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Benny J, Saito T, Liu J. Nitrosation mechanisms, kinetics, and dynamics of the guanine and 9-methylguanine radical cations by nitric oxide-Radical-radical combination at different electron configurations. J Chem Phys 2024; 161:125101. [PMID: 39319660 DOI: 10.1063/5.0230367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2024] [Accepted: 09/06/2024] [Indexed: 09/26/2024] Open
Abstract
As a precursor to various reactive nitrogen species formed in biological systems, nitric oxide (•NO) participates in numerous processes, including enhancing DNA radiosensitivity in ionizing radiation-based radiotherapy. Forming guanine radical cations is another common DNA lesion resulting from ionization and oxidation damage. As such, the interaction of •NO with guanine radical cations (G•+) may contribute to the radiosensitization of •NO. An intriguing aspect of this process is the participation of multiple spin configurations in the reaction, including open-shell singlet 1,OS[G•+(↑)⋯(↓)•NO], closed-shell singlet 1,CS[G(↑↓)⋯NO+], and triplet 3[G•+(↑)⋯(↑)•NO]. In this study, the reactions of •NO with both unsubstituted guanine radical cations (in the 9HG•+ conformation) and 9-methylguanine radical cations (9MG•+, a guanosine-mimicking model compound) were investigated in the absence and presence of monohydration of radical cations. Kinetic-energy dependent reaction product ions and cross sections were measured using an electrospray ionization guided-ion beam tandem mass spectrometer. The reaction mechanisms, kinetics, and dynamics were comprehended by interpreting the reaction potential energy surface using spin-projected density functional theory, coupled cluster theory, and multiconfiguration complete active space second-order perturbation theory, followed by RRKM kinetics modeling. The combined experimental and computational findings revealed closed-shell singlet 1,CS[7-NO-9MG]+ as the major, exothermic product and triplet 3[8-NO-9MG]+ as the minor, endothermic product. Singlet biradical products were not detected due to high reaction endothermicities, activation barriers, and inherent instability.
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Affiliation(s)
- Jonathan Benny
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, New York 11367, USA
- The Ph.D. Program in Chemistry, the Graduate Center of the City University of New York, 365 5th Ave., New York, New York 10016, USA
| | - Toru Saito
- Department of Biomedical Information Science, Graduate School of Information Science, Hiroshima City University, 731-3194 Hiroshima, Japan
| | - Jianbo Liu
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, New York 11367, USA
- The Ph.D. Program in Chemistry, the Graduate Center of the City University of New York, 365 5th Ave., New York, New York 10016, USA
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2
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Luo Z, Zhou W, Jiang Y, Minakata D, Spinney R, Dionysiou DD, Liu J, Xiao R. Bimolecular versus Trimolecular Reaction Pathways for H 2O 2 with Hypochlorous Species and Implications for Wastewater Reclamation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:847-858. [PMID: 38153291 DOI: 10.1021/acs.est.3c06375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
The benchmark advanced oxidation technology (AOT) that uses UV/H2O2 integrated with hypochlorous species exhibits great potential in removing micropollutants and enhancing wastewater treatability for reclamation purposes. Although efforts have been made to study the reactions of H2O2 with hypochlorous species, there exist great discrepancies in the order of reaction kinetics, the rate constants, and the molecule-level mechanisms. This results in an excessive use of hypochlorous reagents and system underperformance during treatment processes. Herein, the titled reaction was investigated systematically through complementary experimental and theoretical approaches. Stopped-flow spectroscopic measurements revealed a combination of bi- and trimolecular reaction kinetics. The bimolecular pathway dominates at low H2O2 concentrations, while the trimolecular pathway dominates at high H2O2 concentrations. Both reactions were simulated using direct dynamics trajectories, and the pathways identified in the trajectories were further validated by high-level quantum chemistry calculations. The theoretical results not only supported the spectroscopic data but also elucidated the molecule-level mechanisms and helped to address the origin of the discrepancies. In addition, the impact of the environmental matrix was evaluated by using two waters with discrete characteristics, namely municipal wastewater and ammonium-rich wastewater. Municipal wastewater had a negligible matrix effect on the reaction kinetics of H2O2 and the hypochlorous species, making it a highly suitable candidate for this integration technique. The obtained in-depth reaction mechanistic insights will enable the development of a viable and economical technology for safe water reuse.
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Affiliation(s)
- Zonghao Luo
- Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha 410083, China
- Chinese National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, Changsha 410083, China
| | - Wenjing Zhou
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, Queens, New York 11367, United States
| | - Ying Jiang
- Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha 410083, China
- Chinese National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, Changsha 410083, China
| | - Daisuke Minakata
- Department of Civil and Environmental Engineering, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Richard Spinney
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Dionysios D Dionysiou
- Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Jianbo Liu
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, Queens, New York 11367, United States
| | - Ruiyang Xiao
- Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha 410083, China
- Chinese National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, Changsha 410083, China
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3
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Tada K, Kawakami T, Hinuma Y. Model calculations for the prediction of the diradical character of physisorbed molecules: p-benzyne/MgO and p-benzyne/SrO. Phys Chem Chem Phys 2023; 25:29424-29436. [PMID: 37795574 DOI: 10.1039/d3cp02988c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/06/2023]
Abstract
The analysis of the diradical state of functional open-shell molecules is important for understanding their physical properties and chemical reactivity. The diradical character is an important factor in the functional elucidation and design of open-shell molecules. In recent years, attempts have been made to immobilise functional open-shell molecules on surfaces to form devices. However, the influence of surface interactions on the diradical state remains unclear. In this study, the physisorption structures of p-benzyne, which is a typical diradical molecule, on MgO(001) and SrO(001) surfaces are used as models to investigate how the diradical character is affected by physisorption. This is done using approximate spin-projected density functional theory calculations with dispersion correction and plane-wave basis (AP-DFT-D3/plane-wave calculations). The diradical character change (Δy) due to adsorption can be categorised into three factors, namely the change due to the distortion of the diradical molecule (Δydis), the interaction between neighbouring diradical molecules (Δycoh), and molecule-surface interactions (Δysurf). In all the calculated models, physisorption reduced the diradical character (Δy < 0), and the contribution of Δysurf was the largest among the three factors. The calculated results show that adsorption induces electron delocalisation to π-conjugated orbitals and intramolecular charge polarisation, both of which contribute to reducing the occupancy of singly occupied molecular orbitals. This indicates that the diradical character of p-benzyne is reduced by the stabilisation of the resonance structures. Furthermore, geometry optimisation of the surfaces shows that the chemical-soft surface (SrO) varies the diradical character more significantly than the chemical-hard surface (MgO). This study shows that the open-shell electronic state and stack structure of diradical molecules can be controlled through the analysis of the surface diradical state.
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Affiliation(s)
- Kohei Tada
- Research Institute of Electrochemical Energy (RIECEN), Department of Energy and Environment, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan.
| | - Takashi Kawakami
- RIKEN Center for Computational Science, Kobe, Hyogo 650-0047, Japan
- Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Yoyo Hinuma
- Research Institute of Electrochemical Energy (RIECEN), Department of Energy and Environment, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan.
