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Yang P, Korshin GV, Dong J, Ji Y, Lu J. Differentiation of Pathways of Nitrated Byproduct Formation from Ammonium and Nitrite During Sulfate Radical Oxidation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:7935-7944. [PMID: 35549166 DOI: 10.1021/acs.est.2c00702] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Recent studies found that both nitrite (NO2-) and ammonium (NH4+) lead to nitrophenolic byproducts in SO4•- oxidation processes, during which NO2• generated through the oxidation of the inorganic nitrogen by SO4•- is the key nitrating agent. This study demonstrates that the formation of phenoxy radicals to which NO2• can be incorporated immediately is another governing factor. Two types of sites having distinct reactivities in natural organic matter (NOM) molecules can be transformed to phenoxy radicals upon SO4•- oxidation. Fast sites associated with phenolic functionalities are primarily targeted in the reaction sequence involving NO2-, because both are preferentially oxidized. Following the depletion of NO2-, NH4+ becomes the main precursor of NO2• that interacts with slow sites associated with the carboxylic functionalities. Experimental data show that the formation of total organic nitrogen in 24 h reached 6.28 μM during SO4•- oxidation of NOM (4.96 mg/L organic carbon) in the presence of both NO2- (0.1 mM) and NH4+ (1.0 mM), while the sum of those formed in the presence of each alone was only 3.52 μM. Results of this study provide further insights into the mechanisms of nitrated byproduct formation when SO4•- is applied for environmental remediation.
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Affiliation(s)
- Peizeng Yang
- Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing 210095, China
| | - Gregory V Korshin
- Department of Civil and Environmental Engineering, University of Washington, Seattle, Washington 98195, United States
| | - Jiayue Dong
- Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing 210095, China
| | - Yuefei Ji
- Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing 210095, China
| | - Junhe Lu
- Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing 210095, China
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Shi Z, Jin C, Bai R, Gao Z, Zhang J, Zhu L, Zhao Z, Strathmann TJ. Enhanced Transformation of Emerging Contaminants by Permanganate in the Presence of Redox Mediators. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:1909-1919. [PMID: 31886657 DOI: 10.1021/acs.est.9b05711] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this study, a permanganate/redox mediator system for enhanced transformation of a series of emerging contaminants was evaluated. The presence of various redox mediators (i.e., 1-hydroxybenzotriazole, N-hydroxyphthalimide, violuric acid, syringaldehyde, vanillin, 4-hydroxycoumarin, and p-coumaric acid) accelerated the degradation of bisphenol A (BPA) by Mn(VII). Since 1-hydroxybenzotriazole (HBT) exhibited the highest reactive ability, it was selected to further investigate the reaction mechanisms and quantify the effects of important reaction parameters on Mn(VII)/redox-mediator reactions with BPA and bisphenol AF (BPAF). Interestingly, not only HBT accelerated the degradation of BPA, but also BPA enhanced the decay of HBT. Evidence for the in situ formation of HBT· radicals as the active oxidant responsible for accelerated BPA and BPAF degradation was obtained by radical scavenging experiments and 31P NMR spin trapping techniques. The routes for HBT· radical formation involving Mn(VII) and the electron-transfer pathway from BPA/BPAF to HBT· radicals demonstrate that the Mn(VII)/HBT system was driven by the electron-transfer mechanism. Compared to Mn(VII) alone, the presence of HBT totally inhibited self-coupling of BPA and BPAF and promoted β-scission, hydroxylation, ring opening, and decarboxylation reactions. Moreover, Mn(VII)/HBT is also effective in real waters with the order of river water > wastewater treatment plant (WWTP) effluent > deionized water.
