1
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Liu S, Li Y, Lin J, Ke Z, Grützmacher H, Su CY, Li Z. Sequential radical and cationic reactivity at separated sites within one molecule in solution. Chem Sci 2024; 15:5376-5384. [PMID: 38577367 PMCID: PMC10988588 DOI: 10.1039/d4sc00201f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 02/29/2024] [Indexed: 04/06/2024] Open
Abstract
Distonic radical cations (DRCs) with spatially separated charge and radical sites are expected to show both radical and cationic reactivity at different sites within one molecule. However, such "dual" reactivity has rarely been observed in the condensed phase. Herein we report the isolation of crystalline 1λ2,3λ2-1-phosphonia-3-phosphinyl-cyclohex-4-enes 2a,b˙+, which can be considered delocalized DRCs and were completely characterized by crystallographic, spectroscopic, and computational methods. These DRCs contain a radical and cationic site with seven and six valence electrons, respectively, which are both stabilized via conjugation, yet remain spatially separated. They exhibit reactivity that differs from that of conventional radical cations (CRCs); specifically they show sequential radical and cationic reactivity at separated sites within one molecule in solution.
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Affiliation(s)
- Shihua Liu
- LIFM, IGCME, School of Chemistry, Sun Yat-Sen University Guangzhou 510006 China
| | - Yinwu Li
- School of Materials Science and Engineering, Sun Yat-Sen University 510006 Guangzhou China
| | - Jieli Lin
- LIFM, IGCME, School of Chemistry, Sun Yat-Sen University Guangzhou 510006 China
| | - Zhuofeng Ke
- School of Materials Science and Engineering, Sun Yat-Sen University 510006 Guangzhou China
| | - Hansjörg Grützmacher
- LIFM, IGCME, School of Chemistry, Sun Yat-Sen University Guangzhou 510006 China
- Department of Chemistry and Applied Biosciences, ETH Zürich Vladimir-Prelog-Weg 1 Zürich 8093 Switzerland
| | - Cheng-Yong Su
- LIFM, IGCME, School of Chemistry, Sun Yat-Sen University Guangzhou 510006 China
| | - Zhongshu Li
- LIFM, IGCME, School of Chemistry, Sun Yat-Sen University Guangzhou 510006 China
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2
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Shiels OJ, Marlton SJP, Poad BLJ, Blanksby SJ, da Silva G, Trevitt AJ. Gas-Phase Phenyl Radical + O 2 Reacts via a Submerged Transition State. J Phys Chem A 2024; 128:413-419. [PMID: 38174881 DOI: 10.1021/acs.jpca.3c06878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
In the gas-phase chemistry of the atmosphere and automotive fuel combustion, peroxyl radical intermediates are formed following O2 addition to carbon-centered radicals which then initiate a complex network of radical reactions that govern the oxidative processing of hydrocarbons. The rapid association of the phenyl radical-a fundamental radical related to benzene-with O2 has hitherto been modeled as a barrierless process, a common assumption for peroxyl radical formation. Here, we provide an alternate explanation for the kinetics of this reaction by deploying double-hybrid density functional theory (DFT), at the DSD-PBEP86-D3(BJ)/aug-cc-pVTZ level of theory, and locate a submerged adiabatic transition state connected to a prereaction complex along the reaction entrance pathway. Using this potential energy scheme, experimental rate coefficients k(T) for the addition of O2 to the phenyl radical are accurately reproduced within a microcanonical kinetic model. This work highlights that purportedly barrierless radical oxidation reactions may instead be modeled using stationary points, which in turn provides insight into pressure and temperature dependence.
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Affiliation(s)
- Oisin J Shiels
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong 2522, Australia
| | - Samuel J P Marlton
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong 2522, Australia
| | - Berwyck L J Poad
- School of Chemistry and Physics and the Central Analytical Research Facility, Queensland University of Technology, Brisbane 4001, Australia
| | - Stephen J Blanksby
- School of Chemistry and Physics and the Central Analytical Research Facility, Queensland University of Technology, Brisbane 4001, Australia
| | - Gabriel da Silva
- Department of Chemical Engineering, the University of Melbourne, Melbourne 3010, Victoria, Australia
| | - Adam J Trevitt
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong 2522, Australia
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3
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Parker K, Bollis NE, Ryzhov V. Ion-molecule reactions of mass-selected ions. MASS SPECTROMETRY REVIEWS 2024; 43:47-89. [PMID: 36447431 DOI: 10.1002/mas.21819] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Gas-phase reactions of mass-selected ions with neutrals covers a very broad area of fundamental and applied mass spectrometry (MS). Oftentimes, ion-molecule reactions (IMR) can serve as a viable alternative to collision-induced dissociation and other ion dissociation techniques when using tandem MS. This review focuses on the literature pertaining applications of IMR since 2013. During the past decade considerable efforts have been made in analytical applications of IMR, including advances in one of the major techniques for characterization of unsaturated fatty acids and lipids, ozone-induced dissociation, and the development of a new technique for sequencing of large ions, hydrogen atom attachment/abstraction dissociation. Many advances have also been made in identifying gas-phase chemistry specific to a functional group in organic and biological compounds, which are useful in structure elucidation of analytes and differentiation of isomers/isobars. With "soft" ionization techniques like electrospray ionization having become mainstream for quite some time now, the efforts in the area of metal ion catalysis have firmly moved into exploring chemistry of ligated metal complexes in their "natural" oxidation states allowing to model individual steps of mechanisms in homogeneous catalysis, especially in combination with high-level DFT calculations. Finally, IMR continue to contribute to the body of knowledge in the area of chemistry of interstellar processes.
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Affiliation(s)
- Kevin Parker
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois, USA
| | - Nicholas E Bollis
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois, USA
| | - Victor Ryzhov
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois, USA
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4
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Qiu Z, Chu C, Wang K, Shen J, Zhu X, Kamran MA, Chen B. Sequential anodic oxidation and cathodic electro-Fenton in the Janus electrified membrane for reagent-free degradation of pollutants. WATER RESEARCH 2023; 246:120674. [PMID: 37857008 DOI: 10.1016/j.watres.2023.120674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 08/26/2023] [Accepted: 09/25/2023] [Indexed: 10/21/2023]
Abstract
Electrified membrane technologies have recently demonstrated high potential in tackling water pollution, yet their practical applications are challenged by relying on large precursor doses. Here, we developed a Janus porous membrane (JPEM) with synergic direct oxidation by Magnéli phase Ti4O7 anode and electro-Fenton reactions by CuFe2O4 cathode. Organic pollutants were first directly oxidized on the Ti4O7 anode, where the extracted electrons from pollutants were transported to the cathode for electro-Fenton production of hydroxyl radical (·OH). The cathodic ·OH further enhanced the mineralization of organic pollutant degradation intermediates. With the sequential anodic and cathodic oxidation processes, the reagent-free JPEM showed competitive performance in rapid degradation (removal rate of 0.417 mg L-1 s-1) and mineralization (68.7 % decrease in TOC) of sulfamethoxazole. The JPEM system displayed general performance to remove phenol, carbamazepine, and perfluorooctanoic acid. The JPEM runs solely on electricity and oxygen that is comparable to that of PEM relies on large precursor doses and, therefore, operation friendly and environmental sustainability. The high pollutant removal and mineralization achieved by rational design of the reaction processes sheds light on a new approach for constructing an efficient electrified membrane.
