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Zhang P, He B, Zhao M, Zhang Y. Role of monomolecular water and bimolecular water in IO + CH2O reaction. J Mol Model 2022; 28:308. [DOI: 10.1007/s00894-022-05295-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 08/25/2022] [Indexed: 11/29/2022]
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2
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Marzouk S, Ajili Y, Lique F, Ben El Hadj Rhouma M, Al Mogren MM, Hochlaf M. IO(X 2Π)-Ar cluster: ab initio potential energy surface and dynamical computations. Phys Chem Chem Phys 2020; 22:740-747. [PMID: 31833508 DOI: 10.1039/c9cp05310g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Iodine oxide (IO) is an important tropospheric molecule. In the present paper, we mapped the potential energy surfaces (PESs) of the doubly degenerate IO(X2Π)-Ar van der Waals system using single- and double-excitation coupled cluster approaches with non-iterative perturbation treatment of triple excitations [RCCSD(T)] extrapolated to the complete basis set (CBS) limit. In addition to bent local minima, we identified a linear Ar-IO complex as a global minimum. Afterwards, we performed scattering calculations on these PESs, considering the non-zero spin-orbit contribution and the Renner-Teller effect. The integral cross-sections exhibit an oscillatory structure vs. the final rotational state, as already observed for the NO(X2Π)-Ar system. Moreover, computations reveal that the Ar-IO complex is stable toward dissociation into IO and Ar. Therefore, it can be found in the atmosphere and participates in iodine compound physical chemical processes occurring there.
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Affiliation(s)
- S Marzouk
- Laboratoire de Recherche d'Etude des Milieux Ionisés et Réactifs (EMIR), Institut Préparatoire aux Etudes d'Ingénieurs de Monastir, Université de Monastir, Tunisia
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3
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Abstract
This review is intended as a comprehensive survey of iodinated metabolites possessing carbon–iodine covalent bond, which have been obtained from living organisms. Generally thought to be minor components produced by many different organisms these interesting compounds now number more than 110. Many from isolated and identified iodine-containing metabolites showed high biological activities. Recent research, especially in the marine area, indicates this number will increase in the future. Sources of iodinated metabolites include microorganisms, algae, marine invertebrates, and some animals. Their origin and possible biological significance have also been discussed.
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Affiliation(s)
- Valery M Dembitsky
- Department of Medicinal Chemistry and Natural Products, School of Pharmacy, P.O. Box 12065, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
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4
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Yeager CM, Amachi S, Grandbois R, Kaplan DI, Xu C, Schwehr KA, Santschi PH. Microbial Transformation of Iodine: From Radioisotopes to Iodine Deficiency. ADVANCES IN APPLIED MICROBIOLOGY 2017; 101:83-136. [PMID: 29050668 DOI: 10.1016/bs.aambs.2017.07.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Iodine is a biophilic element that is important for human health, both as an essential component of several thyroid hormones and, on the other hand, as a potential carcinogen in the form of radioiodine generated by anthropogenic nuclear activity. Iodine exists in multiple oxidation states (-1, 0, +1, +3, +5, and +7), primarily as molecular iodine (I2), iodide (I-), iodate [Formula: see text] , or organic iodine (org-I). The mobility of iodine in the environment is dependent on its speciation and a series of redox, complexation, sorption, precipitation, and microbial reactions. Over the last 15years, there have been significant advances in iodine biogeochemistry, largely spurred by renewed interest in the fate of radioiodine in the environment. We review the biogeochemistry of iodine, with particular emphasis on the microbial processes responsible for volatilization, accumulation, oxidation, and reduction of iodine, as well as the exciting technological potential of these fascinating microorganisms and enzymes.
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5
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Yuan D, Yang GP, He Z. Spatio-temporal distributions of chlorofluorocarbons and methyl iodide in the Changjiang (Yangtze River) estuary and its adjacent marine area. MARINE POLLUTION BULLETIN 2016; 103:247-259. [PMID: 26707981 DOI: 10.1016/j.marpolbul.2015.12.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Revised: 12/04/2015] [Accepted: 12/11/2015] [Indexed: 06/05/2023]
Abstract
Temporal and spatial distribution patterns of volatile halogenated organic compounds (VHOCs), such as dichlorodifluoromethane (CFC-12), trichlorofluoromethane (CFC-11), trichlorotrifluoroethane (CFC-113), and methyl iodide (CH3I), in the Changjiang (Yangtze River) estuary and its adjacent marine area were measured during two cruises from 21 February to 10 March 2014 and from 10 to 21 July 2014. VHOC concentrations showed seasonal variation with higher values during winter. VHOC distributions evidently decreased along the freshwater plume from the river mouth to the open sea and from inshore to offshore regions. VHOC distributions were obviously influenced by the Changjiang runoff, anthropogenic inputs, and biological release of phytoplankton. The study area was a net sink for CFC-12 and CFC-11, but a net source for atmospheric CH3I during the study periods.
