Articles de revues : « Chlora nitrone »

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Humbert, Guillaume, Mathieu Sebilo, Marion Chorin, Véronique Vaury et Anniet M. Laverman. « Analytical pitfalls when using inhibitors in specific nitrification assays ». Environmental Chemistry 18, n^o 7 (2021) : 295. http://dx.doi.org/10.1071/en21118.

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Environmental contextSpecific inhibitors of biological reactions in the nitrogen cycle can be used to determine the origin of reactive nitrogen species; these nitrogen species potentially degrade water quality or influence climate. However, inhibitors can potentially interfere with methods for the analysis of stable isotope ratios and concentrations of ammonium, nitrite and nitrate. The effect of this interference on several commonly used methods was investigated. These findings should help avoid the use of inappropriate analytical methods and improve data quality in studies of the nitrogen cycle.AbstractCharacterisation of the reaction steps involved in nitrification can help determine the processes that produce potentially harmful environmental pollutants such as nitrite, nitrate and nitrous oxide (N2O). The use of nitrification inhibitors can uncouple the reactions and therefore assist in their mechanistic and isotopic characterisation. However, nitrification inhibitors can interfere with the methods for determining the concentrations and stable isotope ratios of ammonium, nitrite and nitrate. The interference of allylthiourea, hydrazine or sodium chlorate in colorimetric methods and stable isotope measurements were assessed. Ammonium concentrations were measured with the salicylate method. Nitrite and nitrate were measured with the Griess reaction, with nitrate first being reduced to nitrite with vanadium (III) chloride. For the stable isotope analysis, nitrite was reduced to N2O in a 1 : 1 sodium azide and acetic acid buffer solution; preceded, when necessary, by ammonium oxidation to nitrite by hypobromite or nitrate reduction to nitrite on an activated cadmium column. Sodium chlorate did not interfere with any of the analyses and none of the inhibitors interfered with the stable isotope ratios determination of nitrate. Allylthiourea interfered with ammonium and nitrate quantification. Both allylthiourea and hydrazine also clearly interfered in the determination of the nitrogen stable isotope ratio of ammonium, while only allylthiourea interfered in the determination of nitrogen and oxygen stable isotope ratios of nitrite. Although we suggest methods to overcome some of these interferences, our study demonstrated that the analytical methods used in combination with allylthiourea or hydrazine as nitrification inhibitors should be considered with caution when designing experiments.

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Klittich, C., et J. F. Leslie. « Nitrate reduction mutants of fusarium moniliforme (gibberella fujikuroi). » Genetics 118, n^o 3 (1 mars 1988) : 417–23. http://dx.doi.org/10.1093/genetics/118.3.417.

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Abstract Twelve strains of Fusarium moniliforme were examined for their ability to sector spontaneously on toxic chlorate medium. All strains sectored frequently; 91% of over 1200 colonies examined formed chlorate-resistant, mutant sectors. Most of these mutants had lesions in the nitrate reduction pathway and were unable to utilize nitrate (nit mutants). nit mutations occurred in seven loci: a structural gene for nitrate reductase (nit1), a regulatory gene specific for the nitrate reduction pathway (nit3), and five genes controlling the production of a molybdenum-containing cofactor that is necessary for nitrate reductase activity (nit2, nit4, nit5, nit6, nit7). No mutations affecting nitrite reductase or a major nitrogen regulatory locus were found among over 1000 nit mutants. Mutations of nit1 were recovered most frequently (39-66%, depending on the strain) followed by nit3 mutations (23-42%). The frequency of isolation of each mutant type could be altered, however, by changing the source of nitrogen in the chlorate medium. We concluded that genetic control of nitrate reduction in F. moniliforme is similar to that in Aspergillus and Neurospora, but that the overall regulation of nitrogen metabolism may be different.

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Fischer, Marco, Jesse Alderson, Geertje van Keulen, Janet White et R. Gary Sawers. « The obligate aerobe Streptomyces coelicolor A3(2) synthesizes three active respiratory nitrate reductases ». Microbiology 156, n^o 10 (1 octobre 2010) : 3166–79. http://dx.doi.org/10.1099/mic.0.042572-0.

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Streptomyces coelicolor A3(2) synthesizes three membrane-associated respiratory nitrate reductases (Nars). During aerobic growth in liquid medium the bacterium was able to reduce 50 mM nitrate stoichiometrically to nitrite. Construction and analysis of a mutant in which all three narGHJI operons were deleted showed that it failed to reduce nitrate. Deletion of the gene encoding MoaA, which catalyses the first step in molybdenum cofactor biosynthesis, also prevented nitrate reduction, consistent with the Nars being molybdoenzymes. In contrast to the triple narGHJI mutant, the moaA mutant was also unable to use nitrate as sole nitrogen source, which indicates that the assimilatory nitrate reductases in S. coelicolor are also molybdenum-dependent. Analysis of S. coelicolor growth on solid medium demonstrated that Nar activity is present in both spores and mycelium (hypha). Development of a survival assay with the nitrate analogue chlorate revealed that wild-type S. coelicolor spores and mycelium were sensitive to chlorate after anaerobic incubation, independent of the presence of nitrate, while both the moaA and triple nar mutants were chlorate-resistant. Complementation of the triple nar mutant with the individual narGHJI operons delivered on cosmids revealed that each operon encoded an enzyme that was synthesized and active in nitrate or chlorate reduction. The data obtained from these studies allow a tentative assignment of Nar1 activity to spores, Nar2 to spores and mycelium, and Nar3 exclusively to mycelium.

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Chapyshev, Sergei V., Denis V. Korchagin, Patrik Neuhaus et Wolfram Sander. « High-spin intermediates of the photolysis of 2,4,6-triazido-3-chloro-5-fluoropyridine ». Beilstein Journal of Organic Chemistry 9 (16 avril 2013) : 733–42. http://dx.doi.org/10.3762/bjoc.9.83.

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In contrast to theoretical expectations, the photolysis of 2,4,6-triazido-3-chloro-5-fluoropyridine in argon at 5 K gives rise to EPR peaks of just two triplet mononitrenes, two quintet dinitrenes, and a septet trinitrene. EPR spectral simulations in combination with DFT calculations show that observable nitrenes can be assigned to triplet 2,4-diazido-3-chloro-5-fluoropyridyl-6-nitrene (D T = 1.026 cm−1, E T = 0), triplet 2,6-diazido-3-chloro-5-fluoropyridyl-4-nitrene (D T = 1.122 cm−1, E T = 0.0018 cm−1), quintet 4-azido-3-chloro-5-fluoropyridyl-2,6-dinitrene (D Q = 0.215 cm−1, E Q = 0.0545 cm−1), quintet 2-azido-3-chloro-5-fluoropyridyl-4,6-dinitrene (D Q = 0.209 cm−1, E Q = 0.039 cm−1) and septet 3-chloro-5-fluoropyridyl-2,4,6-trinitrene (D S = −0.1021 cm−1, E S = −0.0034 cm−1). Preferential photodissociation of the azido groups located in ortho-positions to the fluorine atom of pyridines is associated with strong π-conjugation of these groups with the pyridine ring. On photoexcitation, such azido groups are more efficiently involved in reorganization of the molecular electronic system and more easily adopt geometries of the locally excited predissociation states.

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Oosterkamp, Margreet J., Farrakh Mehboob, Gosse Schraa, Caroline M. Plugge et Alfons J. M. Stams. « Nitrate and (per)chlorate reduction pathways in (per)chlorate-reducing bacteria ». Biochemical Society Transactions 39, n^o 1 (19 janvier 2011) : 230–35. http://dx.doi.org/10.1042/bst0390230.

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The reduction of (per)chlorate and nitrate in (per)chlorate-reducing bacteria shows similarities and differences. (Per)chlorate reductase and nitrate reductase both belong to the type II DMSO family of enzymes and have a common bis(molybdopterin guanine dinucleotide)molybdenum cofactor. There are two types of dissimilatory nitrate reductases. With respect to their localization, (per)chlorate reductase is more similar to the dissimilatory periplasmic nitrate reductase. However, the periplasmic, unlike the membrane-bound, respiratory nitrate reductase, is not able to use chlorate. Structurally, (per)chlorate reductase is more similar to respiratory nitrate reductase, since these reductases have analogous subunits encoded by analogous genes. Both periplasmic (per)chlorate reductase and membrane-bound nitrate reductase activities are induced under anoxic conditions in the presence of (per)chlorate and nitrate respectively. During microbial (per)chlorate reduction, molecular oxygen is generated. This is not the case for nitrate reduction, although an atypical reaction in nitrite reduction linked to oxygen formation has been described recently. Microbial oxygen production during reduction of oxyanions may enhance biodegradation of pollutants under anoxic conditions.

