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Sedmidubská B, Kočišek J. Interaction of low-energy electrons with radiosensitizers. Phys Chem Chem Phys 2024; 26:9112-9136. [PMID: 38376461 DOI: 10.1039/d3cp06003a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
We provide an experimentalist's perspective on the present state-of-the-art in the studies of low-energy electron interactions with common radiosensitizers, including compounds used in combined chemo-radiation therapy and their model systems. Low-energy electrons are important secondary species formed during the interaction of ionizing radiation with matter. Their role in the radiation chemistry of living organisms has become an important topic for more than 20 years. With the increasing number of works and reviews in the field, we would like to focus here on a very narrow area of compounds that have been shown to have radio-sensitizing properties on the one hand, and high reactivity towards low-energy electrons on the other hand. Gas phase experiments studying electron attachment to isolated molecules and environmental effects on reaction dynamics are reviewed for modified DNA components, nitroimidazoles, and organometallics. In the end, we provide a perspective on the future directions that may be important for transferring the fundamental knowledge about the processes induced by low-energy electrons into practice in the field of rational design of agents for concomitant chemo-radiation therapy.
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Affiliation(s)
- Barbora Sedmidubská
- J. Heyrovský Institute of Physical Chemistry of the CAS, Dolejškova 3, 182223 Prague, Czech Republic.
- Department of Nuclear Chemistry, Faculty of Nuclear Sciences and Physical Engineering, Břehová 7, 11519 Prague, Czech Republic
- Institut de Chimie Physique, UMR 8000 CNRS and Faculté des sciences d'Orsay, Université Paris Saclay, F-91405 Orsay Cedex, France
| | - Jaroslav Kočišek
- J. Heyrovský Institute of Physical Chemistry of the CAS, Dolejškova 3, 182223 Prague, Czech Republic.
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2
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Yuan DF, Trabelsi T, Zhang YR, Francisco JS, Wang LS. Probing the Electronic Structure and Bond Dissociation of SO 3 and SO 3- Using High-Resolution Cryogenic Photoelectron Imaging. J Am Chem Soc 2022; 144:13740-13747. [PMID: 35857818 DOI: 10.1021/jacs.2c04698] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The SO3 molecule and its radical anion SO3- are important chemical species atmospherically. However, their thermodynamic properties and electronic structures are not well known experimentally. Using cryogenically cooled anions, we have obtained high-resolution photoelectron images of SO3- and determined accurately the electron affinity (EA) of SO3 and the bond dissociation energy of SO3- → SO2 + O- for the first time. Because of the large geometry changes from the C3v SO3- to the D3h SO3, there is a negligible Franck-Condon factor (FCF) for the 0-0 detachment transition, that defines the EA of SO3. By fitting the high-resolution photoelectron spectra with computed FCFs using structures from high-level ab initio calculations, we have determined the EA of SO3 to be 2.126(6) eV. By monitoring the appearance of the O- signal in the photoelectron images at different photon energies, we are able to measure directly the bond dissociation energy of SO3-(X2A1) → SO2(X1A1) + O-(2P) to be 4.259 ± 0.006 eV, which also allow us to derive the dissociation energy for the spin-forbidden SO3(X1A1') → SO2(X1A1) + O(3P) to be 3.594(6) eV. The excited states of SO3- are calculated using high-level ab initio calculations, which are valuable in aiding the interpretation of autodetachment processes observed at various photon energies. The current study provides valuable information about the fundamental molecular properties of SO3, as well as the radical anion SO3-, which is known in redox reactions involving SO32- and may also play a role in the chemistry of SO2 in the atmosphere.
