Articoli di riviste: "Chelates"

1

Hu, Xiao, Sai Rui Ma, Yan Yan Wu, Lai Hao Li, Xian Qing Yang, Shu Xian Hao, Sheng Jun Chen e Wan Ling Lin. "Antioxidant Activities of Tilapia (Oreochromis niloticus) Protein Hydrolysates-Iron Chelate Based on Properties of Biological Materials". Advanced Materials Research 700 (maggio 2013): 263–67. http://dx.doi.org/10.4028/www.scientific.net/amr.700.263.

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Tilapia (Oreochromis niloticus) protein was hydrolysed by papain, and then the tilapia (Oreochromis niloticus) protein hydrolysates (TPH) chelated with ferrous ions at various mass ratios of TPH to FeCl2 (5:1, 10:1 and 20:1) to obtain the biological materials of chelate I, chelate II and chelate III, respectively. The ferrous-binding rate and antioxidant activities of the chelates were investigated. It was found that the ferrous-binding rate increased with the increase of mass ratios (TPH/FeCl2) from 5:1 to 20:1. The DPPH radical scavenging activity and reducing power activity of chelate III were highest in the chelates, and the lipid peroxidation inhibition activity of the chelate III was obviously higher than that of TPH. Compared with TPH, marked changes in microstructure were observed in the biological material of TPH-iron chelate.

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Nechiporenko, Ivan, Svetlana Akimova, Pavel Kazakov, Elena Nikulina e Nina Tsirulnikova. "Screening of different Fe(III) and Fe(II) chelate complexes in clonal micropropagation technology of highbush blueberry (Vaccinium corymbosum L.)". BIO Web of Conferences 66 (2023): 02002. http://dx.doi.org/10.1051/bioconf/20236602002.

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The element iron plays a key role in plant physiology. For plant nutrition, chelated forms of iron are preferred. Therefore, in clonal micropropagation media, FeSO4 x 7H2O is usually introduced together with Na2EDTA. At the same time, other effective iron chelates with both carboxyl and phosphorus chelates are known. So far, there are few scientific studies on the effect of iron chelates complexes on blueberry plants under in vitro conditions. Therefore, studies were conducted with different iron chelate complexes in 4 concentrations on highbush blueberry (Vaccinium corymbosum L.) cv. Brigitta Blue in clonal micropropagation technology. The best results were obtained using Fe(III)-DTPA in increased (×1.5) and doubled (×2.0) concentrations, where the multiplication factor was 4.59-4.65.

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Malenov, Dušan P., Dušan Ž. Veljković, Michael B. Hall, Edward N. Brothers e Snežana D. Zarić. "Influence of chelate ring type on chelate–chelate and chelate–aryl stacking: the case of nickel bis(dithiolene)". Physical Chemistry Chemical Physics 21, n. 3 (2019): 1198–206. http://dx.doi.org/10.1039/c8cp06312e.

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4

Okada, Chiaki, Noriyuki Hatae e Eiko Toyota. "Structural study of the Schiff base copper(II) chelates as thrombin inhibitor". Acta Crystallographica Section A Foundations and Advances 70, a1 (5 agosto 2014): C1665. http://dx.doi.org/10.1107/s205327331408334x.

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Thrombin is a trypsin-like serine protease that plays a critical role in the blood coagulation cascade. Thus, studies on thrombin-specific inhibitor are useful for the design of clinical useful compounds. We have previously reported of the Schiff base metal chelates carrying benzamidine and amino acid moieties. More than 50 kinds of Schiff base copper(II) chelates were synthesized fromp- orm-amidinosalicylaldehyde and various L- or D-amino acids. These chelates have effective inhibitory activity for trypsin and thrombin (Ki= 10-5~ 10-6M). In this series of inhibitors, the copper(II) chelate derived fromp-amidinosalicylaldehyde and D-tryptophan (chelate1g'in original paper) have shown exceptionally potent inhibitory activity against thrombin (Ki= 2.7×10-8M). To elucidate the structural basis of this high efficient inhibition, we were planning to determine and compare with four protein-inhibitor complex structures, chelate1g'or2g'bound to trypsin or thrombin (chelate2g'is derived fromm-amidinosalicylaldehyde and D-Trp). The crystals of trypsin binding the chelate2g'was obtained by sitting-drop vapor diffusion method by mixing 2.5 μL of 20 mg/mL protein-chelate complex solution with 2.5 μL of 0.1 M HEPES, pH 7.4, containing 0.1 M Li2(SO4), 25.0% PEG 3350. In the crystal structure, the imidazole nitrogen of His57 is coordinated with the copper(II) ion (1.94 Å). This close contact is made possible by conformation change of the His57. The indole ring of the chelate2g'simultaneously interacts with the copper(II) and the His57 by cation-π and π-π stacking interaction, respectively. In addition to trypsin-chelate2g'complex structure, we will report on the other three complex structures of trypsin-chelate1g', thrombin-chelate1g'and thrombin-chelate2g'.

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5

Alshater, Heba, Ahlam I. Al-Sulami, Samar A. Aly, Ehab M. Abdalla, Mohamed A. Sakr e Safaa S. Hassan. "Antitumor and Antibacterial Activity of Ni(II), Cu(II), Ag(I), and Hg(II) Complexes with Ligand Derived from Thiosemicarbazones: Characterization and Theoretical Studies". Molecules 28, n. 6 (13 marzo 2023): 2590. http://dx.doi.org/10.3390/molecules28062590.

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Four new complexes (Ni2+, Cu2+, Ag+, and Hg2+) were prepared from the ligand N-(4-chlorophenyl)-2-(phenylglycyl)hydrazine-1-carbothioamide (H2L). Analytical and spectroscopic techniques were used to clarify the structural composition of the new chelates. In addition, all chelates were tested against bacterial strains and the HepG2 cell line to determine their antiseptic and carcinogenic properties. The Ni(II) complex was preferable to the other chelates. Molecular optimization revealed that H2L had the highest reactivity, followed by Hg-chelate, Ag-chelate, Ni-chelate, and Cu-chelate. Moreover, molecular docking was investigated against two different proteins: the ribosyltransferase enzyme (code: 3GEY) and the EGFR tyrosine kinase receptor (code: 1m17).

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Nikiforov-Nikishin, D. L., N. I. Kochetkov, S. V. Smorodinskaya, P. Yu Tatarenko e D. M. Matveeva. "Toxicity of metal chelates mixture in aquatic environment at Danio rerio". IOP Conference Series: Earth and Environmental Science 839, n. 5 (1 settembre 2021): 052010. http://dx.doi.org/10.1088/1755-1315/839/5/052010.

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Abstract In this paper, the toxic effect of a complex chelate mixture containing microelements (Fe, Mn, Zn, Se, I, Cu) on Danio rerio was investigated. Chelated compounds are used to detoxify elements in the aquatic environment, as well as feed additives for various types of farm animals. The effect of chelate complexes was studied according to the following parameters: LC50, survival in chronic experience (30 days), embryotoxicity and genotoxicity by the micronucleus test method. The established LC50 value was 2.73 mg/l, the maximum allowable concentration that does not have a negative effect on adults fish and eggs was 0.5 mg/l. The genotoxic effect on erythrocytes of fish blood was not found in the entire range of sublethal concentrations. Comparison of the data obtained on the toxicity in this study allows asserting that the toxicity of chelates is lower than that of the ionic forms of the elements, subject to their complex effect. To accurately determine the safe level of exposure to chelates, additional studies on other organisms of the hydrobiocenosis are required.

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Krishnankutty, K., Basheer Ummathur e Perumpalli Ummer. "1-naphthylazo derivatives of some 1,3-dicarbonyl compounds and their Cu (II), Ni(II) and Zn(II) complexes". Journal of the Serbian Chemical Society 74, n. 11 (2009): 1273–82. http://dx.doi.org/10.2298/jsc0911273k.

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The coupling of diazotized 1-aminonaphthalene with 1,3-dicarbonyl compounds (acetylacetone, methylacetoacetate and acetoacetanilide) yielded a new series of bidentate ligand systems (HL). Analytical, IR, 1H-NMR and mass spectral data indicate that the compounds exist in the intramolecularly hydrogen bonded keto-hydrazone form. With Ni(II), Cu(II) and Zn(II), these potential monobasic bidentate ligands formed [ML2] type complexes. The IR, 1H- -NMR and mass spectral data of the complexes are consistent with the replacement of the chelated hydrazone proton of the ligand by a metal ion, thus leading to a stable six-membered chelate ring involving the hydrazone nitrogen and the hydrogen bonded carbonyl oxygen. The Ni(II) and Zn(II) chelates are diamagnetic, while the Cu(II) complexes are paramagnetic. In the metal complexes of the naphthylazo derivatives of acetylacetone and methylacetoacetate, the acetyl carbonyl is involved in coordination, whereas in the chelates of the naphthylazo derivative of acetoacetanilide, the anilide carbonyl is bonded with the metal ion.

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Subramani, Murali, Jawahar Durairaj, Chitdeshwari Thiyagarajan e Jagadesh Muthumani. "Synthesis of iron chelates for remediation of iron deficiency in an alkaline and calcareous soil". Journal of Applied and Natural Science 13, SI (19 luglio 2021): 149–55. http://dx.doi.org/10.31018/jans.v13isi.2818.

