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Ding D, Feng E, Kotha RR, Chapman NC, Jiang H, Nash JJ, Kenttämaa HI. Spin-Spin Coupling Controls the Gas-Phase Reactivity of Aromatic σ-Type Triradicals. Chemistry 2021; 28:e202102968. [PMID: 34786768 DOI: 10.1002/chem.202102968] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Indexed: 11/11/2022]
Abstract
Examination of the reactions of σ-type quinolinium-based triradicals with cyclohexane in the gas phase demonstrated that the radical site that is the least strongly coupled to the other two radical sites reacts first, independent of the intrinsic reactivity of this radical site, in contrast to related biradicals that first react at the most electron-deficient radical site. Abstraction of one or two H atoms and formation of an ion that formally corresponds to a combination of the ion and cyclohexane accompanied by elimination of a H atom ("addition-H") were observed. In all cases except one, the most reactive radical site of the triradicals is intrinsically less reactive than the other two radical sites. The product complex of the first H atom abstraction either dissociates to give the H-atom-abstraction product and the cyclohexyl radical or the more reactive radical site in the produced biradical abstracts a H atom from the cyclohexyl radical. The monoradical product sometimes adds to cyclohexene followed by elimination of a H atom, generating the "addition-H" products. Similar reaction efficiencies were measured for three of the triradicals as for relevant monoradicals. Surprisingly, the remaining three triradicals (all containing a meta-pyridyne moiety) reacted substantially faster than the relevant monoradicals. This is likely due to the exothermic generation of a meta-pyridyne analog that has enough energy to attain the dehydrocarbon atom separation common for H-atom-abstraction transition states of protonated meta-pyridynes.
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Affiliation(s)
- Duanchen Ding
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
| | - Erlu Feng
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
| | - Raghavendhar R Kotha
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
| | - Nathan C Chapman
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
| | - Hanning Jiang
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
| | - John J Nash
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
| | - Hilkka I Kenttämaa
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
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2
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Lau JKC, Esuon F, Berden G, Oomens J, Hopkinson AC, Ryzhov V, Siu KWM. Generation, Characterization, and Dissociation of Radical Cations Derived from Prolyl-glycyl-glycine. J Phys Chem B 2021; 125:6121-6129. [PMID: 34097420 DOI: 10.1021/acs.jpcb.1c01732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Radical cations of an aliphatic tripeptide prolyl-glycyl-glycine (PGG•+) and its sequence ions [a3 + H]•+ and [b2 - H]•+ have been generated by collision-induced dissociation of the [Cu(Phen)(PGG)]•2+ complex, where Phen = 1,10-phenanthroline. Infrared multiple photon dissociation spectroscopy, ion-molecule reaction experiments, and theoretical calculations have been used to investigate the structures of these ions. The unpaired electron in these three radical cations is located at different α-carbons. The PGG•+ radical cation has a captodative structure with the radical at the α-carbon of the proline residue and the proton on the oxygen of the first amide group. This structure is at the global minimum on the potential energy surface (PES). By contrast, the [a3 + H]•+ and [b2 - H]•+ ions are not the lowest-energy structures on their respective PESs, and their radicals are formally located at the C-terminal and second α-carbons, respectively. Density functional theory calculations on the structures of the ternary copper(II) complex ion suggest that the charge-solvated isomer of the metal complex is the precursor ion that dissociates to give the PGG•+ radical cation. The isomer of the complex in which PGG is bound as a zwitterion dissociates to give the [a3 + H]•+ and [b2 - H]•+ ions.
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Affiliation(s)
- Justin Kai-Chi Lau
- Department of Chemistry and Centre for Research in Mass Spectrometry, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada.,Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, Ontario N9B 3P4, Canada
| | - Francis Esuon
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois 60115, United States
| | - Giel Berden
- FELIX Laboratory, Institute for Molecules and Materials, Radboud University, Toernooiveld 7, Nijmegen 6525 ED, the Netherlands
| | - Jos Oomens
- FELIX Laboratory, Institute for Molecules and Materials, Radboud University, Toernooiveld 7, Nijmegen 6525 ED, the Netherlands
| | - Alan C Hopkinson
- Department of Chemistry and Centre for Research in Mass Spectrometry, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada
| | - Victor Ryzhov
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois 60115, United States
| | - K W Michael Siu
- Department of Chemistry and Centre for Research in Mass Spectrometry, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada.,Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, Ontario N9B 3P4, Canada
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3
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Narreddula VR, McKinnon BI, Marlton SJP, Marshall DL, Boase NRB, Poad BLJ, Trevitt AJ, Mitchell TW, Blanksby SJ. Next-generation derivatization reagents optimized for enhanced product ion formation in photodissociation-mass spectrometry of fatty acids. Analyst 2021; 146:156-169. [DOI: 10.1039/d0an01840f] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Next-generation derivatives for photodissociation-mass spectrometry for fatty acids generating photoproduct yields of up to 97% at 266 nm.