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Affiliation(s)
- Zhenyu Shi
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, College of Environment and Ecology , Chongqing University , Chongqing 400045 , PR China
- Environment Monitoring Center of Jiangsu Province , Nanjing 210036 , PR China
| | - Can Jin
- Key Laboratory of Biomass Energy and Material of Jiangsu Province , Institute of Chemical Industry of Forest Products, Chinese Academy of Forestry , Nanjing 210042 , PR China
| | - Ruopeng Bai
- School of Chemistry and Chemical Engineering, Chongqing Key Laboratory of Theoretical and Computational Chemistry , Chongqing University , Chongqing 401331 , PR China
| | - Zhanqi Gao
- Environment Monitoring Center of Jiangsu Province , Nanjing 210036 , PR China
| | - Jing Zhang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, College of Environment and Ecology , Chongqing University , Chongqing 400045 , PR China
| | - Liang Zhu
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, College of Environment and Ecology , Chongqing University , Chongqing 400045 , PR China
| | - Zhiwei Zhao
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, College of Environment and Ecology , Chongqing University , Chongqing 400045 , PR China
| | - Timothy J Strathmann
- Department of Civil and Environmental Engineering , Colorado School of Mines , 1500 Illinois Street , Golden , Colorado 80401 , United States
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Patil SV, Argyropoulos DS. Stable Organic Radicals in Lignin: A Review. CHEMSUSCHEM 2017; 10:3284-3303. [PMID: 28605169 DOI: 10.1002/cssc.201700869] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Indexed: 05/27/2023]
Abstract
Lignin and the quest for the origin of stable organic radicals in it have seen numerous developments. Although there have been various speculations over the years on the formation of these stable radicals, researchers have not been able to arrive at a solid, unequivocal hypothesis that applies to all treatments and types of lignin. The extreme complexity of lignin and its highly aromatic, cross-linked, branched, and rigid structure has made such efforts rather cumbersome. Since the early 1950s, researchers in this field have dedicated their efforts to the establishment of methods for the detection and determination of spin content, theoretical simulations, and reactions on model compounds and spin-trapping studies. Although a significant amount of published research is available on lignin or its model compounds and the reactive intermediates involved during various chemical treatments (pulping, bleaching, extractions, chemical modifications, etc.), the literature provides a limited view on the origin, nature, and stability of such radicals. Consequently, this review is focused on examining the origin of such species in lignin, factors affecting their presence, reactions involved in their formation, and methods for their detection.
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Affiliation(s)
- Shradha V Patil
- Departments of Forest Biomaterials and Chemistry, North Carolina State University, 2820 Faucette Drive, Raleigh, NC, 27695-8005, USA
| | - Dimitris S Argyropoulos
- Departments of Forest Biomaterials and Chemistry, North Carolina State University, 2820 Faucette Drive, Raleigh, NC, 27695-8005, USA
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Schaefer AW, Kieber-Emmons MT, Adam SM, Karlin KD, Solomon EI. Phenol-Induced O-O Bond Cleavage in a Low-Spin Heme-Peroxo-Copper Complex: Implications for O 2 Reduction in Heme-Copper Oxidases. J Am Chem Soc 2017; 139:7958-7973. [PMID: 28521498 PMCID: PMC5605297 DOI: 10.1021/jacs.7b03292] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
This study evaluates the reaction of a biomimetic heme-peroxo-copper complex, {[(DCHIm)(F8)FeIII]-(O22-)-[CuII(AN)]}+ (1), with a phenolic substrate, involving a net H-atom abstraction to cleave the bridging peroxo O-O bond that produces FeIV═O, CuII-OH, and phenoxyl radical moieties, analogous to the chemistry carried out in heme-copper oxidases (HCOs). A 3D potential energy surface generated for this reaction reveals two possible reaction pathways: one involves nearly complete proton transfer (PT) from the phenol to the peroxo ligand before the barrier; the other involves O-O homolysis, where the phenol remains H-bonding to the peroxo OCu in the transition state (TS) and transfers the H+ after the barrier. In both mechanisms, electron transfer (ET) from phenol occurs after the PT (and after the barrier); therefore, only the interaction with the H+ is involved in lowering the O-O cleavage barrier. The relative barriers depend on covalency (which governs ET from Fe), and therefore vary with DFT functional. However, as these mechanisms differ by the amount of PT at the TS, kinetic isotope experiments were conducted to determine which mechanism is active. It is found that the phenolic proton exhibits a secondary kinetic isotope effect, consistent with the calculations for the H-bonded O-O homolysis mechanism. The consequences of these findings are discussed in relation to O-O cleavage in HCOs, supporting a model in which a peroxo intermediate serves as the active H+ acceptor, and both the H+ and e- required for O-O cleavage derive from the cross-linked Tyr residue present at the active site.