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The present study was aimed to investigate the using iron chelates viz., ferrous glycinate and ferrous citrate for the remediation of iron deficiency in alkaline and calcareous soil. The lab experiment was carried out to study the synthesis of Fe chelates by using organic and amino acid based chelating agents. The Fe chelates were synthesized based on 2:1 molar ratio of chelating agents and metal ions. The synthesized iron chelate was characterized by using Fourier transform infrared spectrophotometer (FT-IR). Finally, the synthesized amino acid and organic acid chelated iron were used to remediate the calcareous soil with black gram as a test crop. Iron content in black gram (above ground mass) tented to fluctuate at different growth stages. The highest shoot iron content of 325, 351 and 347 mg kg-1 at vegetative, flowering and harvest stages were recorded with 1% ferrous glycinate as foliar spraying on 25 and 45 Day after sowing (DAS). The root iron content was also higher in 1% ferrous glycinate as foliar spraying on 25 and 45 DAS. The current investigation affirmed that the utilizing different chelating agents like the ferrous glycinate were powerful than ferrous sulfate, which may build the iron substance and iron take-up of blackgram in various development stages.

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9

Wu, Yu Qi, Lian Jin Weng, Yuan Yuan Han, Xin Yang e Di Geng. "Synthesis and Infrared Spectrum Characterization of Phenylalanine Chelated Calcium Complex". Advanced Materials Research 396-398 (novembre 2011): 1549–53. http://dx.doi.org/10.4028/www.scientific.net/amr.396-398.1549.

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The preparation conditions in the water system of phenylalanine chelated calcium complex have been evaluated though single-factor tests and optimized by uniform design. Then the optimal parameters were obtained as follows: reaction temperature is 40 °C, reaction time is 182 min, the molar ratio of phenylalanine to calcium is 4.3 and pH = 9.0. Under the best conditions, the experimental result gives chelating rate = 87.40% that is 17.12% lower than the prediction = 104.52%.The infrared spectrum characterization has confirmed the formation of phenylalanine-Ca2+ chelates and the existence of chelate ring.

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10

Esmaeel RABABAH, Sanaa, e Makasib Saleh Mohammed ALSOUYIHIL. "CORRELATING EXPERIMENTAL RESULT WITH THEORETICAL CALCULATIONS ON: EFFECTS OF SUBSTITUENTS ON EXTRACTION EFFICIENCY OF NAPHTHALENE BASED CHELATES (MONO- AND DI-SUBSTITUTED) FOR Hg(II), Cd(II), AND Pb(II) DIVALENT IONS". MINAR International Journal of Applied Sciences and Technology 05, n. 01 (1 marzo 2023): 69–86. http://dx.doi.org/10.47832/2717-8234.14.7.

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Three of the most dangerous and toxic metal ions—Hg(II), Cd(II), and Pb—were chelated using the naphthalene derivatives (NPC, NPM, NPS, DNP, DMS, and NPH) in this study (II). By calculating the percent extraction for each individual interaction between the provided chelates and each of the stated ions, the effectiveness in capturing (extracting) for the three metal ions was assessed. DNP has an excellent extractor for the three metal ions (77. 2, 31.58, 42.0% percent extraction for Hg, Cd, and Pb, respectively); NPM has a good extractor for Hg ions in particular; however, NPS has a poor extractor for all three ions (23.634.6% 11.706% 1 6.204.5% for Hg, Cd, and Pb, respectively. The structure of the chelate, the structure of the compound formed, the type and number of substituents present on the chelator, which are important in determining stability, the type and number of donor atoms within the chelate were found as parameters by which the extraction efficiency was found to be dependent (oxygen is better as a donor atom than nitrogen) and This affects the charge density distribution on the surface of the chelate on how well it binds to metal ions as well as other chelating properties, such as chelate shape, linearity, and stability.This conclusion was reached following the execution of theoretical computations. APT-Charge density on donor atoms suggests that increasing the charge density on the donor atom is crucial for improving the efficiency of the extraction. DNP chelate is one example which shows good extraction efficiency for all of the three ions

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11

Höpfl, Herbert, e Norberto Farfán. "Article". Canadian Journal of Chemistry 76, n. 12 (1 dicembre 1998): 1853–59. http://dx.doi.org/10.1139/v98-192.

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Boron chelates obtained from salicylaldehyde and 2prime-hydroxyacetophenone azines are colored compounds with potential applications in analytical chemistry. Up to now these complexes have not been studied by X-ray crystallography, although two structures with a six- or a seven-membered chelate ring are possible. This contribution presents the X-ray analysis of 2prime-hydroxyacetophenone azine and its corresponding new mono(diphenylboron) chelate with a six-membered boron heterocyclic ring. With these data structural changes of the ligand on chelate formation and structural differences in comparison to salicylaldehyde azomethine boron chelates are discussed.Key words: boron complex, borinate, azine, azomethine.

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12

Saeedi, Reza, Nematollah Etemadi, Ali Nikbakht, Amir H. Khoshgoftarmanesh e Mohammad R. Sabzalian. "Calcium Chelated with Amino Acids Improves Quality and Postharvest Life of Lisianthus (Eustoma grandiflorum cv. Cinderella Lime)". HortScience 50, n. 9 (settembre 2015): 1394–98. http://dx.doi.org/10.21273/hortsci.50.9.1394.

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Lisianthus is one of the most important specialty cut flowers in the world. Various greenhouse conditions and inadequate evapotranspiration can disturb the transport of calcium and impair its uptake by plants. This study aimed to compare the effects of calcium amino acid chelates and calcium chloride (CaCl2) on flower production, quality, and postharvest life of cut ‘Cinderella Lime’ lisianthus. Therefore, nutrient solutions containing calcium amino acid chelates (1%) were prepared using calcium and equal concentrations of lysine, threonine, or methionine. The control treatment was a solution without amino acids and calcium. Calcium concentrations of flowering stems were significantly higher in plants treated with calcium amino acid chelates than those treated with amino acids or the control treatment. Treatment with calcium methionine chelate led to significantly higher flower numbers compared with treatment with free amino acids and the control treatment. Moreover, calcium amino acid chelates effectively improved the fresh and dry mass of the flowering stems in comparison with the control plants. In summary, among all calcium sources, calcium lysine chelate could most effectively enhance the postharvest life of lisianthus cut flowers.

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13

Hertrampf e Olivares. "Iron Amino Acid Chelates". International Journal for Vitamin and Nutrition Research 74, n. 6 (1 novembre 2004): 435–43. http://dx.doi.org/10.1024/0300-9831.74.6.435.

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Iron amino acid chelates, such as iron glycinate chelates, have been developed to be used as food fortificants and therapeutic agents in the prevention and treatment of iron deficiency anemia. Ferrous bis-glycine chelate (FeBC), ferric tris-glycine chelate, ferric glycinate, and ferrous bis-glycinate hydrochloride are available commercially. FeBC is the most studied and used form. Iron absorption from FeBC is affected by enhancers and inhibitors of iron absorption, but to a lesser extent than ferrous sulfate. Its absorption is regulated by iron stores. FeBC is better absorbed from milk, wheat, whole maize flour, and precooked corn flour than is ferrous sulfate. Supplementation trials have demonstrated that FeBC is efficacious in treating iron deficiency anemia. Consumption of FeBC-fortified liquid milk, dairy products, wheat rolls, and multi-nutrient beverages is associated with an improvement of iron status. The main limitations to the widespread use of FeBC in national fortification programs are the cost and the potential for promoting organoleptic changes in some food matrices. Additional research is required to establish the bioavailability of FeBC in different food matrices. Other amino acid chelates should also be evaluated. Finally there is an urgent need for more rigorous efficacy trials designed to define the relative merits of amino acid chelates when compared with bioavailable iron salts such as ferrous sulfate and ferrous fumarate and to determine appropriate fortification levels

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Muthukumar, C., A. Sabastiyan, S. Valarselvan, M. Subramanian e M. Shanmugavadivel. "SYNTHESIS, CHARACTERIZATION AND ANTIMICROBIAL ACTIVITY OF MANGANESE(II) AND NICKEL(II) COMPLEXES OF 7-DIETHYLAMINOBENZYL-8-HYDROXYQUINOLINE". JOURNAL OF ADVANCES IN CHEMISTRY 12, n. 4 (16 dicembre 2016): 4324–32. http://dx.doi.org/10.24297/jac.v12i4.2172.

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8-Hydroxyquninoline Mannich base namely 7-diethylaminobenzyl-8-hydroxyqunioline(DEBQ) was synthesized and characterized by elemental analysis and spectral studies. Chelates of DEBQ with manganese(II) and nickel(II) were isolated and structurally characterized by elemental analysis, electrical conductance, magnetic susceptibility measurement, thermal analysis, IR,UV-Vis, EPR and Mass spectral data. The Mannich base ligand is bidentate and chelates through the phenolic oxygen and the aliphatic tertiary amino nitrogen atoms. Based on the magnetic and electronic spectral data all the MnII complexes are assigned an octahedral geometry and NiII complexes are assigned a tetrahedral geometry. Antimicrobial susceptibility screening of the Mannich base shows that it possesses excellent activity when compared to the standard drugs and the metal complexes studied. Among the chelates, MnII chelate is more potent than NiII chelate. Thermal analysis of a few compounds shows two stage decomposition patterns.