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Affiliation(s)
- Venkateswara R. Narreddula
- School of Chemistry and Physics
- Science and Engineering Faculty
- Queensland University of Technology
- Brisbane
- Australia
| | - Benjamin I. McKinnon
- Molecular Horizons and School of Chemistry and Molecular Bioscience
- University of Wollongong
- Wollongong
- Australia
| | - Samuel J. P. Marlton
- Molecular Horizons and School of Chemistry and Molecular Bioscience
- University of Wollongong
- Wollongong
- Australia
| | - David L. Marshall
- Central Analytical Research Facility
- Institute for Future Environments
- Queensland University of Technology
- Brisbane
- Australia
| | - Nathan R. B. Boase
- School of Chemistry and Physics
- Science and Engineering Faculty
- Queensland University of Technology
- Brisbane
- Australia
| | - Berwyck L. J. Poad
- Central Analytical Research Facility
- Institute for Future Environments
- Queensland University of Technology
- Brisbane
- Australia
| | - Adam J. Trevitt
- Molecular Horizons and School of Chemistry and Molecular Bioscience
- University of Wollongong
- Wollongong
- Australia
| | - Todd W. Mitchell
- School of Medicine
- University of Wollongong
- Wollongong
- Australia
- Illawarra Health and Medical Research Institute
| | - Stephen J. Blanksby
- School of Chemistry and Physics
- Science and Engineering Faculty
- Queensland University of Technology
- Brisbane
- Australia
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4
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Errabelli R, Zheng Z, Attygalle AB. Formation of Protonated ortho-Quinonimide from ortho-Iodoaniline in the Gas Phase by a Molecular-Oxygen-Mediated, ortho-Isomer-Specific Fragmentation Mechanism. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:864-872. [PMID: 32233379 DOI: 10.1021/jasms.9b00108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Upon collisional activation under mass spectrometric conditions, protonated 2-, 3-, and 4-iodoanilines lose an iodine radical to generate primarily dehydroanilinium radical cations (m/z 93), which are the distonic counterparts of the conventional molecular ion of aniline. When briefly accumulated in the Trap region of a Triwave cell in a SYNAPT G2 instrument, before being released for ion-mobility separation, these dehydroanilinium cations react readily with traces of oxygen present in the mobility gas to form peroxyl radical cations. Although all three isomeric dehydroanilinium ions showed avid affinity for O2, their reactivities were distinctly different. For example, the product-ion spectra recorded from mass-selected m/z 93 ion from 3- and 4-iodoanilines showed a peak at m/z 125 for the respective peroxylbenzenaminium ion. In contrast, an analogous peak at m/z 125 was absent in the spectrum of the 2-dehydroanilinium ion generated from 2-iodoaniline. Evidently, the 2-peroxylbenzenaminium ion generated from the 2-dehydroanilinium ion immediately loses a •OH to form protonated ortho-quinonimide (m/z 108).
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Affiliation(s)
- Ramu Errabelli
- Center for Mass Spectrometry, Department of Chemistry, and Chemical Biology, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States
| | - Zhaoyu Zheng
- Center for Mass Spectrometry, Department of Chemistry, and Chemical Biology, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States
| | - Athula B Attygalle
- Center for Mass Spectrometry, Department of Chemistry, and Chemical Biology, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States
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5
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So S, Kirk BB, Wille U, Trevitt AJ, Blanksby SJ, da Silva G. Reactions of a distonic peroxyl radical anion influenced by SOMO–HOMO conversion: an example of anion-directed channel switching. Phys Chem Chem Phys 2020; 22:2130-2141. [DOI: 10.1039/c9cp05989j] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Deprotonation of a remote site in a peroxyl radical energetically buries the singly occupied molecular orbital, suppressing radical-driven oxidation and promoting reactions involving the anion site.