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Affiliation(s)
- Zhen Qiu
- Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China
| | - Chiheng Chu
- Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China
| | - Kun Wang
- Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China
| | - Jianjian Shen
- Dqchance. Science and Technology co Ltd, Hangzhou 310058, China
| | - Xiaoying Zhu
- Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China
| | - Muhammad Aqeel Kamran
- Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China
| | - Baoliang Chen
- Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China; Innovation Center of Yangtze River Delta, Zhejiang University, Zhejiang 311400, China.
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5
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Shiels OJ, Marlton SJP, Trevitt AJ. Protonation Isomer Specific Ion-Molecule Radical Reactions. J Am Chem Soc 2023. [PMID: 37339086 DOI: 10.1021/jacs.3c02552] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/22/2023]
Abstract
Through a combination of ion-mobility filtering and laser-equipped quadrupole ion-trap mass spectrometry, the gas-phase reaction kinetics of two protonation isomers of the distonic-radical quinazoline cation are independently measured with ethylene. For these radical addition reactions, protonation site variations drive significant changes in nearby radical reactivity, and this is primarily due to through-space electrostatic effects. Furthermore, quantum chemical methods specifically designed for calculating long-range interactions, such as double-hybrid density functional theory, are required to rationalize the experimentally measured difference in reactivity.
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Affiliation(s)
- Oisin J Shiels
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong 2522, New South Wales, Australia
| | - Samuel J P Marlton
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong 2522, New South Wales, Australia
| | - Adam J Trevitt
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong 2522, New South Wales, Australia
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6
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Finazzi L, Martens J, Berden G, Oomens J. Probing radical versus proton migration in the aniline cation with IRMPD spectroscopy. Mol Phys 2023. [DOI: 10.1080/00268976.2023.2192307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
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7
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Gutowski Ł, Liszewska M, Bartosewicz B, Budner B, Weyher JL, Jankiewicz BJ. Investigation of organic monoradicals reactivity using surface-enhanced Raman spectroscopy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 278:121312. [PMID: 35537259 DOI: 10.1016/j.saa.2022.121312] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 03/28/2022] [Accepted: 04/23/2022] [Indexed: 06/14/2023]
Abstract
Surface-enhanced Raman spectroscopy (SERS) and self-assembled monolayer (SAM) approaches were used to investigate the reactions of organic monoradicals with methanol. An attempt was made to generate monoradicals from thiophenols and phenylmethanethiols substituted with bromine, iodine, and nitro groups by irradiation with UV light. Monolayers of radical precursors were deposited on SERS substrates, which were then immersed in methanol and irradiated for 1 and/or 3, 6, 12 and 24 h in a UV photochemical reactor. Pre- and postreaction SERS spectra were obtained by using a confocal Raman microscope and compared with the spectra of expected products of the radical reaction with methanol. Our studies have shown that the efficiency of monoradical generation is highly dependent on the chemical structure of the precursor. In addition, it is shown that both the SERS substrate and experimental conditions used strongly influence the obtained results.
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Affiliation(s)
- Łukasz Gutowski
- Institute of Optoelectronics, Military University of Technology, gen. Sylwestra Kaliskiego 2, 00-908 Warsaw, Poland.
| | - Malwina Liszewska
- Institute of Optoelectronics, Military University of Technology, gen. Sylwestra Kaliskiego 2, 00-908 Warsaw, Poland.
| | - Bartosz Bartosewicz
- Institute of Optoelectronics, Military University of Technology, gen. Sylwestra Kaliskiego 2, 00-908 Warsaw, Poland.
| | - Bogusław Budner
- Institute of Optoelectronics, Military University of Technology, gen. Sylwestra Kaliskiego 2, 00-908 Warsaw, Poland.
| | - Jan L Weyher
- Institute of High-Pressure Physics, Polish Academy of Sciences, Sokołowska 29/37, 01-142 Warsaw, Poland.
| | - Bartłomiej J Jankiewicz
- Institute of Optoelectronics, Military University of Technology, gen. Sylwestra Kaliskiego 2, 00-908 Warsaw, Poland.
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8
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Shiels OJ, Turner JA, Kelly PD, Blanksby S, da Silva G, Trevitt A. Modelling Reaction Kinetics of Distonic Radical Ions: A Systematic Investigation of Phenyl-type Radical Addition to Unsaturated Hydrocarbons. Faraday Discuss 2022; 238:475-490. [DOI: 10.1039/d2fd00045h] [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
Gas phase ion−molecule reactions are central to chemical processes across many environments. A feature of many of these reactions is an inverse relationship between temperature and reaction rate arising from...
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9
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Jacovella U, Rossi C, Romanzin C, Alcaraz C, Thissen R. Structural elucidation of C6H4+· using chemical reaction monitoring: Charge transfer versus bond forming reactions. Chemphyschem 2021; 23:e202100871. [PMID: 34951502 DOI: 10.1002/cphc.202100871] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 12/23/2021] [Indexed: 11/06/2022]
Abstract
Mass spectrometry is a powerful tool but when used on its own, without specific activation of ions, the ion mass is the single observable and the structural information is absent. One way of retrieving this information is by using ion-molecule reactions. We propose a general method to disentangle isomeric structures by combining mass spectrometry, tunable synchrotron light source, and quantum-chemistry calculations. We use reactive chemical monitoring technique, which consists in tracking reactivity changes as a function of photoionization energy i.e. the ionic structure. We illustrate the power of this technique with charge transfer reactions of C6H4+· isomers with allene and propyne and discuss its universal applicability. Furthermore, we emphasize the special reactivity characteristics of distonic ions, where strong charge transfer reactivity but very limited reactivity involving bond formation and following cleavages were observed and attributed to the unconventional ortho -benzyne distonic cation.
