciamician, via, Selmi 2, 40126 Bologna, Italy.
| | | |
Collapse
|
9
|
Pshenichnyuk SA, Modelli A. Can mitochondrial dysfunction be initiated by dissociative electron attachment to xenobiotics? Phys Chem Chem Phys 2013; 15:9125-35. [PMID: 23646356 DOI: 10.1039/c3cp50614b] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Resonance attachment of low-energy electrons to xenobiotic molecules, 2,4-dichlorophenoxyacetic acid (2,4-D), dichlorodiphenyltrichloroethane (DDT) and dichlorodiphenyldichloroethylene (DDE), was investigated under gas-phase conditions by means of complementary experimental techniques. Electron transmission spectroscopy (ETS) and dissociative electron attachment spectroscopy (DEAS), in the 0-6 eV and 0-15 eV energy range, respectively, were applied with the aim of modeling the behavior of these pesticide molecules under reductive conditions in vivo. Formation of long-lived parent molecular anions and fragment negative ions was observed at incident electron energies very close to zero, in agreement with the results of density functional theory calculations. The gas-phase DEA process, analogous to dissociative electron transfer in solution, was considered as a model for the initial step which occurs in the intermembrane space of mitochondria when a xenobiotic molecule captures an electron "leaked" from the respiratory chain. A possible involvement of the fragments produced by DEA to the pesticides under investigation into cellular processes is discussed. It is concluded that the free radicals and potential DNA adducts formed by DEA are expected to be dangerous for mitochondrial functionalities, while several of the products observed could act as messenger molecules, thus interfering with the normal cellular signaling pathways.
Collapse
Affiliation(s)
- Stanislav A Pshenichnyuk
- Institute of Molecule and Crystal Physics, Ufa Research Centre, Russian Academy of Sciences, Ufa, Russia.
| | | |
Collapse
|
10
|
Affiliation(s)
- Bernd Abel
- Leibniz Institute of Surface Modification (IOM), Chemical Department, D-04318 Leipzig, Germany, and Wilhelm-Ostwald Institute for Physical and Theoretical Chemistry, D-04103 Leipzig, Germany;
| |
Collapse
|
11
|
Alizadeh E, Sanche L. Precursors of solvated electrons in radiobiological physics and chemistry. Chem Rev 2012; 112:5578-602. [PMID: 22724633 DOI: 10.1021/cr300063r] [Citation(s) in RCA: 225] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Elahe Alizadeh
- Groupe en Sciences des Radiations, Département de Médecine Nucléaire et Radiobiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Canada
| | | |
Collapse
|
12
|
Saeki A, Yamamoto N, Yoshida Y, Kozawa T. Geminate Charge Recombination in Liquid Alkane with Concentrated CCl4: Effects of CCl4 Radical Anion and Narrowing of Initial Distribution of Cl–. J Phys Chem A 2011; 115:10166-73. [DOI: 10.1021/jp205989r] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Akinori Saeki
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
| | - Naoto Yamamoto
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
| | - Yoichi Yoshida
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
| | - Takahiro Kozawa
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
| |
Collapse
|
13
|
Direct observation of ultrafast-electron-transfer reactions unravels high effectiveness of reductive DNA damage. Proc Natl Acad Sci U S A 2011; 108:11778-83. [PMID: 21730183 DOI: 10.1073/pnas.1104367108] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Both water and electron-transfer reactions play important roles in chemistry, physics, biology, and the environment. Oxidative DNA damage is a well-known mechanism, whereas the relative role of reductive DNA damage is unknown. The prehydrated electron (e(pre)-), a novel species of electrons in water, is a fascinating species due to its fundamental importance in chemistry, biology, and the environment. e(pre)- is an ideal agent to observe reductive DNA damage. Here, we report both the first in situ femtosecond time-resolved laser spectroscopy measurements of ultrafast-electron-transfer (UET) reactions of e(pre)- with various scavengers (KNO(3), isopropanol, and dimethyl sulfoxide) and the first gel electrophoresis measurements of DNA strand breaks induced by e(pre)- and OH(•) radicals co-produced by two-UV-photon photolysis of water. We strikingly found that the yield of reductive DNA strand breaks induced by each e(pre)- is twice the yield of oxidative DNA strand breaks induced by each OH(•) radical. Our results not only unravel the long-standing mystery about the relative role of radicals in inducing DNA damage under ionizing radiation, but also challenge the conventional notion that oxidative damage is the main pathway for DNA damage. The results also show the potential of femtomedicine as a new transdisciplinary frontier and the broad significance of UET reactions of e(pre)- in many processes in chemistry, physics, biology, and the environment.