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4
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Benny J, Liu J. Spin-orbit charge transfer from guanine and 9-methylguanine radical cations to nitric oxide radicals and the induced triplet-to-singlet intersystem crossing. J Chem Phys 2023; 159:085102. [PMID: 37638623 DOI: 10.1063/5.0160921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 08/08/2023] [Indexed: 08/29/2023] Open
Abstract
Nitric oxide (●NO) participates in many biological activities, including enhancing DNA radiosensitivity in ionizing radiation-based radiotherapy. To help understand the radiosensitization of ●NO, we report reaction dynamics between ●NO and the radical cations of guanine (a 9HG●+ conformer) and 9-methylguanine (9MG●+). On the basis of the formation of 9HG●+ and 9MG●+ in the gas phase and the collisions of the radical cations with ●NO in a guided-ion beam mass spectrometer, the charge transfer reactions of 9HG●+ and 9MG●+ with ●NO were examined. For both reactions, the kinetic energy-dependent product ion cross sections revealed a threshold energy that is 0.24 (or 0.37) eV above the 0 K product 9HG (or 9MG) + NO+ asymptote. To interrogate this abnormal threshold behavior, the reaction potential energy surface for [9MG + NO]+ was mapped out at closed-shell singlet, open-shell singlet, and triplet states using density functional and coupled cluster theories. The results showed that the charge transfer reaction requires the interaction of a triplet-state surface originating from a reactant-like precursor complex 3[9MG●+(↑)⋅(↑)●NO] with a closed-shell singlet-state surface evolving from a charge-transferred complex 1[9MG⋅NO+]. During the reaction, an electron is transferred from π∗(NO) to perpendicular π∗(9MG), which introduces a change in orbital angular momentum. The latter offsets the change in electron spin angular momentum and facilitates intersystem crossing. The reaction threshold in excess of the 0 K thermochemistry and the low charge-transfer efficiency are rationalized by the vibrational excitation in the product ion NO+ and the kinetic shift arising from a long-lived triplet intermediate.
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Affiliation(s)
- Jonathan Benny
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, New York 11367, USA
- The Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 5th Ave., New York, New York 10016, USA
| | - Jianbo Liu
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, New York 11367, USA
- The Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 5th Ave., New York, New York 10016, USA
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Ortega P, Gil-Guerrero S, González-Sánchez L, Sanz-Sanz C, Jambrina PG. Spin-Forbidden Addition of Molecular Oxygen to Stable Enol Intermediates-Decarboxylation of 2-Methyl-1-tetralone-2-carboxylic Acid. Int J Mol Sci 2023; 24:ijms24087424. [PMID: 37108586 PMCID: PMC10138960 DOI: 10.3390/ijms24087424] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/12/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
The deprotonation of an organic substrate is a common preactivation step for the enzymatic cofactorless addition of O2 to this substrate, as it promotes charge-transfer between the two partners, inducing intersystem crossing between the triplet and singlet states involved in the process. Nevertheless, the spin-forbidden addition of O2 to uncharged ligands has also been observed in the laboratory, and the detailed mechanism of how the system circumvents the spin-forbiddenness of the reaction is still unknown. One of these examples is the cofactorless peroxidation of 2-methyl-3,4-dihydro-1-naphthol, which will be studied computationally using single and multi-reference electronic structure calculations. Our results show that the preferred mechanism is that in which O2 picks a proton from the substrate in the triplet state, and subsequently hops to the singlet state in which the product is stable. For this reaction, the formation of the radical pair is associated with a higher barrier than that associated with the intersystem crossing, even though the absence of the negative charge leads to relatively small values of the spin-orbit coupling.
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Affiliation(s)
- Pablo Ortega
- Departamento de Química-Física, Universidad de Salamanca, 37008 Salamanca, Spain
| | - Sara Gil-Guerrero
- Departamento de Química-Física, Universidad de Salamanca, 37008 Salamanca, Spain
- CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal
| | | | - Cristina Sanz-Sanz
- Departamento de Química Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Pablo G Jambrina
- Departamento de Química-Física, Universidad de Salamanca, 37008 Salamanca, Spain
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6
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Moe MM, Saito T, Tsai M, Liu J. Singlet O 2 Oxidation of the Radical Cation versus the Dehydrogenated Neutral Radical of 9-Methylguanine in a Watson-Crick Base Pair. Consequences of Structural Context. J Phys Chem B 2022; 126:5458-5472. [PMID: 35849846 DOI: 10.1021/acs.jpcb.2c03748] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In DNA, guanine is the most susceptible to oxidative damage by exogenously and endogenously produced electronically excited singlet oxygen (1O2). The reaction mechanism and the product outcome strongly depend on the nucleobase ionization state and structural context. Previously, exposure of a monomeric 9-methylguanine radical cation (9MG•+, a model guanosine compound) to 1O2 was found to result in the formation of an 8-peroxide as the initial product. The present work explores the 1O2 oxidation of 9MG•+ and its dehydrogenated neutral form [9MG - H]• within a Watson-Crick base pair consisting of one-electron-oxidized 9-methylguanine-1-methylcytosine [9MG·1MC]•+. Emphasis is placed on entangling the base pair structural context and intra-base pair proton transfer with and consequences thereof on the singlet oxygenation of guanine radical species. Electrospray ionization coupled with guided-ion beam tandem mass spectrometry was used to study the formation and reaction of guanine radical species in the gas phase. The 1O2 oxidation of both 9MG•+ and [9MG - H]• is exothermic and proceeds barrierlessly either in an isolated monomer or within a base pair. Single- and multi-referential theories were tested for treating spin contaminations and multi-configurations occurring in radical-1O2 interactions, and reaction potential energy surfaces were mapped out to support experimental findings. The work provides a comprehensive profile for the singlet oxygenation of guanine radicals in different charge states and in the absence and the presence of base pairing. All results point to an 8-peroxide as the major oxidation product in the experiment, and the oxidation becomes slightly more favorable in a neutral radical form. On the basis of a variety of reaction pathways and product profiles observed in the present and previous studies, the interplay between guanine structure, base pairing, and singlet oxygenation and its biological implications are discussed.
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Affiliation(s)
- May Myat Moe
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, New York 11367, United States.,Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 5th Avenue, New York, New York 10016, United States
| | - Toru Saito
- Department of Biomedical Information Science, Graduate School of Information Science, Hiroshima City University, 3-4-1 Ozuka-Higashi, Asa-Minami-Ku, 731-3194 Hiroshima, Japan
| | - Midas Tsai
- Department of Natural Sciences, LaGuardia Community College, 31-10 Thomson Avenue, Long Island City, New York 11101, United States
| | - Jianbo Liu
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, New York 11367, United States.,Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 5th Avenue, New York, New York 10016, United States
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7
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Benny J, Saito T, Moe MM, Liu J. Singlet O 2 Reactions with Radical Cations of 8-Bromoguanine and 8-Bromoguanosine: Guided-Ion Beam Mass Spectrometric Measurements and Theoretical Treatments. J Phys Chem A 2021; 126:68-79. [PMID: 34941276 DOI: 10.1021/acs.jpca.1c09552] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
8-Bromoguanosine is generated in vivo as a biomarker for early inflammation. Its formation and secondary reactions lead to a variety of biological sequelae at inflammation sites, most of which are mutagenic and linked to cancer. Herein, we report the formation of radical cations of 8-bromoguanine (8BrG•+) and 8-bromoguanosine (8BrGuo•+) and their reactions toward the lowest excited singlet molecular oxygen (1O2)─a common reactive oxygen species generated in biological systems. This work aims to investigate synergistic, oxidatively generated damage of 8-brominated guanine and guanosine that may occur upon ionizing radiation, one-electron oxidation, and 1O2 oxidation. Capitalizing on measurements of reaction product ions and cross sections of 8BrG•+ and 8BrGuo•+ with 1O2 using guided-ion beam tandem mass spectrometry and augmented by computational modeling of the prototype reaction system, 8BrG•+ + 1O2, using the approximately spin-projected ωB97XD/6-31+G(d,p) density functional theory, the coupled cluster DLPNO-CCSD(T)/aug-cc-pVTZ and the multireference CASPT2(21,15)/6-31G**, probable reaction products, and potential energy surfaces (PESs) were mapped out. 8BrG•+ and 8BrGuo•+ present similar exothermic oxidation products, and their reaction efficiencies with 1O2 increase with decreasing collision energy. Both single- and multireference theories predicted that the two most energetically favorable reaction pathways correspond to 1O2-addition to the C8 and C5-positions of 8BrG•+, respectively. The CASPT2-calculated PES represents the best quantitative agreement with the experimental benchmark, in that the oxidation exothermicity is close to the water hydration energy of product ions and, thus, is able to eliminate a water ligand in the product ions.