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Affiliation(s)
- Dao-Fu Yuan
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Tarek Trabelsi
- Department of Earth and Environmental Sciences and Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Yue-Rou Zhang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Joseph S Francisco
- Department of Earth and Environmental Sciences and Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Lai-Sheng Wang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
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Valjus J, Tuononen HM, Laitinen RS, Chivers T. Computational investigations of 18-electron triatomic sulfur–nitrogen anions. CAN J CHEM 2018. [DOI: 10.1139/cjc-2018-0047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
MRCI-SD/def2-QZVP and PBE0/def2-QZVP calculations have been employed for the analysis of geometries, stabilities, and bonding of isomers of the 18-electron anions N2S2−, NS2−, and NSO−. Isomers of the isoelectronic neutral molecules SO2, S2O, S3, and O3 are included for comparison. The sulfur-centered acyclic NSN2−, NSS−, and NSO− anions are the most stable isomers of their respective molecular compositions. However, the nitrogen-centered isomers SNS− and SNO− lie close enough in energy to their more stable counterparts to allow their occurrence. The experimental structural information, where available, is in good agreement with the optimized bond parameters. The bonding in all investigated species is qualitatively similar, though electron density analyses reveal important quantitative differences that arise from bond polarization. Most of the investigated systems can be described with a single configuration wave function, the two notable exceptions being isomers SSS and OOO that show some diradical character. The computed MRCI-SD/def2-QZVP absorption maxima for SNS− and NSS− are 342 and 327 nm, respectively. The corresponding PBE0/def2-QZVP values in acetonitrile are 353 and 333 nm. These data support the proposed initial formation of SNS− from electrochemical or chemical reduction of SSNS− based on experimental UV–vis spectra. The interconversion of SNS− and NSS− is calculated to be facile and reversible, leading to an equilibrium mixture that also includes the remarkably stable dianion SNSNSS2−. Thus, salts of either SNS− or NSS− with bulky organic cations represent feasible synthetic targets.
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Affiliation(s)
- Juuso Valjus
- Department of Chemistry, Nanoscience Centre, P.O. Box 35, FI-40014 University of Jyväskylä, Finland
| | - Heikki M. Tuononen
- Department of Chemistry, Nanoscience Centre, P.O. Box 35, FI-40014 University of Jyväskylä, Finland
| | - Risto S. Laitinen
- Laboratory of Inorganic Chemistry, Environmental and Chemical Engineering, P.O. Box 3000, FI-90014 University of Oulu, Finland
| | - Tristram Chivers
- Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada
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Kumar M, Francisco JS. A Coupled Cluster Investigation of SNO Radical Isomers and Their Reactions with Hydrogen Atom: Insight into Structures, Conformers, Barriers, and Energetics. J Phys Chem A 2017; 121:6652-6659. [DOI: 10.1021/acs.jpca.7b06344] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Manoj Kumar
- Department
of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Joseph S. Francisco
- Department
of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
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Fortenberry RC, Thackston R, Francisco JS, Lee TJ. Toward the laboratory identification of the not-so-simple NS2neutral and anion isomers. J Chem Phys 2017; 147:074303. [DOI: 10.1063/1.4985901] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ryan C. Fortenberry
- Department of Chemistry and Biochemistry, Georgia Southern University, Statesboro, Georgia 30460-8064, USA
| | - Russell Thackston
- Department of Information Technology, Georgia Southern University, Statesboro, Georgia 30460-8150, USA
| | - Joseph S. Francisco
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
| | - Timothy J. Lee
- MS 245-1, NASA Ames Research Center, Moffett Field, California 94035-1000, USA
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Lehman JH, Lineberger WC. Photoelectron spectroscopy of the thiazate (NSO -) and thionitrite (SNO -) isomer anions. J Chem Phys 2017; 147:013943. [PMID: 28688423 PMCID: PMC5648556 DOI: 10.1063/1.4984129] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 05/12/2017] [Indexed: 12/15/2022] Open
Abstract
Anion photoelectron spectra of the thiazate (NSO-) and thionitrite (SNO-) isomers are reported. The NSO- photoelectron spectrum showed several well-resolved vibronic transitions from the anion to the NSO radical neutral. The electron affinity of NSO was determined to be 3.113(1) eV. The fundamental vibrational frequencies of NSO were measured and unambiguously assigned to be 1202(6) cm-1 (ν1, asymmetric stretch), 1010(10) cm-1 (ν2, symmetric stretch), and 300(7) cm-1 (ν3, bend). From the presence of vibrational hot band transitions, the fundamental vibrational frequencies of the NSO- anion were also measured: 1280(30) cm-1 (ν1, asymmetric stretch), 990(20) cm-1 (ν2, symmetric stretch), and 480(10) cm-1 (ν3, bend). Combined with the previously measured ΔacidH298 Ko(HNSO), D0(H-NSO) was found to be 102(5) kcal/mol. Unlike the results from NSO-, the SNO- photoelectron spectrum was broad with little structure, indicative of a large geometry change between the anion and neutral radical. In addition to the spectrally congested spectrum, there was evidence of a competition between photodetachment from SNO- and SNO- photodissociation to form S- + NO. Quantum chemical calculations were used to aid in the interpretation of the experimental data and agree well with the observed photoelectron spectra, particularly for the NSO- isomer.