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Van Dam, ME, GE Wuenschell e FH Arnold. "Metal affinity precipitation of proteins". Biotechnology and Applied Biochemistry 11, n. 5 (ottobre 1989): 492–502. http://dx.doi.org/10.1111/j.1470-8744.1989.tb00071.x.

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Proteins containing multiple surface‐accessible histidine residues can be precipitated using small quantities of bis‐copper chelates. The chelates serve to crosslink the proteins, presumably via the accessible histidines, leading to the formation of large, insoluble complexes. When excess copper chelate is used to carry out the precipitation, the resulting precipitate has a stoichiometry of 1:1 copper:accessible histidine. The precipitation is analogous to antibody‐antigen precipitin reactions and can be described qualitatively using simple equilibrium theory developed for those systems. Human hemoglobin contains a large number of surface histidines and is efficiently precipitated by the copper salt CuSO4 as well as by bis‐copper chelates. Sperm whale myoglobin contains many fewer surface histidines and is precipitated only by the bis‐chelates. The effects of the number of accessible histidines on the protein, the chain length separating the two chelates, and the pH on the precipitation reaction have been investigated.

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Martell, Arthur E., Ramunas J. Motekaitis, Dian Chen, Robert D. Hancock e Derek McManus. "Selection of new Fe(III)/Fe(II) chelating agents as catalysts for the oxidation of hydrogen sulfide to sulfur by air". Canadian Journal of Chemistry 74, n. 10 (1 ottobre 1996): 1872–79. http://dx.doi.org/10.1139/v96-210.

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The removal and oxidation to sulfur of H2S, contained in a broad range of sour gas streams including natural gas, by a Fe(III)/Fe(II) chelate system imposes several requirements on the iron chelate that is employed as the redox catalyst. The solution of the catalyst must be neutral or mildly alkaline to efficiently absorb H2S from the gas passed through the solution. The stability of the iron(III) chelate must be high enough that solid Fe(OH)3 not precipitate at the pH employed. Also the stability of the iron(II) chelate must be high enough to prevent the precipitation of FeS from the reaction mixture. The difference in stabilities of the Fe(III) and Fe(II) chelates must be low enough so that the Fe(III) form can be reduced by HS− and that the Fe(III) chelate can be regenerated by aeration of the solution at alkaline pH. An unexpected result of this study is that chelating agents designed for high stability of iron(III) chelates do not form satisfactory redox catalysts. Ligands that form suitable iron complexes as catalysts have both oxygen and nitrogen donors. All complexes investigated are readily reoxidized from the ferrous to the ferric chelate by air. Key words: iron chelates, stability constants, redox potentials, hydrogen sulfide, redox catalysts.

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I. Beshkenadze, L. Japaridze, E. Salukvadze, L. Gogua e G. Kozmanishvili. "Synthesis and study of arginine-containing manganese and zinc chelates". World Journal of Advanced Research and Reviews 14, n. 1 (30 aprile 2022): 029–35. http://dx.doi.org/10.30574/wjarr.2022.14.1.0249.

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Synthesis conditions have been established and arginine-containing manganese and zinc chelate compounds have been synthesized with general formula: Me (Arg)n(CH3COO)2·mH2O, where Me=Mn, Zn; Arg- neutral molecule of arginine; n=1÷3; m=1÷4. Synthesized chelates have been studied using a number of physical-chemical researches. In particular, composition has been identified via trace element analysis, while the individuality has been established through fusion temperature measurement and diffractometric method. According to qualitative solubility research, chelates are highly soluble in water, but poorly soluble in organic solvents. Dissociation constant for chelate compound-containing solutions has been calculated using conductometric study method. With the purpose of biological activity research, on the basis of preliminary trial tests an opinion is expressed that entry of arginine-containing manganese and zinc chelates into composition of broilers’ combined feed premixes has had a positive effect on birds’ live weight gain and their preservation. There is expressed an opinion on the reasonability of main tests conduction in order to identify the optimal doses of arginine-containing manganese and zinc chelate compounds for broilers.

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Ohorodnichuk, H., V. Zagamula, Y. Zagamula e Y. Trembitskyi. "Killing indicators and quality of muscle tissue of pigs after administration of the drug “Kronocid-L” into the diet". Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies 26, n. 100 (21 febbraio 2024): 70–74. http://dx.doi.org/10.32718/nvlvet-a10010.

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The effect of feeding the drug “Kronocid-L” with the content of chelated compounds of microelements on slaughter performance and the quality of muscle tissue of pigs was investigated. Chelate compounds, or chelates (from the English chelate – claw), belong to complex compounds that are formed as a result of the connection of a cation (metal ion) with two or more atoms of a complexon (ligand) molecule. Chelates are significantly different from non-chelated compounds both in terms of chemical and physical properties and in their effects on living organisms. A scientific and economic experiment was conducted on two analogous groups of 75-day-old fattening young pigs, 12 heads in each, obtained from crossing sows of the large white breed with boars of the landrace breed. The control group of pigs consumed the basic diet during the equalization and baseline periods. In addition to the main diet, the experimental group was fed the drug “Kronocid-L” with the content of chelated compounds of microelements at the rate of 1 liter per 1 ton of water. The drug “Kronrocid-L” is a transparent green-blue solution that contains chelate compounds of trace elements (iron, zinc, manganese and copper), formic, acetic, orthophosphoric, lactic, citric, succinic and benzoic acids in an amount of 19 % by weight in an aqueous solution. It was established that feeding pigs on fattening with the above-mentioned preparation contributes to an increase in slaughter weight and slaughter yield in the 2nd experimental group, respectively, by 12.8 kg or by 15 % (P < 0.05) and 5.6 % (P < 0.05 ) against benchmarks. At the same time, under the influence of the feed additive, the thickness of the lard above the 6-7 thoracic vertebra decreased by 3.2 mm or by 10 % (P < 0.05) and the area of the “muscle eye” increased by 2.8 cm2 or 6 % P < 0.01). The use of the drug “Kronocid-L” makes it possible to improve the quality indicators of muscle tissue, namely, to increase the juiciness and intensity of meat color, to increase the content of protein and fat, which indicates an increase in the intensification of protein and fat metabolism.

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Blomqvist, Lennart, Gunnar F. Nordberg, Valeria M. Nurchi e Jan O. Aaseth. "Gadolinium in Medical Imaging—Usefulness, Toxic Reactions and Possible Countermeasures—A Review". Biomolecules 12, n. 6 (24 maggio 2022): 742. http://dx.doi.org/10.3390/biom12060742.

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Gadolinium (Gd) is one of the rare-earth elements. The properties of its trivalent cation (Gd3+) make it suitable to serve as the central ion in chelates administered intravenously to patients as a contrast agent in magnetic resonance imaging. Such Gd-chelates have been used for more than thirty years. During the past decades, knowledge has increased about potential harmful effects of Gd-chelates in patients with severe renal dysfunction. In such patients, there is a risk for a potentially disabling and lethal disease, nephrogenic systemic fibrosis. Restricting the use of Gd-chelates in persons with severely impaired renal function has decreased the occurrence of this toxic effect in the last decade. There has also been an increasing awareness of Gd-retention in the body, even in patients without renal dysfunction. The cumulative number of doses given, and the chemical structure of the chelate given, are factors of importance for retention in tissues. This review describes the chemical properties of Gd and its medically used chelates, as well as its toxicity and potential side effects related to injection of Gd-chelates.

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DeAlba-Montero, I., Jesús Guajardo-Pacheco, Elpidio Morales-Sánchez, Rene Araujo-Martínez, G. M. Loredo-Becerra, Gabriel-Alejandro Martínez-Castañón, Facundo Ruiz e M. E. Compeán Jasso. "Antimicrobial Properties of Copper Nanoparticles and Amino Acid Chelated Copper Nanoparticles Produced by Using a Soya Extract". Bioinorganic Chemistry and Applications 2017 (2017): 1–6. http://dx.doi.org/10.1155/2017/1064918.

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This paper reports a comparison of the antibacterial properties of copper-amino acids chelates and copper nanoparticles againstEscherichia coli,Staphylococcus aureus, andEnterococcus faecalis. These copper-amino acids chelates were synthesized by using a soybean aqueous extract and copper nanoparticles were produced using as a starting material the copper-amino acids chelates species. The antibacterial activity of the samples was evaluated by using the standard microdilution method (CLSI M100-S25 January 2015). In the antibacterial activity assays copper ions and copper-EDTA chelates were included as references, so that copper-amino acids chelates can be particularly suitable for acting as an antibacterial agent, so they are excellent candidates for specific applications. Additionally, to confirm the antimicrobial mechanism on bacterial cells, MTT assay (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) was carried out. A significant enhanced antimicrobial activity and a specific strain were found for copper chelates overE. faecalis. Its results would eventually lead to better utilization of copper-amino acids chelate for specific application where copper nanoparticles can be not used.

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Ziegler, Christopher J. "Isoindoline-Based Open Macrocycles". ECS Meeting Abstracts MA2022-01, n. 14 (7 luglio 2022): 949. http://dx.doi.org/10.1149/ma2022-0114949mtgabs.