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Affiliation(s)
- Sui So
- Department of Chemical Engineering
- The University of Melbourne
- Australia
| | | | - Uta Wille
- School of Chemistry and Bio21 Institute
- The University of Melbourne
- Australia
| | | | - Stephen J. Blanksby
- Central Analytical Research Facility
- Institute for Future Environments
- Queensland University of Technology
- Australia
| | - Gabriel da Silva
- Department of Chemical Engineering
- The University of Melbourne
- Australia
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6
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Shiels OJ, Kelly PD, Blanksby SJ, da Silva G, Trevitt AJ. Barrierless Reactions of Three Benzonitrile Radical Cations with Ethylene. Aust J Chem 2020. [DOI: 10.1071/ch19606] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Reactions of three protonated benzonitrile radical cations with ethylene are investigated. Product branching ratios and reaction kinetics, measured using ion-trap mass spectrometry, are reported and mechanisms are developed with support from quantum chemical calculations. Reactions proceed via pre-reactive van der Waals complexes with no energy barrier (above the reactant energy) and form radical addition and addition–elimination product ions. Rate coefficients are 4-dehydrobenzonitrilium: 1.72±0.01×10−11 cm3 molecule−1 s−1, 3-dehydrobenzonitrilium: 1.85±0.01×10−11 cm3 molecule−1 s−1, and 2-dehydrobenzonitrilium: 5.96±0.06×10−11 cm3 molecule−1 s−1 (with±50% absolute uncertainty). A ring-closure mechanism involving the protonated nitrile substituent is proposed for the 2-dehydrobenzonitrilium case and suggests favourable formation of the protonated indenimine cation.
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7
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Kelly PD, Bright CC, Blanksby SJ, da Silva G, Trevitt AJ. Molecular Weight Growth in the Gas-Phase Reactions of Dehydroanilinium Radical Cations with Propene. J Phys Chem A 2019; 123:8881-8892. [DOI: 10.1021/acs.jpca.9b04088] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Patrick D. Kelly
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong 2522, Australia
| | - Cameron C. Bright
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong 2522, Australia
| | - Stephen J. Blanksby
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane 4001, Australia
| | - Gabriel da Silva
- Department of Chemical and Biomolecular Engineering, The University of Melbourne, Melbourne 3010, Victoria, Australia
| | - Adam J. Trevitt
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong 2522, Australia
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8
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Williams PE, Marshall DL, Poad BLJ, Narreddula VR, Kirk BB, Trevitt AJ, Blanksby SJ. Comparing Positively and Negatively Charged Distonic Radical Ions in Phenylperoxyl Forming Reactions. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:1848-1860. [PMID: 29869328 DOI: 10.1007/s13361-018-1988-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 04/30/2018] [Accepted: 05/03/2018] [Indexed: 06/08/2023]
Abstract
In the gas phase, arylperoxyl forming reactions play a significant role in low-temperature combustion and atmospheric processing of volatile organic compounds. We have previously demonstrated the application of charge-tagged phenyl radicals to explore the outcomes of these reactions using ion trap mass spectrometry. Here, we present a side-by-side comparison of rates and product distributions from the reaction of positively and negatively charge tagged phenyl radicals with dioxygen. The negatively charged distonic radical ions are found to react with significantly greater efficiency than their positively charged analogues. The product distributions of the anion reactions favor products of phenylperoxyl radical decomposition (e.g., phenoxyl radicals and cyclopentadienone), while the comparable fixed-charge cations yield the stabilized phenylperoxyl radical. Electronic structure calculations rationalize these differences as arising from the influence of the charged moiety on the energetics of rate-determining transition states and reaction intermediates within the phenylperoxyl reaction manifold and predict that this influence could extend to intra-molecular charge-radical separations of up to 14.5 Å. Experimental observations of reactions of the novel 4-(1-carboxylatoadamantyl)phenyl radical anion confirm that the influence of the charge on both rate and product distribution can be modulated by increasing the rigidly imposed separation between charge and radical sites. These findings provide a generalizable framework for predicting the influence of charged groups on polarizable radicals in gas phase distonic radical ions. Graphical Abstract.
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Affiliation(s)
- Peggy E Williams
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD, Australia
- Failure and Materials Analysis Branch, Flight Systems Division, Naval Surface Warfare Center Crane, Crane, IN, USA
| | - David L Marshall
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD, Australia
| | - Berwyck L J Poad
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD, Australia
| | - Venkateswara R Narreddula
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD, Australia
| | - Benjamin B Kirk
- School of Chemistry, University of Wollongong, Wollongong, NSW, Australia
| | - Adam J Trevitt
- School of Chemistry, University of Wollongong, Wollongong, NSW, Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD, Australia.
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9
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Ellis SR, Pham HT, In Het Panhuis M, Trevitt AJ, Mitchell TW, Blanksby SJ. Radical Generation from the Gas-Phase Activation of Ionized Lipid Ozonides. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:1345-1358. [PMID: 28484972 PMCID: PMC5486690 DOI: 10.1007/s13361-017-1649-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 01/13/2017] [Accepted: 01/19/2017] [Indexed: 05/29/2023]
Abstract
Reaction products from the ozonolysis of unsaturated lipids at gas-liquid interfaces have the potential to significantly influence the chemical and physical properties of organic aerosols in the atmosphere. In this study, the gas-phase dissociation behavior of lipid secondary ozonides is investigated using ion-trap mass spectrometry. Secondary ozonides were formed by reaction between a thin film of unsaturated lipids (fatty acid methyl esters or phospholipids) with ozone before being transferred to the gas phase as [M + Na]+ ions by electrospray ionization. Activation of the ionized ozonides was performed by either energetic collisions with helium buffer-gas or laser photolysis, with both processes yielding similar product distributions. Products arising from the decomposition of the ozonides were characterized by their mass-to-charge ratio and subsequent ion-molecule reactions. Product assignments were rationalized as arising from initial homolysis of the ozonide oxygen-oxygen bond with subsequent decomposition of the nascent biradical intermediate. In addition to classic aldehyde and carbonyl oxide-type fragments, carbon-centered radicals were identified with a number of decomposition pathways that indicated facile unimolecular radical migration. These findings reveal that photoactivation of secondary ozonides formed by the reaction of aerosol-bound lipids with tropospheric ozone may initiate radical-mediated chemistry within the particle resulting in surface modification. Graphical Abstract ᅟ.