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Affiliation(s)
- Julia H Lehman
- JILA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - W Carl Lineberger
- JILA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
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Fortenberry RC. The rovibrational nature of cis- and trans-HNNS: A possible nitrogen molecule progenitor. J Chem Phys 2017; 145:204302. [PMID: 27908132 DOI: 10.1063/1.4968036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The HNNS radical has been promoted recently as a viable intermediate in the interstellar creation of the spectroscopically elusive nitrogen molecule. Any confirmation of this pathway or utilizing HNNS as a tracer of N2 depends upon the ability to observe the radical intermediate whether in the laboratory or in the interstellar medium. Established and accurate quantum chemical procedures are employed here to produce spectroscopic constants, fundamental vibrational frequencies, and intensities that can be utilized for any possible detection of HNNS. While trans-HNNS is confirmed here to be 3.0 kcal/mol lower in energy than cis-HNNS, the latter will be more readily observed rotationally due to its significantly larger dipole moment. The N-N bond in cis-HNNS is stronger than in trans-HNNS, and earlier work has suggested that cis-HNNS is more useful in the creation of N2 from NH and NS. Hence, the detection of cis-HNNS may be of greater value anyway. Furthermore, the N-N stretch in either conformer is also exceptionally bright and will occur in the mid-infrared with nearly 30 cm-1 separating the fundamentals of the two conformers. Finally, the low isomerization barrier can be affected significantly upon deuteration also making ND an interesting consideration as a starting material in the interstellar formation of N2.
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Affiliation(s)
- Ryan C Fortenberry
- Department of Chemistry and Biochemistry, Georgia Southern University, Statesboro, Georgia 30460, USA
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Chivers T, Laitinen RS. Fundamental chemistry of binary S,N and ternary S,N,O anions: analogues of sulfur oxides and N,O anions. Chem Soc Rev 2017; 46:5182-5192. [DOI: 10.1039/c6cs00925e] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The fundamental chemistry and significance of S,N and S,N,O anions and their conjugate acids in a variety of settings are discussed.
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Affiliation(s)
- Tristram Chivers
- Department of Chemistry
- University of Calgary
- Calgary
- Canada T2N 1N4
| | - Risto S. Laitinen
- Laboratory of Inorganic Chemistry
- Environmental and Chemical Engineering
- University of Oulu
- 90014 Oulu
- Finland
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Sghaier O, Abdallah HH, Abdullah HY, Jaidane NE, Al Mogren MM, Hochlaf M. Theoretical investigation of the long-lived metastable AlO2+ dication in gas phase. Chem Phys 2016. [DOI: 10.1016/j.chemphys.2016.08.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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10
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Cortese-Krott MM, Butler AR, Woollins JD, Feelisch M. Inorganic sulfur-nitrogen compounds: from gunpowder chemistry to the forefront of biological signaling. Dalton Trans 2016; 45:5908-19. [PMID: 26898846 DOI: 10.1039/c5dt05034k] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The reactions between inorganic sulfur and nitrogen-bearing compounds to form S-N containing species have a long history and, besides assuming importance in industrial synthetic processes, are of relevance to microbial metabolism; waste water treatment; aquatic, soil and atmospheric chemistry; and combustion processes. The recent discovery that hydrogen sulfide and nitric oxide exert often similar, sometimes mutually dependent effects in a variety of biological systems, and that the chemical interaction of these two species leads to formation of S-N compounds brought this chemistry to the attention of physiologists, biochemists and physicians. We here provide a perspective about the potential role of S-N compounds in biological signaling and briefly review their chemical properties and bioactivities in the context of the chronology of their discovery. Studies of the biological role of NO revealed why its chemistry is ideally suited for the tasks Nature has chosen for it; realising how the distinctive properties of sulfur can enrich this bioactivity does much to revive 'die Freude am experimentellen Spiel' of the pioneers in this field.
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Affiliation(s)
- Miriam M Cortese-Krott
- Cardiovascular Research Laboratory, Department of Cardiology, Pneumology and Angiology, Medical Faculty, Heinrich Heine University of Düsseldorf, Düsseldorf, Germany
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Fortenberry RC, Francisco JS. Energetics, structure, and rovibrational spectroscopic properties of the sulfurous anions SNO− and OSN−. J Chem Phys 2015; 143:184301. [DOI: 10.1063/1.4935056] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ryan C. Fortenberry
- Department of Chemistry, Georgia Southern University, Statesboro, Georgia 30460, USA
| | - Joseph S. Francisco
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
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