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Affiliation(s)
- Jonathan Benny
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, New York 11367, United States.,Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 5th Avenue, New York, New York 10016, United States
| | - Toru Saito
- Department of Biomedical Information Science, Graduate School of Information Science, Hiroshima City University, 3-4-1 Ozuka-Higashi, Asa-Minami-Ku, 731-3194 Hiroshima, Japan
| | - May Myat Moe
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, New York 11367, United States.,Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 5th Avenue, New York, New York 10016, United States
| | - Jianbo Liu
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, New York 11367, United States.,Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 5th Avenue, New York, New York 10016, United States
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8
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Barrios B, Mohrhardt B, Doskey PV, Minakata D. Mechanistic Insight into the Reactivities of Aqueous-Phase Singlet Oxygen with Organic Compounds. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:8054-8067. [PMID: 34096699 DOI: 10.1021/acs.est.1c01712] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Singlet oxygen (1O2) is a selective reactive oxygen species that plays a key role for the fate of various organic compounds in the aquatic environment under sunlight irradiation, engineered water oxidation systems, atmospheric water droplets, and biomedical systems. While the initial rate-determining charge-transfer reaction mechanisms and kinetics of 1O2 have been studied extensively, no comprehensive studies have been performed to elucidate the reaction mechanisms with organic compounds that have various functional groups. In this study, we use density functional theory calculations to determine elementary reaction mechanisms with a wide variety of organic compounds. The theoretically calculated aqueous-phase free energies of activation of single electron transfer and 1O2 addition reactions are compared to the experimentally determined rate constants in the literature to determine linear free-energy relationships. The theoretically calculated free energies of activation for the groups of phenolates and phenols show excellent correlations with the Hammett constants that accept electron densities by through-resonance. The dominant elementary reaction mechanism is discussed for each group of compounds. As a practical implication, we demonstrate the fate of environmentally relevant organic compounds induced by photochemically produced intermediate species at different pH and evaluate the impact of predicting rate constants to the half-life.
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Affiliation(s)
- Benjamin Barrios
- Department of Civil and Environmental Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton, Michigan 49931, United States
| | - Benjamin Mohrhardt
- Department of Civil and Environmental Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton, Michigan 49931, United States
| | - Paul V Doskey
- College of Forest Resources and Environmental Science, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Daisuke Minakata
- Department of Civil and Environmental Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton, Michigan 49931, United States
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Saito T, Takano Y. Spin-projected QM/MM Free Energy Simulations for Oxidation Reaction of Guanine in B-DNA by Singlet Oxygen. Chemphyschem 2021; 22:561-568. [PMID: 33462992 PMCID: PMC8048875 DOI: 10.1002/cphc.202000978] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 01/17/2021] [Indexed: 12/11/2022]
Abstract
Guanine is the most susceptible base to oxidation damage induced by reactive oxygen species including singlet oxygen (1 O2 , 1 Δg ). We clarify whether the first step of guanine oxidation in B-DNA proceeds via either a zwitterionic or a diradical intermediate. The free energy profiles are calculated by means of a combined quantum mechanical and molecular mechanical (QM/MM) method coupled with the adaptive biasing force (ABF) method. To describe the open-shell electronic structure of 1 O2 correctly, the broken-symmetry spin-unrestricted density functional theory (BS-UDFT) with an approximate spin projection (AP) correction is applied to the QM region. We find that the effect of spin contamination on the activation and reaction free energies is up to ∼8 kcal mol-1 , which is too large to be neglected. The QM(AP-ULC-BLYP)/MM-based free energy calculations also reveal that the reaction proceeds through a diradical transition state, followed by a conversion to a zwitterionic intermediate. Our computed activation energy of 5.2 kcal mol-1 matches experimentally observed range (0∼6 kcal mol-1 ).
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Affiliation(s)
- Toru Saito
- Department of Biomedical Information ScienceGraduate School of Information ScienceHiroshima City University3-4-1 Ozuka-Higashi, Asa-Minami-Ku731-3194HiroshimaJapan
| | - Yu Takano
- Department of Biomedical Information ScienceGraduate School of Information ScienceHiroshima City University3-4-1 Ozuka-Higashi, Asa-Minami-Ku731-3194HiroshimaJapan
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10
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Sun Y, Tsai M, Moe MM, Liu J. Dynamics and Multiconfiguration Potential Energy Surface for the Singlet O2 Reactions with Radical Cations of Guanine, 9-Methylguanine, 2′-Deoxyguanosine, and Guanosine. J Phys Chem A 2021; 125:1564-1576. [DOI: 10.1021/acs.jpca.1c00095] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Yan Sun
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, New York 11367, United States
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 Fifth Avenue, New York, New York 10016, United States
| | - Midas Tsai
- Department of Natural Sciences, LaGuardia Community College 31-10 Thomson Avenue, Long Island City, New York 11101, United States
| | - May Myat Moe
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, New York 11367, United States
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 Fifth Avenue, New York, New York 10016, United States
| | - Jianbo Liu
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, New York 11367, United States
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 Fifth Avenue, New York, New York 10016, United States
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11
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Buettner AD, Dilday BJ, Craigmile RA, Drummer MC, Standard JM, Quandt RW. The reaction of O( 3P) with alkynes: a dynamic and computational study focusing on formyl radical production. Phys Chem Chem Phys 2020; 22:24583-24599. [PMID: 33094751 DOI: 10.1039/d0cp03698f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Production of formyl radical, HCO, from reactions of O(3P) with alkynes (acetylene, propyne, 1-butyne, and 1-pentyne) has been investigated using cavity ringdown laser absorption spectroscopy (CRDLAS) and computational methods. No HCO was detected from reaction with acetylene, while the amount of HCO increased for propyne and 1-butyne, dropping off somewhat for 1-pentyne. These results differ from trends previously observed for reactions of O(3P) with alkenes, which exhibit the largest HCO production for the smallest alkene and drop off as the alkene size increases. Computational studies employing density functional and coupled cluster methods have been employed to investigate the triplet and singlet state pathways for HCO production. Because intersystem crossing (ISC) has been shown to be important in these processes, the minimum energy crossing point (MECP) between the triplet and singlet surfaces has been studied. We find the MECP for propyne to possess C1 symmetry and to lie lower in energy than previous studies have found. Natural Bond Orbital and Natural Resonance Theory analyses have been performed to investigate the changes in spin density and bond order along the reaction pathways for formation of HCO. Explanations are suggested for the trend in HCO formation observed for the alkynes. The trend in alkyne HCO yield also is compared and contrasted with the trend previously observed for the alkenes.
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Affiliation(s)
- Andrew D Buettner
- Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160, USA.