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Affiliation(s)
- Shane R Ellis
- M4I, The Maastricht Multimodal Molecular Imaging Institute, University of Maastricht, 6229 ER, Maastricht, The Netherlands.
- School of Chemistry, University of Wollongong, Wollongong, NSW, 2522, Australia.
| | - Huong T Pham
- School of Chemistry, University of Wollongong, Wollongong, NSW, 2522, Australia
- Boreal Ecosystem Research Initiative (BERI), Environmental Science, Memorial University, Grenfell Campus, Corner Brook, NL, A2H 5G4, Canada
| | - Marc In Het Panhuis
- School of Chemistry, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Adam J Trevitt
- School of Chemistry, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Todd W Mitchell
- School of Medicine, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, QLD, 4001, Australia.
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10
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Prendergast MB, Kirk BB, Savee JD, Osborn DL, Taatjes CA, Masters KS, Blanksby SJ, da Silva G, Trevitt AJ. Formation and stability of gas-phase o-benzoquinone from oxidation of ortho-hydroxyphenyl: a combined neutral and distonic radical study. Phys Chem Chem Phys 2016; 18:4320-32. [DOI: 10.1039/c5cp02953h] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The o-hydroxyphenyl radical reacts with O2 to form o-benzoquinone + OH and cyclopentadienone is assigned as a secondary product.
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Affiliation(s)
| | | | - John D. Savee
- Combustion Research Facility
- Sandia National Laboratories
- Livermore
- USA
| | - David L. Osborn
- Combustion Research Facility
- Sandia National Laboratories
- Livermore
- USA
| | - Craig A. Taatjes
- Combustion Research Facility
- Sandia National Laboratories
- Livermore
- USA
| | - Kye-Simeon Masters
- School of Chemistry, Physics and Mechanical Engineering
- Faculty of Science and Engineering
- Queensland University of Technology
- Brisbane
- Australia
| | - Stephen J. Blanksby
- Central Analytical Research Facility
- Queensland University of Technology
- Brisbane
- Australia
| | - Gabriel da Silva
- Department of Chemical and Biomolecular Engineering
- The University of Melbourne
- Melbourne
- Australia
| | - Adam J. Trevitt
- School of Chemistry
- University of Wollongong
- Wollongong
- Australia
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11
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Baba T, Campbell JL. Capturing Polyradical Protein Cations after an Electron Capture Event: Evidence for their Stable Distonic Structures in the Gas Phase. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:1695-1701. [PMID: 26231348 DOI: 10.1007/s13361-015-1207-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 05/22/2015] [Accepted: 05/26/2015] [Indexed: 06/04/2023]
Abstract
We report on the formation and "capture" of polyradical protein cations after an electron capture event. Performed in a unique electron-capture dissociation (ECD) instrument, these experiments can generate reduced forms of multiply protonated proteins by sequential charge reduction using electrons with ~1 eV. The true structures of these possible polyradicals is considered: Do the introduced unpaired electrons recombine quickly to form a new two-electron bond, or do these unpaired electrons exist as radical sites with appropriate chemical reactivity? Using an established chemical probe--radical quenching with molecular oxygen--we demonstrate that these charge-reduced protein cations are indeed polyradicals that form adducts with up to three molecules of oxygen (i.e., tri-radical protein cations) that are stable for at least 100 ms.
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Affiliation(s)
- Takashi Baba
- Sciex, 71 Four Valley Drive, Concord, ON, L4K 4V8, Canada.