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Nelson, J. A., et P. A. Lefebvre. « Targeted disruption of the NIT8 gene in Chlamydomonas reinhardtii. » Molecular and Cellular Biology 15, n^o 10 (octobre 1995) : 5762–69. http://dx.doi.org/10.1128/mcb.15.10.5762.

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We have used homologous recombination to disrupt the nuclear gene NIT8 in Chlamydomonas reinhardtii. This is the first report of targeted gene disruption of an endogenous locus in C. reinhardtii and only the second for a photosynthetic eukaryote. NIT8 encodes a protein necessary for nitrate and nitrite assimilation by C. reinhardtii. A disruption vector was constructed by placing the CRY1-1 selectable marker gene, which confers emetine resistance, within the NIT8 coding region. nit8 mutants are unable to grow on nitrate as their sole nitrogen source (Nit-) and are resistant to killing by chlorate. One of 2,000 transformants obtained after selection on emetine-chlorate medium contained a homologous insertion of five copies of the disruption plasmid into the NIT8 gene, producing an emetine-resistant, chlorate-resistant Nit- phenotype. The mutant phenotype was rescued by the wild-type NIT8 gene upon transformation. Seven other mutations at the nit8 locus, presumably resulting from homologous recombination with the disruption plasmid, were identified but were shown to be accompanied by deletions of the surrounding genomic region.

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Ye, Miaomiao, Tuqiao Zhang, Zhiwei Zhu, Yan Zhang et Yiping Zhang. « Photodegradation of 4-chloronitrobenzene in the presence of aqueous titania suspensions in different gas atmospheres ». Water Science and Technology 64, n^o 7 (1 octobre 2011) : 1466–72. http://dx.doi.org/10.2166/wst.2011.531.

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The photocatalytic degradation of 4-chloronitrobenzene (4-CNB) was carried out using Degussa P25 TiO2 as photocatalyst in three different gas atmospheres: nitrogen, oxygen, and ozone. The total organic carbon (TOC) and inorganic anions including chloride, nitrite, and nitrate anions were measured to monitor the mineralization processes, while the degradation of 4-CNB and the formation of intermediates were followed by liquid chromatography–mass spectrometry (LC/MS). Results showed that the photocatalytic efficiency followed the order of TiO2/UV/N2 < TiO2/UV/O2 < TiO2/UV/O3, which was further proved by evaluating the reaction activities using electron paramagnetic resonance (EPR) spin trapping technique. Chlorine atom, nitro group and hydrogen atom of the benzene ring could be displaced by hydroxyl radical (•OH) leading to the formation of chloride, nitrite (III) anions and a variety of phenols, then the nitrite (III) anions were further oxidized to nitrate (V) anions. 4-Nitrophenol and 5-chloro-2-nitrophenol were identified and quantified in both of the TiO2/UV/N2 and TiO2/UV/O2 processes while no aromatic intermediates were monitored in the process of TiO2/UV/O3.

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Ren, Tie, RÃ¯Â¿Â½al Roy et Roger Knowles. « Production and Consumption of Nitric Oxide by Three Methanotrophic Bacteria ». Applied and Environmental Microbiology 66, n^o 9 (1 septembre 2000) : 3891–97. http://dx.doi.org/10.1128/aem.66.9.3891-3897.2000.

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ABSTRACT We studied nitrogen oxide production and consumption by methanotrophs Methylobacter luteus (group I),Methylosinus trichosporium OB3b (group II), and an isolate from a hardwood swamp soil, here identified by 16S ribosomal DNA sequencing as Methylobacter sp. strain T20 (group I). All could consume nitric oxide (nitrogen monoxide, NO), and produce small amounts of nitrous oxide (N2O). OnlyMethylobacter strain T20 produced large amounts of NO (>250 parts per million by volume [ppmv] in the headspace) at specific activities of up to 2.0 Ã¯Â¿Â½ 10−17 mol of NO cell−1 day−1, mostly after a culture became O2 limited. Production of NO by strain T20 occurred mostly in nitrate-containing medium under anaerobic or nearly anaerobic conditions, was inhibited by chlorate, tungstate, and O2, and required CH4. Denitrification (methanol-supported N2O production from nitrate in the presence of acetylene) could not be detected and thus did not appear to be involved in the production of NO. Furthermore, cd1 and Cu nitrite reductases, NO reductase, and N2O reductase could not be detected by PCR amplification of the nirS,nirK, norB, and nosZ genes, respectively. M. luteus and M. trichosporiumproduced some NO in ammonium-containing medium under aerobic conditions, likely as a result of methanotrophic nitrification and chemical decomposition of nitrite. For Methylobacter strain T20, arginine did not stimulate NO production under aerobiosis, suggesting that NO synthase was not involved. We conclude that strain T20 causes assimilatory reduction of nitrate to nitrite, which then decomposes chemically to NO. The production of NO by methanotrophs such as Methylobacter strain T20 could be of ecological significance in habitats near aerobic-anaerobic interfaces where fluctuating O2 and nitrate availability occur.

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PÉREZ, M. Dolores, Celedonio GONZÁLEZ, Julio ÁVILA, Nélida BRITO et José M. SIVERIO. « The YNT1 gene encoding the nitrate transporter in the yeast Hansenula polymorpha is clustered with genes YNI1 and YNR1 encoding nitrite reductase and nitrate reductase, and its disruption causes inability to grow in nitrate ». Biochemical Journal 321, n^o 2 (15 janvier 1997) : 397–403. http://dx.doi.org/10.1042/bj3210397.

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DNA sequencing in the phage λJA13isolated from a λEMBL3 Hansenula polymorphagenomic DNA library containing the nitrate reductase- (YNR1) and nitrite reductase- (YNI1) encoding genes revealed an open reading frame (YNT1) of 1524 nucleotides encoding a putative protein of 508 amino acids with great similarity to the nitrate transporters from Aspergillus nidulansand Chlamydomonas reinhardtii. Disruption of the chromosomal YNT1copy resulted in incapacity to grow in nitrate and a significant reduction in rate of nitrate uptake. The disrupted strain is still sensitive to chlorate, and, in the presence of 0.1 mM nitrate, the expression of YNR1 and YNI1 and the activity of nitrate reductase and nitrite reductase are significantly reduced compared with the wild-type. Northern-blot analysis showed that YNT1 is expressed when the yeast is grown in nitrate and nitrite but not in ammonium solution.

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Hemissi, Hanene, Sonia Abid et Mohamed Rzaigui. « 5-Chloro-2-methoxyanilinium nitrate ». Acta Crystallographica Section E Structure Reports Online 64, n^o 5 (4 avril 2008) : o801. http://dx.doi.org/10.1107/s1600536808008805.

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Ng, Seik Weng. « 5-Chloro-8-hydroxyquinolinium nitrate ». Acta Crystallographica Section E Structure Reports Online 65, n^o 6 (29 mai 2009) : o1450. http://dx.doi.org/10.1107/s160053680901993x.

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The 5-chloro-8-hydroxyquinolinium cation in the the title ion pair, C9H7ClNO+·NO3−, is approximately coplanar with the nitrate anion [dihedral angle = 16.1 (1)°]. Two ion pairs are hydrogen bonded (2 × O—H...O and 2 × N—H...O) about a center of inversion, generating anR44(14) ring.

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Cherubim, P., et LW Deady. « Nucleophilic Substitution Reactions in Benzo[C][1,8]naphthyridines. II. » Australian Journal of Chemistry 43, n^o 8 (1990) : 1469. http://dx.doi.org/10.1071/ch9901469.

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3-Chloro-1-methyl-6-(p- methylphenoxy ) benzo [c][1,8] naphthyridine has been prepared, the reactions with various nitrogen, oxygen and sulfur nucleophiles studied, and the results compared with those for the 1- chloro-3-methyl isomer. The 6-position was more reactive for oxygen and nitrogen nucleophiles, so much so that an initially added 6-NHR group was displaced by a second R′NH2 nucleophile at least as readily as was the 3-chloro group. With p- chloro ( thiophenol ), however, the 3-chloro group was preferentially displaced.

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Childs, Bradley J., Donald C. Craig, Marcia L. Scudder et Harold A. Goodwin. « The Crystal Structure of Chloro(1,10-phenanthroline-2-carboxamide Oxime)copper(II) Nitrate ». Australian Journal of Chemistry 50, n^o 10 (1997) : 1017. http://dx.doi.org/10.1071/c97022.