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12
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Sun Y, Tsai M, Zhou W, Lu W, Liu J. Reaction Kinetics, Product Branching, and Potential Energy Surfaces of 1O 2-Induced 9-Methylguanine-Lysine Cross-Linking: A Combined Mass Spectrometry, Spectroscopy, and Computational Study. J Phys Chem B 2019; 123:10410-10423. [PMID: 31718186 DOI: 10.1021/acs.jpcb.9b08796] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report a kinetics and mechanistic study on the 1O2 oxidation of 9-methylguanine (9MG) and the cross-linking of the oxidized intermediate 2-amino-9-methyl-9H-purine-6,8-dione (9MOGOX) with Nα-acetyl-lysine-methyl ester (abbreviated as LysNH2) in aqueous solutions of different pH. Experimental measurements include the determination of product branching ratios and reaction kinetics using mass spectrometry and absorption spectroscopy, and the characterization of product structures by employing collision-induced dissociation. Strong pH dependence was revealed for both 9MG oxidation and the addition of nucleophiles (water and LysNH2) at the C5 position of 9MOGOX. The 1O2 oxidation rate constant of 9MG was determined to be 3.6 × 107 M-1·s-1 at pH 10.0 and 0.3 × 107 M-1·s-1 at pH 7.0, both of which were measured in the presence of 15 mM LysNH2. The ωB97XD density functional theory coupled with various basis sets and the SMD implicit solvation model was used to explore the reaction potential energy surfaces for the 1O2 oxidation of 9MG and the formation of C5-water and C5-LysNH2 adducts of 9MOGOX. Computational results have shed light on reaction pathways and product structures for the different ionization states of the reactants. The present work has confirmed that the initial 1O2 addition represents the rate-limiting step for the oxidative transformations of 9MG. All of the downstream steps are exothermic with respect to the starting reactants. The C5-cross-linking of 9MOGOX with LysNH2 significantly suppressed the formation of spiroiminodihydantoin (9MSp) resulting from the C5-water addition. The latter became dominant only at the low concentration (∼1 mM) of LysNH2.
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Affiliation(s)
- Yan Sun
- Department of Chemistry and Biochemistry , Queens College of the City University of New York , 65-30 Kissena Blvd. , Queens , New York 11367 , United States.,Ph.D. Program in Chemistry , The Graduate Center of the City University of New York , 365 5th Avenue , New York , New York 10016 , United States
| | - Midas Tsai
- Department of Natural Sciences , LaGuardia Community College , 31-10 Thomson Avenue , Long Island City , New York 11101 , United States
| | - Wenjing Zhou
- Department of Chemistry and Biochemistry , Queens College of the City University of New York , 65-30 Kissena Blvd. , Queens , New York 11367 , United States
| | - Wenchao Lu
- Department of Chemistry and Biochemistry , Queens College of the City University of New York , 65-30 Kissena Blvd. , Queens , New York 11367 , United States.,Ph.D. Program in Chemistry , The Graduate Center of the City University of New York , 365 5th Avenue , New York , New York 10016 , United States
| | - Jianbo Liu
- Department of Chemistry and Biochemistry , Queens College of the City University of New York , 65-30 Kissena Blvd. , Queens , New York 11367 , United States.,Ph.D. Program in Chemistry , The Graduate Center of the City University of New York , 365 5th Avenue , New York , New York 10016 , United States
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13
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Fudickar W, Linker T. Theoretical insights into the effect of solvents on the [4 + 2] cycloaddition of singlet oxygen to substituted anthracenes: A change from a stepwise process to a concerted process. J PHYS ORG CHEM 2019. [DOI: 10.1002/poc.3951] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Werner Fudickar
- Department of ChemistryUniversity of Potsdam Potsdam Germany
| | - Torsten Linker
- Department of ChemistryUniversity of Potsdam Potsdam Germany
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14
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Tada K, Maruyama T, Koga H, Okumura M, Tanaka S. Extent of Spin Contamination Errors in DFT/Plane-wave Calculation of Surfaces: A Case of Au Atom Aggregation on a MgO Surface. Molecules 2019; 24:molecules24030505. [PMID: 30704148 PMCID: PMC6385026 DOI: 10.3390/molecules24030505] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 01/28/2019] [Accepted: 01/30/2019] [Indexed: 11/16/2022] Open
Abstract
The aggregation of Au atoms onto a Au dimer (Au₂) on a MgO (001) surface was calculated by restricted (spin-un-polarized) and unrestricted (spin-polarized) density functional theory calculations with a plane-wave basis and the approximate spin projection (AP) method. The unrestricted calculations included spin contamination errors of 0.0⁻0.1 eV, and the errors were removed using the AP method. The potential energy curves for the aggregation reaction estimated by the restricted and unrestricted calculations were different owing to the estimation of the open-shell structure by the unrestricted calculations. These results show the importance of the open-shell structure and correction of the spin contamination error for the calculation of small-cluster-aggregations and molecule dimerization on surfaces.
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Affiliation(s)
- Kohei Tada
- Research Institute of Electrochemical Energy, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31, Midorigaoka, Ikeda, Osaka 563-8577, Japan.
| | - Tomohiro Maruyama
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1, Machikaneyama, Toyonaka, Osaka 560-0043, Japan.
| | - Hiroaki Koga
- Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, 1-30 Goryo Ohara, Nishikyo, Kyoto 615-8245, Japan.
| | - Mitsutaka Okumura
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1, Machikaneyama, Toyonaka, Osaka 560-0043, Japan.
- Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, 1-30 Goryo Ohara, Nishikyo, Kyoto 615-8245, Japan.
| | - Shingo Tanaka
- Research Institute of Electrochemical Energy, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31, Midorigaoka, Ikeda, Osaka 563-8577, Japan.
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15
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Trogolo D, Arey JS, Tentscher PR. Gas-Phase Ozone Reactions with a Structurally Diverse Set of Molecules: Barrier Heights and Reaction Energies Evaluated by Coupled Cluster and Density Functional Theory Calculations. J Phys Chem A 2019; 123:517-536. [DOI: 10.1021/acs.jpca.8b10323] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Daniela Trogolo
- School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - J. Samuel Arey
- School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
| | - Peter R. Tentscher
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
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16
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Saito T, Fujiwara M, Takano Y. Quantitative Assessment of rPM6 for Fluorine- and Chlorine-Containing Metal Complexes: Comparison with Experimental, First-Principles, and Other Semiempirical Results. Molecules 2018; 23:E3332. [PMID: 30558286 PMCID: PMC6321459 DOI: 10.3390/molecules23123332] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 12/12/2018] [Accepted: 12/14/2018] [Indexed: 11/17/2022] Open
Abstract
We report a reparameterization of PM6 parameters for fluorine and chlorine using our training set containing transition metal complexes. Spin unrestricted calculations with the resulting rPM6 (UrPM6) were examined quantitatively using two test sets: (i) the description of magnetic interactions in 25 dinuclear metal complexes and (ii) the prediction of barrier heights and reaction energies for epoxidation and fluorination reactions catalyzed by high-valent manganese-oxo species. The conventional UPM6 and UPM7 methods were also evaluated for comparison on the basis of either experimental or computational (the UB3LYP/SVP level) outcomes. The merits of UrPM6 are highlighted by both the test sets. As regards magnetic exchange coupling constants, the UrPM6 method had the smallest mean absolute errors from the experimental data (19 cm-1), followed by UPM7 (119 cm-1) and UPM6 (373 cm-1). For the epoxidation and fluorination reactions, all of the transition state searches were successful using UrPM6, while the success rates obtained by UPM6 and UPM7 were only 50%. The UrPM6-optimized stationary points also agreed well with the reference UB3LYP-optimized geometries. The accuracy for estimating reaction energies was also greatly remedied.