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Jariwala FB, Hibbs JA, Weisbecker CS, Ressler J, Khade RL, Zhang Y, Attygalle AB. A distonic radical-ion for detection of traces of adventitious molecular oxygen (O2) in collision gases used in tandem mass spectrometers. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2014; 25:1670-3. [PMID: 25001381 DOI: 10.1007/s13361-014-0945-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Revised: 05/26/2014] [Accepted: 05/27/2014] [Indexed: 05/18/2023]
Abstract
We describe a diagnostic ion that enables rapid semiquantitative evaluation of the degree of oxygen contamination in the collision gases used in tandem mass spectrometers. Upon collision-induced dissociation (CID), the m/z 359 positive ion generated from the analgesic etoricoxib undergoes a facile loss of a methyl sulfone radical [(•)SO(2)(CH(3)); 79-Da] to produce a distonic radical cation of m/z 280. The product-ion spectrum of this m/z 280 ion, recorded under low-energy activation on tandem-in-space QqQ or QqTof mass spectrometers using nitrogen from a generator as the collision gas, or tandem-in-time ion-trap (LCQ, LTQ) mass spectrometers using purified helium as the buffer gas, showed two unexpected peaks at m/z 312 and 295. This enigmatic m/z 312 ion, which bears a mass-to-charge ratio higher than that of the precursor ion, represented an addition of molecular oxygen (O(2)) to the precursor ion. The exceptional affinity of the m/z 280 radical cation towards oxygen was deployed to develop a method to determine the oxygen content in collision gases.
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Affiliation(s)
- Freneil B Jariwala
- Center for Mass Spectrometry, Department of Chemistry, Chemical Biology and Biomedical Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA
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13
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So S, Kirk BB, Trevitt AJ, Wille U, Blanksby SJ, da Silva G. Unimolecular reaction chemistry of a charge-tagged beta-hydroxyperoxyl radical. Phys Chem Chem Phys 2014; 16:24954-64. [DOI: 10.1039/c4cp02981j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The study of unimolecular isomerization and decomposition of a charge-tagged β-hydroxyperoxyl radical anion ˙CH2C(OH)(CH3)CH2C(O)O− using mass spectrometry, quantum mechanical calculations and master equation kinetic simulations.
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Affiliation(s)
- Sui So
- Department of Chemical and Biomolecular Engineering
- The University of Melbourne
- , Australia
| | - Benjamin B. Kirk
- School of Chemistry
- University of Wollongong
- , Australia
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology
- Hosted by The University of Melbourne
| | - Adam J. Trevitt
- School of Chemistry
- University of Wollongong
- , Australia
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology
- Hosted by The University of Melbourne
| | - Uta Wille
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology
- Hosted by The University of Melbourne
- , Australia
- School of Chemistry and Bio21 Institute
- The University of Melbourne
| | - Stephen J. Blanksby
- School of Chemistry
- University of Wollongong
- , Australia
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology
- Hosted by The University of Melbourne
| | - Gabriel da Silva
- Department of Chemical and Biomolecular Engineering
- The University of Melbourne
- , Australia
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Affiliation(s)
| | - Steven R. Kass
- Department
of Chemistry, University of Minnesota,
Minneapolis, Minnesota 55455,
United States
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15
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Poad BLJ, Kirk BB, Hettiarachchi PI, Trevitt AJ, Blanksby SJ, Clark T. Direct Detection of a Persistent Carbonyloxyl Radical in the Gas Phase. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201304316] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | - Benjamin B. Kirk
- School of Chemistry, University of Wollongong, NSW 2522 (Australia)
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Chemistry, University of Wollongong, NSW 2522 (Australia)
| | | | - Adam J. Trevitt
- School of Chemistry, University of Wollongong, NSW 2522 (Australia)
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Chemistry, University of Wollongong, NSW 2522 (Australia)
| | - Stephen J. Blanksby
- School of Chemistry, University of Wollongong, NSW 2522 (Australia)
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Chemistry, University of Wollongong, NSW 2522 (Australia)
| | - Timothy Clark