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Affiliation(s)
- Da Yuan
- Key Laboratory of Marine Chemistry Theory and Technology, Ocean University of China, Ministry of Education/Qingdao Collaborative Innovation Center of Marine Science and Technology, Qingdao 266100, China; Institute of Marine Chemistry, Ocean University of China, Qingdao 266100, China
| | - Gui-Peng Yang
- Key Laboratory of Marine Chemistry Theory and Technology, Ocean University of China, Ministry of Education/Qingdao Collaborative Innovation Center of Marine Science and Technology, Qingdao 266100, China; Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266200, China; Institute of Marine Chemistry, Ocean University of China, Qingdao 266100, China.
| | - Zhen He
- Key Laboratory of Marine Chemistry Theory and Technology, Ocean University of China, Ministry of Education/Qingdao Collaborative Innovation Center of Marine Science and Technology, Qingdao 266100, China; Institute of Marine Chemistry, Ocean University of China, Qingdao 266100, China
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6
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Bai FY, Wang X, Sun YQ, Pan XM. Atmospheric chemistry of alkyl iodides: theoretical studies on the mechanisms and kinetics of CH3I/C2H5I + NO3 reactions. RSC Adv 2015. [DOI: 10.1039/c5ra16215g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Mechanisms and kinetics of the reactions of the NO3 radical with CH3I and C2H5I have been investigated from a sound theoretical basis.
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Affiliation(s)
- Feng-Yang Bai
- Institute of Functional Material Chemistry
- Faculty of Chemistry
- Northeast Normal University
- Changchun
- People's Republic of China
| | - Xu Wang
- Institute of Functional Material Chemistry
- Faculty of Chemistry
- Northeast Normal University
- Changchun
- People's Republic of China
| | - Yan-Qiu Sun
- Institute of Functional Material Chemistry
- Faculty of Chemistry
- Northeast Normal University
- Changchun
- People's Republic of China
| | - Xiu-Mei Pan
- Institute of Functional Material Chemistry
- Faculty of Chemistry
- Northeast Normal University
- Changchun
- People's Republic of China
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7
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Thurlow ME, Co DT, O'Brien AS, Hannun RA, Lapson LB, Hanisco TF, Anderson JG. The development and deployment of a ground-based, laser-induced fluorescence instrument for the in situ detection of iodine monoxide radicals. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:044101. [PMID: 24784629 DOI: 10.1063/1.4869857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
High abundances of iodine monoxide (IO) are known to exist and to participate in local photochemistry of the marine boundary layer. Of particular interest are the roles IO plays in the formation of new particles in coastal marine environments and in depletion episodes of ozone and mercury in the Arctic polar spring. This paper describes a ground-based instrument that measures IO at mixing ratios less than one part in 10(12). The IO radical is measured by detecting laser-induced fluorescence at wavelengths longer that 500 nm. Tunable visible light is used to pump the A(2)Π3/2 (v(') = 2) ← X(2)Π3/2 (v(″) = 0) transition of IO near 445 nm. The laser light is produced by a solid-state, Nd:YAG-pumped Ti:Sapphire laser at 5 kHz repetition rate. The laser-induced fluorescence instrument performs reliably with very high signal-to-noise ratios (>10) achieved in short integration times (<1 min). The observations from a validation deployment to the Shoals Marine Lab on Appledore Island, ME are presented and are broadly consistent with in situ observations from European Coastal Sites. Mixing ratios ranged from the instrumental detection limit (<1 pptv) to 10 pptv. These data represent the first in situ point measurements of IO in North America.
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Affiliation(s)
- M E Thurlow
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA
| | - D T Co
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA
| | - A S O'Brien
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA
| | - R A Hannun
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA
| | - L B Lapson
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA
| | - T F Hanisco
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA
| | - J G Anderson
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA
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8
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Šulka M, Šulková K, Louis F, Neogrády P, Černušák I. A Theoretical Study of the X-Abstraction Reactions (X = H, Br, or I) from CH2IBr by OH Radicals: Implications for Atmospheric Chemistry. Z PHYS CHEM 2013. [DOI: 10.1524/zpch.2013.0391] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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9
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Šulková K, Šulka M, Louis F, Neogrády P. Atmospheric Reactivity of CH2ICl with OH Radicals: High-Level OVOS CCSD(T) Calculations for the X-Abstraction Pathways (X = H, Cl, or I). J Phys Chem A 2013; 117:771-82. [PMID: 23294186 DOI: 10.1021/jp312447x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Katarína Šulková
- Department of Physical and Theoretical
Chemistry, Faculty of Natural Sciences, Comenius University, Mlynská dolina CH1, 84215 Bratislava, Slovakia
| | - Martin Šulka
- Department of Physical and Theoretical
Chemistry, Faculty of Natural Sciences, Comenius University, Mlynská dolina CH1, 84215 Bratislava, Slovakia
| | - Florent Louis
- PhysicoChimie des Processus
de Combustion et de l’Atmosphère (PC2A), UMR 8522 CNRS/Lille1, Université Lille 1 Sciences et Technologies,
Cité Scientifique, Bât. C11/C5, 59655 Villeneuve d’Ascq
Cedex, France
| | - Pavel Neogrády
- Department of Physical and Theoretical
Chemistry, Faculty of Natural Sciences, Comenius University, Mlynská dolina CH1, 84215 Bratislava, Slovakia
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10
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Saunders RW, Kumar R, MacDonald SM, Plane JMC. Insights into the photochemical transformation of iodine in aqueous systems: humic acid photosensitized reduction of iodate. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:11854-61. [PMID: 23038990 DOI: 10.1021/es3030935] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Marine aerosol is highly enriched in iodine, mostly in the form of iodate (IO(3)(-)) ions, compared to its relative abundance in seawater. This paper describes a laboratory study of the photochemical reduction of IO(3)(-) in the presence of humic acid. Spectroscopic analysis showed that ~20% of IO(3)(-) was converted to "free" iodide (I(-)) ions and this fraction remained constant as a function of time. Direct detection of an organically fixed fraction (i.e., ∼ 80%) was not possible, but a number of test reactions with surrogate organic compounds containing functional groups identified in humic acid structures indicate that efficient substitution of iodine occurs at aromatic 1,2 diol sites. These iodinated humic acids are stable with respect to photolysis at near-UV/visible wavelengths and are likely to account for a significant proportion of the soluble iodine-containing organic material occurring within aerosols. In the lower atmosphere, oxidation of I(-) to I(2) in marine aerosol occurs mostly through the uptake of O(3), with H(2)O(2) playing a very minor role. A model of iodine chemistry in the open ocean tropical boundary layer, which incorporates these experimental results, is able to account for the observed enrichment of iodine in marine aerosol.