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Diiminoisoindoline (DII) continues to be a useful reagent for the synthesis of phthalocyanine-inspired macrocycles and chelate systems. When combined with pyrazole, indazole, and benzimidazole-based heterocycles, DII forms a chelate that can undergo a template reaction at metal sites to produce phthalocyanine analog compounds. These analogs are ring open macrocycles, where the ring either closes via a non-covalent interaction (biliazine and subbiliazine) or forms a helical structure, the new heliphyrin chelates. This talk will present recent developments and the electrochemical properties of these new phthalocyanine analogs, as well as introduce new isoindoline and phthalazine-based bidentate chelates.

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Klem-Marciniak, Ewelina, Marta Huculak-Mączka, Kinga Marecka, Krystyna Hoffmann e Józef Hoffmann. "Chemical Stability of the Fertilizer Chelates Fe-EDDHA and Fe-EDDHSA over Time". Molecules 26, n. 7 (30 marzo 2021): 1933. http://dx.doi.org/10.3390/molecules26071933.

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Abstract (sommario):

In application conditions, the influence of environmental parameters on used fertilizer chelates and their distribution over time is important. For this purpose, the changes in the content of micronutrient ions and Fe-EDDHA and Fe-EDDHSA chelates in an aqueous medium at different pH values were studied. In the assumed time, changes in the ions content were analyzed using the voltammetry method at pH 3, 5 and 7. The content of isomers and chelate forms was analyzed by ion pair chromatography at pH 3, 5 and 7. These studies allowed us to determine the effect of pH on the stability of iron chelates over time.

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23

Kurajica, Stanislav, Gregor Mali, Vilko Mandić e Iva Minga. "Multinuclear Magnetic Resonance Study on Aluminium Sec-butoxide Chelated with Ethyl Acetoacetate in Various Amounts". Croatica chemica acta 92, n. 1 (2019): 17–28. http://dx.doi.org/10.5562/cca3426.

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Abstract (sommario):

Reactive aluminum alkoxide (ASB, aluminium sec-butoxide) was chelated using β-diketone (EAA, ethyl acetoacetate) in order to gain control over rapid hydrolysis in the course of the sol-gel process. Derived chelates were analysed using several NMR spectroscopic techniques: one-dimensional 1H, 13C, 27Al NMR and two-dimensional COSY, HSQC and DOSY. The NMR analysis enabled identification of the formed chelate species, as well as determination of their quantitative relationships. Several complexation products were observed: tris-chelated monomer, Al(EAA)3, bis-chelated dimmer, Al2(OnBu)4(EAA) 2, tris-chelated dimmer, Al2(OnBu)3(EAA)3, tetra-chelated dimmer, Al2(OnBu)2(EAA)4, and monochelated trimer, Al3(OnBu)8(EAA). Of the formed oligomer compounds, this is the first evidence of Al2(OR)3L3 in any alkoxide and β-ketoester or β-diketone combination. Aluminium sec-butoxide and ethyl acetoacetate complexes Al2(OnBu)4(EAA) 2 and Al2(OnBu)2(EAA)4 were also observed for the first time. With the increase of the EAA/ASB ratio the coordination of aluminium shifts towards six, whereas above the EAA/ASB ratio of 2.5 solely six-coordinated aluminium exists.

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24

Malenov, Dušan P., e Snežana D. Zarić. "Chelated metal ions modulate the strength and geometry of stacking interactions: energies and potential energy surfaces for chelate–chelate stacking". Physical Chemistry Chemical Physics 20, n. 20 (2018): 14053–60. http://dx.doi.org/10.1039/c7cp06262a.

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Abstract (sommario):

CCSD(T)/CBS and DFT calculations show very strong stacking of acac-type chelates, up to −9.70 kcal mol⁻¹. Different electrostatic potentials above the metals cause different geometries of the most stable chelate–chelate stacking interactions.

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25

MODAIHSH, A. S. "FOLIAR APPLICATION OF CHELATED AND NON-CHELATED METALS FOR SUPPLYING MICRONUTRIENTS TO WHEAT GROWN ON CALCAREOUS SOIL". Experimental Agriculture 33, n. 2 (aprile 1997): 237–45. http://dx.doi.org/10.1017/s001447979700001x.

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Abstract (sommario):

A field experiment was conducted from 1992 to 1994 to study the effect of supplying micronutrients to wheat (Triticum aestivum L., cv. Yecora rojo) grown on calcareous soil. Chelated and/or non-chelated forms of Fe, Mn, Zn and Cu were administered through a wide range of foliar applications, sprayed either individually or in combination. All the chelated micronutrients were applied in the form of EDTA with the exception of Fe (EDDHA). However, all the non-chelated elements were in the form of sulphate. The grain yield was significantly increased by the application of individual micronutrients either in the form of sulphate or chelate, but much higher amounts of sulphates were required. Application of micronutrient combinations either in chelated or non-chelated forms gave greater biological and grain yields than individual applications of the micronutrients. Wheat response to micronutrient applications followed in rank order: combined elements > Fe > Cu = Zn > Mn. Application of the micronutrients in sulphate form generally resulted in higher concentrations of these elements in grain than when the chelated forms were applied. Foliar application of the micronutrients in the form of sulphates at higher application rates may be more effective than the chelates due to lower cost despite the higher application rates.

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26

Kliegel, Wolfgang, Ulf Riebe, Steven J. Rettig e James Trotter. "Structural studies of organoboron compounds LXIII. Reaction of ketoximes with aldehydes and diphenylborinic acid, and the crystal and molecular structures of two different types of boron chelates and one of the precursor aldehyde adducts". Canadian Journal of Chemistry 73, n. 6 (1 giugno 1995): 835–45. http://dx.doi.org/10.1139/v95-104.

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Abstract (sommario):

The diphenylboron chelates of ketoxime adducts to formaldehyde and trichloroacetaldehyde (chloral) have been synthesized. The reactions were carried out as three-component one-pot reactions, and also as two-step reactions for the ketoxime chloral adducts, which were isolated and characterized before reaction with oxybis(diphenylborane) to form the diphenylboron chelates. One of the intermediate adducts and two of the diphenylboron chelates have been characterized by X-ray crystallographic analysis. Crystals of O-(2,2,2-trichloro-1-hydroxyethyl)-2-propanonoxime, 8d, are monoclinic, a = 7.010(2), b = 11.832(3), c = 11.684(2) Å, β = 90.48(2)°, Z = 4, space group P21/c; those of 4-isopropylidene-2,2-diphenyl-1,3-dioxa-4-azonia-2-boratacyclopentane, 9a, are orthorhombic, a = 11.098(2), b = 15.364(1), c = 8.715(2) Å, Z = 4, space group P212121; and those of 5-trichloromethyl-2-isopropylidene-3,3-diphenyl-1,4-dioxa-2-azonia-3-boratacyclopentane, 10d, are monoclinic, a = 9.164(2), b = 15.304(3), c = 13.859(2) Å, β = 105.28(1)°, Z = 4, space group P21/n. The structures were solved by direct methods and refined by full-matrix least-squares procedures to R = 0.037, 0.044, and 0.040 (Rw = 0.041, 0.016, and 0.042) for 1082, 1256, and 3062 reflections with I ≥ 3σ(F2), respectively. The X-ray analyses show that the products from the reaction between acetonoxime, oxybis(diphenylborane), and formaldehyde or trichloroacetaldehyde, respectively, possess different boron chelate structures. With formaldehyde a COBON chelate ring is obtained and with trichloroacetaldehyde a BOCON chelate ring is formed. Keywords: boron chelates, boron compounds, organboron compounds, crystal structures.

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27

Winiarska-Mieczan, Anna, Karolina Jachimowicz, Małgorzata Kwiecień, Svitlana Kislova, Ewa Baranowska-Wójcik, Zvenyslava Zasadna, Dmytro Yanovych e Edyta Kowalczuk-Vasilev. "The Impact of Zn, Cu and Fe Chelates on the Fatty-Acid Profile and Dietary Value of Broiler-Chicken Thigh Meat". Animals 11, n. 11 (30 ottobre 2021): 3115. http://dx.doi.org/10.3390/ani11113115.

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Abstract (sommario):

This study aimed to compare the effect of Zn, Cu and Fe glycine chelates on the proximate composition, cholesterol levels, fatty-acid profile and dietary value of the thigh meat of broiler chickens. The experiment involved three hundred and fifty Ross 308 chickens divided into seven groups. The chickens were administered Zn, Cu and Fe glycine chelates in an amount corresponding to 50% of the requirement or 25% of the requirement for 42 days. It was found that the use of Zn, Cu and Fe glycine chelates did affect the fatty acid profile and dietary value of meat. A positive impact was most frequently (p < 0.05) noted in chickens receiving Zn chelate in an amount covering 50% of the requirement: the lowest levels of SFA and atherogenic and thrombogenic indices, the highest content of PUFA n−3 and PUFA/SFA ratios and hypocholesterolemic/hypercholesterolemic indices. Positive effects were more often recorded for chickens receiving Zn in an amount corresponding to 50% of the requirement. The results did not show that the use of Cu and Fe glycine chelates can reduce the dietary value of thigh meat in broiler chickens since, generally, the outcomes were not worse than those in the control group. It should be highlighted that due to ambiguous results, it is impossible to determine a dose of Cu and Fe glycine chelate which would be more efficient for broiler chickens. However, chickens receiving chelates in amounts corresponding to 25% of the requirement showed far better results.