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In chloro(1,10-phenanthroline-2-carboxamide oxime)copper(II) nitrate thecopper atom adopts a distorted square pyramidal structure with bridging chlorogroups producing a zigzag chain in which each tridentate phenanthroline amideoxime group coordinates through the oxime nitrogen atom and is essentiallyplanar. The planes of the tridentates are almost parallel, giving a stackedarray of the ligands within the chain. The nitrate ions link chains throughhydrogen bonding with the amino and oxime hydrogen atoms of the carboxamideoxime group. The crystals are monoclinic, space group P21/c,a9·2199(6), b21·794(1), c 7·2889(4) Å, β99· 900(3)˚, Z 4.

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Izzati Mohd Zainudin, Nur, Nor Ismail, Nik Izham Mohamed Nor, Azmi Razak, Siti Mohd Sidique et Baharuddin Salleh. « Nitrate Non-Utilizing Mutants and Vegetative Compatibility Groups of Fusarium Proliferatum and F. Sacchari Isolated from Rice in the Peninsular Malaysia and Kalimantan, Indonesia ». Journal of Plant Protection Research 49, n^o 2 (1 juin 2009) : 229–35. http://dx.doi.org/10.2478/v10045-009-0035-z.

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Nitrate Non-Utilizing Mutants and Vegetative Compatibility Groups ofFusarium ProliferatumandF. SacchariIsolated from Rice in the Peninsular Malaysia and Kalimantan, IndonesiaA total of 26 isolates ofFusarium proliferatumandF. sacchariwere isolated from rice in the Peninsular Malaysia and Kalimantan, Indonesia. Spontaneous chlorate-resistant sectors (CRSs) were recovered from all wild type of bothFusariumspecies when cultured on two chlorate media. The non-utilizing (nit) mutants were generated ascrn(chlorate resistant, nitrate utilizing),nit1, nit3and nitM based on phenotyping growth-types on diagnostic media with different sources of nitrogen. Thenitmutants were paired on minimal medium (MM) for examining the vegetative compatibility. The majority ofnitmutants (32.3-46.5%) recovered werenit1.Eight and seven vegetative compatibility groups (VCGs) ofF. proliferatumandF. sacchariwere identified, respectively. The isolates ofF. proliferatumandF. sacchariwere genetically diverse as shown by the number and distribution of the VCGs. No strong correlation was observed between VCGs of both species and location.

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Gorge, Astrid, Ute Patt-Siebel, Ulrich Müller et Kurt Dehnicke. « N-Chloronitrenokomplexe des Wolframs : Synthesen und Kristallstrukturen von PPh3Me[Cl5W(NCl)] und (PPh4)3{[Cl5W(NCl)]2Cl} • CCl4 • 4CH3CN / N-Chloro-Nitrene Complexes of Tungsten : Syntheses and Crystal Structures of PPh3Me[Cl5W(NCl)] and (PPh4)3{[Cl5W(NCl)]2Cl} CCl4-4CH3CN ». Zeitschrift für Naturforschung B 43, n^o 12 (1 décembre 1988) : 1633–38. http://dx.doi.org/10.1515/znb-1988-1217.

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Abstrct The N-chloro-nitrene complexes PPh3Me[Cl5W(NCl)] and (PPh4)3{ [Cl5W(NCl)]2Cl} • CCl4 • 4CH3CN were prepared by the reaction of [CI4W(NCl)]2 with [PPh3Me]Ci in CH2Cl2 and with [PPh4]Cl in CH3CN. respectively, followed by precipitation with CCl4. Both compounds form red, moisture-sensitive crystals, which were characterized by IR spectroscopy as well as by X-ray structure determinations. PPh3Me[CUW(NCl)]: space group P1̄, Z = 2, a = 862.7(3), b = 1108.4(2), c = 1411.0(5) pm. a = 71.74(3)°, β = 76.78(3)°, y = 77.55(2)° (at 18 °C); 2843 unique observed reflexions, R = 0.042. The compound consists of ions PPh3Me+ and [Cl5W(NCl)]-, in which the tungsten atom has a distorted octahedral environment of five chlorine atoms and the nitrogen atom of the N-chloro-nitrene ligand with bond distances WN = 169 pm and N-Cl = 160 pm. bond angle WNCl = 175°. (PPh4)3{[Cl5W(NCl)]2Cl} • CCl4• 4CH3CN: space group P4/n, Z = 2, a = 1298.2(8). c = 2720.4(7) pm (at 17 °C); (1979 unique observed reflexions. R = 0.096). The compound contains cations PPh4+ and anions {[CI5W(NCl)]2Cl}3-, in which two [Cl5W(NCl)]- ions are bridged by a chloride ion to form the linear unit [Cl5W≡N-Cl ··· Cl -Cl-N≡WCl5]3- with Cl ··· Cl-contactsof 288 and 278 pm

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Makus, D. J. « NITROGEN LEVEL AND LIGHT INTENSITY CAN EFFECT VEGETABLE AMARANTH LEAF NUTRIENTS ». HortScience 28, n^o 4 (avril 1993) : 267A—267. http://dx.doi.org/10.21273/hortsci.28.4.267a.

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Three-week-old transplants of Amaranthus tricolor cultivars 'RRC 241' (RC) and 'Hinn Choy' (HC) were given split applications of supplemental N of 0, 100 and 200 kg/ha and in the 5th week after sowing were exposed to 100, 70 and 50% of ambient solar radiation for nine and ten days, respectively. Increased shading had a linear (L) effect on leaf blade NO3, protein, K, Mg, S, P, Al, Fe and Cu (dry wt basis). There were L and quadratic (Q) increases in chlorophyll (chloro) and carotenoids. Increasing supplemental N increased leaf blade protein (L,Q), Na (L), Mn (L), chloro (L,Q), carotenoids (L,Q), but decreased Mg (L), P (L,Q) and Zn (L,Q). Nitrate levels showed L and Q increases in RC and HC, respectively. HC was higher in leaf blade K, Mg, Na, Fe, Zn, Cu, NO3, chloro and carotenoides, but lower in CA than RC. Shading had no effect on leaf area or plant fresh wt, but decreased plant dry wt while increasing plant water content. Nitrogen application increased stem length, and plant fresh and dry wt.

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Voortman, W. J., A. E. Simpson, C. A. Kerr et C. A. Buckley. « Application of Electrochemical Membrane Processes to the Treatment of Aqueous Effluent Streams ». Water Science and Technology 25, n^o 10 (1 mai 1992) : 329–37. http://dx.doi.org/10.2166/wst.1992.0259.

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Electrolysis cellss incorporating ion-exchange membranes are used in the chlor-alkali industry. Similar cells may also be used for selective concentration, purification or chemical conversion of aqueous effluents. The Pollution Research Group, University of Natal has applied electrochemical membrane processes to the recovery of sodium hydroxide from textile scour and bottle wash effluents, the removal and neutralisation of sulphuric acid from underground mine water and the removal of ammonium nitrate from effluents arising in a nitrogen chemicals manufacturing complex.

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ANTIPOV, Alexey N., Dimitry Y. SOROKIN, Nikolay P. L'VOV et J. Gijs KUENEN. « New enzyme belonging to the family of molybdenum-free nitrate reductases1 ». Biochemical Journal 369, n^o 1 (1 janvier 2003) : 185–89. http://dx.doi.org/10.1042/bj20021193.

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A novel molybdenum-free nitrate reductase was isolated from the obligate chemolithoautotrophic and facultative anaerobic, (halo)alkaliphilic sulphur-oxidizing bacterium Thioalkalivibrio nitratireducens strain ALEN 2. The enzyme was found to contain vanadium and haem c as cofactors. Its native molecular mass was determined as 195kDa, and the enzyme consists of four identical subunits with apparent molecular masses of 57kDa. Apart from nitrate, the enzyme can utilize nitrite, chlorate, bromate, selenate and sulphite as electron acceptors. Moreover, it also has a haloperoxidase activity.

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Soto, Yesenia L., Emily A. Baumgartner, Francesca R. Bertoletti, Ellen F. Gardner, Bridget M. Hofsteadter, Adis Hrvat, Aurimas Jackunas et al. « Synthesis and Styrene Copolymerization of New Halogen and Methoxy Ring-Trisubstituted Propyl Cyanophenylpropenoates ». International Journal of Chemistry 11, n^o 2 (27 juin 2019) : 60. http://dx.doi.org/10.5539/ijc.v11n2p60.

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New ring-trisubstituted propyl cyanophenylpropenoates, RPhCH=C(CN)CO2C3H7 (where R is 2-bromo-3-hydroxy-4-methoxy, 5-bromo-2,3-dimethoxy, 5-bromo-2,4-dimethoxy, 6-bromo-3,4-dimethoxy, 2-chloro-3,4-dimetoxy, 5-chloro-2,3-dimetoxy, 4-bromo-2,6-difluoro, 3-chloro-2,6-difluoro, 4-chloro-2,6-difluoro) were prepared by the piperidine catalyzed Knoevenagel condensation of ring-trisubstituted benzaldehydes and propyl cyanoacetate and characterized by CHN elemental analysis, IR, 1H and 13C-NMR. The propenoates formed copolymers with styrene in solution with radical initiation (ABCN) at 70°C. The copolymers were characterized by nitrogen elemental analysis, IR, 1H and 13C-NMR, DSC. Decomposition of the copolymers in nitrogen (TGA) occurred in two steps, first in the 200-500ºC range with residue (4.2 -8.1% wt.), which then decomposed in the 500-800ºC range.