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Affiliation(s)
- Ugo Jacovella
- Université Paris-Saclay, ISMO, Bat. 520, Rue André Rivière, 91405, Orsay, FRANCE
| | - Corentin Rossi
- Université Paris-Saclay, Institut Chimie Physique, FRANCE
| | - Claire Romanzin
- Université Paris-Saclay: Universite Paris-Saclay, Institut Chimie Physique, FRANCE
| | | | - Roland Thissen
- Université Paris-Saclay: Universite Paris-Saclay, Institut Chimie physique, FRANCE
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10
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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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11
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Bonney JR, Prentice BM. Perspective on Emerging Mass Spectrometry Technologies for Comprehensive Lipid Structural Elucidation. Anal Chem 2021; 93:6311-6322. [PMID: 33856206 PMCID: PMC8177724 DOI: 10.1021/acs.analchem.1c00061] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Lipids and metabolites are of interest in many clinical and research settings because it is the metabolome that is increasingly recognized as a more dynamic and sensitive molecular measure of phenotype. The enormous diversity of lipid structures and the importance of biological structure-function relationships in a wide variety of applications makes accurate identification a challenging yet crucial area of research in the lipid community. Indeed, subtle differences in the chemical structures of lipids can have important implications in cellular metabolism and many disease pathologies. The speed, sensitivity, and molecular specificity afforded by modern mass spectrometry has led to its widespread adoption in the field of lipidomics on many different instrument platforms and experimental workflows. However, unambiguous and complete structural identification of lipids by mass spectrometry remains challenging. Increasingly sophisticated tandem mass spectrometry (MS/MS) approaches are now being developed and seamlessly integrated into lipidomics workflows to meet this challenge. These approaches generally either (i) alter the type of ion that is interrogated or (ii) alter the dissociation method in order to improve the structural information obtained from the MS/MS experiment. In this Perspective, we highlight recent advances in both ion type alteration and ion dissociation methods for lipid identification by mass spectrometry. This discussion is aimed to engage investigators involved in fundamental ion chemistry and technology developments as well as practitioners of lipidomics and its many applications. The rapid rate of technology development in recent years has accelerated and strengthened the ties between these two research communities. We identify the common characteristics and practical figures of merit of these emerging approaches and discuss ways these may catalyze future directions of lipid structural elucidation research.
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Affiliation(s)
- Julia R Bonney
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
| | - Boone M Prentice
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
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12
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Mondal T, Shaik S, Kenttämaa H, Stuyver T. Modulating the radical reactivity of phenyl radicals with the help of distonic charges: it is all about electrostatic catalysis. Chem Sci 2021; 12:4800-4809. [PMID: 34163733 PMCID: PMC8179573 DOI: 10.1039/d0sc07111k] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 02/16/2021] [Indexed: 11/21/2022] Open
Abstract
This manuscript reports the modulation of H-abstraction reactivity of phenyl radicals by (positive and negative) distonic ions. Specifically, we focus on the origins of this modulating effect: can the charged functional groups truly be described as "extreme forms of electron-withdrawing/donating substituents" - implying a through-bond mechanism - as argued in the literature, or is the modulation mainly caused by through-space effects? Our analysis indicates that the effect of the remote charges can be mimicked almost perfectly with the help of a purely electrostatic treatment, i.e. replacing the charged functional groups by a simple uniform electric field is sufficient to recover the quantitative reactivity trends. Hence, through-space effects dominate, whereas through-bond effects play a minor role at best. We elucidate our results through a careful Valence Bond (VB) analysis and demonstrate that such a qualitative analysis not only reveals through-space dominance, but also demonstrates a remarkable reversal in the reactivity trends of a given polarity upon a rational modification of the reaction partner. As such, our findings demonstrate that VB theory can lead to productive predictions about the behaviour of distonic radical ions.
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Affiliation(s)
- Totan Mondal
- Institute of Chemistry, The Hebrew University Jerusalem 91904 Israel
| | - Sason Shaik
- Institute of Chemistry, The Hebrew University Jerusalem 91904 Israel
| | - Hilkka Kenttämaa
- Department of Chemistry, Purdue University West Lafayette Indiana 47907-1393 USA
| | - Thijs Stuyver
- Institute of Chemistry, The Hebrew University Jerusalem 91904 Israel
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13
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Shiels OJ, Kelly PD, Bright CC, Poad BLJ, Blanksby SJ, da Silva G, Trevitt AJ. Reactivity Trends in the Gas-Phase Addition of Acetylene to the N-Protonated Aryl Radical Cations of Pyridine, Aniline, and Benzonitrile. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:537-547. [PMID: 33444019 DOI: 10.1021/jasms.0c00386] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
A key step in gas-phase polycyclic aromatic hydrocarbon (PAH) formation involves the addition of acetylene (or other alkyne) to σ-type aromatic radicals, with successive additions yielding more complex PAHs. A similar process can happen for N-containing aromatics. In cold diffuse environments, such as the interstellar medium, rates of radical addition may be enhanced when the σ-type radical is charged. This paper investigates the gas-phase ion-molecule reactions of acetylene with nine aromatic distonic σ-type radical cations derived from pyridinium (Pyr), anilinium (Anl), and benzonitrilium (Bzn) ions. Three isomers are studied in each case (radical sites at the ortho, meta, and para positions). Using a room temperature ion trap, second-order rate coefficients, product branching ratios, and reaction efficiencies are measured. The rate coefficients increase from para to ortho positions. The second-order rate coefficients can be sorted into three groups: low, between 1 and 3 × 10-12 cm3 molecule-1 s-1 (3Anl and 4Anl); intermediate, between 5 and 15 × 10-12 cm3 molecule-1 s-1 (2Bzn, 3Bzn, and 4Bzn); and high, between 8 and 31 × 10-11 cm3 molecule-1 s-1 (2Anl, 2Pyr, 3Pyr, and 4Pyr); and 2Anl is the only radical cation with a rate coefficient distinctly different from its isomers. Quantum chemical calculations, using M06-2X-D3(0)/6-31++G(2df,p) geometries and DSD-PBEP86-NL/aug-cc-pVQZ energies, are deployed to rationalize reactivity trends based on the stability of prereactive complexes. The G3X-K method guides the assignment of product ions following adduct formation. The rate coefficient trend can be rationalized by a simple model based on the prereactive complex forward barrier height.