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Affiliation(s)
- Andrew W Schaefer
- Department of Chemistry, Stanford University , Stanford, California 94305, United States
| | - Matthew T Kieber-Emmons
- Department of Chemistry, Stanford University , Stanford, California 94305, United States
- Department of Chemistry, The University of Utah , Salt Lake City, Utah 84112, United States
| | - Suzanne M Adam
- Department of Chemistry, The Johns Hopkins University , Baltimore, Maryland 21218, United States
| | - Kenneth D Karlin
- Department of Chemistry, The Johns Hopkins University , Baltimore, Maryland 21218, United States
| | - Edward I Solomon
- Department of Chemistry, Stanford University , Stanford, California 94305, United States
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Liu S, Zhao J, Zhang K, Yang L, Sun M, Yu H, Yan Y, Zhang Y, Wu L, Wang S. Dual-emissive fluorescence measurements of hydroxyl radicals using a coumarin-activated silica nanohybrid probe. Analyst 2017; 141:2296-302. [PMID: 26958658 DOI: 10.1039/c5an02261d] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
This work reports a novel dual-emissive fluorescent probe based on dye hybrid silica nanoparticles for ratiometric measurement of the hydroxyl radical (˙OH). In the probe sensing system, the blue emission of coumarin dye (coumarin-3-carboxylic acid, CCA) immobilized on the nanoparticle surface is selectively enhanced by ˙OH due to the formation of a coumarin hydroxylation product with strong fluorescence, whereas the emission of red fluorescent dye encapsulated in the silica nanoparticle is insensitive to ˙OH as a self-referencing signal, and so the probe provides a good quantitative analysis based on ratiometric fluorescence measurement with a detection limit of 1.65 μM. Moreover, the probe also shows high selectivity for ˙OH determination against metal ions, other reactive oxygen species and biological species. More importantly, it exhibits low cytotoxicity and high biocompatibility in living cells, and has been successfully used for cellular imaging of ˙OH, showing its promising application for monitoring of intracellular ˙OH signaling events.
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Affiliation(s)
- Saisai Liu
- Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, China. and Department of Materials Science and Engineering, University of Science & Technology of China, Hefei, Anhui 230026, China and State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Jun Zhao
- Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, China. and State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Kui Zhang
- Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, China. and State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Lei Yang
- Department of Chemistry, University of North Carolina at Chapel Hill, CB 3290, Chapel Hill, NC 27599, USA
| | - Mingtai Sun
- Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, China. and State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Huan Yu
- Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, China. and State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Yehan Yan
- Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, China. and State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Yajun Zhang
- Key Laboratory of Ion Beam Bioengineering, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Lijun Wu
- Key Laboratory of Ion Beam Bioengineering, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Suhua Wang
- Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, China. and State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Hefei, Anhui 230031, China
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Oxidation of the Flavonolignan Silybin. In situ EPR Evidence of the Spin-Trapped Silybin Radical. Electrochim Acta 2016. [DOI: 10.1016/j.electacta.2016.04.107] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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7
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Crestini C, Marsh J, Bianchetti G, Lange H. Identification and quantification of radical species by 31P NMR-based spin trapping — A case study: NH4OH/H2O2-based hair bleaching. Microchem J 2015. [DOI: 10.1016/j.microc.2015.01.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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8