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Affiliation(s)
- Toru Saito
- Graduate School of Information Sciences, Hiroshima City University, 3-4-1 Ozuka-Higashi, Asa-Minami-Ku, Hiroshima 731-3194, Japan.
| | - Manami Fujiwara
- Graduate School of Information Sciences, Hiroshima City University, 3-4-1 Ozuka-Higashi, Asa-Minami-Ku, Hiroshima 731-3194, Japan.
| | - Yu Takano
- Graduate School of Information Sciences, Hiroshima City University, 3-4-1 Ozuka-Higashi, Asa-Minami-Ku, Hiroshima 731-3194, Japan.
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17
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Lu W, Sun Y, Tsai M, Zhou W, Liu J. Singlet O 2 Oxidation of a Deprotonated Guanine-Cytosine Base Pair and Its Entangling with Intra-Base-Pair Proton Transfer. Chemphyschem 2018; 19:2645-2654. [PMID: 30047606 DOI: 10.1002/cphc.201800643] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Indexed: 12/24/2022]
Abstract
We report an experimental and computational study on the 1 O2 oxidation of gas-phase deprotonated guanine-cytosine base pair [G ⋅ C-H]- that is composed of 9HG ⋅ [C-H]- and 7HG ⋅ [C-H]- (pairing 9H- or 7H-guanine with N1-deprotonated cytosine), and 9HG ⋅ [C-H]- _PT and 7HG ⋅ [C-H]- _PT (formed by intra-base-pair proton transfer from the N1 of guanine to the N3 of [C-H]- ). The conformer-averaged reaction product ions and cross section were measured over a center-of-mass collision energy range from 0.1 to 0.5 eV using a guided-ion-beam tandem mass spectrometer. To explore conformation-specific reactivity, collision dynamics of 1 O2 with each of the four [G ⋅ C-H]- conformers was simulated at B3LYP/6-31G(d). Trajectories showed that the 1 O2 oxidation of the base pair entangles with intra-base-pair proton transfer, and prefers to occur in a collision when the base pair adopts a proton-transferred structure; trajectories also indicate that the 9HG-containing base pair favors stepwise formation of 4,8-endoperoxide of guanine, whereas the 7HG-containing base pair prefers concerted formation of guanine 5,8-endoperoxide. Using trajectory results as a guide, potential energy surfaces (PESs) along all possible reaction pathways were established using the approximately spin-projected ωB97XD/6-311++G(d,p)//B3LYP/6-311++G(d,p) method. PESs have not only rationalized trajectory findings but provided more accurate energetics and indicated that the proton-transferred base-pair conformers have lower activation barriers for oxidation than their non-proton-transferred counterparts.
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Affiliation(s)
- Wenchao Lu
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, NY, 11367, USA.,Ph.D. Program in Chemistry, the, Graduate Center of the City University of New York, 365 5th Ave., New York, NY, 10016, USA
| | - Yan Sun
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, NY, 11367, USA.,Ph.D. Program in Chemistry, the, Graduate Center of the City University of New York, 365 5th Ave., New York, NY, 10016, USA
| | - Midas Tsai
- Department of Natural Sciences, LaGuardia Community College, 31-10 Thomson Ave., Long Island City, NY, 11101, USA
| | - Wenjing Zhou
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, NY, 11367, USA
| | - Jianbo Liu
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, NY, 11367, USA.,Ph.D. Program in Chemistry, the, Graduate Center of the City University of New York, 365 5th Ave., New York, NY, 10016, USA
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18
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Stoneburner SJ, Truhlar DG, Gagliardi L. MC-PDFT can calculate singlet–triplet splittings of organic diradicals. J Chem Phys 2018; 148:064108. [DOI: 10.1063/1.5017132] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Samuel J. Stoneburner
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, 207 Pleasant Street Southeast, Minneapolis, Minnesota 55455-0431, USA
| | - Donald G. Truhlar
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, 207 Pleasant Street Southeast, Minneapolis, Minnesota 55455-0431, USA
| | - Laura Gagliardi
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, 207 Pleasant Street Southeast, Minneapolis, Minnesota 55455-0431, USA
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19
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Lu W, Sun Y, Zhou W, Liu J. pH-Dependent Singlet O2 Oxidation Kinetics of Guanine and 9-Methylguanine: An Online Mass Spectrometry and Spectroscopy Study Combined with Theoretical Exploration. J Phys Chem B 2017; 122:40-53. [DOI: 10.1021/acs.jpcb.7b09515] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Wenchao Lu
- Department
of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Boulevard, Queens, New York 11367, United States
- Ph.D.
Program in Chemistry, The Graduate Center of the City University of New York, 365 Fifth Avenue, New York, New York 10016, United States
| | - Yan Sun
- Department
of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Boulevard, Queens, New York 11367, United States
- Ph.D.
Program in Chemistry, The Graduate Center of the City University of New York, 365 Fifth Avenue, New York, New York 10016, United States
| | - Wenjing Zhou
- Department
of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Boulevard, Queens, New York 11367, United States
| | - Jianbo Liu
- Department
of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Boulevard, Queens, New York 11367, United States
- Ph.D.
Program in Chemistry, The Graduate Center of the City University of New York, 365 Fifth Avenue, New York, New York 10016, United States
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20
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Lu W, Tsai IH“M, Sun Y, Zhou W, Liu J. Elucidating Potential Energy Surfaces for Singlet O2 Reactions with Protonated, Deprotonated, and Di-Deprotonated Cystine Using a Combination of Approximately Spin-Projected Density Functional Theory and Guided-Ion-Beam Mass Spectrometry. J Phys Chem B 2017; 121:7844-7854. [DOI: 10.1021/acs.jpcb.7b05674] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Wenchao Lu
- Department
of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, New York 11367, United States
- Ph.D.
Program in Chemistry, The Graduate Center of the City University of New York, 365 5th Avenue, New York, New York 10016, United States
| | - I-Hsien “Midas” Tsai
- Department
of Natural Sciences, LaGuardia Community College, 31-10 Thomson Avenue, Long Island City, New York 11101, United States
| | - Yan Sun
- Department
of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, New York 11367, United States
- Ph.D.
Program in Chemistry, The Graduate Center of the City University of New York, 365 5th Avenue, New York, New York 10016, United States
| | - Wenjing Zhou
- Department
of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, New York 11367, United States
| | - Jianbo Liu
- Department
of Chemistry and Biochemistry, Queens College of the City University of New York, 65-30 Kissena Blvd., Queens, New York 11367, United States
- Ph.D.
Program in Chemistry, The Graduate Center of the City University of New York, 365 5th Avenue, New York, New York 10016, United States
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21
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Ghogare AA, Debaz CJ, Silva Oliveira M, Abramova I, Mohapatra PP, Kwon K, Greer EM, Prado FM, Valerio HP, Di Mascio P, Greer A. Experimental and DFT Computational Insight into Nitrosamine Photochemistry—Oxygen Matters. J Phys Chem A 2017; 121:5954-5966. [DOI: 10.1021/acs.jpca.7b02414] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ashwini A. Ghogare
- Department
of Chemistry, Brooklyn College, 2900 Bedford Avenue, Brooklyn, New York 11210, United States
- Ph.D.