- Computer‐Chemie‐Centrum, Department Chemie und Parmazie, Friedrich‐Alexander‐University at Erlangen‐Nürnberg, 91052 Erlangen (Germany)
- Centre for Molecular Design, University of Portsmouth, King Henry Building, Portsmouth PO1 2DY (United Kingdom)
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16
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Poad BLJ, Kirk BB, Hettiarachchi PI, Trevitt AJ, Blanksby SJ, Clark T. Direct Detection of a Persistent Carbonyloxyl Radical in the Gas Phase. Angew Chem Int Ed Engl 2013; 52:9301-4. [DOI: 10.1002/anie.201304316] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Indexed: 11/07/2022]
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17
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Maccarone AT, Kirk BB, Hansen CS, Griffiths TM, Olsen S, Trevitt AJ, Blanksby SJ. Direct Observation of Photodissociation Products from Phenylperoxyl Radicals Isolated in the Gas Phase. J Am Chem Soc 2013; 135:9010-4. [DOI: 10.1021/ja402610s] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Alan T. Maccarone
- ARC Centre of Excellence for
Free Radical Chemistry and Biotechnology, School of Chemistry, University of Wollongong, NSW 2522, Australia
| | - Benjamin B. Kirk
- ARC Centre of Excellence for
Free Radical Chemistry and Biotechnology, School of Chemistry, University of Wollongong, NSW 2522, Australia
| | - Christopher S. Hansen
- ARC Centre of Excellence for
Free Radical Chemistry and Biotechnology, School of Chemistry, University of Wollongong, NSW 2522, Australia
| | - Thomas M. Griffiths
- ARC Centre of Excellence for
Free Radical Chemistry and Biotechnology, School of Chemistry, University of Wollongong, NSW 2522, Australia
| | - Seth Olsen
- School of Physics, University of Queensland, QLD 4072, Australia
| | - Adam J. Trevitt
- ARC Centre of Excellence for
Free Radical Chemistry and Biotechnology, School of Chemistry, University of Wollongong, NSW 2522, Australia
| | - Stephen J. Blanksby
- ARC Centre of Excellence for
Free Radical Chemistry and Biotechnology, School of Chemistry, University of Wollongong, NSW 2522, Australia
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18
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Osburn S, Berden G, Oomens J, Gulyuz K, Polfer NC, O'Hair RAJ, Ryzhov V. Structure and Reactivity of the Glutathione Radical Cation: Radical Rearrangement from the Cysteine Sulfur to the Glutamic Acid α-Carbon Atom. Chempluschem 2013; 78:970-978. [DOI: 10.1002/cplu.201300057] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Indexed: 12/19/2022]
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19
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Switching radical stability by pH-induced orbital conversion. Nat Chem 2013; 5:474-81. [DOI: 10.1038/nchem.1625] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Accepted: 03/16/2013] [Indexed: 11/09/2022]
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20
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Li C, Lam AKY, Khairallah GN, White JM, O'Hair RAJ, da Silva G. Using distonic radical ions to probe the chemistry of key combustion intermediates: the case of the benzoxyl radical anion. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2013; 24:493-501. [PMID: 23512425 DOI: 10.1007/s13361-013-0596-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 02/20/2013] [Accepted: 02/20/2013] [Indexed: 06/01/2023]
Abstract
The benzoxyl radical is a key intermediate in the combustion of toluene and other aromatic hydrocarbons, yet relatively little experimental work has been performed on this species. Here, a combination of electrospray ionization (ESI), multistage mass spectrometry experiments, and density functional theory (DFT) calculations are used to examine the formation and fragmentation of a benzoxyl (benzyloxyl) distonic radical anion. Excited 4-carboxylatobenzoxyl radical anions were produced via two methods: (1) collision induced dissociation (CID) of the nitrate ester 4-(nitrooxymethyl)benzoate, (-)O2CC6H4CH2ONO2, and (2) reaction of ozone with the 4-carboxylatobenzyl radical anion, (-)O2CC6H4CH2(•). In neither case was the stabilized (-)O2CC6H4CH2O(•) radical anion intermediate detected. Instead, dissociation products at m/z 121 and 149 were observed. These products are attributed to benzaldehyde (O2(-)CC6H4CHO) and benzene ((-)O2CC6H5) products from respective loss of H and HCO radicals in the vibrationally excited benzoxyl intermediate. In no experiments was a product at m/z 120 (i.e., (-)O2CC6H4(•)) detected, corresponding to absence of the commonly assumed phenyl radical + CH2=O channel. The results reported suggest that distonic ions are useful surrogates for reactive intermediates formed in combustion chemistry.