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Song T, Zhou B, Peng GW, Zhang QB, Wu LZ, Liu Q, Wang Y. Aerobic Oxidative Coupling of Resveratrol and its Analogues by Visible Light Using Mesoporous Graphitic Carbon Nitride (mpg-C3N4) as a Bioinspired Catalyst. Chemistry 2013; 20:678-82. [DOI: 10.1002/chem.201303587] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Indexed: 11/10/2022]
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Lim HK, Yang M, Lam W, Xu F, Chen J, Xu Y, Shetty HU, Yang K, Silva J, Evans DC. Free radical metabolism of raloxifene in human liver microsomes. Xenobiotica 2013; 42:737-47. [PMID: 22375838 DOI: 10.3109/00498254.2012.662306] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Raloxifene was metabolized predominantly by CYP3A4 in human liver microsomes to a pair of carbon-carbon (RD1–2) and ether (RD3–4) linked homodimers in an nicotinamide adenine dinucleotide phosphate-dependent manner. The major homodimer formed by human liver microsomes (RD3) was different from the major homodimer formed by peroxidases (RD1). RD1, 3 and 4 were identified by both mass spectrometry (MS) and nuclear magnetic resonance (NMR) as symmetrical carbon-carbon (both carbon 7 from benzo[b]thiopen-6-ol) linked homodimer, asymmetrical ether (oxygen from 4-hydroxyphenyl and carbon 7 from benzo[b]thiopen-6-ol) linked homodimer and asymmetrical ether (oxygen and carbon 7 from benzo[b]thiopen-6-ol) linked homodimer, respectively. The structures of the homodimers RD1, 3 and 4 provided evidence for free radical metabolism of raloxifene by predominantly CYP3A4 in human liver microsomes to oxygen-centered phenoxy radicals from 4-hydroxyphenyl and benzo[b]thiopen-6-ol moieties. Further delocalization to ortho carbon-centered radical was only observed for benzo[b]thiopen-6-ol derived phenoxy radical.
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Affiliation(s)
- Heng-Keang Lim
- Drug Metabolism and Pharmacokinetics, Drug Safety Sciences, Janssen Research and Development, 1000 Route 202 South, Raritan, NJ 08869, USA.
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D'Antonio J, Ghiladi RA. Reactivity of deoxy- and oxyferrous dehaloperoxidase B from Amphitrite ornata: identification of compound II and its ferrous-hydroperoxide precursor. Biochemistry 2011; 50:5999-6011. [PMID: 21619067 DOI: 10.1021/bi200311u] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dehaloperoxidase (DHP) from the terebellid polychaete Amphitrite ornata is a bifunctional enzyme that possesses both hemoglobin and peroxidase activities. The bifunctional nature of DHP as a globin peroxidase appears to be at odds with the traditional starting oxidation state for each individual activity. Namely, reversible oxygen binding is only mediated via a ferrous heme in globins, and peroxidase activity is initiated from ferric centers and to the exclusion of the oxyferrous oxidation state from the peroxidase cycle. Thus, to address what appears to be a paradox, herein we report the details of our investigations into the DHP catalytic cycle when initiated from the deoxy- and oxyferrous states using biochemical assays, stopped-flow UV-visible, and rapid-freeze-quench electron paramagnetic resonance spectroscopies, and anaerobic methods. We demonstrate the formation of Compound II directly from deoxyferrous DHP B upon its reaction with hydrogen peroxide and show that this occurs both in the presence and in the absence of trihalophenol. Prior to the formation of Compound II, we have identified a new species that we have preliminarily attributed to a ferrous-hydroperoxide precursor that undergoes heterolysis to generate the aforementioned ferryl intermediate. Taken together, the results demonstrate that the oxyferrous state in DHP is a peroxidase competent starting species, and an updated catalytic cycle for DHP is proposed in which the ferric oxidation state is not an obligatory starting point for the peroxidase catalytic cycle of dehaloperoxidase. The data presented herein provide a link between the peroxidase and oxygen transport activities, which furthers our understanding of how this bifunctional enzyme is able to unite its two inherent functions in one system.