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Kim, Seulgi, In-Hyeok Park, Han-Byeol Choi, Huiyeong Ju, Eunji Lee, Tun Seng Herng, Jun Ding, Jong Hwa Jung et Shim Sung Lee. « Formation of a four-bladed waterwheel-type chloro-bridged dicopper(ii) complex with dithiamacrocycle via double exo-coordination ». Dalton Transactions 49, n^o 5 (2020) : 1365–69. http://dx.doi.org/10.1039/c9dt04372a.

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A four-bladed waterwheel-like chloro-bridged dicopper(ii) complex! The self-assembly of O₃S₂-macrocycle (L) with copper(ii) nitrate afforded a chloro-bridged tetra(macrocycle) dicopper(ii) complex.

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Korolev, Nadia, et Talma Katan. « Improved Medium for Selecting Nitrate-Nonutilizing (nit) Mutants of Verticillium dahliae ». Phytopathology® 87, n^o 10 (octobre 1997) : 1067–70. http://dx.doi.org/10.1094/phyto.1997.87.10.1067.

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Nitrate-nonutilizing (nit) mutants are commonly used to determine vegetative compatibility between isolates of Verticillium dahliae by complementation (heterokaryon) testing. These mutants emerge spontaneously as chlorate-resistant sectors growing out of partially restricted, wild-type colonies on chlorate-amended media. The commonly used chlorate media are based on minimal medium (MMC) or cornmeal agar (CMC), amended with potassium chlorate. nit mutants recovered on these media constituted 10 to 36%(on MMC) and 25 to 45%(on CMC) of the apparently resistant sectors. An improved water agar chlorate medium (WAC) is described that is more effective for selecting chlorate-resistant nit mutants. WAC medium consists of agar (2%), glucose (0.02%), and potassium chlorate (2 to 5%). On WAC, growth of most V. dahliae isolates was strongly inhibited, and 66 to 100%(average >80%) of the chlorate-resistant sectors formed were nit mutants. Most mutants were characterized as nit1, and about 6% as NitM.

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Fenske, Dieter, Karin Völp et Kurt Dehnicke. « N-Chlor-Nitrenokomplexe des Molybdäns : MoF4(NCl) und [CH3CN-MoF4(NCl)] / N-Chloro-Nitrene Complexes of Molybdenum : MoF4(NCl) and [CH3CN-MoF4(NCl)] ». Zeitschrift für Naturforschung B 42, n^o 11 (1 novembre 1987) : 1398–402. http://dx.doi.org/10.1515/znb-1987-1106.

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MoF4(NCl) has been prepared as a yellow crystal powder by the reaction of diluted fluorine with MoCl3(N3S2) at room temperature. The compound is associated via fluorine bridges, according to the IR spectrum. With acetonitrile, the monomeric complex [CH3CN -MoF4(NCl)] is obtained, which was characterized by its IR and 19F NMR spectra as well as by an X-ray structure determination. Crystal data: space group Pm, Z = 2 (1068 observed, independent reflexions, R = 0.03). Lattice dimensions at -90 °C: a = 507.1. b = 704.8, c = 995.8 pm, β = 102.02°. The unit cell contains two crystallographically independent molecules [CH3CN -MoF4(NCl)], the Mo≡N-Cl groups being linear (bond angles 176°, 178°) with bond lengths MoN = 172 and NCI = 159, 162 pm. In the trans position to the MoNCl group, the nitrogen atom of the acetonitrile molecule is coordinated.

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Zhu, Lei, Zhi Yong Guo, Xiu Yi Hua, De Ming Dong, Da Peng Liang et Ying Ying Sun. « Ammonia Nitrogen Removal from Chlor-Alkali Chemical Industry Wastewater by Magnesium Ammonium Phosphate Precipitation Method ». Advanced Materials Research 573-574 (octobre 2012) : 1096–100. http://dx.doi.org/10.4028/www.scientific.net/amr.573-574.1096.

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This study introduces a method of ammonia nitrogen removal from chlor-alkali industry wastewater by magnesium ammonium phosphate (MAP) precipitation. The effect of pH, reagent ratio and temperature were investigated. The pH was found to be the most significant factor. The optimal ammonia nitrogen removal ratio is about 46% under the condition of pH=10, reagent ratio n(Mg) : n(N) : n(P)=1.2 : 1.0 : 1.0 and temperature=35°C. According to this study, MAP precipitation method has the potential ability to be applied to remove ammonia nitrogen from chlor-alkali chemical industry wastewater.

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Bedzyk, Laura, Tao Wang et Rick W. Ye. « The Periplasmic Nitrate Reductase inPseudomonas sp. Strain G-179 Catalyzes the First Step of Denitrification ». Journal of Bacteriology 181, n^o 9 (1 mai 1999) : 2802–6. http://dx.doi.org/10.1128/jb.181.9.2802-2806.1999.

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ABSTRACT Both membrane-bound and periplasmic nitrate reductases have been found in denitrifying bacteria. Yet the role of periplasmic nitrate reductase in denitrification has not been clearly defined. To analyze the function of the periplasmic nitrate reductase inPseudomonas sp. strain G-179, the nap gene cluster was identified and found to be linked to genes involved in reduction of nitrite and nitric oxide and anaerobic heme biosynthesis. Mutation in the nap region rendered the cells incapable of growing under anaerobic conditions with nitrate as the alternative electron acceptor. No nitrate reduction activity was detected in the Nap− mutant, but that activity could be restored by complementation with the nap region. Unlike the membrane-bound nitrate reductase, the nitrate reduction activity in strain G-179 was not inhibited by a low concentration of azide. Nor could it use NADH as the electron donor to reduce nitrate or use chlorate as the alternative substrate. These results suggest that the periplasmic nitrate reductase in this strain plays a primary role in dissimilatory nitrate reduction.

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Kučera, Igor. « Interference of chlorate and chlorite with nitrate reduction in resting cells of Paracoccus denitrificans ». Microbiology 152, n^o 12 (1 décembre 2006) : 3529–34. http://dx.doi.org/10.1099/mic.0.29276-0.

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When grown anaerobically on a succinate+nitrate (SN) medium, Paracoccus denitrificans forms the membrane-bound, cytoplasmically oriented, chlorate-reducing nitrate reductase Nar, while the periplasmic enzyme Nap is expressed during aerobic growth on butyrate+oxygen (BO) medium. Preincubation of SN cells with chlorate produced a concentration-dependent decrease in nitrate utilization, which could be ascribed to Nar inactivation. Toluenization rendered Nar less sensitive to chlorate, but more sensitive to chlorite, suggesting that the latter compound may be the true inactivator. The Nap enzyme of BO cells was inactivated by both chlorate and chlorite at concentrations that were at least two orders of magnitude lower than those shown to affect Nar. Partial purification of Nap resulted in insensitivity to chlorate and diminished sensitivity to chlorite. Azide was specific for SN cells in protecting nitrate reductase against chlorate attack, the protective effect of nitrate being more pronounced in BO cells. The results are discussed in terms of different metabolic activation of chlorine oxoanions in both types of cells, and limited permeation of chlorite across the cell membrane.

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Schnurr, Werner, et Manfred Regitz. « Phosphorverbindungen ungewöhnlicher Koordination, 31 [1] Cycloaddition von Diazoverbindungen an ein P—Chlor-phosphaalken / Phosphorus Compounds with Unusual Coordination, 31 [1] Cycloaddition of Diazo Compounds onto a P—Chloro-phosphaalkene ». Zeitschrift für Naturforschung B 43, n^o 10 (1 octobre 1988) : 1285–92. http://dx.doi.org/10.1515/znb-1988-1014.

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Chloro bis(trimethylsilyl)methylene phosphane (4) reacts with the diazo compounds 5, 10, 15 and 20 even at low temperatures with formation of the 3H-1,2,4-diazaphospholes 6,11,16 and 21. The products are unstable and decompose either with elimination of nitrogen to yield 1-chloro phosphiranes (9,14, 19 and 22), or isomerize with aromatization (11 → 13) or transformation into 4,5-dihydro-1,2,4-diazaphospholes (6 → 8, 16 → 18) by trimethylsilyl shifts. Silyl groups attached to ring nitrogen are easily hydrolized (8 → 7,13 → 12, 18 → 17), those attached to ring carbon are cleaved by treatment with potassium fluoride in dimethyl formamide (7 → 23, 12 → 24).