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Affiliation(s)
- Oisin J Shiels
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - P D Kelly
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Cameron C Bright
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Berwyck L J Poad
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, Queensland 4001, Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology, Brisbane, Queensland 4001, Australia
| | - Gabriel da Silva
- Department of Chemical Engineering, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Adam J Trevitt
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
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14
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Chen X, Liu LL, Liu S, Grützmacher H, Li Z. A Room‐Temperature Stable Distonic Radical Cation. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202011677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Xiaodan Chen
- College of Chemistry and Materials Science Jinan University Guangzhou 510632 China
| | - Liu Leo Liu
- Shenzhen Grubbs Institute and Department of Chemistry Southern University of Science and Technology Shenzhen 518055 China
| | - Shihua Liu
- Lehn Institute of Functional Materials (LIFM) School of Chemistry Sun Yat-Sen University Guangzhou 510275 China
- State Key Laboratory of Elemento-Organic Chemistry Nankai University Tianjin 30071 China
| | - Hansjörg Grützmacher
- Lehn Institute of Functional Materials (LIFM) School of Chemistry Sun Yat-Sen University Guangzhou 510275 China
- State Key Laboratory of Elemento-Organic Chemistry Nankai University Tianjin 30071 China
- Department of Chemistry and Applied Biosciences ETH Zürich Vladimir-Prelog-Weg 1 Zürich 8093 Switzerland
| | - Zhongshu Li
- Lehn Institute of Functional Materials (LIFM) School of Chemistry Sun Yat-Sen University Guangzhou 510275 China
- State Key Laboratory of Elemento-Organic Chemistry Nankai University Tianjin 30071 China
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15
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Chen X, Liu LL, Liu S, Grützmacher H, Li Z. A Room-Temperature Stable Distonic Radical Cation. Angew Chem Int Ed Engl 2020; 59:23830-23835. [PMID: 32914528 DOI: 10.1002/anie.202011677] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Indexed: 12/28/2022]
Abstract
Distonic radical cations (DRCs) with spatially separated charge and radical sites have, so far, largely been observed by gas-phase mass spectrometry and/or matrix isolation spectroscopy work. Herein, we disclose the isolation of a crystalline dicarbondiphosphide-based β-distonic radical cation salt 3.+ (BARF) (BARF=[B(3,5-(CF3 )2 C6 H3 )4 )]- ) stable at room temperature and formed by a one-electron-oxidation-induced intramolecular skeletal rearrangement reaction. Such a species has been validated by electron paramagnetic resonance (EPR) spectroscopy, single-crystal X-ray diffraction, UV/Vis spectroscopy and density functional theory (DFT) calculations. Compound 3.+ (BARF) exhibits a large majority of spin density at a two-coordinate phosphorus atom (0.74 a.u.) and a cationic charge located predominantly at the four-coordinate phosphorus atom (1.53 a.u.), which are separated by one carbon atom. This species represents an isolable entity of a phosphorus radical cation that is the closest to a genuine phosphorus DRC to date.
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Affiliation(s)
- Xiaodan Chen
- College of Chemistry and Materials Science, Jinan University, Guangzhou, 510632, China
| | - Liu Leo Liu
- Shenzhen Grubbs Institute and Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Shihua Liu
- Lehn Institute of Functional Materials (LIFM), School of Chemistry, Sun Yat-Sen University, Guangzhou, 510275, China.,State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin, 30071, China
| | - Hansjörg Grützmacher
- Lehn Institute of Functional Materials (LIFM), School of Chemistry, Sun Yat-Sen University, Guangzhou, 510275, China.,State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin, 30071, China.,Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1, Zürich, 8093, Switzerland
| | - Zhongshu Li
- Lehn Institute of Functional Materials (LIFM), School of Chemistry, Sun Yat-Sen University, Guangzhou, 510275, China.,State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin, 30071, China
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16
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Ding D, Jiang H, Ma X, Nash JJ, Kenttämaa HI. Effects of the Distance between Radical Sites on the Reactivities of Aromatic Biradicals. J Org Chem 2020; 85:8415-8428. [PMID: 32482062 DOI: 10.1021/acs.joc.0c00658] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Coupling of the radical sites in isomeric benzynes is known to hinder their radical reactivity. In order to determine how far apart the radical sites must be for them not to interact, the gas-phase reactivity of several isomeric protonated (iso)quinoline- and acridine-based biradicals was examined. All the (iso)quinolinium-based biradicals were found to react slower than the related monoradicals with similar vertical electron affinities (i.e., similar polar effects). In sharp contrast, the acridinium-based biradicals, most with the radical sites farther apart than in the (iso)quinolinium-based systems, showed greater reactivities than the relevant monoradicals with similar vertical electron affinities. The greater distances between the two radical sites in these biradicals lead to very little or no spin-spin coupling, and no suppression of radical reactivity was observed. Therefore, the radical sites can still interact if they are located on adjacent benzene rings and only after being separated further than that does no coupling occur. The most reactive radical site of each biradical was experimentally determined to be the one predicted to be more reactive based on the monoradical reactivity data. Therefore, the calculated vertical electron affinities of relevant monoradicals can be used to predict which radical site is most reactive in the biradicals.
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Affiliation(s)
- Duanchen Ding
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Hanning Jiang
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Xin Ma
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - John J Nash
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Hilkka I Kenttämaa
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
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17
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Andrikopoulos B, Sidhu PK, Taggert BI, Nathanael JG, O'Hair RAJ, Wille U. Reaction of Distonic Aryl and Alkyl Radical Cations with Amines: The Role of Charge and Spin Revealed by Mass Spectrometry, Kinetic Studies, and DFT Calculations. Chempluschem 2020. [DOI: 10.1002/cplu.201900706] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Benjamin Andrikopoulos
- School of Chemistry Bio21 Institute The University of Melbourne 30 Flemington Road, Parkville Victoria 3010 Australia
| | - Parvinder K. Sidhu
- School of Chemistry Bio21 Institute The University of Melbourne 30 Flemington Road, Parkville Victoria 3010 Australia
| | - Bethany I. Taggert
- School of Chemistry Bio21 Institute The University of Melbourne 30 Flemington Road, Parkville Victoria 3010 Australia
| | - Joses G. Nathanael
- School of Chemistry Bio21 Institute The University of Melbourne 30 Flemington Road, Parkville Victoria 3010 Australia
| | - Richard A. J. O'Hair
- School of Chemistry Bio21 Institute The University of Melbourne 30 Flemington Road, Parkville Victoria 3010 Australia
| | - Uta Wille
- School of Chemistry Bio21 Institute The University of Melbourne 30 Flemington Road, Parkville Victoria 3010 Australia
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18
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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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19
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Stuyver T, Chen B, Zeng T, Geerlings P, De Proft F, Hoffmann R. Do Diradicals Behave Like Radicals? Chem Rev 2019; 119:11291-11351. [DOI: 10.1021/acs.chemrev.9b00260] [Citation(s) in RCA: 139] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Thijs Stuyver
- Algemene Chemie, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Bo Chen
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca New York 14853, United States
| | - Tao Zeng
- Department of Chemistry, York University, Toronto, Ontario M3J1P3, Canada
- Department of Chemistry, Carleton University, Ottawa, Ontario K1S5B6, Canada
| | - Paul Geerlings
- Algemene Chemie, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Frank De Proft
- Algemene Chemie, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Roald Hoffmann
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca New York 14853, United States
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20
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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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21
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Chattopadhyay S. Simplified Treatment of Electronic Structures of the Lowest Singlet and Triplet States of Didehydropyrazines. J Phys Chem A 2019; 123:5980-5994. [DOI: 10.1021/acs.jpca.9b03998] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Sudip Chattopadhyay
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103, India
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22
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Kotha RR, Yerabolu R, Aqueel MS, Riedeman JS, Szalwinski L, Ding D, Nash JJ, Kenttämaa HI. Quinoline Triradicals: A Reactivity Study. J Am Chem Soc 2019; 141:6672-6679. [PMID: 30945540 DOI: 10.1021/jacs.9b01740] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The gas-phase reactivities of several protonated quinoline-based σ-type (carbon-centered) mono-, bi-, and triradicals toward dimethyl disulfide (DMDS) were studied by using a linear quadrupole ion trap mass spectrometer. The mono- and biradicals produce abundant thiomethyl abstraction products and small amounts of DMDS radical cation, as expected. Surprisingly, all triradicals produce very abundant DMDS radical cations. A single-step mechanism involving electron transfer from DMDS to the triradicals is highly unlikely because the (experimental) adiabatic ionization energy of DMDS is almost 3 eV greater than the (calculated) adiabatic electron affinities of the triradicals. The unexpected reactivity can be explained based on an unprecedented two-step mechanism wherein the protonated triradical first transfers a proton to DMDS, which is then followed by hydrogen atom abstraction from the protonated sulfur atom in DMDS by the radical site in the benzene ring of the deprotonated triradical to generate the conventional DMDS radical cation and a neutral biradical. Quantum chemical calculations as well as examination of deuterated and methylated triradicals provide support for this mechanism. The proton affinities of the neutral triradicals (and DMDS) influence the first step of the reaction while the vertical electron affinities and spin-spin coupling of the neutral triradicals influence the second step. The calculated total reaction exothermicities for the triradicals studied range from 27.6 up to 29.9 kcal mol-1.