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Affiliation(s)
- Jennifer D'Antonio
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
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Zoia L, Perazzini R, Crestini C, Argyropoulos DS. Understanding the radical mechanism of lipoxygenases using 31P NMR spin trapping. Bioorg Med Chem 2011; 19:3022-8. [PMID: 21474321 DOI: 10.1016/j.bmc.2011.02.046] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Revised: 02/16/2011] [Accepted: 02/23/2011] [Indexed: 11/28/2022]
Abstract
In this paper, we use our quantitative (31)P NMR spin trapping methods, already developed for simple oxygen- and carbon-centered radicals, to understand the radical intermediates generated by enzymatic systems and more specifically lipoxygenases. Our methodology rests on the fact that free radicals react with the nitroxide phosphorus compound, 5-diisopropoxy-phosphoryl-5-methyl-1-pyrroline-N-oxide (DIPPMPO), to form stable radical adducts, which are suitably detected and accurately quantified using (31)P NMR in the presence of a phosphorus containing internal standard. This system was thus applied to better understand the mechanism of enzymatic oxidation of linoleic acid by soybean lipoxygenases-1 (LOX). The total amount of radicals trapped by DIPPMPO was detected by (31)P NMR at different experimental conditions. In particular the effect of dioxygen concentration on the amount of radicals being trapped was studied. At low dioxygen concentration, a huge increase of radicals trapped was observed with respect to the amount of radicals being trapped at normal dioxygen concentrations.
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Affiliation(s)
- Luca Zoia
- Dipartimento di Scienze dell'Ambiente e del Territorio, Università degli Studi di Milano-Bicocca, Piazza della Scienza 1, 20126 Milano, Italy
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Li H, Zhang L, Han L, Sun W, Bu Y. Internucleotide J-couplings and chemical shifts of the NH···N hydrogen-bonds in the radiation-damaged guanine-cytosine base pairs. J Comput Chem 2010; 32:1159-69. [DOI: 10.1002/jcc.21699] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2010] [Revised: 09/08/2010] [Accepted: 09/17/2010] [Indexed: 11/06/2022]
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Zoia L, Argyropoulos DS. Characterization of free radical spin adducts of the DIPPMPO using mass spectrometry and (31)P NMR. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2010; 16:175-185. [PMID: 20212327 DOI: 10.1255/ejms.1062] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
5-Diisopropyloxy-phosphoryl-5-methyl-1-pyrroline-N-oxide (DIPPMPO) was used to trap a variety of free radicals and the stable compounds generated by the natural decomposition of the initially formed spin adducts were characterized by (31)P nuclear magnetic resonance (NMR) and mass spectrometry. Initially, the starting spin trap DIPPMPO was completely characterized using GC-MS and its fragmentation pathway was studied in detail. Then, DIPPMPO was used to trap an oxygen-centered free radical (the hydroxyl radical *OH) and two carbon- centered free radicals (methyl *CH(3) and 1-phenyl-ethanol-1-yl *CCH(3)(OH)Ph radicals). The (31)P NMR signals were thus assigned and the structures of adducts were studied and confirmed by mass spectrometry. Overall, the fragmentation pathways of the radical adducts proceed mainly via the loss of the diisopropyloxy(oxido)phosphoranyl radical. For the specific case of trapping *OH radicals, it is possible to visualize the rearrangement of the nitroxide radical adduct to its nitrone form as invoked in the literature. This spin trapping technique, coupled with (31)P NMR and MS, provides a tool for the identification of short-lived and low molecular weight free radicals present in a variety of processes.
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Affiliation(s)
- Luca Zoia
- Dipartimento di Scienze dell'Ambiente e del Territorio, Universitá degli Studi di Milano-Bicocca, 20125, Milano, Italy
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