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11
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Toda H, Itoh N. Isolation and characterization of a gene encoding a S-adenosyl-l-methionine-dependent halide/thiol methyltransferase (HTMT) from the marine diatom Phaeodactylum tricornutum: Biogenic mechanism of CH(3)I emissions in oceans. PHYTOCHEMISTRY 2011; 72:337-343. [PMID: 21227473 DOI: 10.1016/j.phytochem.2010.12.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Revised: 11/19/2010] [Accepted: 12/03/2010] [Indexed: 05/27/2023]
Abstract
Several marine algae including diatoms exhibit S-adenosyl-l-methionine (SAM) halide/thiol methyltransferase (HTMT) activity, which is involved in the emission of methyl halides. In this study, the in vivo biogenic emission of methyl iodide from the diatom Phaeodactylum tricornutum was found to be clearly correlated with iodide concentration in the incubation media. The gene encoding HTMT (Pthtmt) was isolated from P. tricornutum CCAP 1055/1, and expressed in Escherichia coli. The molecular weight of the enzyme was 29.7kDa including a histidine tag, and the optimal pH was around pH 7.0. The kinetic properties of recombinant PtHTMT towards Cl(-), Br(-), I(-), [SH](-), [SCN](-), and SAM were 637.88mM, 72.83mM, 8.60mM, 9.92mM, 7.9mM, and 0.016mM, respectively, and were similar to those of higher-plant HTMTs, except that the activity towards thiocyanate was lower. The biogenic emission of methyl halides from the cultured cells and the enzymatic properties of HTMT suggest that the HMT/HTMT reaction is key to understanding the biogenesis of methyl halides in oceanic environments as well as terrestrial ones.
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Affiliation(s)
- Hiroshi Toda
- Department of Biotechnology, Faculty of Engineering, Biotechnology Research Center, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
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12
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Podsiadło M, Katrusiak A. Electrostatic matching in phase IV of chloroiodomethane: a new aggregation pattern in the isostructural classes of dihalomethanes. CrystEngComm 2009. [DOI: 10.1039/b820422e] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Podsiadło M, Katrusiak A. High-pressure crystal structure of methyl iodide: molecular aggregation in the crystals of halomethanes and their isostructural relations,. CrystEngComm 2009. [DOI: 10.1039/b903526e] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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14
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Liu Y, Xiao H, Sun M, Fang W. Spin-orbitAb initioinvestigation of the photodissociation of dibromomethane in the gas and solution phases. J Comput Chem 2008; 29:2513-9. [DOI: 10.1002/jcc.21008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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15
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Dookwah-Roberts V, Nicovich JM, Wine PH. Spectroscopic and Kinetic Study of the Gas-Phase CH3I−Cl and C2H5I−Cl Adducts. J Phys Chem A 2008; 112:9535-43. [PMID: 18517179 DOI: 10.1021/jp800270r] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- V. Dookwah-Roberts
- School of Earth and Atmospheric Sciences, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - J. M. Nicovich
- School of Earth and Atmospheric Sciences, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - P. H. Wine
- School of Earth and Atmospheric Sciences, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332
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16
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Varner RK, Zhou Y, Russo RS, Wingenter OW, Atlas E, Stroud C, Mao H, Talbot R, Sive BC. Controls on atmospheric chloroiodomethane (CH2ClI) in marine environments. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jd008889] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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17
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Amachi S. Microbial Contribution to Global Iodine Cycling: Volatilization, Accumulation, Reduction, Oxidation, and Sorption of Iodine. Microbes Environ 2008; 23:269-76. [DOI: 10.1264/jsme2.me08548] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Seigo Amachi
- Graduate School of Horticulture, Chiba University
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18
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Podsiadło M, Katrusiak A. Isostructural relations in dihalomethanes and disproportionation of bromoiodomethane. CrystEngComm 2008. [DOI: 10.1039/b805065a] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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19
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Quack B, Peeken I, Petrick G, Nachtigall K. Oceanic distribution and sources of bromoform and dibromomethane in the Mauritanian upwelling. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jc003803] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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20
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Archer SD, Goldson LE, Liddicoat MI, Cummings DG, Nightingale PD. Marked seasonality in the concentrations and sea-to-air flux of volatile iodocarbon compounds in the western English Channel. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jc003963] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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21
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Abstract
This review describes volatiles released into the air by bacteria growing on defined media. Their occurrence, function, and biosynthesis are discussed, and a total of 308 references are cited. An effort has been made to organize the compounds according to their biosynthetic origin.