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Affiliation(s)
- Raghavendhar R Kotha
- Department of Chemistry , Purdue University , 560 Oval Drive , West Lafayette , Indiana 47907 , United States
| | - Ravikiran Yerabolu
- Department of Chemistry , Purdue University , 560 Oval Drive , West Lafayette , Indiana 47907 , United States
| | - Mohammad Sabir Aqueel
- Department of Chemistry , Purdue University , 560 Oval Drive , West Lafayette , Indiana 47907 , United States
| | - James S Riedeman
- Department of Chemistry , Purdue University , 560 Oval Drive , West Lafayette , Indiana 47907 , United States
| | - Lucas Szalwinski
- Department of Chemistry , Purdue University , 560 Oval Drive , West Lafayette , Indiana 47907 , United States
| | - Duanchen Ding
- Department of Chemistry , Purdue University , 560 Oval Drive , West Lafayette , Indiana 47907 , United States
| | - John J Nash
- Department of Chemistry , Purdue University , 560 Oval Drive , West Lafayette , Indiana 47907 , United States
| | - Hilkka I Kenttämaa
- Department of Chemistry , Purdue University , 560 Oval Drive , West Lafayette , Indiana 47907 , United States
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23
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Ma X, Jin C, Wang D, Nash JJ, Kenttämaa HI. Relative Reactivities of Three Isomeric Aromatic Biradicals with a 1,4‐Biradical Topology Are Controlled by Polar Effects. Chemistry 2019; 25:6355-6361. [PMID: 30811712 DOI: 10.1002/chem.201806106] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Revised: 02/24/2019] [Indexed: 01/22/2023]
Affiliation(s)
- Xin Ma
- Department of ChemistryPurdue University 560 Oval Drive West Lafayette Indiana 47907 USA
| | - Chunfen Jin
- Department of ChemistryPurdue University 560 Oval Drive West Lafayette Indiana 47907 USA
| | - Duanda Wang
- Department of ChemistryPurdue University 560 Oval Drive West Lafayette Indiana 47907 USA
| | - John J. Nash
- Department of ChemistryPurdue University 560 Oval Drive West Lafayette Indiana 47907 USA
| | - Hilkka I. Kenttämaa
- Department of ChemistryPurdue University 560 Oval Drive West Lafayette Indiana 47907 USA
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24
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Chattopadhyay S. Ab Initio Probing of the Ground State of Tetraradicals: Breakdown of Hund's Multiplicity Rule. J Phys Chem A 2019; 123:2211-2226. [PMID: 30794415 DOI: 10.1021/acs.jpca.8b10514] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The electronic structure of organic σ-type polyradical including 2,4,6-tridehydropyridine radical cation (246-TDHP) and three isomers of tetradehydrobenzene (TDHB) have been studied using a computationally robust and cost-effective second-order multireference perturbative model which provides a balanced treatment of nondynamic and dynamic contributions to the electron correlation problem in the ground or excited electronic states which are imperative for predicting structural properties (e.g., ground state multiplicity, energy gaps between high-spin and low-spin states, etc.) of polyradicals. Energy gaps are useful to capture insight into the degree of interaction between the radical sites. An important finding of this study is that the tetraradicals considered here possess singlet ground states, contrary to Hund's rule. Present findings are in close agreement with the available high-level ab initio estimates at attainable cost implying that a perturbative description of the systems is adequate. The impact of N+ on the nature of ground state for the 246-TDHP have also analyzed. The singlet-triplet energy gaps for 1245- and 1234-TDHB are smaller than for o-benzyne mainly due to the ring strain. 1235-TDHB is 14.42 and 11.05 kcal/mol lower in energy than 1245- and 1234-isomers, respectively. IVO-SSMRPT predicts 1A1-3B2 and 1A1-5B2 gaps of 25.84 and 105.15 kcal/mol, respectively for the 246-TDHP cation.
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Affiliation(s)
- Sudip Chattopadhyay
- Department of Chemistry , Indian Institute of Engineering Science and Technology , Shibpur , Howrah 711103 , India
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25
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Kotha RR, Yerabolu R, Ding D, Szalwinski L, Ma X, Wittrig A, Kong J, Nash JJ, Kenttämaa HI. Spin–Spin Coupling Between Two
meta
‐Benzyne Moieties In a Quinolinium Tetraradical Cation Increases Their Reactivities. Chemistry 2019; 25:4472-4477. [PMID: 30648302 DOI: 10.1002/chem.201806096] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 01/12/2019] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Duanchen Ding
- Department of Chemistry Purdue University West Lafayette IN 47907 USA
| | - Lucas Szalwinski
- Department of Chemistry Purdue University West Lafayette IN 47907 USA
| | - Xin Ma
- Department of Chemistry Purdue University West Lafayette IN 47907 USA
| | - Ashley Wittrig
- ExxonMobil Research & Engineering Company Annandale NJ 08801 USA
| | - John Kong
- Department of Chemistry Purdue University West Lafayette IN 47907 USA
| | - John J. Nash
- Department of Chemistry Purdue University West Lafayette IN 47907 USA
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26
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Weragoda GK, Pilkington RL, Polyzos A, O'Hair RAJ. Regioselectivity of aryl radical attack onto isocyanates and isothiocyanates. Org Biomol Chem 2018; 16:9011-9020. [PMID: 30427050 DOI: 10.1039/c8ob02209g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The combination of multistage mass spectrometry experiments employing the distonic radical approach together with DFT calculations are used to examine addition of the N-methyl-pyridinium-4-yl radical cation (γ-NMP) to iso(thio)cyanates in the gas-phase. The type of products formed depend on the nature of the iso(thio)cyanate: (1) hydrogen atom abstraction occurs for alkyl isocyanates; (2) aryl isocyanates undergo radical-ipso substitution; (3) radical attack occurs at the C[double bond, length as m-dash]C bond of allyl isocyanate; (4) radical attack occurs at the C[double bond, length as m-dash]S bond of isothiocyanates to generate S adducts of γ-NMP and isonitriles. DFT calculations provide insight into the reactivity differences of these heterocumulenes towards the electrophilic C-centered γ-distonic radical cations. Translation of these gas phase results to the solution phase were hampered by dominating radical recombination reactions which appear to be favoured over the radical-iso(thio)cyanate reactions.