Program in Chemistry, The Graduate Center of the City University of New York, 365 Fifth Avenue, New York, New York 10016, United States
| | - Ciro J. Debaz
- Department
of Chemistry, Brooklyn College, 2900 Bedford Avenue, Brooklyn, New York 11210, United States
| | - Marilene Silva Oliveira
- Department
of Chemistry, Brooklyn College, 2900 Bedford Avenue, Brooklyn, New York 11210, United States
- Departamento
de Bioquímica, Instituto de Química, Universidade de São Paulo, CEP, 05508-000 São Paulo, Brazil
| | - Inna Abramova
- Department
of Chemistry, Brooklyn College, 2900 Bedford Avenue, Brooklyn, New York 11210, United States
| | - Prabhu P. Mohapatra
- Department
of Chemistry, Brooklyn College, 2900 Bedford Avenue, Brooklyn, New York 11210, United States
| | - Kitae Kwon
- Department
of Natural Sciences, Baruch College, City University of New York, New York 10010, United States
| | - Edyta M. Greer
- Department
of Natural Sciences, Baruch College, City University of New York, New York 10010, United States
| | - Fernanda Manso Prado
- Departamento
de Bioquímica, Instituto de Química, Universidade de São Paulo, CEP, 05508-000 São Paulo, Brazil
| | - Hellen Paula Valerio
- Departamento
de Bioquímica, Instituto de Química, Universidade de São Paulo, CEP, 05508-000 São Paulo, Brazil
| | - Paolo Di Mascio
- Departamento
de Bioquímica, Instituto de Química, Universidade de São Paulo, CEP, 05508-000 São Paulo, Brazil
| | - Alexander Greer
- Department
of Chemistry, Brooklyn College, 2900 Bedford Avenue, Brooklyn, New York 11210, United States
- Ph.D.
Program in Chemistry, The Graduate Center of the City University of New York, 365 Fifth Avenue, New York, New York 10016, United States
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22
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Thapa B, Munk BH, Burrows CJ, Schlegel HB. Computational Study of Oxidation of Guanine by Singlet Oxygen ( 1 Δ g ) and Formation of Guanine:Lysine Cross-Links. Chemistry 2017; 23:5804-5813. [PMID: 28249102 DOI: 10.1002/chem.201700231] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Indexed: 12/20/2022]
Abstract
Oxidation of guanine in the presence of lysine can lead to guanine-lysine cross-links. The ratio of the C4, C5 and C8 crosslinks depends on the manner of oxidation. Type II photosensitizers such as Rose Bengal and methylene blue can generate singlet oxygen, which leads to a different ratio of products than oxidation by type I photosensitizers or by one electron oxidants. Modeling reactions of singlet oxygen can be quite challenging. Reactions have been explored using CASSCF, NEVPT2, DFT, CCSD(T), and BD(T) calculations with SMD implicit solvation. The spin contamination in open-shell calculations were corrected by Yamaguchi's approximate spin projection method. The addition of singlet oxygen to guanine to form guanine endo- peroxide proceeds step-wise via a zwitterionic peroxyl intermediate. The subsequent barrier for ring closure is smaller than the initial barrier for singlet oxygen addition. Ring opening of the endoperoxide by protonation at C4-O is followed by loss of a proton from C8 and dehydration to produce 8-oxoGox . The addition of lysine (modelled by methylamine) or water across the C5=N7 double bond of 8-oxoGox is followed by acyl migration to form the final spiro products. The barrier for methylamine addition is significantly lower than for water addition and should be the dominant reaction channel. These results are in good agreement with the experimental results for the formation of guanine-lysine cross-links by oxidation by type II photosensitizers.
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Affiliation(s)
- Bishnu Thapa
- Chemistry Department, Wayne State University, Detroit, Michigan, 48202, USA
| | - Barbara H Munk
- Chemistry Department, Wayne State University, Detroit, Michigan, 48202, USA
| | - Cynthia J Burrows
- Chemistry Department, University of Utah, Salt Lake City, Utah, 84112, USA
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23
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Tsuchimochi T, Ten-no S. Bridging Single- and Multireference Domains for Electron Correlation: Spin-Extended Coupled Electron Pair Approximation. J Chem Theory Comput 2017; 13:1667-1681. [DOI: 10.1021/acs.jctc.7b00073] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Takashi Tsuchimochi
- Graduate
School of Science, Technology, and Innovation, and ‡Graduate School
of System Informatics, Kobe University, Kobe, Hyogo 657-0025, Japan
| | - Seiichiro Ten-no
- Graduate
School of Science, Technology, and Innovation, and ‡Graduate School
of System Informatics, Kobe University, Kobe, Hyogo 657-0025, Japan
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24
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Breslavskaya NN, Dolin SP, Markov AA, Mikhailova TY, Moiseeva NI, Gekhman AE. Quantum-chemical simulation of the elementary step of the oxidation reactions of styrene and its derivatives involving 1О2 (1Δg). RUSS J INORG CHEM+ 2016. [DOI: 10.1134/s0036023616120056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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25
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Breslavskaya NN, Dolin SP, Markov AA, Mikhailova TY, Moiseeva NI, Gekhman AE. Quantum-chemical simulation of unit process for the oxidation reactions of ethylene and its derivatives invoving 1O2 (1Δg). RUSS J INORG CHEM+ 2016. [DOI: 10.1134/s0036023616100041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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26
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Zeinali N, Altarawneh M, Li D, Al-Nu’airat J, Dlugogorski BZ. New Mechanistic Insights: Why Do Plants Produce Isoprene? ACS OMEGA 2016; 1:220-225. [PMID: 31457127 PMCID: PMC6640788 DOI: 10.1021/acsomega.6b00025] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Accepted: 08/04/2016] [Indexed: 05/07/2023]
Abstract
In this article, we argue that the primary role of isoprene is to remove the singlet delta oxygen (O2 1Δg) that forms inside plants by ultraviolet excitation rather than to provide heat protection or scavenge ozone, OH, or other reactive oxygen species (ROS) in the gas phase. By deploying a quantum chemical framework, we address for the first time the exact mode of isoprene reactions with O2 1Δg, the most prominent ROS that causes damage to leaves. Initial reactions of isoprene with O2 1Δg comprise its addition at the two terminal carbon atoms. The two primary open-shell adducts that appear in these reactions undergo 1,2-cycloaddition to generate methyl vinyl ketone and methacrolein, the sole products detected from in-house (i.e., inside of plants) oxidation of isoprene. Formation of other products, comprising the peroxy O-O bonds, is kinetically insignificant. Furthermore, these adducts are thermodynamically too unstable to diffuse outside of plants. Oxidation of isoprene with O2 1Δg does not produce new ROS (such as OH or HO2), supporting the well-documented role of isoprene as an effective ROS scavenger. Deploying a solvation model reduces the energy requirements for the primary pathways in the range of 10-56 kJ/mol. The present results indicate that plants attach significant value to the in-home protection against O2 1Δg by investing carbon and energy into the formation of isoprene, in spite of the appearance of the cytotoxic methyl vinyl ketone as one of the reaction products. (The same chemical species also form in unrelated gas-phase reactions involving isoprene and other ROS.) This finding explains the primary reason for the appearance of the dynamic biosphere-atmosphere exchange of methyl vinyl ketone.
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Affiliation(s)
- Nassim Zeinali
- School of Engineering and
Information Technology, Murdoch University, 90 South Street, Murdoch, Western Australia 6150, Australia
| | - Mohammednoor Altarawneh
- School of Engineering and
Information Technology, Murdoch University, 90 South Street, Murdoch, Western Australia 6150, Australia
| | - Dan Li
- School of Engineering and
Information Technology, Murdoch University, 90 South Street, Murdoch, Western Australia 6150, Australia
| | - Jomana Al-Nu’airat
- School of Engineering and
Information Technology, Murdoch University, 90 South Street, Murdoch, Western Australia 6150, Australia
| | - Bogdan Z. Dlugogorski
- School of Engineering and
Information Technology, Murdoch University, 90 South Street, Murdoch, Western Australia 6150, Australia
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27
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Marchetti B, Karsili TNV. An exploration of the reactivity of singlet oxygen with biomolecular constituents. Chem Commun (Camb) 2016; 52:10996-9. [PMID: 27538187 DOI: 10.1039/c6cc05392k] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The thermal reaction between biomolecules and singlet oxygen ((1)O2) is important for rendering the genetic material within toxic cells inactive. Here we present results obtained from state-of-the-art multi-reference computational methods that reveal the mechanistic details of the reaction between (1)O2 and two exemplary biomolecular systems: guanine (Gua) and histidine (His). The results highlight the splitting of the doubly degenerate (1)Δg state of O2 upon complexation and the essentially barrierless potential energy profile of the thermally allowed cycloaddition reaction when the O2 molecule is in its lower energy (1)Δg state.