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Affiliation(s)
- Cong Li
- School of Chemistry, The University of Melbourne, Melbourne, VIC, Australia
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21
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Prendergast MB, Cooper PA, Kirk BB, Silva GD, Blanksby SJ, Trevitt AJ. Hydroxyl radical formation in the gas phase oxidation of distonic 2-methylphenyl radical cations. Phys Chem Chem Phys 2013; 15:20577-84. [DOI: 10.1039/c3cp53690d] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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22
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Li CH, Khairallah GN, Lam AKY, O'Hair RAJ, Kirk BB, Blanksby SJ, da Silva G, Wille U. Reaction of Aromatic Peroxyl Radicals with Alkynes: A Mass Spectrometric and Computational Study Using the Distonic Radical Ion Approach. Chem Asian J 2012; 8:450-64. [DOI: 10.1002/asia.201200933] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Indexed: 11/12/2022]
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23
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Affiliation(s)
- Sandra Osburn
- Department of Chemistry and Biochemistry and Center for Biochemical and Biophysical Studies, Northern Illinois University, DeKalb, Illinois 60115, USA
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24
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Osburn S, Burgie T, Berden G, Oomens J, O’Hair RAJ, Ryzhov V. Structure and Reactivity of Homocysteine Radical Cation in the Gas Phase Studied by Ion–Molecule Reactions and Infrared Multiple Photon Dissociation. J Phys Chem A 2012; 117:1144-50. [DOI: 10.1021/jp304769y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sandra Osburn
- Department of Chemistry and
Biochemistry, and Center for Biochemical and Biophysical Studies, Northern Illinois University, Dekalb, Illinois 60115,
United States
| | - Ticia Burgie
- Department of Chemistry and
Biochemistry, and Center for Biochemical and Biophysical Studies, Northern Illinois University, Dekalb, Illinois 60115,
United States
| | - Giel Berden
- FOM Institute for Plasma Physics Rijnhuizen, Nieuwegein, The Netherlands
| | - Jos Oomens
- FOM Institute for Plasma Physics Rijnhuizen, Nieuwegein, The Netherlands
- University of Amsterdam, Amsterdam, The Netherlands
| | - Richard A. J. O’Hair
- School of Chemistry, The University of Melbourne, Melbourne, Victoria 3010,
Australia
- Bio21 Institute
of Molecular
Science and Biotechnology, The University of Melbourne, Melbourne, Victoria 3010, Australia
- ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, Melbourne,
Victoria 3010, Australia
| | - Victor Ryzhov
- Department of Chemistry and
Biochemistry, and Center for Biochemical and Biophysical Studies, Northern Illinois University, Dekalb, Illinois 60115,
United States
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25
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Curcuma longa and Curcuma mangga leaves exhibit functional food property. Food Chem 2012; 135:634-40. [PMID: 22868139 DOI: 10.1016/j.foodchem.2012.04.129] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 03/27/2012] [Accepted: 04/24/2012] [Indexed: 01/12/2023]
Abstract
Although leaves of Curcuma mangga and Curcuma longa are used in food preparations, the bioactive components in it are not known. In this study, antioxidant, antiinflammatory and anticancer activities of leave extracts and its isolates were investigated using established bioassay procedures in our laboratory. The leaf extracts of both plants gave similar bioassay and chromatographic profiles. The methanolic and water extracts of C. mangga (CMM and CMW) and C. longa (CLM and CLW), at 100 μg/mL, inhibited lipid peroxidation (LPO) by 78%, 63%, 81% and 43%, cyclooxygenase enzymes COX-1 by 55%, 33%, 43% and 24% and COX-2 by 65%, 55%, 77% and 69%, respectively. At same concentration, CMM, CMW, CLM and CLW showed growth inhibition of human tumour cell lines by 0-46%. Therefore, a bioassay-guided isolation of water and methanolic extracts of C. longa was carried out and afforded nine isolates. At 25 μg/mL, these compounds inhibited LPO by 11-87%, COX-1 and -2 enzymes by 0-35% and 0-82% and growth of human tumour cells by 0-36%, respectively.
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da Silva G, Kirk BB, Lloyd C, Trevitt AJ, Blanksby SJ. Concerted HO2 Elimination from α-Aminoalkylperoxyl Free Radicals: Experimental and Theoretical Evidence from the Gas-Phase NH2(•)CHCO2(-) + O2 Reaction. J Phys Chem Lett 2012; 3:805-811. [PMID: 26286401 DOI: 10.1021/jz300118k] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We have investigated the gas-phase reaction of the α-aminoacetate (glycyl) radical anion (NH2(•)CHCO2(-)) with O2 using ion trap mass spectrometry, quantum chemistry, and statistical reaction rate theory. This radical is found to undergo a remarkably rapid reaction with O2 to form the hydroperoxyl radical (HO2(•)) and an even-electron imine (NHCHCO2(-)), with experiments and master equation simulations revealing that reaction proceeds at the ion-molecule collision rate. This reaction is facilitated by a low-energy concerted HO2(•) elimination mechanism in the NH2CH(OO(•))CO2(-) peroxyl radical. These findings can explain the widely observed free-radical-mediated oxidation of simple amino acids to amides plus α-keto acids (their imine hydrolysis products). This work also suggests that imines will be the main intermediates in the atmospheric oxidation of primary and secondary amines, including amine carbon capture solvents such as 2-aminoethanol (commonly known as monoethanolamine, or MEA), in a process that avoids the ozone-promoting conversion of (•)NO to (•)NO2 commonly encountered in peroxyl radical chemistry.