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Affiliation(s)
- Stefan Schulz
- Institute of Organic Chemistry, Technical University of Braunschweig, Hagenring 30, 38106, Braunschweig, Germany.
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22
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Sun Q, Mackie J, Dlugogorski B, Kennedy E. Theoretical exploration of the potential energy surface of the HOI → HIO isomerization reaction. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.01.049] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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23
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Leblanc C, Colin C, Cosse A, Delage L, La Barre S, Morin P, Fiévet B, Voiseux C, Ambroise Y, Verhaeghe E, Amouroux D, Donard O, Tessier E, Potin P. Iodine transfers in the coastal marine environment: the key role of brown algae and of their vanadium-dependent haloperoxidases. Biochimie 2006; 88:1773-85. [PMID: 17007992 DOI: 10.1016/j.biochi.2006.09.001] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2006] [Accepted: 09/01/2006] [Indexed: 11/22/2022]
Abstract
Brown algal kelp species are the most efficient iodine accumulators among all living systems, with an average content of 1.0% of dry weight in Laminaria digitata, representing a ca. 30,000-fold accumulation of this element from seawater. Like other marine macroalgae, kelps are known to emit volatile short-lived organo-iodines, and molecular iodine which are believed to be a main vector of the iodine biogeochemical cycle as well as having a significant impact on atmospheric chemistry. Therefore, radioactive iodine can potentially accumulate in seaweeds and can participate in the biogeochemical cycling of iodine, thereby impacting human health. From a radioecological viewpoint, iodine-129 (129I, half-life of 1.6 x 10(7) years) is one of the most persistent radionuclide released from nuclear facilities into the environment. In this context, the speciation of iodine by seaweeds is of special importance and there is a need to further understand the mechanisms of iodine uptake and emission by kelps. Recent results on the physiological role and biochemistry of the vanadium haloperoxidases of brown algae emphasize the importance of these enzymes in the control of these processes.
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Affiliation(s)
- Catherine Leblanc
- Centre national de la recherche scientifique, université Pierre et Marie Curie-Paris-VI, laboratoire international Associé-Dispersal and Adaptation in Marine Species, unité mixte de recherche 7139, 29682 Roscoff cedex, France.
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24
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Auer NR, Manzke BU, Schulz-Bull DE. Development of a purge and trap continuous flow system for the stable carbon isotope analysis of volatile halogenated organic compounds in water. J Chromatogr A 2006; 1131:24-36. [PMID: 16899248 DOI: 10.1016/j.chroma.2006.07.043] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2006] [Revised: 07/13/2006] [Accepted: 07/17/2006] [Indexed: 11/22/2022]
Abstract
A purge and trap (P&T) continuous flow system was developed in order to concentrate high volumes of water for trace analyses and stable carbon isotope measurements of volatile halogenated organic compounds (VHOCs) in seawater. The P&T parameters were evaluated regarding quality parameters, extraction efficiency and isotope fractionation. Precision (about 20%), linearity (>0.9676), and recoveries (between 75% and 99%) were reasonable within the large concentration range tested. Isotope fractionation was between 1 per thousand and 3 per thousand. Finally, the developed system was successfully applied to the quantitative and stable carbon isotope analysis of three water samples of different origin.
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Affiliation(s)
- Nicole R Auer
- Department of Marine Chemistry, Baltic Sea Research Institute Warnemünde, IOW, Seestrasse 15, 18119 Rostock, Germany
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25
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Orlando JJ, Piety CA, Nicovich JM, McKee ML, Wine PH. Rates and Mechanisms for the Reactions of Chlorine Atoms with Iodoethane and 2-Iodopropane. J Phys Chem A 2005; 109:6659-75. [PMID: 16834018 DOI: 10.1021/jp051715x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The reaction of Cl atoms with iodoethane has been studied via a combination of laser flash photolysis/resonance fluorescence (LFP-RF), environmental chamber/Fourier transform (FT)IR, and quantum chemical techniques. Above 330 K, the flash photolysis data indicate that the reaction proceeds predominantly via hydrogen abstraction. The following Arrhenius expressions (in units of cm3 molecule(-1) s(-1)) apply over the temperature range 334-434 K for reaction of Cl with CH3CH2I (k4(H)) and CD3CD2I (k4(D)): k4(H) = (6.53 +/- 3.40) x 10(-11) exp[-(428 +/- 206)/T] and k4(D) = (2.21 +/- 0.44) x 10(-11) exp[-(317 +/- 76)/T]. At room temperature and below, the reaction proceeds both via hydrogen abstraction and via reversible formation of an iodoethane/Cl adduct. Analysis of the LFP-RF data yields a binding enthalpy (0 K) for CD3CD2I x Cl of 57 +/- 10 kJ mol(-1). Calculations using density functional theory show that the adduct is characterized by a C-I-Cl bond angle of 84.5 degrees; theoretical binding enthalpies of 38.2 kJ/mol, G2'[ECP(S)], and 59.0 kJ mol(-1), B3LYP/ECP, are reasonably consistent with the experimentally derived result. Product studies conducted in the environmental chamber show that hydrogen abstraction from both the -CH2I and -CH3 groups occur to a significant extent and also provide evidence for a reaction of the CH3CH2I x Cl adduct with CH3CH2I, leading to CH3CH2Cl formation. Complementary environmental chamber studies of the reaction of Cl atoms with 2-iodopropane, CH3CHICH3, are also presented. As determined by relative rate methods, the reaction proceeds with an effective rate coefficient, k6, of (5.0 +/- 0.6) x 10(-11) cm3 molecule(-1) s(-1) at 298 K. Product studies indicate that this reaction also occurs via two abstraction channels (from the CH3 groups and from the -CHI- group) and via reversible adduct formation.