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Affiliation(s)
- Barbara Marchetti
- Technische Universität München, Lichtenbergstrasse 4, Garching bei München 85748, Germany.
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Dumont E, Grüber R, Bignon E, Morell C, Moreau Y, Monari A, Ravanat JL. Probing the reactivity of singlet oxygen with purines. Nucleic Acids Res 2015; 44:56-62. [PMID: 26656495 PMCID: PMC4705671 DOI: 10.1093/nar/gkv1364] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 11/24/2015] [Indexed: 11/30/2022] Open
Abstract
The reaction of singlet molecular oxygen with purine DNA bases is investigated by computational means. We support the formation of a transient endoperoxide for guanine and by classical molecular dynamics simulations we demonstrate that the formation of this adduct does not affect the B-helicity. We thus identify the guanine endoperoxide as a key intermediate, confirming a low-temperature nuclear magnetic resonance proof of its existence, and we delineate its degradation pathway, tracing back the preferential formation of 8-oxoguanine versus spiro-derivates in B-DNA. Finally, the latter oxidized 8-oxodGuo product exhibits an almost barrierless reaction profile, and hence is found, coherently with experience, to be much more reactive than guanine itself. On the contrary, in agreement with experimental observations, singlet-oxygen reactivity onto adenine is kinetically blocked by a higher energy transition state.
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Affiliation(s)
- Elise Dumont
- Laboratoire de Chimie, UMR 5182, Ecole Normale Supérieure de Lyon, Lyon France
| | - Raymond Grüber
- Laboratoire de Chimie, UMR 5182, Ecole Normale Supérieure de Lyon, Lyon France
| | - Emmanuelle Bignon
- Laboratoire de Chimie, UMR 5182, Ecole Normale Supérieure de Lyon, Lyon France Institut des Sciences Analytiques, Université de Lyon 1 and CNRS, Villeurbanne, France
| | - Christophe Morell
- Institut des Sciences Analytiques, Université de Lyon 1 and CNRS, Villeurbanne, France
| | | | - Antonio Monari
- Theory-Modeling-Simulation, SRSMC, Université de Lorraine Nancy, Vandoeuvre-lès-Nancy, France CNRS, Theory-Modeling-Simulation, SRSMC, Vandoeuvre-lès-Nancy, France
| | - Jean-Luc Ravanat
- INAC-SCIB, Université Grenoble Alpes, F-38000 Grenoble, France CEA, INAC-SCIB-LAN, F-38000 Grenoble, France
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Dolin SP, Breslavskaya NN, Markov AA, Mikhailova TY, Moiseeva NI, Gekhman AE. Mechanism and energetics of 1,2-addition of dioxygen 1O2(1Δg) to ethylene. RUSS J INORG CHEM+ 2015. [DOI: 10.1134/s0036023615120104] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Oliveira MS, Ghogare AA, Abramova I, Greer EM, Prado FM, Di Mascio P, Greer A. Mechanism of Photochemical O-Atom Exchange in Nitrosamines with Molecular Oxygen. J Org Chem 2015; 80:6119-27. [PMID: 26000876 DOI: 10.1021/acs.joc.5b00633] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The detection of an oxygen-atom photoexchange process of N-nitrosamines is reported. The photolysis of four nitrosamines (N-nitrosodiphenylamine 1, N-nitroso-N-methylaniline 2, N-butyl-N-(4-hydroxybutyl)nitrosamine 3, and N-nitrosodiethylamine 4) with ultraviolet light was examined in an (18)O2-enriched atmosphere in solution. HPLC/MS and HPLC-MS/MS data show that (18)O-labeled nitrosamines were generated for 1 and 2. In contrast, nitrosamines 3 and 4 do not exchange the (18)O label and instead decomposed to amines and/or imines under the conditions. For 1 and 2, the (18)O atom was found not to be introduced by moisture or by singlet oxygen [(18)((1)O2 (1)Δg)] produced thermally by (18)O-(18)O labeled endoperoxide of N,N'-di(2,3-hydroxypropyl)-1,4-naphthalene dipropanamide (DHPN(18)O2) or by visible-light sensitization. A density functional theory study of the structures and energetics of peroxy intermediates arising from reaction of nitrosamines with O2 is also presented. A reversible head-to-tail dimerization of the O-nitrooxide to the 1,2,3,5,6,7-hexaoxadiazocane (30 kcal/mol barrier) with extrusion of O═(18)O accounts for exchange of the oxygen atom label. The unimolecular cyclization of O-nitrooxide to 1,2,3,4-trioxazetidine (46 kcal/mol barrier) followed by a retro [2 + 2] reaction is an alternative, but higher energy process. Both pathways would require the photoexcitation of the nitrooxide.
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Affiliation(s)
- Marilene Silva Oliveira
- †Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, CEP 05508-000, São Paulo, Brazil.,‡Department of Chemistry and Graduate Center, Brooklyn College, City University of New York, Brooklyn, New York 11210, United States
| | - Ashwini A Ghogare
- ‡Department of Chemistry and Graduate Center, Brooklyn College, City University of New York, Brooklyn, New York 11210, United States
| | - Inna Abramova
- ‡Department of Chemistry and Graduate Center, Brooklyn College, City University of New York, Brooklyn, New York 11210, United States
| | - Edyta M Greer
- §Department of Natural Sciences, Baruch College, City University of New York, New York, New York 10010, United States
| | - Fernanda Manso Prado
- †Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, CEP 05508-000, São Paulo, Brazil
| | - Paolo Di Mascio
- †Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, CEP 05508-000, São Paulo, Brazil
| | - Alexander Greer
- ‡Department of Chemistry and Graduate Center, Brooklyn College, City University of New York, Brooklyn, New York 11210, United States
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Grüber R, Monari A, Dumont E. Stability of the Guanine Endoperoxide Intermediate: A Computational Challenge for Density Functional Theory. J Phys Chem A 2014; 118:11612-9. [DOI: 10.1021/jp508330r] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Raymond Grüber
- Laboratoire
de Chimie, UMR 5182 CNRS, École Normale Supérieure de Lyon, 46, allée d’Italie, 69364 Lyon Cedex 07, France
| | - Antonio Monari
- Université de Lorraine Nancy, Théorie-Modélisation-Simulation,
SRSMC, Boulevard des Aiguillettes 54506, Vandoeuvre-lès-Nancy, France
- CNRS,
Théorie-Modélisation-Simulation, SRSMC, Boulevard des
Aiguillettes 54506, Vandoeuvre-lès-Nancy, France
| | - Elise Dumont
- Laboratoire
de Chimie, UMR 5182 CNRS, École Normale Supérieure de Lyon, 46, allée d’Italie, 69364 Lyon Cedex 07, France
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Saito T, Thiel W. Quantum mechanics/molecular mechanics study of oxygen binding in hemocyanin. J Phys Chem B 2014; 118:5034-43. [PMID: 24762083 DOI: 10.1021/jp5003885] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report a combined quantum mechanics/molecular mechanics (QM/MM) study on the mechanism of reversible dioxygen binding in the active site of hemocyanin (Hc). The QM region is treated by broken-symmetry density functional theory (DFT) with spin projection corrections. The X-ray structures of deoxygenated (deoxyHc) and oxygenated (oxyHc) hemocyanin are well reproduced by QM/MM geometry optimizations. The computed relative energies strongly depend on the chosen density functional. They are consistent with the available thermodynamic data for oxygen binding in hemocyanin and in synthetic model complexes when the BH&HLYP hybrid functional with 50% Hartree-Fock exchange is used. According to the QM(BH&HLYP)/MM results, the reaction proceeds stepwise with two sequential electron transfer (ET) processes in the triplet state followed by an intersystem crossing to the singlet product. The first ET step leads to a nonbridged superoxo CuB(II)-O2(•-) intermediate via a low-barrier transition state. The second ET step is even more facile and yields a side-on oxyHc complex with the characteristic Cu2O2 butterfly core, accompanied by triplet-singlet intersystem crossing. The computed barriers are very small so that the two ET processes are expected to very rapid and nearly simultaneous.