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Bella, Maroš, et Viktor Milata. « New syntheses of 5,6- and 7,8-diaminoquinolines ». Beilstein Journal of Organic Chemistry 9 (27 novembre 2013) : 2669–74. http://dx.doi.org/10.3762/bjoc.9.302.

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The synthesis of 5,6- and 7,8-diaminoquinoline derivatives starting from angularly annelated selenadiazoloquinolones is presented. Simple chlorination of the pyridone ring followed by reductive deselenation of the 1,2,5-selenadiazole ring afforded novel 4-chloro-o-diaminoquinolines. Dechlorination of 4-chloro-7,8-diaminoquinoline gave 7,8-diaminoquinoline hydrochloride which was successfully employed as starting material in the synthesis of condensed nitrogen heterocycles.

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Harnden, MR, et DT Hurst. « The Synthesis and Chlorination of Some Pyrimidin-4-ols Having 5-Nitrogen Functionality ». Australian Journal of Chemistry 43, n^o 1 (1990) : 47. http://dx.doi.org/10.1071/ch9900047.

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Syntheses of a number of pyrimidin-4-ols having 5-nitrogen functionality are described. Phosphorus oxychloride/diethylaniline chlorination of 6-amino-2-methylthio-5-nitropyrimidin-4-ol gave the corresponding 6-chloro derivative. However, 2-amino-6-methylthio-5-nitropyrimidin-4-ol failed to yield a 4-chloro derivative under the same conditions. Similar chlorination of 2,5-diaminopyrimidine-4,6-diol gave a poor yield of the 4,6-dichloro product but under these conditions 2-amino-5-benzoylaminopyrimidine-4,6-diol* gave 7-chloro-2-phenyloxazolo[5,4-d]pyrimidin-5-amine. 5-Acetylamino-2-methylthiopyrimidine-4,6-diol yielded 7-chloro-2- methyl-5-methylthiooxazolo[5,4-d] pyrimidine as the major product together with some 5-acetylamino-4,6-dichloro-2-methylthiopyrimidine under the same chlorination conditions.

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Bickel-Sandkötter, Susanne, et Martina Ufer. « Properties of a Dissimilatory Nitrate Reductase from the Halophilic Archaeon Haloferax volcanii ». Zeitschrift für Naturforschung C 50, n^o 5-6 (1 juin 1995) : 365–72. http://dx.doi.org/10.1515/znc-1995-5-606.

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Abstract Grown under anaerobic conditions in presence of nitrate, Haloferax volcanii shows nitrate reduction and accumulation of nitrite in the culture medium. We found a membrane-associated nitrate reductase, which could easily be solubilized by gently stirring of isolated membranes. Surprisingly, this nitrate reductase requires no NaCl for its activity. A medium pH of 7.5 and high temperatures up to 80 °C are necessary for optimum activity. Kinetic studies showed that the apparent Kᴍ was 0.36 mmol/l for nitrate and 80 μmol/l for dithionite-reduced methyl viologen. The respiratory chain inhibitor cyanide effects nitrate reduction noncompe-titively with respect to nitrate with a Ki of 0.3 mmol/l. Azide was a strong inhibitor: The concentration required for half maximal inhibition was 60 μmol/l, whereas thiocyanate and chlorate were much weaker inhibitors. The isolated enzyme was partially purified by fractionated precipitation using polyethylene glycol. SDS gel electrophoresis resulted in three putative subunits of the nitrate reductase of molecular masses of about 100, 61, and 31 kDa.

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Montgomery, Matthew J., Thomas J. O'Connor et Joseph M. Tanski. « Crystal structures of 4-chloropyridine-2-carbonitrile and 6-chloropyridine-2-carbonitrile exhibit different intermolecular π-stacking, C—H...Nnitrileand C—H...Npyridineinteractions ». Acta Crystallographica Section E Crystallographic Communications 71, n^o 7 (27 juin 2015) : 852–56. http://dx.doi.org/10.1107/s2056989015011767.

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The two title compounds are isomers of C6H3ClN2containing a pyridine ring, a nitrile group, and a chloro substituent. The molecules of each compound pack together in the solid state with offset face-to-face π-stacking, and intermolecular C—H...Nnitrileand C—H...Npyridineinteractions. 4-Chloropyridine-2-carbonitrile, (I), exhibits pairwise centrosymmetric head-to-head C—H...Nnitrileand C—H...Npyridineinteractions, forming one-dimensional chains, which are π-stacked in an offset face-to-face fashion. The intermolecular packing of the isomeric 6-chloropyridine-2-carbonitrile, (II), which differs only in the position of the chloro substituent on the pyridine ring, exhibits head-to-tail C—H...Nnitrileand C—H...Npyridineinteractions, forming two-dimensional sheets which are π-stacked in an offset face-to-face fashion. In contrast to (I), the offset face-to-face π-stacking in (II) is formed between molecules with alternating orientations of the chloro and nitrile substituents.

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Lindbäck, Emil, Bo Wegge Laursen, Jens Christian Navarro Poulsen, Kristine Kilså, Christian Marcus Pedersen et Mikael Bols. « A fluorescence study of isofagomine protonation in β-glucosidase ». Organic & ; Biomolecular Chemistry 13, n^o 23 (2015) : 6562–66. http://dx.doi.org/10.1039/c5ob00624d.

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Schenzle, Andreas, Hiltrud Lenke, Jim C. Spain et Hans-Joachim Knackmuss. « Chemoselective Nitro Group Reduction and Reductive Dechlorination Initiate Degradation of 2-Chloro-5-Nitrophenol by Ralstonia eutropha JMP134 ». Applied and Environmental Microbiology 65, n^o 6 (1 juin 1999) : 2317–23. http://dx.doi.org/10.1128/aem.65.6.2317-2323.1999.

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ABSTRACT Ralstonia eutropha JMP134 utilizes 2-chloro-5-nitrophenol as a sole source of nitrogen, carbon, and energy. The initial steps for degradation of 2-chloro-5-nitrophenol are analogous to those of 3-nitrophenol degradation in R. eutropha JMP134. 2-Chloro-5-nitrophenol is initially reduced to 2-chloro-5-hydroxylaminophenol, which is subject to an enzymatic Bamberger rearrangement yielding 2-amino-5-chlorohydroquinone. The chlorine of 2-amino-5-chlorohydroquinone is removed by a reductive mechanism, and aminohydroquinone is formed. 2-Chloro-5-nitrophenol and 3-nitrophenol induce the expression of 3-nitrophenol nitroreductase, of 3-hydroxylaminophenol mutase, and of the dechlorinating activity. 3-Nitrophenol nitroreductase catalyzes chemoselective reduction of aromatic nitro groups to hydroxylamino groups in the presence of NADPH. 3-Nitrophenol nitroreductase is active with a variety of mono-, di-, and trinitroaromatic compounds, demonstrating a relaxed substrate specificity of the enzyme. Nitrosobenzene serves as a substrate for the enzyme and is converted faster than nitrobenzene.

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Anderson, Robin C., Mark A. Rasmussen, Milton J. Allison et Alan A. DiSpirito. « Characteristics of a nitropropanol-metabolizing bacterium isolated from the rumen ». Canadian Journal of Microbiology 43, n^o 7 (1 juillet 1997) : 617–24. http://dx.doi.org/10.1139/m97-088.

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We report some characteristics of a ruminai bacterium (strain NPOH1) that metabolizes 3-nitropropanol, the toxic principle of various milk vetchs that are distributed worldwide. The gram-positive bacterium was nonmotile and did not produce spores. Growth of strain NPOH1 occurred under anaerobic conditions and was supported by the electron acceptors 3-nitropropanol, 3-nitropropionate, nitrate, 2-nitropropanol, nitroethane, nitroethanol, or 3-nitro-1-propyl-β-D-glucopyranoside (miserotoxin). Other potential electron acceptors, namely sulfate, sulfite, azide, chlorate, perchlorate, nitrite, fumarate, 2-nitrobutane, or nitrobenzene, did not support growth. Formate, lactate, and H2stimulated growth of strain NPOH1 in the presence of the appropriate nitrocompound, whereas a variety of other potential H2donors did not. When grown in medium containing both nitrate and either 3-nitropropanol or 3-nitropropionate, nitrate was the preferred acceptor. Strain NPOH1 reduced nitrate to nitrite and, when grown with excess reductant, nitrite was further reduced to ammonia. The products formed during the metabolism of 3-nitropropanol and 3-nitropropionate by mixed ruminal populations, 3-aminopropanol and β-alanine, were not found in culture fluids of strain NPOH1. Analysis of total cellular fatty acid profiles and of the mole percent guanine plus cytosine suggests that strain NPOH1 is a novel bacterium. The capacity of strain NPOH1 to metabolize 3-nitropropanol suggests that this organism may play an important role in detoxification of 3-nitropropanol in the rumen.Key words: nitropropanol, nitropropionate, anaerobic, rumen, detoxification.

