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Lottes B, Carter KP. Capture and Stabilization of the Hydroxyl Radical in a Uranyl Peroxide Cluster. Chemistry 2023; 29:e202300749. [PMID: 37249248 DOI: 10.1002/chem.202300749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 05/26/2023] [Accepted: 05/30/2023] [Indexed: 05/31/2023]
Abstract
Here we describe the synthesis and characterization of a new uranyl peroxide cluster (UPC), U60 Ox30 *, which captures and stabilizes oxygen-based free radicals for more than one week. These radical species were first detected with a nitroblue tetrazolium colorimetric assay and U60 Ox30 * was characterized by single crystal X-ray diffraction as well as infrared (IR), Raman, UV-Vis-NIR, and electron paramagnetic resonance (EPR) spectroscopies. Identification of the free radicals present in U60 Ox30 * was done via room temperature solid and solution state X-band EPR studies using spin trapping methods. The spin trapping agent 5,5-dimethyl-1-pyrroline N-oxide (DMPO) was definitive for identifying the free radicals in U60 Ox30 *, which are hydroxyl radicals (⋅OH) that are stable for up to ten days that also persist upon addition of the metalloenzymes catalase and superoxide dismutase. Addition of the spin trapping agent α-(4-pyridyl N-oxide)-N-tert-butylnitrone (POBN) further confirmed the radicals were oxygen based, and deuteration experiments showed that the origin of the free radicals was from the decomposition of H2 O2 in water. These results demonstrate that highly oxidizing species such as the ⋅OH radical can be stabilized in UPCs, which alters our understanding of the role of free radicals present in spent nuclear fuel.
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Affiliation(s)
- Brett Lottes
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Korey P Carter
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA
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Li X, Lu B, Jiang J, Wang L, Trabelsi T, Francisco JS, Fang W, Zhou M, Zeng X. Water Complex of Imidogen. J Am Chem Soc 2023; 145:1982-1987. [PMID: 36633923 DOI: 10.1021/jacs.2c12808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Imidogen (NH) is the simplest nitrogen hydride that plays an important role in combustion and interstellar chemistry, and its combination with H2O is the prototypical amidation reaction of O-H bonds involving a nitrene intermediate. Herein, we report the observation of the elusive water complex of NH, a prereaction complex associated with the amidation reaction in a solid N2 matrix at 10 K. The hydrogen-bonded structure of NH···OH2 (versus HN···HOH) is confirmed via IR spectroscopy with comprehensive isotope labeling (D, 18O, and 15N) and quantum chemical calculations at the UCCSD(T)/aug-cc-pVQZ level of theory. In line with the observed absorption at 350 nm, irradiation of the complex at 365 nm leads to O-H bond insertion, yielding hydroxylamine NH2OH.
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Affiliation(s)
- Xiaolong Li
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials, Fudan University, 200433 Shanghai, China
| | - Bo Lu
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials, Fudan University, 200433 Shanghai, China
| | - Junjie Jiang
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials, Fudan University, 200433 Shanghai, China
| | - Lina Wang
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials, Fudan University, 200433 Shanghai, China
| | - Tarek Trabelsi
- Department of Earth and Environment Science, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6243, United States
| | - Joseph S Francisco
- Department of Earth and Environment Science, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6243, United States
| | - Wei Fang
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials, Fudan University, 200433 Shanghai, China
| | - Mingfei Zhou
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials, Fudan University, 200433 Shanghai, China
| | - Xiaoqing Zeng
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials, Fudan University, 200433 Shanghai, China
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Tsuge M, Watanabe N. Radical reactions on interstellar icy dust grains: Experimental investigations of elementary processes. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2023; 99:103-130. [PMID: 37121737 DOI: 10.2183/pjab.99.008] [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: 05/03/2023]
Abstract
Molecular clouds (MCs) in space are the birthplace of various molecular species. Chemical reactions occurring on the cryogenic surfaces of cosmic icy dust grains have been considered to play important roles in the formation of these species. Radical reactions are crucial because they often have low barriers and thus proceed even at low temperatures such as ∼10 K. Since the 2000s, laboratory experiments conducted under low-temperature, high-vacuum conditions that mimic MC environments have revealed the elementary physicochemical processes on icy dust grains. In this review, experiments conducted by our group in this context are explored, with a focus on radical reactions on the surface of icy dust analogues, leading to the formation of astronomically abundant molecules such as H2, H2O, H2CO, and CH3OH and deuterium fractionation processes. The development of highly sensitive, non-destructive methods for detecting adsorbates and their utilization for clarifying the behavior of free radicals on ice, which contribute to the formation of complex organic molecules, are also described.
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Affiliation(s)
- Masashi Tsuge
- Institute of Low Temperature Science, Hokkaido University
| | - Naoki Watanabe
- Institute of Low Temperature Science, Hokkaido University
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Abstract
In the present work, we have estimated the gas-phase acidity of different water clusters, i.e., (H2O)n, n = 1-20, 30, 35, 42, 54, 80, and 100. The present work indicates that the gas-phase acidity of the terminal hydrogen atom increases with the size of water clusters and starts converging at (H2O)30. Furthermore, the present work also indicates that the gas-phase acidity of a terminal hydrogen atom is higher than that of the corresponding bulk hydrogen atom for the same size of water cluster.
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Affiliation(s)
- Amit Kumar
- Department of Chemistry, Malaviya National Institute of Technology Jaipur, Jaipur, 302017, India.
| | - Pradeep Kumar
- Department of Chemistry, Malaviya National Institute of Technology Jaipur, Jaipur, 302017, India.
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Linares-Hernández I, Antonio Castillo-Suárez L, Ibanez JG, Vasquez-Medrano R, Miguel López-Rebollar B, Santoyo-Tepole F, Alejandra Teutli-Sequeira E, Martínez-Cienfuegos IG. Degradation of commercial paraquat in a solar-Fenton pilot lagoon using iron oxalate as a chelating agent: Hydro-thermal analysis with CFD. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2022.113914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
Excess protons play a key role in the chemical reactions of ice because of their exceptional mobility, even when the diffusion of atoms and molecules is suppressed in ice at low temperatures. This article reviews the current state of knowledge on the properties of excess protons in ice, with a focus on the involvement of protons in chemical reactions. The mechanism of efficient proton transport in ice, which involves a proton-hopping relay along the hydrogen-bond ice network and the reorientation of water, is discussed and compared with the inefficient transport of hydroxide in ice. Distinctly different properties of protons residing in the ice interior and on the ice surface are emphasized. Recent observations of the spontaneous occurrence of reactions in ice at low temperatures, which include the dissociation of protic acids and the hydrolysis of acidic oxides, are discussed with regard to the kinetic and thermodynamic effects of mobile protons on the promotion of unique chemical processes of ice.
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Affiliation(s)
- Du Hyeong Lee
- Korea Polar Research Institute, 26 Songdomirae-ro, Incheon 21990, South Korea
| | - Heon Kang
- Department of Chemistry and The Research Institute of Basic Sciences, Seoul National University, 1 Gwanak-ro, Seoul 08826, South Korea
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