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Affiliation(s)
- John J Orlando
- Atmospheric Chemistry Division, National Center for Atmospheric Research, Boulder, Colorado 80305, USA
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26
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Zhao C, Lin X, Kwok WM, Guan X, Du Y, Wang D, Hung KF, Phillips DL. Water-Catalyzed Dehalogenation Reactions of the Isomer of CBr4 and Its Reaction Products and a Comparison to Analogous Reactions of the Isomers of Di- and Trihalomethanes. Chemistry 2005; 11:1093-108. [PMID: 15742469 DOI: 10.1002/chem.200400695] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A combined experimental and theoretical study of the UV photolysis of a typical tetrahalomethane, CBr4, in water and acetonitrile/water was performed. Ultraviolet photolysis of low concentrations of CBr4 in water mostly leads to the production of four HBr leaving groups and CO2. Picosecond time-resolved resonance Raman (Ps-TR3) experiments and ab initio calculations indicate that water-catalyzed O-H insertion/HBr elimination of the isomer of CBr4 and subsequent reactions of its products lead to the formation of these products. The UV photolyses of di-, tri-, and tetrahalomethanes at low concentrations in water-solvated environments are compared to one another. This comparison enables a general reaction scheme to be deduced that can account for the different products produced by UV photolysis of low concentrations of di-, tri-, and tetrahalomethanes in water. The fate of the (halo)formaldehyde intermediate in the chemical reaction mechanism is the key to determining how many strong acid leaving groups are produced and which carbon atom final product is likely formed by UV photolysis of a polyhalomethane at low concentrations in a water-solvated environment.
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Affiliation(s)
- Cunyuan Zhao
- Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
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Zhou Y, Varner RK, Russo RS, Wingenter OW, Haase KB, Talbot R, Sive BC. Coastal water source of short-lived halocarbons in New England. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2004jd005603] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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28
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Chuck AL. Oceanic distributions and air-sea fluxes of biogenic halocarbons in the open ocean. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2004jc002741] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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29
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Kwok WM, Zhao C, Guan X, Li YL, Du Y, Phillips DL. Efficient dehalogenation of polyhalomethanes and production of strong acids in aqueous environments: Water-catalyzed O–H-insertion and HI-elimination reactions of isodiiodomethane (CH2I–I) with water. J Chem Phys 2004; 120:9017-32. [PMID: 15267837 DOI: 10.1063/1.1701699] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A combined experimental and theoretical study of the ultraviolet photolysis of CH2I2 in water is reported. Ultraviolet photolysis of low concentrations of CH2I2 in water was experimentally observed to lead to almost complete conversion into CH2(OH)2 and 2HI products. Picosecond time-resolved resonance Raman spectroscopy experiments in mixed water/acetonitrile solvents (25%-75% water) showed that appreciable amounts of isodiiodomethane (CH2I-I) were formed within several picoseconds and the decay of the CH2I-I species became substantially shorter with increasing water concentration, suggesting that CH2I-I may be reacting with water. Ab initio calculations demonstrate the CH2I-I species is able to react readily with water via a water-catalyzed O--H-insertion and HI-elimination reaction followed by its CH2I(OH) product undergoing a further water-catalyzed HI-elimination reaction to make a H2C=O product. These HI-elimination reactions produce the two HI leaving groups observed experimentally and the H2C=O product further reacts with water to produce the other final CH2(OH)2 product observed in the photochemistry experiments. These results suggest that CH2I-I is the species that reacts with water to produce the CH2(OH)2 and 2HI products seen in the photochemistry experiments. The present study demonstrates that ultraviolet photolysis of CH2I2 at low concentration leads to efficient dehalogenation and release of multiple strong acid (HI) leaving groups. Some possible ramifications for the decomposition of polyhalomethanes and halomethanols in aqueous environments as well as the photochemistry of polyhalomethanes in the natural environment are briefly discussed.