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27
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Wenthold PG, Winter AH. Nucleophilic Addition to Singlet Diradicals: Homosymmetric Diradicals. J Org Chem 2018; 83:12390-12396. [DOI: 10.1021/acs.joc.8b01413] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Paul G. Wenthold
- The Department of Chemistry and Biochemistry, Purdue University, West Lafayette, Indiana 47906, United States
| | - Arthur H. Winter
- The Department of Chemistry and Biochemistry, Iowa State University, Ames, Iowa 52101, United States
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28
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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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29
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Bright CC, Prendergast MB, Kelly PD, Bezzina JP, Blanksby SJ, da Silva G, Trevitt AJ. Highly efficient gas-phase reactivity of protonated pyridine radicals with propene. Phys Chem Chem Phys 2018; 19:31072-31084. [PMID: 29152628 DOI: 10.1039/c7cp06644a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Small nitrogen containing heteroaromatics are fundamental building blocks for many biological molecules, including the DNA nucleotides. Pyridine, as a prototypical N-heteroaromatic, has been implicated in the chemical evolution of many extraterrestrial environments, including the atmosphere of Titan. This paper reports on the gas-phase ion-molecule reactions of the three dehydro-N-pyridinium radical cation isomers with propene. Photodissociation ion-trap mass spectrometry experiments are used to measure product branching ratios and reaction kinetics. Reaction efficiencies for 2-dehydro-N-pyridinium, 3-dehydro-N-pyridinium and 4-dehydro-N-pyridinium with propene are 70%, 47% and 41%, respectively. The m/z 106 channel is the major product channel across all cases and assigned 2-, 3-, and 4-vinylpyridinium for each reaction. The m/z 93 channel is also significant and assigned the 2-, 3-, and 4-N-protonated-picolyl radical cation for each case. H-Abstraction from propene is not competitive under experimental conditions. Potential energy schemes, at the M06-2X/6-31(2df,p) level of theory and basis set, are described to assist in rationalising observed product branching ratios and elucidating possible reaction mechanisms. Reaction barriers to the production of vinylpyridinium (m/z 106) + CH3 are the lowest identified for the 3- and 4-dehydro-N-pyridinium reactions, in support of the observed dominance of the m/z 106 ion signal. Ethylene loss via ring-mediated H-transfer along the propyl group is found to be the lowest energy pathway for the 2-dehydro-N-pyridinium reaction, suggesting a preference toward m/z 93 (N-protonated-picolyl radical cation) over the experimentally observed products. Entropic bottle-necks along the m/z 93 pathway however, associated with ring-mediated H-atom transfer, are responsible for the dominance of m/z 106 in the 2-dehydro-N-pyridinium + propene reaction. For all three isomers, computed barriers for all observed reaction channels were below the entrance channel, suggesting these reactions can contribute to molecular weight growth in extraterrestrial environments with accelerated reaction rates in low temperature regions of space.
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Affiliation(s)
- Cameron C Bright
- School of Chemistry, University of Wollongong, Wollongong, NSW 2522, Australia.
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30
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Bezzina JP, Prendergast MB, Blanksby SJ, Trevitt AJ. Gas-Phase Oxidation of the Protonated Uracil-5-yl Radical Cation. J Phys Chem A 2018; 122:890-896. [PMID: 29295616 DOI: 10.1021/acs.jpca.7b09411] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This study targets the kinetics and product detection of the gas-phase oxidation reaction of the protonated 5-dehydrouracil (uracil-5-yl) distonic radical cation using ion-trap mass spectrometry. Protonated 5-dehydrouracil radical ions (5-dehydrouracilH+ radical ion, m/z 112) are produced within an ion trap by laser photolysis of protonated 5-iodouracil. Storage of the 5-dehydrouracilH+ radical ion in the presence of controlled concentration of O2 reveals two main products. The major reaction product pathway is assigned as the formation of protonated 2-hydroxypyrimidine-4,5-dione (m/z 127) + •OH. A second product ion (m/z 99), putatively assigned as a five-member-ring ketone structure, is tentatively explained as arising from the decarbonylation (-CO) of protonated 2-hydroxypyrimidine-4,5-dione. Because protonation of the 5-dehydrouracil radical likely forms a dienol structure, the O2 reaction at the 5 position is ortho to an -OH group. Following this addition of O2, the peroxyl-radical intermediate isomerizes by H atom transfer from the -OH group. The ensuing hydroperoxide then decomposes to eliminate •OH radical. It is shown that this elimination of •OH radical (-17 Da) is evidence for the presence of an -OH group ortho to the initial phenyl radical site, in good accord with calculations. The subsequent CO loss mechanism, to form the aforementioned five-member-ring structure, is unclear, but some pathways are discussed. By following the kinetics of the reaction, the room temperature second-order rate coefficient of the 5-dehydrouracilH+ distonic radical cation with molecular oxygen is measured at 7.2 × 10-11 cm3 molecule-1 s-1, Φ = 12% (with ±50% total accuracy). For aryl radical reactions with O2, the presence of the •OH elimination product pathway, following the peroxyl-radical formation, is an indicator of an -OH group ortho to the radical site.