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28

Iamze Alim Beshkenadze, Giorgi Apolon Kozmanishvili, Leila Konstantine Japaridze, Eteri Shalva Salukvadze, Nino Ushangi Nonikashvili e Lia Dimitri Gogua. "Synthesis and study of Arginin-containing copper and chrome chelates". World Journal of Advanced Research and Reviews 22, n. 3 (30 giugno 2024): 1708–14. http://dx.doi.org/10.30574/wjarr.2024.22.3.1775.

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Abstract (sommario):

Synthesis conditions have been established and arginin (Arg)-containing copper and chrome chelate compounds with the following general formulas: CuArgn(CH3COO)2·mH2O and CrArgn(CH3COO)3·mH2O (where n =1÷3; m=2 or 4) have been synthesized. Synthesized chelates have been studied using a number of physical and chemical research methods. In particular, their composition has been established via trace element analysis, while the individuality has been identified through melting temperature measurement and diffractographic method. Through study of qualitative solubility in different solvents there has been established that chelates are highly soluble in water and poorly soluble in organic solvents. Using the conductometric research method there has been calculated a dissociation constant of chelate compounds-containing solutions. Based on the preliminary trial tests carried out in order to study the biological activity, there is expressed an opinion that entry of arginin-containing copper and chrome chelates into composition of combined feed premixes of egg-laying (oviparous) poultry has had a positive impact on egg-laying intensity and poultry survival rate. There is given an opinion on the expediency of basic test conduct in order to determine the optimum doses of arginin-containing copper and chrome chelate compounds for egg-laying birds.

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29

Bultreys, Alain, Isabelle Gheysen, Henri Maraite e Edmond de Hoffmann. "Characterization of Fluorescent and Nonfluorescent Peptide Siderophores Produced by Pseudomonas syringaeStrains and Their Potential Use in Strain Identification". Applied and Environmental Microbiology 67, n. 4 (1 aprile 2001): 1718–27. http://dx.doi.org/10.1128/aem.67.4.1718-1727.2001.

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Abstract (sommario):

ABSTRACT Nonfluorescent highly virulent strains of Pseudomonas syringae pv. aptata isolated in different European countries and in Uruguay produce a nonfluorescent peptide siderophore, the production of which is iron repressed and specific to these strains. The amino acid composition of this siderophore is identical to that of the dominant fluorescent peptide siderophore produced by fluorescentP. syringae strains, and the molecular masses of the respective Fe(III) chelates are 1,177 and 1,175 atomic mass units. The unchelated nonfluorescent siderophore is converted into the fluorescent siderophore at pH 10, and colors and spectral characteristics of the unchelated siderophores and of the Fe(III)-chelates in acidic conditions are similar to those of dihydropyoverdins and pyoverdins, respectively. The nonfluorescent siderophore is used by fluorescent and nonfluorescent P. syringae strains. These results and additional mass spectrometry data strongly suggest the presence of a pyoverdin chromophore in the fluorescent siderophore and a dihydropyoverdin chromophore in the nonfluorescent siderophore, which are both ligated to a succinamide residue. When chelated, the siderophores behave differently from typical pyoverdins and dihydropyoverdins in neutral and alkaline conditions, apparently because of the ionization occurring around pH 4.5 of carboxylic acids present in β-hydroxyaspartic acid residues of the peptide chains. These differences can be detected visually by pH-dependent changes of the chelate colors and spectrophotochemically. These characteristics and the electrophoretic behavior of the unchelated and chelated siderophores offer new tools to discriminate between saprophytic fluorescent Pseudomonas species and fluorescent P. syringae and P. viridiflava strains and to distinguish between the two siderovars in P. syringae pv. aptata.

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30

Thakulla, Dharti, e Paul R. Fisher. "Effects of Cold Plasma and Ozone Water Treatment on Micronutrient Solubility". Horticulturae 9, n. 5 (11 maggio 2023): 568. http://dx.doi.org/10.3390/horticulturae9050568.

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Abstract (sommario):

Cold plasma and ozone sanitation of irrigation solutions can oxidize both microbes and non-target micronutrients because their high oxidation-reduction potential (ORP) is a non-selective mode of action. The objective of this study was to evaluate the effects of cold plasma and ozone treatment on oxidation of iron and manganese in nutrient solutions containing one of four iron chelates (iron-ethylenediaminetetraacetic acid (Fe-EDTA), iron-diethylenetriaminepentaacetic acid (Fe-DTPA), iron-ethylenediamine-N,N′-bis(2-hydroxyphenylacetic acid) (Fe-EDDHA), and hydroxybenzyl ethylenediamine (Fe-HBED)). Nutrient solutions were recirculated through the cold plasma or ozone system until the ORP reached 700 mV. The concentrations of total dissolved iron, manganese, and chelated iron were measured before and after passing through the treatment systems. Both cold plasma and ozone oxidized chelates and decreased the solubility of iron and manganese. Cold plasma and ozone had similar effects on micronutrients, pH, electrical conductivity, and dissolved oxygen at a standardized target ORP of 700 mV. Fe-EDTA was the most resistant chelate to oxidation. With Fe-EDTA, ORP increased more quickly, and the concentration of chelated Fe decreased less with the increasing ORP over time compared with Fe-DTPA, Fe-EDDHA, and Fe-HBED. The concentration of chelated Fe decreased by up to 80% for EDDHA at 700 mV compared with a 20% decrease for EDTA. The concentration of Mn decreased by up to 85% at 700 mV. The design of water treatment with cold plasma or ozone therefore requires consideration of secondary effects on micronutrients. The treatment dosage, flow rate, and nutrient solution at a particular grower operation are likely to affect the quantity of micronutrient fertilizer that needs to be supplemented following treatment. Use of Fe-EDTA is one strategy to reduce the loss of iron and increase residual ORP that is available for sanitation.

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31

GOMAN, N. V., I. A. BOBRENKO, V. V. POPOVA e A. A. GAIDAR. "AGROCHEMICAL REGULATORY INDICATORS OF MINERAL NUTRITION OF SPRING WHEAT IN THE FOREST STEPPE OF WESTERN SIBERIA". Izvestiâ Timirâzevskoj selʹskohozâjstvennoj akademii, n. 1 (2021): 5–17. http://dx.doi.org/10.26897/0021-342x-2021-1-5-17.

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Abstract (sommario):

The authors studied the influence of different methods of using micronutrient fertilizers on the yield of spring wheat grain and established standard agrochemical indicators of mineral nutrition on the grassland-chernozem soil of the Omsk region. Use was made of helated micronutrient fertilizers (zinc and copper). Chelated micronutrient fertilizers are an organic complex of a microelement with a chelating agent, in which the microelement is freely absorbed by the plant. The advantages of chelated micronutrient fertilizers are an increase in the availability of trace elements, because these compounds are entirely supplied to the leaf during foliar feeding or during pre-sowing treatment of seeds, protection against the formation of insoluble, inaccessible, economical consumption. The experiment established that the use of zinc and copper chelates in the cultivation of spring wheat in the forest-steppe conditions of the Omsk region is effective. The best rate of zinc and copper for pre-sowing seed treatment is 200 g/t. For foliar top dressing in the tillering phase, the best rate of zinc chelate is 20 g/ha, the most effective top dressing is copper chelate at a rate of 10 g/ha, as it is less expensive in terms of the amount of the applied product. Optimizing spring wheat nutrition by using zinc and copper chelates by foliar feeding of plants in the phase of stemming provided an average increase in yield from 0.03 to 0.16 t/ha of grain (1.4–7.3% compared to control). Experiments revealed a positive effect of zinc chelate in this phase of the yield development, when zinc was used at a rate of 20 g/ha, the greatest yield increase was obtained 0.14 t/ha (2.20 t/ha in control), when using copper chelate the maximum yield was obtained at a rate of 20 g/ha. To obtain a ton of yield in the best version of Zn200, spring wheat required: N – 35.7 kg, P2О5 – 21.9 kg, K2О – 22.6 kg, Zn – 47.56 g, Cu – 5.91 kg. When treating Cu200, the removal of nutrients amounted to: N – 33.9 kg, P2О5 – 21.8 kg, K2О – 22.1 kg, Zn – 54.03 g, Cu – 4.80 g. When carrying out foliar top dressing in the tillering phase of Zn20, the removal of nutrients from a ton of crop yield amounted to: N – 35.4 kg, P2О5 – 23.4 kg, K2O – 23.4 kg, Zn – 49.7 g, Cu – 4.87 g; in the Cu10 variant it was required: N – 34.3 kg, P2O5 – 22.5 kg, K2O – 23.6 kg, Zn – 52.9 g, Cu – 4.36 g. Foliar dressing in the booting phase at a rate of Zn20 was characterized by the following per-ton removal: N – 34.6 kg, P2О5 – 25.3 kg, K2О – 24.9 kg, Zn – 65.0 g, Cu – 5.13 g, treatment with copper chelates Cu20, the removal of nutrients amounted to: N – 34.7 kg, P2О5 – 24.4 kg, K2O – 25.9 kg, Zn – 61.1 g, Cu – 6.4 g. The element utilization coefficients from the soil (EUC) accounted for: nitrogen – 87%, phosphorus – 8.0%, potassium – 6.0%, zinc – 7.0%, copper – 2.0%.