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Elias, Karol S., et Peter J. Cotty. « A rose bengal amended medium for selecting nitrate-metabolism mutants from fungi ». Canadian Journal of Botany 73, n^o 4 (1 avril 1995) : 680–82. http://dx.doi.org/10.1139/b95-072.

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A rose bengal amended medium for selecting nitrate-metabolism mutants from fungi with reduced sensitivity to chlorate is described. Isolates of several species known to resist development of nitrate-metabolism mutants on chlorate medium formed such mutants when grown on the rose bengal – chlorate medium. These species include Aspergillus flavus (Link.), Fusarium lateritium (Nees ex Link.), Fusarium oxysporum (Schlecht.), Fusarium solani (Mart.) Sacc., Alternaria cassiae (Jurair and Khan), Alternaria macrospora (Zimmerman), and Alternaria tagetica (Shome and Mustafee). The medium allows selection of nitrate-metabolism mutants of certain fungal strains for which chlorate-based techniques have not been satisfactory. Resulting mutants, following phenotype determination and identification of complementary testers, can be paired to enable macroscopic observation of heterokaryon formation during vegetative compatibility analyses. Thus, this medium may facilitate development of information on delimitation of vegetative compatibility groups among strains within these taxa. Key words: chlorate resistance, population structure, vegetative compatibility group, VCG.

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Zeynep Ceylan and eyda Deniz Ayd n, Zeynep Ceylan and eyda Deniz Ayd n. « Investigation of the Effect of Substituent Species/Positions and Numbers on Removal of Toxicity from Chloro and Nitro Phenol Compounds with Fenton and Fenton-like Processes ». Journal of the chemical society of pakistan 42, n^o 5 (2020) : 639. http://dx.doi.org/10.52568/000676/jcsp/42.05.2020.

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Phenol derivatives containing substutient are used intensely in industry and their presence in surface and waste water is a problem requiring urgent solution due to their tendency for bioaccumulation, cancerogenic effects, high toxicity and weak biodegradability. In this study, the degradability and toxicity of chlorinated phenols 2-CP, 2,4-DCP and 4-CP and nitrated phenols 2-NP, 2,4-DNP and 4-NP were investigated. These phenols are included on the priority toxic pollutant list within the scope of clean water regulations according to both the US EPA-2014 and the European Union (2455/2001/CE) and form serious threats to public health and aqueous ecosystems. The degradability of chloro and nitro phenols was researched by applying the Fenton/Fenton-like processes (under optimal conditions) and measuring the model pollutant concentrations, COD and TOC parameters. The effects of substituent type/position and number were determined with toxicity measurements using Vibrio fischeri bacteria (DIN/EN/ISO 11348-2). Statistical analysis was performed in detail for both Fenton/Fenton-like processes (T test) and toxicology measurement results (One-Way ANOVA) for the model pollutants (Pandlt;0.05). In the first stage of the study, model pollutant removal of 95-100%, COD removal of 64-85% / 60-77% and TOC removal efficiency of 52-65% and 40-61% were achieved respectively with Fenton and Fenton-like processes. In the second stage of the study, the results of toxicity measurements of the pollutants performed before processing found EC50(mg/L) and toxic unit values (TU) were 8.10-12.34 for 2-CP, 2.24-44.67 for 2,4-DCP, 1.20-83.33 for 4-CP, 13.43-7.44 for 2-NP, 8.92-11.21 for 2,4-DNP, and 4.77-20.9 for 4-NP, respectively. After processing, the EC50/EC20 and TU values were determined to fall to unobservable levels. According to the order obtained with toxicity measurements of 4-CP andgt; 2,4-DCP andgt; 4-NP andgt; 2-CP andgt; 2,4-DNP andgt; 2-NP, the chlor substituent had higher toxic effect compared to nitro. As the substituent numbers increase the toxicity increased; however, para position was identified to be more toxic compared to other positions. The reason for the 4 (para) position being more toxic than the 2,4 (ortho-para) position is thought to be due to the chlor or nitro linked to the 2 or ortho position binding to the OH group of phenol with a 5- and 6-member H-bridge in cis position forming a ring, which leads to inactivity.

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Zhang, Zhongyu, Meng Chen, Mingqiong Tong, Wan Sun, Pingxuan Dong, Xinfeng Song et Xiaoyue Wang. « Syntheses, crystal structure, thermal behavior, and anti-tumor activity of three ternary metal complexes with 2-chloro-5-nitrobenzoic acid and heterocyclic compounds ». Heterocyclic Communications 28, n^o 1 (1 janvier 2022) : 84–94. http://dx.doi.org/10.1515/hc-2022-0011.

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Abstract Three complexes, namely complex (1), complex (2), and complex (3), were synthesized and characterized by X-ray diffraction, thermogravimetric study, and elemental study. Complex (1) comprises discrete binuclear clusters, where two oxygen atoms of 2-chloro-5-nitrobenzoic acid bridge the two copper atoms. Complex (2) is a six-coordination structure consisting of four nitrogen atoms and two oxygen atoms in 2-chloro-5-nitrobenzoic acid and 1,10-phenanthroline to furnish a twisted octahedron. Complex (3) is a six-coordination structure consisting of four oxygen atoms and two nitrogen atoms from the 2-chloro-5-nitrobenzoic acid, methanol, and 2,2′-dipyridyl to furnish a distorted octahedral geometry. Metal complexes’ anti-tumor activity was also investigated by the MTT assay. Of the complexes tested, complex (1) could induce apoptosis in these A549 lung cancer and Caco-2 colon adenocarcinoma cells and complex (2) could induce apoptosis in Caco-2 colon adenocarcinoma cells. CCDC for complex (1) was 1543354, CCDC for complex (2) was 1546991, and CCDC for complex (3) was 1543417.

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Bender, Kelly S., Ching Shang, Romy Chakraborty, Sara M. Belchik, John D. Coates et Laurie A. Achenbach. « Identification, Characterization, and Classification of Genes Encoding Perchlorate Reductase ». Journal of Bacteriology 187, n^o 15 (1 août 2005) : 5090–96. http://dx.doi.org/10.1128/jb.187.15.5090-5096.2005.

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ABSTRACT The reduction of perchlorate to chlorite, the first enzymatic step in the bacterial reduction of perchlorate, is catalyzed by perchlorate reductase. The genes encoding perchlorate reductase (pcrABCD) in two Dechloromonas species were characterized. Sequence analysis of the pcrAB gene products revealed similarity to α- and β-subunits of microbial nitrate reductase, selenate reductase, dimethyl sulfide dehydrogenase, ethylbenzene dehydrogenase, and chlorate reductase, all of which are type II members of the microbial dimethyl sulfoxide (DMSO) reductase family. The pcrC gene product was similar to a c-type cytochrome, while the pcrD gene product exhibited similarity to molybdenum chaperone proteins of the DMSO reductase family members mentioned above. Expression analysis of the pcrA gene from Dechloromonas agitata indicated that transcription occurred only under anaerobic (per)chlorate-reducing conditions. The presence of oxygen completely inhibited pcrA expression regardless of the presence of perchlorate, chlorate, or nitrate. Deletion of the pcrA gene in Dechloromonas aromatica abolished growth in both perchlorate and chlorate but not growth in nitrate, indicating that the pcrABCD genes play a functional role in perchlorate reduction separate from nitrate reduction. Phylogenetic analysis of PcrA and other α-subunits of the DMSO reductase family indicated that perchlorate reductase forms a monophyletic group separate from chlorate reductase of Ideonella dechloratans. The separation of perchlorate reductase as an activity distinct from chlorate reductase was further supported by DNA hybridization analysis of (per)chlorate- and chlorate-reducing strains using the pcrA gene as a probe.

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Wang, Da-Qi. « 7-Chloro-2,4-dimethyl-1,8-naphthyridin-1-ium nitrate ». Acta Crystallographica Section E Structure Reports Online 62, n^o 6 (10 mai 2006) : o2181—o2182. http://dx.doi.org/10.1107/s1600536806015200.

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Zorn, Chiara, Andrea Goti, Alberto Brandi, Keyji Johnsen, Mathias Noltemeyer, Sergei I. Kozhushkov et Armin de Meijere. « Chameleon Thermal Behavior of Cycloadducts of Nitrones to Methyl 2-Chloro-2-cyclopropylidene- and 2-Chloro-2-spiropentylideneacetates ». Journal of Organic Chemistry 64, n^o 3 (février 1999) : 755–63. http://dx.doi.org/10.1021/jo981366l.