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Affiliation(s)
- James P Bezzina
- School of Chemistry, University of Wollongong , Wollongong, Australia 2522
| | | | - Stephen J Blanksby
- Central Analytical Research Facility, Institute for Future Environments, Queensland University of Technology , Brisbane, Australia 4001
| | - Adam J Trevitt
- School of Chemistry, University of Wollongong , Wollongong, Australia 2522
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31
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Zhou S, Schlangen M, Schwarz H. Spin-Selective, Competitive Hydrogen-Atom Transfer versus CH2
O-Generation from the CH4
/[ReO4
]+
Couple at Ambient Conditions. Chemistry 2017; 23:17469-17472. [DOI: 10.1002/chem.201704892] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Indexed: 12/22/2022]
Affiliation(s)
- Shaodong Zhou
- Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering; Zhejiang University; 310027 Hangzhou P.R. China
- Institut für Chemie; Technische Universität Berlin; Straße des 17. Juni 135 10623 Berlin Germany
| | - Maria Schlangen
- Institut für Chemie; Technische Universität Berlin; Straße des 17. Juni 135 10623 Berlin Germany
| | - Helmut Schwarz
- Institut für Chemie; Technische Universität Berlin; Straße des 17. Juni 135 10623 Berlin Germany
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32
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Hossain E, Deng SM, Gozem S, Krylov AI, Wang XB, Wenthold PG. Photoelectron Spectroscopy Study of Quinonimides. J Am Chem Soc 2017; 139:11138-11148. [DOI: 10.1021/jacs.7b05197] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Ekram Hossain
- The
Department of Chemistry Purdue University West Lafayette, Indiana 47906, United States
| | - Shihu M. Deng
- Physical
Sciences Division, Pacific Northwest National Laboratory P.O. Box 999, MS k8-88 Richland, Washington 99352, United States
| | - Samer Gozem
- Department
of Chemistry University of Southern California Los Angeles, 90089, United States
| | - Anna I. Krylov
- Department
of Chemistry University of Southern California Los Angeles, 90089, United States
| | - Xue-Bin Wang
- Physical
Sciences Division, Pacific Northwest National Laboratory P.O. Box 999, MS k8-88 Richland, Washington 99352, United States
| | - Paul G. Wenthold
- The
Department of Chemistry Purdue University West Lafayette, Indiana 47906, United States
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33
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Taggert BI, O'Hair RAJ, Wille U. Environmental Polymer Degradation: Using the Distonic Radical Ion Approach to Study the Gas-Phase Reactions of Model Polyester Radicals. J Phys Chem A 2017. [PMID: 28644629 DOI: 10.1021/acs.jpca.7b04217] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A novel precursor to the distonic O- and C-centered radical cations Oxo+O• and Oxo+C• was designed and synthesized, which represents model systems for radicals produced during polyester degradation. The precursor is equipped with a nitrate functional group, which serves as a masked site for these alkoxyl and carbon radicals that are unleashed through collision-induced dissociation (CID). Oxo+O• and Oxo+C• feature a cyclic carboxonium ion as permanent charge tag to enable monitoring their ion-molecule reactions on the millisecond to second time scale in the ion trap of the mass spectrometer. The reactions of Oxo+O• and Oxo+C• with cyclohexene, cyclohexadiene, ethyl acetate, 1,1-dimethoxyethane, and 1,2-dimethoxyethane, which exhibit structural features present in both intact and defective polyesters, were explored through product and kinetic studies to identify "hot spots" for radical-induced damage in polyesters. All reactions with Oxo+O• were extremely fast and proceeded predominantly through HAT. Oxo+C• was about two orders of magnitude less reactive and did not noticeably damage aliphatic ester moieties through hydrogen abstraction on the time scale of our experiments. Radical addition to alkene π systems was identified as an important pathway for C-radicals, which needs to be included in polymer degradation mechanisms.
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Affiliation(s)
- Bethany I Taggert
- School of Chemistry, Bio21 Institute, The University of Melbourne , 30 Flemington Road, Parkville, Victoria 3010, Australia
| | - Richard A J O'Hair
- School of Chemistry, Bio21 Institute, The University of Melbourne , 30 Flemington Road, Parkville, Victoria 3010, Australia
| | - Uta Wille
- School of Chemistry, Bio21 Institute, The University of Melbourne , 30 Flemington Road, Parkville, Victoria 3010, Australia
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34
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Kotha RR, Nash JJ, Kenttämaa HI. An Oxygen‐
peri
‐Bridged Quinolinium Cation and Its Monoradical Counterpart. European J Org Chem 2017. [DOI: 10.1002/ejoc.201601572] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Raghavendhar R. Kotha
- Department of Chemistry Purdue University 560 Oval Drive 47907‐2084 West Lafayette IN USA
| | - John J. Nash
- Department of Chemistry Purdue University 560 Oval Drive 47907‐2084 West Lafayette IN USA
| | - Hilkka I. Kenttämaa
- Department of Chemistry Purdue University 560 Oval Drive 47907‐2084 West Lafayette IN USA
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35
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Osburn S, Chan B, Ryzhov V, Radom L, O'Hair RAJ. Role of Hydrogen Bonding on the Reactivity of Thiyl Radicals: A Mass Spectrometric and Computational Study Using the Distonic Radical Ion Approach. J Phys Chem A 2016; 120:8184-8189. [PMID: 27726360 DOI: 10.1021/acs.jpca.6b08544] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Experimental and computational quantum chemistry investigations of the gas-phase ion-molecule reactions between the distonic ions +H3N(CH2)nS• (n = 2-4) and the reagents dimethyl disulfide, allyl bromide, and allyl iodide demonstrate that intramolecular hydrogen bonding can modulate the reactivity of thiyl radicals. Thus, the 3-ammonium-1-propanethiyl radical (n = 3) exhibits the lowest reactivity of these distonic ions toward all substrates. Theoretical calculations on this distonic ion highlight that its most stable conformation involves a six-membered ring configuration, and that it has the strongest intramolecular hydrogen bond. In addition, the calculations indicate that the barrier heights for radical abstraction by this hydrogen-bond-stabilized 3-ammonium-1-propanethiyl radical are the highest among the systems examined, consistent with the experimental observations.