Collapse
|
14
|
Siefermann KR, Abel B. The Hydrated Electron: A Seemingly Familiar Chemical and Biological Transient. Angew Chem Int Ed Engl 2011; 50:5264-72. [DOI: 10.1002/anie.201006521] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 02/15/2011] [Indexed: 11/05/2022]
|
15
|
Siefermann KR, Abel B. Das hydratisierte Elektron - eine scheinbar vertraute transiente Spezies in chemischen und biologischen Systemen. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201006521] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
16
|
Wang CR, Lu QB. Molecular Mechanism of the DNA Sequence Selectivity of 5-Halo-2′-Deoxyuridines as Potential Radiosensitizers. J Am Chem Soc 2010; 132:14710-3. [DOI: 10.1021/ja102883a] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Chun-Rong Wang
- Department of Physics and Astronomy and Departments of Biology and Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1
| | - Qing-Bin Lu
- Department of Physics and Astronomy and Departments of Biology and Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1
| |
Collapse
|
17
|
Binding energies, lifetimes and implications of bulk and interface solvated electrons in water. Nat Chem 2010; 2:274-9. [PMID: 21124507 DOI: 10.1038/nchem.580] [Citation(s) in RCA: 251] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Accepted: 01/26/2010] [Indexed: 01/14/2023]
Abstract
Solvated electrons in liquid water are one of the seemingly simplest, but most important, transients in chemistry and biology, but they have resisted disclosing important information about their energetics, binding motifs and dynamics. Here we report the first ultrafast liquid-jet photoelectron spectroscopy measurements of solvated electrons in liquid water. The results prove unequivocally the existence of solvated electrons bound at the water surface and of solvated electrons in the bulk solution, with vertical binding energies of 1.6 eV and 3.3 eV, respectively, and with lifetimes longer than 100 ps. The unexpectedly long lifetime of solvated electrons bound at the water surface is attributed to a free-energy barrier that separates surface and interior states. Beyond constituting important energetic and kinetic benchmark and reference data, the results also help to understand the mechanisms of a number of very efficient electron-transfer processes in nature.
Collapse
|
18
|
Wang CR, Nguyen J, Lu QB. Bond breaks of nucleotides by dissociative electron transfer of nonequilibrium prehydrated electrons: a new molecular mechanism for reductive DNA damage. J Am Chem Soc 2009; 131:11320-2. [PMID: 19634911 DOI: 10.1021/ja902675g] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
DNA damage is a central mechanism in the pathogenesis and treatment of human diseases, notably cancer. Little is known about reductive DNA damage in causing genetic mutations during oncogenesis and killing cancer cells during radiotherapy. The prehydrated electron (e(-)(pre)) has the highest yield among all the radicals generated in cells during ionizing radiation and has subpicosecond lifetimes (10(-13) s) and energies below 0 eV, but its role in DNA damage is unknown. In this work, our real-time measurements by femtosecond time-resolved laser spectroscopy have revealed that while adenine and cytosine can effectively trap an e(-)(pre) to form stable anions, thymidine and especially guanine are highly susceptible to dissociative electron transfer of e(-)(pre), leading to bond dissociation in DNA. Our finding demonstrates a dissociative electron transfer pathway for reductive DNA damage that might be related to various diseases such as cancer and stroke. Moreover, this finding challenges the conventional notion that damage to the genome is mainly induced by the oxidizing OH* radical and might eventually lead to improved radiotherapy of cancer and radioprotection of humans.
Collapse
Affiliation(s)
- Chun-Rong Wang
- Department of Physics and Astronomy, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | | | | |
Collapse
|
19
|
Müller R, Grooss JU. Does cosmic-ray-induced heterogeneous chemistry influence stratospheric polar ozone loss? PHYSICAL REVIEW LETTERS 2009; 103:228501. [PMID: 20366127 DOI: 10.1103/physrevlett.103.228501] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Indexed: 05/29/2023]
Abstract
Cosmic-ray (CR) -induced heterogeneous reactions of halogenated species have been suggested to play the dominant role in causing the Antarctic ozone hole. However, measurements of total ozone in Antarctica do not show a compact and significant correlation with CR activity. Further, a substantial CR-induced heterogeneous loss of chlorofluorocarbons is incompatible with multiyear satellite observations of N2O and CFC-12. Thus, CR-induced heterogeneous reactions cannot be considered as an alternative mechanism causing the Antarctic ozone hole.
Collapse
Affiliation(s)
- Rolf Müller
- ICG-1, Forschungszentrum Jülich, 52425 Jülich, Germany.
| | | |
Collapse
|
20
|
Lu QB. Correlation between cosmic rays and ozone depletion. PHYSICAL REVIEW LETTERS 2009; 102:118501. [PMID: 19392251 DOI: 10.1103/physrevlett.102.118501] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Indexed: 05/27/2023]
Abstract
This Letter reports reliable satellite data in the period of 1980-2007 covering two full 11-yr cosmic ray (CR) cycles, clearly showing the correlation between CRs and ozone depletion, especially the polar ozone loss (hole) over Antarctica. The results provide strong evidence of the physical mechanism that the CR-driven electron-induced reaction of halogenated molecules plays the dominant role in causing the ozone hole. Moreover, this mechanism predicts one of the severest ozone losses in 2008-2009 and probably another large hole around 2019-2020, according to the 11-yr CR cycle.
Collapse
Affiliation(s)
- Q-B Lu
- Department of Physics, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
| |
Collapse
|
21
|
Müller R. Comment on “Resonant dissociative electron transfer of the presolvated electron to CCl4 in liquid: Direct observation and lifetime of the CCl4∗− transition state” [J. Chem. Phys. 128, 041102 (2008)]. J Chem Phys 2008; 129:027101; author reply 027102. [DOI: 10.1063/1.2953723] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
22
|
Wang CR, Drew K, Luo T, Lu MJ, Lu QB. Response to “Comment on ‘Resonant dissociative electron transfer of the presolvated electron to CCl4 in liquid: Direct observation and lifetime of the CCl4∗− transition state’ [J. Chem. Phys. 129, 027101 (2008)]”. J Chem Phys 2008. [DOI: 10.1063/1.2953728] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
23
|
Wang CR, Luo T, Lu QB. On the lifetimes and physical nature of incompletely relaxed electrons in liquid water. Phys Chem Chem Phys 2008; 10:4463-70. [DOI: 10.1039/b806287k] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
|