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Affiliation(s)
- Wai Ming Kwok
- Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong, China
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30
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Kwok WM, Zhao C, Li YL, Guan X, Phillips DL. Direct observation of an isopolyhalomethane O–H insertion reaction with water: Picosecond time-resolved resonance Raman (ps-TR3) study of the isobromoform reaction with water to produce a CHBr2OH product. J Chem Phys 2004; 120:3323-32. [PMID: 15268486 DOI: 10.1063/1.1640997] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Picosecond time-resolved resonance Raman (ps-TR3) spectroscopy was used to obtain the first definitive spectroscopic observation of an isopolyhalomethane O-H insertion reaction with water. The ps-TR3 spectra show that isobromoform is produced within several picoseconds after photolysis of CHBr3 and then reacts on the hundreds of picosecond time scale with water to produce a CHBr2OH reaction product. Photolysis of low concentrations of bromoform in aqueous solution resulted in noticeable formation of HBr strong acid. Ab initio calculations show that isobromoform can react with water to produce a CHBr2(OH) O-H insertion reaction product and a HBr leaving group. This is consistent with both the ps-TR3 experiments that observe the reaction of isobromoform with water to form a CHBr2(OH) product and photolysis experiments that show HBr acid formation. We briefly discuss the implications of these results for the phase dependent behavior of polyhalomethane photochemistry in the gas phase versus water solvated environments.
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Affiliation(s)
- Wai Ming Kwok
- Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong, People's Republic of China
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31
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Guan X, Du Y, Li YL, Kwok WM, Phillips DL. Comparison of the dehalogenation of polyhalomethanes and production of strong acids in aqueous and salt (NaCl) water environments: Ultraviolet photolysis of CH[sub 2]I[sub 2]. J Chem Phys 2004; 121:8399-409. [PMID: 15511161 DOI: 10.1063/1.1803508] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The ultraviolet photolysis of CH(2)I(2) was studied in water and salt water solutions using photochemistry and picosecond time-resolved resonance Raman spectroscopy. Photolysis in both types of environments produces mainly CH(2)(OH)(2) and HI products. However, photolysis of CH(2)I(2) in salt water leads to the formation of different products/intermediates (CH(2)ICl and Cl(2) (-)) not observed in the absence of salt in aqueous solutions. The amount of CH(2)(OH)(2) and HI products appears to decrease after photolysis of CH(2)I(2) in salt water compared to pure water. We briefly discuss possible implications of these results for photolysis of CH(2)I(2) and other polyhalomethanes in sea water and other salt aqueous environments compared to nonsalt water solvated environments.
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Affiliation(s)
- Xiangguo Guan
- Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong, People's Republic of China
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32
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Fuse H, Inoue H, Murakami K, Takimura O, Yamaoka Y. Production of free and organic iodine byRoseovariusspp. FEMS Microbiol Lett 2003; 229:189-94. [PMID: 14680698 DOI: 10.1016/s0378-1097(03)00839-5] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Two strains of iodine-producing bacteria were isolated from marine samples. 16S rRNA gene sequences indicated the strains were most closely related to Roseovarius tolerans, and phylogenetic analysis indicated both belong to the same genus. 5 mM iodide inhibited the growth of strain 2S5-2 almost completely, and of strain S6V slightly. Both strains produced free iodine and organic iodine from iodide. CH2I2, CHI3 and CH2ClI were the main organic iodines produced by strain 2S5-2, and CHI3 and CH2I2 by strain S6V. Experiments using cells and spent media suggested that the organic iodines were produced from the compounds released or contained in the media and cells were necessary for the considerable production of CH2I2 and CH2ClI, though CHI3 was produced by spent media with H2O2 or free iodine.
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Affiliation(s)
- Hiroyuki Fuse
- Institute for Marine Resources and Environment, National Institute of Advanced Industrial Science and Technology, 2-2-2 Hirosuehiro, Kure, Hiroshima 737-0197, Japan.
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Affiliation(s)
- Lucy J Carpenter
- Department of Chemistry, University of York, York YO10 5DD, U.K.