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Michel, Vincent V., et T. W. Mew. « Effect of a Soil Amendment on the Survival of Ralstonia solanacearum in Different Soils ». Phytopathology® 88, n^o 4 (avril 1998) : 300–305. http://dx.doi.org/10.1094/phyto.1998.88.4.300.

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The effect of a soil amendment (SA) composed of urea (200 kg of N per ha) and CaO (5,000 kg/ha) on the survival of Ralstonia solanacearum in four Philippine soils was investigated in a series of laboratory experiments. Within 3 weeks after application, the SA either caused an initial decrease, a final decline, or no change in the pathogen population, depending on the particular soil type. An initial decrease occurred in a soil with a basic pH and resulted in a significantly (P < 0.001) lower pathogen population immediately and at 1 week after amending the soil. This decrease was probably due to the high pH in the soil during urea hydrolysis. A final decline in the R. solanacearum population after 3 weeks occurred in two soils in which nitrite accumulated after 1 week. In these soils, no decline in bacterial levels occurred when nitrite formation was inhibited by 2-chloro-6-trichloromethylpyridine. In the soil with low pH, no nitrite accumulated and the R. solanacearum population did not decline. The suppressive effects of pH and nitrite on R. solanacearum growth were confirmed by in vitro experiments. Ammonium reduced the growth of R. solanacearum, but was not suppressive. Interactions of pH with ammonium and nitrite also occurred, whereby ammonium reduced growth of R. solanacearum only at pH 9 and nitrite was suppressive only at pH 5. Nitrate had no effect on R. solanacearum growth in vitro.

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Lyukshenko, Natalya I., Roman G. Nikitin et Yury V. Morozhenko. « New technology to obtain 1-methyl-5-pnenyl-7-chloro- 1,3-dihydro-2H-[1,4]-benzodiazepine-2-one ». Butlerov Communications 60, n^o 10 (31 octobre 2019) : 24–31. http://dx.doi.org/10.37952/roi-jbc-01/19-60-10-24.

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At present, benzodiazepine derivatives being used widely, they continue to occupy a leading position among the drugs of the anxiolytic group. Most anxiolytics of the benzodiazepine structure are derivatives of 1,4-benzodiazepine. The basis of the chemical benzodiazepine structure consists of a benzene ring connected to a seven-membered heterocyclic ring containing two nitrogen atoms (diazepine) at positions 1 and 4. All the benzodiazepine derivatives used in the clinic also have a second benzene ring attached to carbon. The presence of a halogen or a nitro group is essential to display its activity. Diazepam (1-methyl-5-phenyl-7-chloro-1,3-dihydro-2H- [1,4] benzodiazepin-2-one) is in the list of necessary and important medicinal products. The urgent issue is the development of a new method to synthesize 1-methyl-5-phenyl-7-chloro-1,3-dihydro-2H-[1,4]-benzodiazepines-2-one that would allow producing the drug in the required quantities and for mass consumption. The search for possible effective ways of synthesizing 1-methyl-5-phenyl-7-chlorine-1,3-dihydro-2H-[1,4]-benzodiazepines-2-one for manufacturing application is of great scientific and practical interest. The purpose of our work is to search for a rational method to synthesize the target product, experimental study of the chemical processes to develop the most optimal methods to produce the product. The technology to produce 1-methyl-5-phenyl-7-chlor-1,3-dihydro-2H-[1,4]-benzodiazepine-2-one on an industrial scale was developed. The synthesis of 2-benzoyl-2',4-dichloro-N-methylacetanilide by condensation of 2-methylamine-5-chlorobenzophenone with chloracetyl chloride in carbon tetrachloride without further treatment of the reaction mass with water and sodium carbonate was developed. The highest yield of 1-methyl-5-phenyl-7-chlorine-1,3-dihydro-2H-[1,4]-benzodiazepines-2-one was shown to be obtained if the cyclization reaction is carried out in isopropyl alcohol. The reaction mixture composition in interaction of 2-benzoyl- 2',4 -dichloro-N-methylacetanilide with urotropin plays the defining role in the formation of the target product.

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Singha, Nikhil K., S. Sivaram et S. S. Talwar. « A New Method to Hydrogenate Nitrile Rubber in the Latex Form ». Rubber Chemistry and Technology 68, n^o 2 (1 mai 1995) : 281–86. http://dx.doi.org/10.5254/1.3538742.

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Abstract A water soluble analog of Wilkinson catalyst — chloro-tris-(sodium diphenylphosphino-benzene-m-sulfonate) rhodium(I), CAS 67178-14-7, i.e. RhCl(DPM)3— has been found to hydrogenate NBR latex. More than 60 mol% hydrogenation can be achieved at 75°C and 1 atmosphere hydrogen pressure. Hydrogenation was accompanied by an increase in gel content of the latex.

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Paun, Iuliana, Vasile Ion Iancu, Florentina Laura Chiriac, Nicoleta Vasilache, Florinela Pirvu, Marcela Niculescu et Toma Galaon. « New ion-chromatography method for detection of chlorite, chlorate, and bromate in drinking water ». Romanian Journal of Ecology & ; Environmental Chemistry 2, n^o 2 (14 octobre 2020) : 49–55. http://dx.doi.org/10.21698/rjeec.2020.207.

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A direct ion chromatographic method for the determination of chlorite, chlorate, and bromate in the presence of fluoride, chloride, nitrate, nitrite, and bromide in treated drinking waters was described. Separation of target analytes was achieved using an AS19-HC analytical column (250 mm x 4 mm), AG 19- HC guard column (50 mm x 4 mm), and KOH 25 mmol/L as mobile phase. Inorganic analytes were eluted using a flow rate of 1 mL/min. The column temperature was set up and maintained at 300C. The analyte ions were quantified using a suppressed conductivity detector.

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ANDERSON, ROBIN C., SANDRA A. BUCKLEY, TODD R. CALLAWAY, KENNETH J. GENOVESE, LEON F. KUBENA, ROGER B. HARVEY et DAVID J. NISBET. « Effect of Sodium Chlorate on Salmonella Typhimurium Concentrations in the Weaned Pig Gut ». Journal of Food Protection 64, n^o 2 (1 février 2001) : 255–58. http://dx.doi.org/10.4315/0362-028x-64.2.255.

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Salmonella cause economic losses to the swine industry due to disease and compromised food safety. Since the gut is a major reservoir for Salmonella, strategies are sought to reduce their concentration in pigs immediately before processing. Respiratory nitrate reductase activity possessed by Salmonella also catalyzes the intracellular reduction of chlorate (an analog of nitrate) to chlorite, which is lethal to the microbe. Since most gastrointestinal anaerobes lack respiratory nitrate reductase, we conducted a study to determine if chlorate may selectively kill Salmonella within the pig gut. Weaned pigs orally infected with 8 × 107 CFU of a novobiocin- and nalidixic acid–resistant strain of Salmonella Typhimurium were treated 8 and 16 h later via oral gavage (10 ml) with 0 or 100 mM sodium chlorate. Pigs were euthanized at 8-h intervals after receiving the last treatment. Samples collected by necropsy were cultured qualitatively and quantitatively for Salmonella and for most probable numbers of total culturable anaerobes. A significant (P < 0.05) chlorate treatment effect was observed on cecal concentrations of Salmonella, with the largest reductions occurring 16 h after receiving the last chlorate treatment. An observed treatment by time after treatment interaction suggests the chlorate effect was concentration dependent. Chlorate treatment may provide a means to reduce foodborne pathogens immediately before harvest.

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Romero-Ortega, Moisés, Michelle Trujillo-Lagunas, Ignacio Medina-Mercado, Ivann Zaragoza-Galicia et Horacio Olivo. « A Synthesis of 4-Chloro-2-(trichloromethyl)pyrimidines and Their Study in Nucleophilic Substitution ». Synthesis 51, n^o 02 (11 septembre 2018) : 530–37. http://dx.doi.org/10.1055/s-0037-1610270.

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A convenient two-step, one-pot synthesis of 4-chloro-2-(trichloromethyl)pyrimidines starting from 2-(trichloromethyl)-1,3-diazabutadienes is described. These nitrogen heterocycles were prepared by a sequential acylation/intramolecular cyclization reaction between 2-(trichloromethyl)-1,3-diazabutadienes and acyl chlorides in the presence of triethylamine followed by treatment with POCl3. This is the first report for the synthesis of this type of 4-chloro-2-(trichloromethyl)pyrimidine derivatives and serves as a source for a wide variety of other substituted pyrimidines by nucleophilic substitution reactions.