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32

Tong, Bihai, Hsiao-Yun Ku, I. Jen Chen, Yun Chi, Hao-Che Kao, Chia-Chi Yeh, Chih-Hao Chang, Shih-Hung Liu, Gene-Hsiang Lee e Pi-Tai Chou. "Heteroleptic Ir(iii) phosphors with bis-tridentate chelating architecture for high efficiency OLEDs". Journal of Materials Chemistry C 3, n. 14 (2015): 3460–71. http://dx.doi.org/10.1039/c5tc00163c.

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33

Mohamed, Amira A., Fatma M. Ahmed, Wael A. Zordok, Walaa H. El-Shwiniy, Sadeek A. Sadeek e Hazem S. Elshafie. "Novel Enrofloxacin Schiff Base Metal Complexes: Synthesis, Spectroscopic Characterization, Computational Simulation and Antimicrobial Investigation against Some Food and Phyto-Pathogens". Inorganics 10, n. 11 (25 ottobre 2022): 177. http://dx.doi.org/10.3390/inorganics10110177.

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Abstract (sommario):

Condensation of the reaction between enrofloxacin and ethylenediamine in the existence of glacial acetic acid produced a new N,N-ethylene (bis 1-cyclopropyl-7-(4-ethylpiperazin-1-yl)-6-fluoro-1,4-dihydroquinoline-3-carboxylic acid Schiff base (H2Erx-en). H2Erx-en was used as a tetra-dentate ligand to produce novel complexes by interacting with metal ions iron(III), yttrium(III), zirconium(IV), and lanthanum(III). The synthetic H2Erx-en and its chelates had been detected with elemental analysis, spectroscopic methods, mass spectrometry, thermal studies, conductometric and magnetic measurements experiments. The calculated molar conductance of the complexes in 1 × 10−3 M DMF solution shows that iron(III), yttrium(III) and lanthanum(III) are 1:1 electrolytes, however the zirconium(IV) complex is non-electrolyte. The infrared spectra of H2Erx-en chelates indicated that the carboxylic group is deprotonated and H2Erx-en is associated with metals as a tetra-dentate through nitrogen and oxygen atoms. The disappearance of the carboxylic proton in all complexes corroborated information concerning H2Erx-en deprotonation and complexation with metal ions, according to 1H NMR data. Thermal analysis revealed the abundance of H2O particles in the chelates’ entrance and outlet spheres, indicating the disintegration pattern of H2Erx-en and their chelates. The Coats–Redfern and Horowitz–Metzeger approaches were utilized to calculate the thermodynamic items (Ea, ΔS *, ΔH *, and ΔG *) at n = 1 and n ≠ 1. The resulting data reveal better organized chelate building activation. Density functional theory (DFT) was created to properly grasp the optimal architecture of the molecules. The chelates are softer than H2Erx-en, with estimates varying between 95.23 eV to 400.00 eV, compared to 31.47 eV for H2Erx-en. The disc diffusion technique was utilized to assess H2Erx-en and their chelates in an antimicrobial assay against various food and phytopathogens. The zirconium(IV) chelate has the most potent antibacterial action and is particularly efficient against Salmonella typhi.

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34

Glinushkin, Alexey, Svetlana Akimova, Elena Nikulina, Nina Tsirulnikova, Vadim Kirkach, Valery Kalinitchenko, Agamagomed Radzhabov et al. "Preliminary Study: Micropropagation Using Five Types of Chelated Iron and the Subsequent Acclimation of Blue Honeysuckle (Lonicera caerulea var. kamtschatica Sevast.)". Forests 14, n. 4 (17 aprile 2023): 821. http://dx.doi.org/10.3390/f14040821.

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Abstract (sommario):

Blue honeysuckle (Lonicera caerulea var. kamtschatica Sevast.) is a valuable berry crop with a unique biochemical composition. It is rich in vitamins, minerals, and biologically active substances. Different species and cultivars of honeysuckle require different cultivation conditions in the field of accelerated reproduction in vitro. Taking into account the high clonal replication potential of the plant, we conducted research on the chelated-iron form’s influence on the micropropagation productivity of the blue honeysuckle “Lulia” cultivar at the multiplication, rooting, and subsequent acclimatization stages of microplants. In a preliminary study, five types of iron chelates were tested with carboxyl- and phosphorus-containing ligands: Fe(III)-EDTA, Fe(III)-DTPA, Fe(III)-EDDHA, Fe(III)-HEDP, and Fe(II)-HEDP. Each type of iron chelate was applied at four concentrations: standard, decreased by 2 times, and increased by 1.5 times and 2 times in the basic Murashige and Skoog (MS) nutrient medium. It was found that the blue honeysuckle “Lulia” had a selectivity to the type of iron chelate that was used. The nutrient-medium modifications with iron chelates, which caused the plant response, contributed to a significant improvement in the plant’s physiological status and increased its survival rate during the microplant’s acclimation to the nonsterile conditions stage. At the rooting stage, an increase in the rooting rate of up to 100% (Fe (III)-EDDHA), an increase in the number of shoots by 1.5–2 times, and an increase in the number of roots by 1.4–1.9 times were observed. The positive effect of the iron’s chelated forms was also observed at the acclimation stage. According to the results of the research, the most suitable iron forms for clonal micropropagation of blue honeysuckle were carboxyl-containing Fe(III)-EDDHA and phosphonate-containing Fe(II)-HEDP. Moreover, the effectiveness of both complexonates was confirmed in a wide concentration range: Fe(III)-EDDHA from (×1.0) to (×2.0), and Fe(II)-HEDP from (×0.5) up to (×1.5).

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35

Wu, Hong Wei, Wan Cui Xie, Xi Hong Yang, Fu Rao Lai, Hui Wu e Dong Wei Cheng. "Influence of Chelation Rate on the Oligochitosan Preparation by Enzymolysis of CTS-Cu (II)". Advanced Materials Research 962-965 (giugno 2014): 1252–57. http://dx.doi.org/10.4028/www.scientific.net/amr.962-965.1252.

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Abstract (sommario):

To prepare a homogenous low-molecular-weight chitosan oligosaccharide with high solubility and physiological activity, the CTS-Cu (II) chelate was degraded by cellulose, xylanase, semi-cellulase, pectinase, lipase. Cellulose was used to investigate the enzymolysis of the CTS-Cu (II) chelates at various chelation rates. The oligochitosan yields were determined by ultrafiltration and spectrophotometry. The molecular weight distributions of the degradation products were compared by gel column chromatography. Results showed that the generation of the CTS-Cu (II) chelate promoted chitosan degradation. Product yield can be changed by controlling the chelation rates of the CTS-Cu (II) chelates. When the CTS-Cu (II) chelate was degraded at a chelation rate of 100%, most molecular weights of the products were about 2500 Da, and the oligochitosan yield was 89.21%. All these results provided a theoretical basis and experimental method for preparing oligochitosan with a homogenous molecular weight.

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36

Makarova, Anna, Elena Nikulina, Tatiana Avdeenkova e Ksenia Pishaeva. "The Improved Phytoextraction of Heavy Metals and the Growth of Trifolium repens L.: The Role of K2HEDP and Plant Growth Regulators Alone and in Combination". Sustainability 13, n. 5 (24 febbraio 2021): 2432. http://dx.doi.org/10.3390/su13052432.

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Abstract (sommario):

Heavy metals are among the most widespread pollutants in soil. Phytoextraction technology is used to solve the problem of multi-metal-contaminated soil. The efficiency of this process can be increased by introducing various amendments. A soil amendment is any material added to a soil to improve its physical properties, such as water retention, permeability, water infiltration, drainage, aeration, and structure. Some chemical amendments for enhanced phytoextraction, such as amino polycarboxylates chelators, can be hazardous to the environment and perform poorly at pH > 8. The effect of the potassium salt of hydroxyethylidene diphosphonic acid (K2HEDP), plant growth regulators (PGRs), and iron chelate alone and in combination on the phytoextraction by Trifolium repens L. seedlings of Cd, Ni, and Cu was studied in this work. K2HEDP works in a wider pH range. The results of this study confirmed that amino polycarboxylate chelators, with the sodium salt of ethylene diamine tetraacetic acid (Na2EDTA) as an example, have a pronounced negative effect on the growth and development (organ mass) of Trifolium repens L. seedlings. K2HEDP, proposed by the authors instead of Na2EDTA, produced a pronounced positive effect on plant growth and development, which was further enhanced by the use of PGRs and with iron chelates. However, it should be noted that K2HEDP showed significantly lower efficiency in trials on the Trifolium repens L. seedlings. The highest was the efficiency of K2HEDP with PGRs and iron chelates for the phytoextraction of Cd.

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37

Sasikala T, Greeshma KP, Gnana Priya K, Muthulingam S e Nandhakumar C. "Synthesis, characterization and chelating properties of tannin-8-hydroxy quinoline - formaldehyde polymer". GSC Advanced Research and Reviews 5, n. 2 (30 novembre 2020): 019–23. http://dx.doi.org/10.30574/gscarr.2020.5.2.0083.