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Affiliation(s)
- Toru Saito
- Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
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33
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Rudshteyn B, Castillo A, Ghogare AA, Liebman JF, Greer A. Theoretical study of the reaction formalhydrazone with singlet oxygen. Fragmentation of the C=N bond, ene reaction and other processes. Photochem Photobiol 2013; 90:431-8. [PMID: 24354600 DOI: 10.1111/php.12199] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 10/21/2013] [Indexed: 01/03/2023]
Abstract
Photobiologic and synthetic versatility of hydrazones has not yet been established with (1)O2 as a route to commonly encountered nitrosamines. Thus, to determine whether the "parent" reaction of formalhydrazone and (1)O2 leads to facile C=N bond cleavage and resulting nitrosamine formation, we have carried out CCSD(T)//DFT calculations and analyzed the energetics of the oxidation pathways. A [2 + 2] pathway occurs via diradicals and formation of 3-amino-1,2,3-dioxazetidine in a 16 kcal/mol(-1) process. Reversible addition or physical quenching of (1)O2 occurs either on the formalhydrazone carbon for triplet diradicals at 2-3 kcal mol(-1), or on the nitrogen (N(3)) atom forming zwitterions at ~15 kcal/mol(-1), although the quenching channel by charge-transfer interaction was not computed. The computations also predict a facile conversion of formalhydrazone and (1)O2 to hydroperoxymethyl diazene in a low-barrier 'ene' process, but no 2-amino-oxaziridine-O-oxide (perepoxide-like) intermediate was found. A Benson-like analysis (group increment calculations) on the closed-shell species are in accord with the quantum chemical results.
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Affiliation(s)
- Benjamin Rudshteyn
- Department of Chemistry, Graduate Center & The City University of New York (CUNY), Brooklyn College, Brooklyn, NY
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34
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Rivero P, Jiménez-Hoyos CA, Scuseria GE. Predicting Singlet–Triplet Energy Splittings with Projected Hartree–Fock Methods. J Phys Chem A 2013; 117:8073-80. [DOI: 10.1021/jp405755z] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Pablo Rivero
- Department of Chemistry, Rice University, Houston, Texas 77005-1892, United
States
| | | | - Gustavo E. Scuseria
- Department of Chemistry, Rice University, Houston, Texas 77005-1892, United
States
- Department of Physics
and Astronomy, Rice University, Houston,
Texas 77005-1892, United
States
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35
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Saito T, Thiel W. Analytical Gradients for Density Functional Calculations with Approximate Spin Projection. J Phys Chem A 2012; 116:10864-9. [DOI: 10.1021/jp308916s] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Toru Saito
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
| | - Walter Thiel
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
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36
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Sharipov AS, Starik AM. Theoretical Study of the Reaction of Ethane with Oxygen Molecules in the Ground Triplet and Singlet Delta States. J Phys Chem A 2012; 116:8444-54. [DOI: 10.1021/jp304906u] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Alexander S Sharipov
- Scientific Educational Centre Physical-Chemical Kinetics and Combustion, Central Institute of Aviation Motors, Moscow, Russia
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37
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Rajeev R, Sunoj RB. On the origin of regio- and stereoselectivity in singlet oxygen addition to enecarbamates. J Org Chem 2012; 77:2474-85. [PMID: 22324308 DOI: 10.1021/jo3001707] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The reactions of excited state singlet molecular oxygen ((1)Δ(g),(1)O(2)) continue to witness interesting new developments. In the most recent manifestation, (1)O(2) is tamed to react with enecarbamates in a stereoselective manner, which is remarkable, in view of its inherently high reactivity (Acc. Chem. Res. 2008, 41, 387). Herein, we employed the CAS-MP2(8,7)/6-31G* as well as the CAS-MP2(10,8)/6-31G* computations to unravel the origin of (i) diastereoselectivities in dioxetane or hydroperoxide formation and (ii) regioselectivity leading to a [2 + 2] cycloadduct or an ene product when (1)O(2) reacts with an oxazolidinone tethered 2-phenyl-1-propenyl system. The computed Gibbs free energy profiles for E- and Z-isomers when (1)O(2) approaches through the hindered and nonhindered diastereotopic faces (by virtue of chiral oxazolidinone) of the enecarbamates exhibit distinct differences. In the case of E-isomer, the relative energies of the transition structures responsible for hydroperoxide (ene product) are lower than that for dioxetane formation. On the other hand, the ene pathway is predicted to involve higher barriers as compared to the corresponding dioxetane pathway for Z-isomer. The energy difference between the rate-determining diastereomeric transition structures involved in the most favored ene reaction for E-enecarbamate suggests high diastereoselectivity. In contrast, the corresponding energy difference for Z-enecarbamate in the ene pathway is found to be diminishingly close, implying low diastereoselectivity. However, the dioxetane formation from Z-enecarbamate is predicted to exhibit high diastereoselectivity. The application of activation strain model as well as the differences in stereoelectronic effects in the stereocontrolling transition structures is found to be effective toward rationalizing the origin of selectivities reported herein. These predictions are found to be in excellent agreement with the experimental observations.
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Affiliation(s)
- Ramanan Rajeev
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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38
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Kinoshita K, Saito T, Ito A, Kawakami T, Kitagawa Y, Yamanaka S, Yamaguchi K, Okumura M. Theoretical study on singlet oxygen adsorption onto surface of graphene-like aromatic hydrocarbon molecules. Polyhedron 2011. [DOI: 10.1016/j.poly.2011.04.036] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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39
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Saito T, Yasuda N, Kataoka Y, Nakanishi Y, Kitagawa Y, Kawakami T, Yamanaka S, Okumura M, Yamaguchi K. Potential Energy Curve for Ring-Opening Reactions: Comparison Between Broken-Symmetry and Multireference Coupled Cluster Methods. J Phys Chem A 2011; 115:5625-31. [DOI: 10.1021/jp201463h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Toru Saito
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Natsumi Yasuda
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Yusuke Kataoka
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Yasuyuki Nakanishi
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Yasutaka Kitagawa
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Takashi Kawakami
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Shusuke Yamanaka
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Mitsutaka Okumura
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Kizashi Yamaguchi
- Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
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40
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Saito T, Nishihara S, Kitagawa Y, Kawakami T, Yamanaka S, Okumura M, Yamaguchi K. A broken-symmetry study on the automerization of cyclobutadiene. Comparison with UNO- and DNO-MRCC methods. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2010.08.081] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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