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Szemes, Fridrich, Alfonz Rybár, Pavol Hrnčiar, Eva Solčániová et Ondrej Gattnár. « 6-(6-Substituted amino-2-hydroxypropyl)-5,6,7,8-tetrahydrodibenz[c, e]azocines ». Collection of Czechoslovak Chemical Communications 56, n^o 8 (1991) : 1725–31. http://dx.doi.org/10.1135/cccc19911725.

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Nucleophilic addition of alkyl-, cycloalkylamines, or saturated nitrogen-containing heterocycles to isolated or in situ generated 6-(2,3-epoxypropyl)-5,6,7,8-tetrahydrodibenz[c,e]azocine (III) afforded 6-(3-substituted amino-2-hydroxypropyl)-5,6,7,8-tetrahydrodibenz[c,e]azocines IV and their hydrochlorides. The starting 5,6,7,8-tetrahydrodibenz[c,e]azocine (I) reacted with 1-chloro-2,3-epoxypropane to yield 6-(3-chloro-2-hydroxypropyl)-5,6,7,8-tetrahydrodibenz[c,e]azocine (II), which, on treatment with sodium ethoxide or an excess of an amine eliminated hydrogen chloride to give the intermediate III.

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Gowda, Basavalinganadoddy Thimme, Sabine Foro, Jozef Kožíšek et Hartmut Fuess. « Crystal Structure Studies on Arylsulphonamides and N-Chloro-Arylsulphonamides ». Zeitschrift für Naturforschung A 62, n^o 7-8 (1 août 2007) : 417–24. http://dx.doi.org/10.1515/zna-2007-7-811.

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The effect of ring substitution and N-chlorination on the molecular geometry of arylsulphonamides and N-chloro-arylsulphonamides have been studied by determining the crystal structures of 2-methyl- 4-chloro-benzenesulphonamide (2M4CBSA) and the sodium salt of N-chloro-2-methyl-4-chlorobenzenesulphonamide (NaNC2M4CBSA). The results are analyzed along with the crystal structures of benzenesulphonamide, 4-methyl-benzenesulphonamide and 4-chloro-benzenesulphonamide. The crystal structure of NaNC2M4CBSA has also been compared and correlated with the crystal structures of the above compounds and those of the sodium salts of N-chloro-benzenesulphonamide, Nchloro- 4-methyl-benzenesulphonamide, N-chloro-4-chloro-benzenesulphonamide and N-chloro-2,4- dichloro-benzenesulphonamide. The crystal system, space group, formula units and lattice constants in Å of the new structures are: 2M4CBSA: triclinic, P1, Z = 4, a = 7.9030(10), b = 8.6890(10), c = 13.272(2), α = 100.680(10)°, β = 98.500(10)°, γ = 90.050(10)°; NaNC2M4CBSA: monoclinic, C2/c, Z =4, a = 10.9690(10), b = 6.7384(6), c = 30.438(2), β = 98.442(7)°. The structure of 2M4CBSA is quite complex with four molecules in its asymmetric unit. The S-N bond length slightly decreases with substitution of electron-withdrawing groups, while the effect is more pronounced with disubstitution. The structure of NaNC2M4CBSA confirms that there is no interaction between nitrogen and sodium, and Na+ is attached to one of the sulphonyl oxygen atoms. The Na+ coordination sphere involves oxygen atoms from water moleculess of crystallization and neighbouring molecules. The S-N distance of 1.586 Å for the compound is consistent with a S-N double bond. The molecules are held together by hydrogen bonds with distances varying from 2.12 to 2.85 Å.

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Anwar, Syed, et Pathan Mohd Arif Ali Khan. « EVALUATION OF QUALITY CONTROL OF FAVIPIRAVIR FOR ITS TEN RELATED SUBSTANCES USING HIGHPERFORMANCE LIQUID CHROMATOGRAPHY : DEVELOPMENT OF PROCEDURE AND VALIDATION ». RASAYAN Journal of Chemistry 16, n^o 03 (2023) : 1262–70. http://dx.doi.org/10.31788/rjc.2023.1638262.

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This study deals with designing and validating an HPLC procedure for the determination of favipiravir and ten favipiravir-related impurities simultaneously in favipiravir bulk forms. The ten favipiravir related substances investigated herein included 6-Bromo-3-hydroxy-amide; 6-Fluoro-3-hydroxy-nitrile; 6-Chloro-3-hydroxy-amide; Favipiravir acid; 3-Hydroxy amide; 3,6-Difluoro amide; 3,6-Dichloro amide; 6-Chloro-3-hydroxy-nitrile; 3,6- Difluoro nitrile; and 3,6-Dichloro nitrile. Column Inert Sustain C18 is used to analyze favipiravir and favipiravirrelated impurities. Mobile phases employed included 20 mM KH2PO4 (system A) and 20 mM KH2PO4: Acetonitrile combined in 700:300 (vol/vol) parts (system B,) and given to column through gradient elution. The system was examined in accordance with the ICH prerequisite and was capable of providing accurate (96.4-114.8%) and precise (0.1-0.4%) quantitative results. The peak purities measures for favipiravir and its ten impurities revealed specificity. Linearity was evidenced from the LOQ amount level to 120% amount of the specification level (0.0015 mg/mL) with R 2 measures ˃ 0.999 for favipiravir and its ten related impurities. This method concluded it was beneficial for the evaluation expected.

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Fuentealba, Mauricio, Deborah Gonzalez et Vania Artigas. « Structural Characterization of Iron(iii) Dinuclear Complexes ». Acta Crystallographica Section A Foundations and Advances 70, a1 (5 août 2014) : C1695. http://dx.doi.org/10.1107/s2053273314083041.

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Dinuclear complexes have been studied for different purposes: magnetic materials[1], Non-linear optics materials[2], molecular switches [3], mixed-valence systems, etc. With these antecedents in mind, we present in this work a new series of dinuclear Iron(III) complexes formed by different Schiff bases ligands. The reaction starting from the iron chloride salts with the 5-chloro or 5-bromo-salycilaldehyde and ethylendiamine yields two different kinds of dinuclear iron complexes in different reaction conditions. The first one (Fig N°1), are methoxo-bridged dinuclear iron(III) complexes in which each metal centre is coordinated with one mono-condensated Schiff base ligand, one 4-chloro or 4-bromo-2-(dimethoxymethyl)phenoxo ligand and two bridging methoxo ligands. The iron(III) centres are hexacoordinated (FeN2O4), the coordination sphere is formed by 2 nitrogen atoms of the ethylendiamine fragment, 2 oxygen atoms from the hydroxyl of the Schiff base and two O atoms from the methoxo ligands. Both iron(III) centres are related by a inversion centre. The second one (Fig N°2), the dinuclear complex is formed for the double condensation of ethylendiamine with 5-chloro or 5-bromo-salycilaldehyde and one oxygen from the dianionic ligand act as bridge with another unit. The iron (III) centres are also hexaccordinated (FeN2O3Cl) formed by 2 nitrogen atoms from ethylendiamine fragment and 3 oxygen atoms from hydroxyl from Schiff base ligands and one chloro ligand. Finally, the electronic and redox properties have been studied by UV-Visible and cyclic voltammetry. ACKNOWLEDGMENT FONDECYT N01130640, FONDEQUIP EQM120095 and Beca CONICYT folio 21130944

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Glover, Stephen A., Adam A. Rosser et Robert M. Spence. « Studies of the Structure, Amidicity, and Reactivity of N-Chlorohydroxamic Esters and N-Chloro-β,β-dialkylhydrazides : Anomeric Amides with Low Resonance Energies ». Australian Journal of Chemistry 67, n^o 9 (2014) : 1344. http://dx.doi.org/10.1071/ch14270.

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Density functional calculations have been carried out to determine the properties of the title anomeric amides. At the B3LYP/6-31G(d) level, N-chloro-N-methoxyacetamide 8a is computed to be strongly pyramidal at nitrogen with a long amide bond that is untwisted. N-Chloro-N-dimethylaminoacetamide 9a is completely planar, but its amide bond is still much longer than that in N,N-dimethylacetamide 4. This is a steric, rather than a resonance, effect. COSNAR and a trans-amidation method calculate low resonance energies for both model amides, which is attributed to the combined electronegativity of the heteroatoms at the amide nitrogen and the strong anomeric effect when there is a chlorine substituent on nitrogen. When M06 and ωB97X-D dispersion-corrected density functional methods are used with the expanded 6-311++G(d,p) basis set, the resonance energies of 8a (–34 kJ mol–1) and 9a (–49 kJ mol–1) are in line with the gross electronegativity of the substituent atoms. Unlike other anomeric amides, 8a and 9a are not predicted to undergo HERON reactivity.

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