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Affiliation(s)
- Gabriel da Silva
- †Department of Chemical and Biomolecular Engineering, The University of Melbourne, Victoria 3010, Australia
| | - Benjamin B Kirk
- ‡ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Chemistry, University of Wollongong, NSW 2522, Australia
| | - Celli Lloyd
- ‡ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Chemistry, University of Wollongong, NSW 2522, Australia
| | - Adam J Trevitt
- ‡ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Chemistry, University of Wollongong, NSW 2522, Australia
| | - Stephen J Blanksby
- ‡ARC Centre of Excellence for Free Radical Chemistry and Biotechnology, School of Chemistry, University of Wollongong, NSW 2522, Australia
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Lam AKY, Li C, Khairallah G, Kirk BB, Blanksby SJ, Trevitt AJ, Wille U, O'Hair RAJ, da Silva G. Gas-phase reactions of aryl radicals with 2-butyne: experimental and theoretical investigation employing the N-methyl-pyridinium-4-yl radical cation. Phys Chem Chem Phys 2012; 14:2417-26. [DOI: 10.1039/c2cp22970f] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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28
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Kirk BB, Harman DG, Kenttämaa HI, Trevitt AJ, Blanksby SJ. Isolation and characterization of charge-tagged phenylperoxyl radicals in the gas phase: direct evidence for products and pathways in low temperature benzene oxidation. Phys Chem Chem Phys 2012; 14:16719-30. [DOI: 10.1039/c2cp43507a] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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29
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Osburn S, Berden G, Oomens J, O'Hair RAJ, Ryzhov V. Structure and reactivity of the N-acetyl-cysteine radical cation and anion: does radical migration occur? JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2011; 22:1794-1803. [PMID: 21952893 DOI: 10.1007/s13361-011-0198-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 06/20/2011] [Accepted: 06/21/2011] [Indexed: 05/31/2023]
Abstract
The structure and reactivity of the N-acetyl-cysteine radical cation and anion were studied using ion-molecule reactions, infrared multi-photon dissociation (IRMPD) spectroscopy, and density functional theory (DFT) calculations. The radical cation was generated by first nitrosylating the thiol of N-acetyl-cysteine followed by the homolytic cleavage of the S-NO bond in the gas phase. IRMPD spectroscopy coupled with DFT calculations revealed that for the radical cation the radical migrates from its initial position on the sulfur atom to the α-carbon position, which is 2.5 kJ mol(-1) lower in energy. The radical migration was confirmed by time-resolved ion-molecule reactions. These results are in contrast with our previous study on cysteine methyl ester radical cation (Osburn et al., Chem. Eur. J. 2011, 17, 873-879) and the study by Sinha et al. for cysteine radical cation (Phys. Chem. Chem. Phys. 2010, 12, 9794-9800) where the radical was found to stay on the sulfur atom as formed. A similar approach allowed us to form a hydrogen-deficient radical anion of N-acetyl-cysteine, (M - 2H)( •- ). IRMPD studies and ion-molecule reactions performed on the radical anion showed that the radical remains on the sulfur, which is the initial and more stable (by 63.6 kJ mol(-1)) position, and does not rearrange.
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Affiliation(s)
- Sandra Osburn
- Department of Chemistry and Biochemistry, and Center for Biochemical and Biophysical Studies, Northern Illinois University, DeKalb, IL 60115, USA
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30
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Ly T, Zhang X, Sun Q, Moore B, Tao Y, Julian RR. Rapid, quantitative, and site specific synthesis of biomolecular radicals from a simple photocaged precursor. Chem Commun (Camb) 2011; 47:2835-7. [PMID: 21258679 DOI: 10.1039/c0cc03363d] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Novel p-iodobenzoate-based labelling reagents are shown to be effective photocaged precursors for synthesizing biomolecular radicals site-selectively in the gaseous and condensed phases. In vacuo, a single pulse of UV photons (266 nm) is sufficient to quantitatively photolyse the C-I bond. In aqueous solutions, the photolysis half-life is estimated to be 2.5 minutes when irradiating with a 15 W compact fluorescent lamp (254 nm).
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Affiliation(s)
- Tony Ly
- Department of Chemistry, University of California, Riverside, Riverside, CA, USA.
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31
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Barlow CK, Wright A, Easton CJ, O'Hair RAJ. Gas-phase ion-molecule reactions using regioselectively generated radical cations to model oxidative damage and probe radical sites in peptides. Org Biomol Chem 2011; 9:3733-45. [DOI: 10.1039/c0ob01245a] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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32
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Ly T, Kirk BB, Hettiarachchi PI, Poad BLJ, Trevitt AJ, da Silva G, Blanksby SJ. Reactions of simple and peptidic alpha-carboxylate radical anions with dioxygen in the gas phase. Phys Chem Chem Phys 2011; 13:16314-23. [DOI: 10.1039/c1cp20784a] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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33
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Meyer M, Chan B, Radom L, Kass S. Gas-Phase Synthesis and Reactivity of Lithium Acetylide Ion, LiCC −. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201001485] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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34
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Meyer M, Chan B, Radom L, Kass S. Gas-Phase Synthesis and Reactivity of Lithium Acetylide Ion, LiCC−. Angew Chem Int Ed Engl 2010; 49:5161-4. [DOI: 10.1002/anie.201001485] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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