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Abstract (sommario):

Tannin obtained from Eucalyptus plant, condensed with formaldehyde and then 8-hydroxy quinoline. The so called obtained polymer designated as TFQ was used for metal chelate formation. Thus Transition metal chelates of TFQ with Zn+2, Co+2, Cu+2, Ni+2 and Mn+2 metal ions were prepared. The ligand TFQ and its all five metal chelates were characterized by nitrogen content, IR, UV-Visible spectral studies, magnetic moments and thermogravimetry. The antimicrobial activity of all the samples has also been monitored against common microbes.

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38

Lane, Aiden M., Ny T. C. Luong, Jordan C. Kelly, Martin J. Neal, Jeremiah Jamrom, Aaron J. Bloomfield, Paul A. Lummis, Thomas D. Montgomery e Daniel T. Chase. "Synthetic Exploration of Bis(phenolate) Aza-BODIPYs and Heavier Group 13 Chelates". Molecules 27, n. 23 (26 novembre 2022): 8256. http://dx.doi.org/10.3390/molecules27238256.

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Abstract (sommario):

A series of boron, aluminum, gallium, and indium chelates containing the underexplored bis(phenolate) aza-dipyrromethene (aza-DIPY) core were prepared. These compounds were found to possess near-infrared absorption and emission profiles in the 710 to 770 nm domain and exhibit quantum yield values up to 14%. X-ray diffraction analysis revealed that heavier group 13 bis(phenolate) aza-DIPY chelates possessed octahedral geometries with either THF or pyridine groups occupying the axial positions as opposed to the tetrahedral geometry of the boron chelate.

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39

Noguchi, Daisuke. "ANALYSIS OF SPECIALTIES OF CRYSTAL STRUCTURE FOR NON-CHELATE CONFORMATIONS OF ETHYLENE-DIAMINETETRAACETIC ACID AND ITS SALTS WITH ALKALI AND ALKALINE EARTH METALS". Ukrainian Chemistry Journal 88, n. 10 (25 novembre 2022): 55–69. http://dx.doi.org/10.33609/2708-129x.88.10.2022.55-69.

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In the present study, the crystal structures of non-chelating EDTA molecules and their non-chelation salts in a zwitterionic state, along with the EDTA-chelates of alkali and alkaline earth metals, were searched and overviewed. 25 non-chelating molecules of EDTA, and zwitterions of ethylenediammonium-diacetate diacetic acid HOOC-CH2-(-OOC-CH2-)NH+-CH2-CH2-NH+(-CH2-COO-)-CH2-COOH and their salts (ethylenediammonium-tetraacetic acid (HOOC-CH2-)2NH+-CH2-CH2-NH+(-CH2-COOH)2, ethylenediammonium-acetate triacetic acid (HOOC-CH2-)2NH+-CH2-CH2-NH+(-CH2-COO-)-CH2-COOH, and ethylenediammonium-tetraacetate (-OOC-CH2-)2NH+-CH2-CH2-NH+(-CH2-COO-)2 with counterions), as well as 17 types of EDTA-chelates of alkali metal ions (Li+, Na+, K+, Rb+) and alkaline earth metal ions (Mg2+, Ca2+, Sr2+, Ba2+) were analyzed using data from the Cambridge Crystallographic Data Center (CCDC). Each intramolecular contact distance between nitrogen and oxygen atoms (NH+···O) has been examined and found to be around 2.7 Å. Investigation on the distribution of the intramolecular NH+··· NH+-distances of EDTA and non-chelated salts thereof also revealed that bulky counterion and certain crystal solvent molecules correspond to change in crystal packing, and that they influenced the conformers of EDTA molecules among gauche form to anti form. In the existing crystalline EDTA-chelates of alkali metals as well as alkaline earth metals, various coordination numbers (CN) and the denticity (к) of EDTA anions are displayed; CN 5 to 9, and tri- and hexadentate fashions. Intramolecular contact N···O and N···N distances correspond to the metal ion radii except for the case of Sr-EDTA chelate, probably due to differences of crystal packings in addition to the number of counterions and crystal solvent molecules. The existing data on crystalline EDTA and its salts have been gathered herein, which contributes to a further understanding and exploring applications hereafter.

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40

Malikova, Hana, e Michal Holesta. "Gadolinium Contrast Agents - Are they Really Safe?" Journal of Vascular Access 18, n. 2_suppl (21 marzo 2017): S1—S7. http://dx.doi.org/10.5301/jva.5000713.

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Gadolinium-based contrast agents (GBCA) are used worldwide for enhanced MRI examinations, including heart and vessels. Gadolinium is a highly toxic heavy metal. If used in GBCA it must be tightly bound to ligands. The configuration of ligands influences the stability of the GBCA and two types of chelates have been used. Macrocyclic chelates offer better protection and binding of gadolinium ion than linear chelates with a flexible open chain - gadolinium could be more easily released from the latter ones. GBCAs are excreted from the body mostly by the kidneys, which is of importance in chronic kidney disease. Two states are related to gadolinium: nephrogenic systemic fibrosis (NSF) and gadolinium body storage. NSF is a severe and debilitating disease, directly connected to gadolinium toxicity, proven after the use of linear chelates. Due to strict recommendations of radiology societies, NSF was practically eradicated. Gadolinium deposition was observed especially in bones and in some brain areas: in dentate nucleus and in globus pallidus, even years after the GBCA administration. The form of the storage (chelated or free), as well as their clinical impact, are not clear, but first observations of “gadolinium deposition disease” have been reported.

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41

Cruickshank, Dana R., e Leonard G. Luyt. "The development of organometallic OBOC peptide libraries and sequencing of N-terminal rhenium(I) tricarbonyl-containing peptides utilizing MALDI tandem mass spectrometry". Canadian Journal of Chemistry 93, n. 2 (febbraio 2015): 234–43. http://dx.doi.org/10.1139/cjc-2014-0259.

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The development of peptide-based imaging agents through screening of large peptide libraries is hindered by the additional requirement of a radionuclide−chelator complex that can negatively affect the binding properties of the peptide. Herein, we report N-terminal rhenium(I)tricarbonyl OBOC (one-bead, one-compound) peptide libraries for use in the direct screening of potential imaging agents. The rhenium(I) tricarbonyl is incorporated directly in the library as an imaging entity surrogate to account for the presence of a technetium-99m radionuclide chelate. The identification of unknown organometallic peptides on single beads is successfully accomplished through MALDI tandem mass spectrometry, preceded by a systematic investigation of the effects of a variety of N-terminal rhenium(I) tricarbonyl chelates on peptide fragmentation patterns.

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42

Smentek, Lidia, e B. Andes Hess. "Conformational Analysis of Eu(III)-(Ethylenedinitrilo)tetrakis(methylphosphonates) (EDTMP)". Collection of Czechoslovak Chemical Communications 73, n. 11 (2008): 1437–56. http://dx.doi.org/10.1135/cccc20081437.

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The optimal geometries obtained from DFT calculations are presented for Eu(III)-EDTMP (the parent system) and cages associated with the water molecules and carbonate and hydroxide ions. The numerical results demonstrate the existence of two conformers of each cage, which might explain the observation of two spectroscopic lines previously assigned to the electric dipole transition 7F0 ↔ 5D0 of Eu3+. It is also found that the water molecules are associated with the chelate via hydrogen bonds with the oxygens of the phoshonate arms, while the carbonate and hydroxide ions are chelated with the lanthanide ion due to strong electrostatic interactions between the negatively charged oxygen atoms and positively charged metal ion. The analysis is illustrated by the qualitative comparison of the energies and is concluded with the relative stability of various chelates and energetically favorable, hypothetical reactions.

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43

Aslani, Maryam, e Mohammad Kazem Souri. "Growth and Quality of Green Bean (Phaseolus vulgaris L.) under Foliar Application of Organic-Chelate Fertilizers". Open Agriculture 3, n. 1 (1 maggio 2018): 146–54. http://dx.doi.org/10.1515/opag-2018-0015.

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Abstract Organic-based chelate fertilizers can effectively improve nutrient uptake and use efficiency of plants. In the present study, foliar applications of three organic-chelate fertilizers on green bean (Phaseolus vulgaris L.) plants were compared to soil application of a mix chemical fertilizer (NPK) under greenhouse conditions. The treatments were foliar application (six sprays at 0.2% concentration) of Biomin, Humifolin, DelfonPlus, a mixture of micro and macronutrients, soil application of chemical fertilizer (NPK 0.5 g.kg-1 soil), and no fertilizer control. Foliar applications of organic-chelate fertilizers improved plant height, leaf area, shoot dry weight, leaf N and K concentration, pod number and pod yield compared to control plants. Pod soluble solids, vitamin C and total protein contents were significantly increased by foliar application of organic-chelate fertilizers. Soil applied NPK also improved green bean productivity compared to no fertilizer control. For most plant growth traits, there was no significant difference among the three organic-chelates. Foliar application of the macro- micro- nutrient mixture was not able to enhance the same growth, yield and pod quality traits like organic-chelates. Therefore, application of nutrient elements in form of organic-chelate and particularly by foliar application can guarantee better green bean plant performance.