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Li YL, Zhao C, Kwok WM, Guan X, Zuo P, Phillips DL. Observation of a HI leaving group following ultraviolet photolysis of CH2I2 in water and anab initioinvestigation of the O–H insertion/HI elimination reactions of the CH2I–I isopolyhalomethane species with H2O and 2H2O. J Chem Phys 2003. [DOI: 10.1063/1.1595636] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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35
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Kwok WM, Ma C, Parker AW, Phillips D, Towrie M, Matousek P, Phillips DL. Picosecond Time-Resolved Resonance Raman Study of CH2I−I Produced after Ultraviolet Photolysis of CH2I2 in CH3OH, CH3CN/H2O and CH3OH/H2O Solutions. J Phys Chem A 2003. [DOI: 10.1021/jp021611b] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Wai Ming Kwok
- Department of Chemistry, Imperial College of Science, Technology and Medicine, Exhibition Road, London SW7 2AY, U.K., Central Laser Facility, CLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, U.K., and Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong S. A. R., P. R. China
| | - Chensheng Ma
- Department of Chemistry, Imperial College of Science, Technology and Medicine, Exhibition Road, London SW7 2AY, U.K., Central Laser Facility, CLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, U.K., and Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong S. A. R., P. R. China
| | - Anthony W. Parker
- Department of Chemistry, Imperial College of Science, Technology and Medicine, Exhibition Road, London SW7 2AY, U.K., Central Laser Facility, CLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, U.K., and Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong S. A. R., P. R. China
| | - David Phillips
- Department of Chemistry, Imperial College of Science, Technology and Medicine, Exhibition Road, London SW7 2AY, U.K., Central Laser Facility, CLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, U.K., and Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong S. A. R., P. R. China
| | - Michael Towrie
- Department of Chemistry, Imperial College of Science, Technology and Medicine, Exhibition Road, London SW7 2AY, U.K., Central Laser Facility, CLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, U.K., and Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong S. A. R., P. R. China
| | - Pavel Matousek
- Department of Chemistry, Imperial College of Science, Technology and Medicine, Exhibition Road, London SW7 2AY, U.K., Central Laser Facility, CLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, U.K., and Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong S. A. R., P. R. China
| | - David Lee Phillips
- Department of Chemistry, Imperial College of Science, Technology and Medicine, Exhibition Road, London SW7 2AY, U.K., Central Laser Facility, CLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, U.K., and Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong S. A. R., P. R. China
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37
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Li YL, Wang D, Phillips DL. Time-resolved resonance Raman spectroscopy and density functional theory investigation of the CH2I–I isomer and CH2I2⋯I molecular complex products produced from ultraviolet photolysis of CH2I2 in the solution phase: Comparison of the structure and chemical reactivity of polyhalomethane isomers and polyhalomethane–halogen atom molecular complexes. J Chem Phys 2002. [DOI: 10.1063/1.1511724] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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38
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Li YL, Chen DM, Wang D, Phillips DL. Time-resolved resonance Raman and density functional theory investigation of iodocyclopropanation and addition reactions with alkenes after ultraviolet photolysis of iodoform. J Org Chem 2002; 67:4228-35. [PMID: 12054958 DOI: 10.1021/jo011163o] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A time-resolved resonance Raman spectroscopic investigation is reported for the ultraviolet photolysis of CHI(3) in pure cyclohexane and mixed cyclohexane/cyclohexene solvents. The ICHI-I species is observed in pure cyclohexane solvent. Upon addition of cyclohexene, the ICHI-I species lifetime is reduced and new bands from an I(2):cyclohexene complex are observed. Density functional theory computations show that ICHI-I and CHI(2) species have similar barriers of reaction toward addition to the C=C of ethylene. The addition reaction of ICHI-I with ethylene results in formation of an iodocyclopropane and I(2) molecule while addition of.CHI(2) results in initial formation of a diiodopropyl radical intermediate. Ultraviolet photolysis of CHI(3) in the presence of cyclohexene is known to produce a reasonable yield of iodonorcarane product and some addition reaction products. We present a mechanism for the iodocyclopropanation reaction that is consistent with both experimental and theoretical characterization of reaction intermediates formed after ultraviolet photolysis of CHI(3). We briefly discuss the concentration dependence of the time-resolved resonance Raman spectra and photochemistry in relation to the competition between the reaction of the ICHI-I and CHI(2) species with the C=C bond of olefins.
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Affiliation(s)
- Yun-Liang Li
- Department of Chemistry, University of Hong Kong, Pokfulam Road, SAR, People's Republic of China
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39
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Minaev B, Loboda O, Vahtras O, Agren H, Bilan E. Physical properties and spectra of IO, IO- and HOI studied by ab initio methods. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2002; 58:1039-1053. [PMID: 11942391 DOI: 10.1016/s1386-1425(01)00580-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Structure and properties of the IO, IO- and HOI species, which are of potential importance for the ozone destruction catalytic cycle in the troposphere, have been calculated together with the EPR, NMR and UV-visible spectra by ab initio methodology with account of spin-orbit coupling (SOC) effects. Multi-configuration self-consistent field calculations with linear and quadratic response techniques and the multi-reference configuration interaction method have been employed. Photodissociation of these species, crucial for the catalytic ozone-destruction cycle, is critically reviewed and analyzed. Calculations predict that the singlet-triplet (S-T) transition to the lowest triplet state (X1 A' --> 3A'') should be responsible for the weak long-wavelength tail absorption (approximately 450-560 nm) and photodissociation of the HOI molecule. The second, more intense, band around 400 nm is produced by two overlapping S-S and S-T transitions. In order to check this assignment of the HOI photodissociation the isoelectronic IO- anion and IO radical have been studied by the same methods. Comparison with the EPR spectrum of the IO radical indicates that the methods are reliable which gives credit to the accuracy of the HOI spectral interpretation. NMR spectra of HOI and IO- molecules and some other properties are calculated for the first time.