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Affiliation(s)
- Sandra Osburn
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne , 30 Flemington Rd, Parkville, Victoria 3010, Australia
| | - Bun Chan
- Graduate School of Engineering, Nagasaki University , Bunkyo 1-14, Nagasaki 852-8521, Japan
| | - Victor Ryzhov
- Department of Chemistry and Biochemistry and Center for Biochemical and Biophysical studies, Northern Illinois University , Dekalb, Illinois 60115, United States
| | - Leo Radom
- School of Chemistry, University of Sydney , Sydney, NSW 2006, Australia
| | - Richard A J O'Hair
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne , 30 Flemington Rd, Parkville, Victoria 3010, Australia
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36
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Sinha Ray S, Ghosh A, Chattopadhyay S, Chaudhuri RK. Taming the Electronic Structure of Diradicals through the Window of Computationally Cost Effective Multireference Perturbation Theory. J Phys Chem A 2016; 120:5897-916. [DOI: 10.1021/acs.jpca.6b03211] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Suvonil Sinha Ray
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103, India
| | - Anirban Ghosh
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103, India
| | - Sudip Chattopadhyay
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711103, India
| | - Rajat K. Chaudhuri
- Theoretical Physics, Indian Institute of Astrophysics, Bangalore 560034, India
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37
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Wang Y, Zhang H, Pink M, Olankitwanit A, Rajca S, Rajca A. Radical Cation and Neutral Radical of Aza-thia[7]helicene with SOMO–HOMO Energy Level Inversion. J Am Chem Soc 2016; 138:7298-304. [DOI: 10.1021/jacs.6b01498] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Ying Wang
- Department
of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Hui Zhang
- Department
of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Maren Pink
- Department
of Chemistry, Indiana University, Bloomington, Indiana 47405-7102, United States
| | - Arnon Olankitwanit
- Department
of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Suchada Rajca
- Department
of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Andrzej Rajca
- Department
of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
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38
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Kazakova AN, Nenajdenko CG, Vasilyev AV. Oxidative dimerization of 2-chloro-3,3,3-trifluoro- 1-(4-methoxyphenyl)propene in the system PbO2–CF3SO3H. RUSSIAN JOURNAL OF ORGANIC CHEMISTRY 2016. [DOI: 10.1134/s1070428016040230] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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39
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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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40
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Jin L, Feng J, Lu G, Cai C. Di-tert-butyl Peroxide (DTBP)-Mediated Oxidative Cross- Coupling of Isochroman and Indole Derivatives. Adv Synth Catal 2015. [DOI: 10.1002/adsc.201500048] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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41
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Crestoni ME, Chiavarino B, Fornarini S. Nitrosyl–heme and anion–arene complexes: structure, reactivity and spectroscopy. PURE APPL CHEM 2015. [DOI: 10.1515/pac-2014-1203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
AbstractTwo topics are selected and illustrated to exemplify (i) a biological and (ii) an organic ionic intermediate. The reactivity behavior of NO adducts with ferric and ferrous hemes has shown remarkable similarities when examined in the gas phase, demonstrating that the largely different NO affinity displayed in solution and in biological media is due to the different coordination environment. In fact, ferrous hemes present a vacant or highly labile axial coordination site, prone to readily bind NO. The vibrational signatures of the NO ligand have also been probed in vacuo for the first time in the nitrosyl complexes deriving from ferrous and ferric hemes under strictly comparable five-coordination at the metal center. Negatively charged σ-adducts, from the association of anions with 1,3,5-trinitrobenzene, an exemplary π-electron-deficient arene, have been probed by IRMPD spectroscopy and found to display variable binding motifs from a strongly covalent σ-adduct (Meisenheimer complex) to a weakly covalent σ-complex, depending on the anion basicity.
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Affiliation(s)
- Maria Elisa Crestoni
- 1Dipartimento di Chimica e Tecnologie del Farmaco, Università degli Studi di Roma La Sapienza, P.le A. Moro 5, I-00185, Roma, Italy
| | - Barbara Chiavarino
- 1Dipartimento di Chimica e Tecnologie del Farmaco, Università degli Studi di Roma La Sapienza, P.le A. Moro 5, I-00185, Roma, Italy
| | - Simonetta Fornarini
- 1Dipartimento di Chimica e Tecnologie del Farmaco, Università degli Studi di Roma La Sapienza, P.le A. Moro 5, I-00185, Roma, Italy
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42
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Yang D, Xia B, Jiang Y, Mei W, Kuck D. Fragmentation of protonated 2-(2-phenylethyl)chromones from agarwood: the diagnostic role of ion/neutral complexes as reactive intermediates. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2015; 21:609-621. [PMID: 26307740 DOI: 10.1255/ejms.1326] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A positive-ion electrospray ionisation collision-induced dissociation mass spectrometric study on the fragmentation of the [M + H](+) ions of 2-(2-phenylethyl)chromone and a set of nine hydroxyl- and/or methoxy-substituted derivatives has revealed a highly prominent fragmentation channel, the loss of benzoquinomethanes or a benzaldehyde, respectively, as a diagnostic feature for 2-(2-phenylethyl)chromones that bear a hydroxyl group at the para- (4'-), ortho- (2'-) and/or benzylic (α-) position of the phenylethyl residue. Derivatives that bear only a meta- (3'-) hydroxyl group do not undergo this elimination. The intermediacy of ion/neutral complexes (INCs) is invoked to explain this fragmentation, which involves the remarkable intra-complex proton or hydrogen atom transfer from the remote 4'-OH (or the 2'- or α-OH) functionalities. Density functional theory (B3LYP/6-31G(d)) calculations confirm the energetic preference for these elimination channels and agree with the limited thermochemical data known for para- and ortho- benzoquinomethanes. The INC-mediated losses of the benzaldehydes from the [M + H](+) ions of the α-hydroxy-substituted 2-(2-phenylethyl)chromones correspond to a particularly facile (vinylogous) Grob fragmentation. The study may be viewed as a telling example of the diagnostic role of ion/neutral complexes as intermediates for the structural assignment of constitutional isomers by mass spectrometry.
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Affiliation(s)
- Delan Yang
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agriculture Sciences, Haikou 571101, P.R. China.
| | - Bing Xia
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, P. R. China.
| | - Yan Jiang
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, P. R. China.
| | - Wenli Mei
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agriculture Sciences, Haikou 571101, P.R. China.
| | - Dietmar Kuck
- Department of Chemistry, Bielefeld University,33615 Bielefeld, Germany.
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43
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Gervasoni BD, Khairallah GN, O'Hair RAJ, Wille U. The role of peroxyl radicals in polyester degradation – a mass spectrometric product and kinetic study using the distonic radical ion approach. Phys Chem Chem Phys 2015; 17:9212-21. [DOI: 10.1039/c4cp06056c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mass spectrometric techniques were employed to reveal detailed insight into the reaction of peroxyl radicals with structural motifs in polyesters.
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Affiliation(s)
- B. D. Gervasoni
- School of Chemistry and Bio21 Institute
- The University of Melbourne
- Parkville
- Australia
| | - G. N. Khairallah
- School of Chemistry and Bio21 Institute
- The University of Melbourne
- Parkville
- Australia
| | - R. A. J. O'Hair
- School of Chemistry and Bio21 Institute
- The University of Melbourne
- Parkville
- Australia
| | - U. Wille
- School of Chemistry and Bio21 Institute
- The University of Melbourne
- Parkville
- Australia
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44
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Korte A, Mardyukov A, Sander W. Pyridyl- and Pyridylperoxy Radicals – A Matrix Isolation Study. Aust J Chem 2014. [DOI: 10.1071/ch14149] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The three isomeric pyridyl radicals 2a–c were synthesised using flash vacuum pyrolysis in combination with matrix isolation and characterised by infrared spectroscopy. The IR spectra are in good agreement with spectra calculated using density functional theory methods. The reaction of the pyridyl radicals 2 with molecular oxygen leads to the formation of the corresponding pyridylperoxy radicals 3a–c. The peroxy radicals 3 are photolabile, and irradiation results in syn–anti isomerisation of 3a and 3b and ring expansion of all three isomers of 3.
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45
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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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