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44

Olakanmi, Oyebode, Larry S. Schlesinger, Ambar Ahmed e Bradley E. Britigan. "The Nature of Extracellular Iron Influences Iron Acquisition by Mycobacterium tuberculosis Residing within Human Macrophages". Infection and Immunity 72, n. 4 (aprile 2004): 2022–28. http://dx.doi.org/10.1128/iai.72.4.2022-2028.2004.

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ABSTRACT We have reported that Mycobacterium tuberculosis residing within the phagosomes of human monocyte-derived macrophages (MDM) can acquire Fe from extracellular transferrin (TF) and sources within the MDM. In the lung, Fe is also bound to lactoferrin (LF) and low-molecular-weight chelates. We therefore investigated the ability of intraphagosomal M. tuberculosis to acquire Fe from these sources. M. tuberculosis acquired 30-fold and 3-fold more Fe from LF and citrate, respectively, compared to TF, in spite of similar MDM-associated Fe. M. tuberculosis infection decreased MDM-associated Fe relative to uninfected MDM as follows: TF (38.7%), citrate (21.1%), and LF (15.3%). M. tuberculosis Fe acquisition from extracellular chelates (exogenous source) and from endogenous MDM Fe initially acquired from the three chelates (endogenous source) was compared. M. tuberculosis Fe acquisition was similar from exogenous and endogenous sources supplied as Fe-TF. In contrast, there was much greater intracellular M. tuberculosis Fe uptake from LF and citrate from the exogenous than endogenous source. Gamma interferon (IFN-γ) reduced MDM Fe uptake from each chelate by ∼50% and augmented the M. tuberculosis-induced decrease in MDM Fe uptake from exogenous TF, but not from LF or citrate. IFN-γ minimally decreased intracellular M. tuberculosis Fe acquisition from exogenous Fe-TF but significantly increased Fe uptake from LF and citrate. Intraphagosomal M. tuberculosis Fe acquisition from both exogenous and endogenous MDM sources, and the effect of IFN-γ on this process, is influenced by the nature of the extracellular Fe chelate. M. tuberculosis has developed efficient mechanisms of acquiring Fe from a variety of Fe chelates that it likely encounters within the human lung.

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45

Naumov, Pancě, Mirjana Ristova, Bojan Soˇptrajanov, Moon-Jib Kim, Han-Jun Lee e Seik Weng Ng. "A rhombohedral polymorph of aqua(malonato)cadmium(II) hydrate". Acta Crystallographica Section E Structure Reports Online 57, n. 1 (8 dicembre 2000): m14—m16. http://dx.doi.org/10.1107/s1600536800018833.

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The Cd atom in the rhombohedral modification of aqua(malonato)cadmium(II) hydrate, [Cd(C3H2O4)(H2O)].H2O, shows pentagonal bipyramidal coordination. The malonate group chelates to the water-coordinated Cd atom; its two carboxyl groups also chelate adjacent Cd atoms.

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46

Elo, Hannu. "Antimicrobial Activity of Two Antitumour Agents and Ribonucleotide Reductase Inhibitors, Pyridine-2-carboxaldehyde Thiosemicarbazone and the Acetate Form of its Copper(II) Chelate". Zeitschrift für Naturforschung C 62, n. 7-8 (1 agosto 2007): 498–506. http://dx.doi.org/10.1515/znc-2007-7-807.

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Some copper chelates have potent antitumour activity, and in some cases also the free ligands have activity in vivo. Yet, little is known about their antimicrobial properties. Copper( II) chelates of the thiosemicarbazones of α-N-heterocyclic carboxaldehydes constitute one important group of such agents, also their ligands having marked antitumour activity. Both the ligands and chelates inhibit ribonucleotide reductase. Some ligands have been or are under clinical trials as antineoplastic agents. I report here a study on the antimicrobial properties of the prototype compounds of this group, pyridine-2-carboxaldehyde thiosemicarbazone and its copper(II) chelate. They were tested against nine microbes, including bacteria (Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus lactis), yeasts (Candida albicans and Saccharomyces cerevisiae) and one mold (Aspergillus niger). Two clinical isolates of Bacillus sp. and one reference strain were also studied. Both the ligand and the chelate had marked activity. The ligand displayed considerable activity against all bacteria except for S. lactis, and its activity against E. coli and P. aeruginosa was that high that practical applications might be considued. It was highly active against A. niger and moderately active against C. albicans. The chelate was highly active against S. epidermidis and S. cerevisiae. Both compounds inhibited the clinical isolates markedly. Since some related ligands have been or are in clinical trials on humans or are entering them, their route to clinical use, also as antimicrobials, might be much more straightforward than that of substances, whose toxicity in humans is wholly unexplored

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47

Asylbekova, D. D., M. Zh Duisembiyev, N. N. Issabayev, G. F. Sagitova, A. Zh Suigenbayeva, A. E. Bitemirova e A. S. Abdibek. "ELECTROCHEMICAL SYNTHESIS OF ZINC CHELATES IN NON-AQUEOUS MEDIA". Rasayan Journal of Chemistry 15, n. 01 (2022): 612–18. http://dx.doi.org/10.31788/rjc.2022.1516637.

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Electrochemical synthesis of zinc chelates in non-aqueous media has been studied by polarization, capacitance measurements, infrared spectrometry and electron microscopy. The dependences of the substance content and current yield on current density, ligand concentration, temperature and time were determined. Optimal conditions for the process were determined. The aim of the study is to perform electrochemical synthesis of polycarboxylic acidbased chelates in non-aqueous media and to determine the possibility of electrosynthesis in non-aqueous media. In order to study adsorption and material release, the electrochemical behavior of chelate complexes was studied by measuring the volt-ampere E-gi, i-τ, E-τ and capacitance curves. The measurements were performed using graphite and platinum electrodes in acidic alcohol solutions. Based on preliminary experiments it was found that the influence of the process temperature on the yield of the target product, copper chelate, was very small; increasing the temperature leads to some decrease in the yield of the target product, mainly due to resin formation. end products.

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48

Emama, Sanaa M., Saeyda A. AbouEl-Enein, Sanaa A. Othman e Eman M. El-Mahdey. "Novel metal chelates with thiourea and nicotinic acid: Synthesis, structural characterization, and biological properties". Current Chemistry Letters 12, n. 2 (2023): 317–34. http://dx.doi.org/10.5267/j.ccl.2022.12.007.

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The interaction of nicotinic acid and thiourea with the chloride salts of Ca(II), Mg(II), Co(II), Ni(II), Cu(II), and Fe(III) ions led to the synthesis of a unique series of metal chelates. All formed metal complexes were clarified using a variety of analytical and spectral techniques, besides magnetic moment and thermal tests. The electronic and magnetic measurements indicated that the paramagnetic chelates (3) and (4), as well as the diamagnetic complexes (1) and (2), were responsible for the tetrahedral geometrical structure. The outcomes also led to the production of square-planar, and high-spin octahedral structures for chelates (5) and (6). Thermodynamic studies using activation energy values revealed that complex (1) is more thermally stable than complex (2) and complex (3) is more stable than complex (4). Fe(III) complex exhibits higher antibacterial and antifungal activities than other metal complexes. Chelate (6) exhibits the highest rate of germination in wheat.

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49

Chen, Xiangning, Edwin R. Hortelano, Ernest L. Eliel e Stephen V. Frye. "Are chelates truly intermediates in Cram's chelate rule?" Journal of the American Chemical Society 112, n. 16 (agosto 1990): 6130–31. http://dx.doi.org/10.1021/ja00172a040.

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50

Gavryluck, А., M. Solomiychuk e O. Rozhok. "Efficiency of application of the complex based on pseudomonas fluorescens bacteria on potato plantations in the Western Forest Steppe of Ukraine". Interdepartmental Thematic Scientific Collection of Phytosanitary safety, n. 69 (14 marzo 2024): 36–51. http://dx.doi.org/10.36495/1606-9773.2023.69.36-51.

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Goal. To form effective complexes based upon bacterium Pseudomonas fluorenscens in combination with stimulation growth preparations and microelements with their efficiency study on potato plantations. Methods. The researches conducted during 2021—2022 in breeding- seeding rotation on the base Ukrainian Research Plant Quarantine Station of Institute of Plant Protection of NAAS. The experiment conducted on variety Slovyanka. The preparations efficiency determined in different rates against fungi diseases. Records conducted as per generally approved techniques with experimental methods in plant pathology and plant protection. Results. The efficiency of complex based upon Pseudomonas fluorescens АР-33 with stimulating matter nature and chelated microelementson potato plantations in growing period. The yield increased in 1.1—1.5 times during chelate 1 adding to preparation based upon bacterium Pseudomonas fluоrescens, and it increased in 1.3—1.6 times during chelate 2 addition. All biocomplexes combinations showed the preparation efficiency against Alternaria blight in scope 41.5—66.8%, but for late blight it had the following indexes 65.6—85.2. Conclusions. Combinations with chelates № 2 (Fe + Mn + Zn + Mo + Co + B) provided best growing results and yield. The combination Pseudomonas fluоrescens + xymedon + accinic acid + DMAE2ml/l + DМSО2 ml/l chelate (3.6%) showed the best result against potato Alternaria blight. It’s efficiency consisted of 66.8%.The combination Pseudomonas fluоrescens + xymedon + accinic acid + DMAE2ml/l + DМSО2 ml/l chelate(3.6%) showed 85.2% against late blight. It was the best index.

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