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Affiliation(s)
- Boris Minaev
- Laboratory of Theoretical Chemistry, Royal Institute of Technology, Stockholm, Sweden
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40
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Wang D, Phillips DL, Fang WH. Density functional theory investigation of the reactions of CH2Br–I, CH2I–Br, CH2Cl–I, and CH2I–Cl isopolyhalomethanes with ethylene. Phys Chem Chem Phys 2002. [DOI: 10.1039/b204898c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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41
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Li YL, Wang D, Leung KH, Phillips DL. Transient Resonance Raman Investigation of the ∼570 nm Transient Absorption Band Observed after Ultraviolet Photolysis of Diiodomethane in the Solution Phase. J Phys Chem A 2001. [DOI: 10.1021/jp012608f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yun-Liang Li
- Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong S.A.R., P. R. China
| | - Dongqi Wang
- Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong S.A.R., P. R. China
| | - King Hung Leung
- Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong S.A.R., P. R. China
| | - David Lee Phillips
- Department of Chemistry, University of Hong Kong, Pokfulam Road, Hong Kong S.A.R., P. R. China
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42
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Ohsawa N, Tsujita M, Morikawa S, Itoh N. Purification and characterization of a monohalomethane-producing enzyme S-adenosyl-L-methionine: halide ion methyltransferase from a marine microalga, Pavlova pinguis. Biosci Biotechnol Biochem 2001; 65:2397-404. [PMID: 11791711 DOI: 10.1271/bbb.65.2397] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A monohalomethane-producing enzyme, S-adenosyl-L-methionine-dependent halide ion methyltransferase (EC 2.1.1.-) was purified from the marine microalga Pavlova pinguis by two anion exchange, hydroxyapatite and gel filtration chromatographies. The methyltransferase was a monomeric molecule having a molecular weight of 29,000. The enzyme had an isoelectric point at 5.3, and was optimally active at pH 8.0. The Km for iodide and SAM were 12 mM and 12 microM, respectively, which were measured using a partially purified enzyme. Various metal ions had no significant effect on methyl iodide production, suggesting that the enzyme does not require metal ions. The enzyme reaction strictly depended on SAM as a methyl donor, and the enzyme catalyzed methylation of the I-, Br-, and Cl- to corresponding monohalomethanes and of bisulfide to methyl mercaptan.
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Affiliation(s)
- N Ohsawa
- Biotechnology Research Center, Toyama Prefectural University, Japan
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43
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Baker AR, Tunnicliffe C, Jickells TD. Iodine speciation and deposition fluxes from the marine atmosphere. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2000jd000004] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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44
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Huang J, Xu D, Fink WH, Jackson WM. Photodissociation of the dibromomethane cation at 355 nm by means of ion velocity imaging. J Chem Phys 2001. [DOI: 10.1063/1.1402993] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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45
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Yamamoto H, Yokouchi Y, Otsuki A, Itoh H. Depth profiles of volatile halogenated hydrocarbons in seawater in the Bay of Bengal. CHEMOSPHERE 2001; 45:371-377. [PMID: 11592427 DOI: 10.1016/s0045-6535(00)00541-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Measurements were made of bromocarbons (CHBr3 and CH2Br2), iodocarbons (CH2I2 and CH2ClI), and dimethylsulfide (DMS, CH3SCH3) in seawater collected from the Bay of Bengal under tropical stratified conditions. These compounds showed different depth profiles, characteristic of each group. CH2I2 and CH2ClI showed very similar depth profiles to chlorophyll-a, suggesting their production by phytoplankton followed by rapid decay in seawater. The CH2I2 maximum at a depth a little below the CH2ClI maximum was consistent with its more significant photolytic decay. The bromocarbons were less localized in their distributions than were the iodocarbons, suggesting their longer residence time in seawater after their release from phytoplankton. Both of these profiles were different from the pattern of DMS, which had its maxima above the chlorophyll-a maximum layer near the surface.
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Affiliation(s)
- H Yamamoto
- National Institute for Environmental Studies, Tsukuba, Ibaraki, Japan
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46
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Ming Kwok W, Ma C, Phillips D, Parker AW, Towrie M, Matousek P, Lee Phillips D. Picosecond time-resolved resonance Raman observation of Iso-CH2Br–I following A-band photodissociation of CH2BrI in the solution phase. Chem Phys Lett 2001. [DOI: 10.1016/s0009-2614(01)00491-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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47
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Zheng X, Lee CW, Li YL, Fang WH, Phillips DL. Transient resonance Raman spectroscopy and density functional theory investigation of iso-CHBr2Cl and iso-CCl3Br photoproducts produced following ultraviolet excitation of CHBr2Cl and CCl3Br. J Chem Phys 2001. [DOI: 10.1063/1.1367391] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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48
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Affiliation(s)
- Juliane C. Mössinger
- Centre for Atmospheric Science, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, U. K
| | - R. Anthony Cox
- Centre for Atmospheric Science, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, U. K
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49
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Kwok WM, Ma C, Parker AW, Phillips D, Towrie M, Matousek P, Zheng X, Phillips DL. Picosecond time-resolved resonance Raman observation of the iso-CH2Cl–I and iso-CH2I–Cl photoproducts from the “photoisomerization” reactions of CH2ICl in the solution phase. J Chem Phys 2001. [DOI: 10.1063/1.1362178] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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50
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Zheng X, Fang WH, Phillips DL. Transient resonance Raman spectroscopy and density functional theory investigation of iso-polyhalomethanes containing bromine and/or iodine atoms. J Chem Phys 2000. [DOI: 10.1063/1.1326064] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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