Artículos de revistas: "Oxydes à base de Co"

1

BAL, Mustafa. "Synthesis and Characterization of Tetradentate Schiff Base Ligand Containing 3,4-Diamino Benzophenone and Investigation of Complex Formation with Ni (II), Cu (II) and Co (II) metal ions". Cumhuriyet Science Journal 44, n.º 2 (30 de junio de 2023): 289–95. http://dx.doi.org/10.17776/csj.1210668.

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Compound that is a novel tetradentate Schiff base ligand [(3,4-bis(((E)-4-(diethylamino)-2-hydroxybenzylidene)amino)phenyl)(phenyl) methanone] (1), 4-(diethylamino) It was synthesized by the reaction of (3,4-diaminophenyl)(phenyl)methanone with -2-hydroxybenzaldehyde. Complex reactions with Co(II) (1a), Cu(II) (1b) and Ni(II) (1c) metals were prepared based on the obtained Schiff base ligand. The synthesized Schiff base and its Ni(II), Cu(II) and Co(II) complexes were featured using FT-IR, UV-vis, photoluminescence, mass and 1H and 13C-NMR spectroscopy. The characterization processes show that the tetradentate Schiff base compound coordinates with metal ions, oxygen of the hydroxyl group and nitrogen of the azomethine group.

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Li, Qu, Jing Liang, Dong Teng Long, Wei Liang Cheng, Chang Qing Dong y Jun Jiao Zhang. "Research on Chemical Materials with Characteristic on Chemical Looping Combustion of Co-Doped Fe₂O₃ Oxygen Carrier with CO". Applied Mechanics and Materials 540 (abril de 2014): 30–34. http://dx.doi.org/10.4028/www.scientific.net/amm.540.30.

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Co-doped Fe2O3 oxygen carriers reacted with CO were investigated in order to study the temperature effect on the redox characterization.Co-Fe2O3 were characterized with X-ray diffraction (XRD), BET and transmission electron microscope (TEM), which showed that the surface structure was regular, and the polymorph was stable. The TG (Thermo Gravimetric Analyzer) analysis indicted that, rational doping Co could enhance the reactivity of iron-base oxygen carrier reacted with CO under different conditions. Oxygen carrier with Fe: Co molar ratio of 1:0.1 had best reactivity. With the temperature increased, the reduction degree became deeper and the complete conversion time shortened. The reduction reaction Co0.1Fe oxygen carrier with CO was carried out step by step, and the entire process was divided into three stages, namely 344.7-391.0, 414.7-472.5 and 607.6-681.5°C.

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3

Bhowmik, K. R. Nath Bhowmik, R. N. Dutta Purkayastha y S. Roy. "Synthesis, Structural Characterization, Reactivity and Bioactivity Studies of Some Binuclear Salen Type Schiff Base Complexes of Manganese(III)". Asian Journal of Chemistry 36, n.º 3 (28 de febrero de 2024): 690–96. http://dx.doi.org/10.14233/ajchem.2024.31074.

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Four new phenoxy bridged binuclear Salen type Schiff base complexes of manganese(III), [MnLX]2 with tetradentate Schiff base, H2L [H2L = N,N′-O-phenylene bis(salicylaldimine)] containing anionic co-ligands, X (X = benzoate, p-hydroxy benzoate, p-aminobenzoate, 3,5-dinitrobenzoate) have been synthesized from manganese(II) acetate, Schiff base (H2L) and the corresponding co-ligands in methanol medium. Schiff base ligand (H2L) was obtained in situ by condensation of salicylaldehyde and o-phenylenediamine in aqueous methanol. Elemental analyses, FT-IR, molar conductance, UV-visible spectroscopic studies and magnetic moment measurements at room temperature were used to characterize the binuclear Schiff base complexes. The IR spectra of [MnLX]2 (X = benzoate, p-hydroxy benzoate, p-aminobenzoate, 3,5-dinitrobenzoate) complexes showed the characteristic absorptions due to coordinated azomethine nitrogen and phenolic oxygen atoms of the Schiff base. In addition, IR spectra of the compounds also suggest coordination of the co-ligands namely benzoate, p-hydroxy benzoate, p-aminobenzoate, 3,5-dinitrobenzoate in the respective complexes. A consistent presence of a band at ca. 755 cm-1 in all the binuclear complexes arises due to (Mn-O-Mn) moiety originated from interactions of phenoxy oxygen and manganese atoms, resulted in dimeric structure of the compounds. The magnetic moment values ranging from 4.74-4.91 B.M. per manganese centre for the complexes suggest presence of Mn(III) ion in the complexes. The overall coordination geometry around the manganese centres is distorted octahedral. Redox behaviour of the synthesized complexes was ascertained from cyclic voltametric studies. The Schiff base complexes, [Mn(L)X]2 (X = p-aminobenzoate, 3,5-dinitrobenzoate) have demonstrated their catalytic potentials in oxidizing selective organic substrates namely cyclohexene and styrene by hydrogen peroxide as oxidant. The oxidized products were characterized as trans-cyclohexane 1,2-diol and styrene epoxide, respectively. Complex 4 demonstrated a considerable level of effectiveness against a wide variety of pathogenic microorganisms.

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4

Li, Qu, Chang Feng Lin, Jun Jiao Zhang, Wei Liang Cheng y Wu Qin. "Experimental Investigation of Chemical Looping Combustion of CO with Fe-Based Oxygen Carrier". Advanced Materials Research 986-987 (julio de 2014): 72–75. http://dx.doi.org/10.4028/www.scientific.net/amr.986-987.72.

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Reaction activities of Ni-doped and Cu-doped Fe2O3 oxygen carriers (OCs) with CO were investigated using thermo gravimetric (TG-DTG).The structures of the prepared OC were characterized by X-ray diffract meter (XRD).TG-DTG investigations indicated that rational Ni and Cu doping could efficiently enhance the reactivity of Fe-base oxygen carrier for oxidizing CO under different conditions. And Fe-based OC doped with 20 wt. % Ni can realize the highest reactivity.

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5

Mendu, Padmaja, J. Pragathi, B. Anupama y C. Gyana Kumari. "Synthesis, Spectral Characterization, Molecular Modeling, and Antimicrobial Studies of Cu(II), Ni(II), Co(II), Mn(II), and Zn(II) Complexes of ONO Schiff Base". E-Journal of Chemistry 9, n.º 4 (2012): 2145–54. http://dx.doi.org/10.1155/2012/839789.

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A series of Cu(II), Ni(II), Co(II), Mn(II), and Zn(II) complexes have been synthesized from the schiff base ligand L. The schiff base ligand [(4-oxo-4H-chromen-3-yl) methylene] benzohydrazide (L) has been synthesized by the reaction between chromone-3-carbaldehyde and benzoyl hydrazine. The nature of bonding and geometry of the transition metal complexes as well as schiff base ligand L have been deduced from elemental analysis, FT-IR, UV-Vis,1HNMR, ESR spectral studies, mass, thermal (TGA and DTA) analysis, magnetic susceptibility, and molar conductance measurements. Cu(II), Ni(II), Co(II), and Mn(II) metal ions are forming 1:2 (M:L) complexes, Zn(II) is forming 1:1 (M:L) complex. Based on elemental, conductance and spectral studies, six-coordinated geometry was assigned for Cu(II), Ni(II), Co(II), Mn(II), and Zn(II) complexes. The complexes are 1:2 electrolytes in DMSO except zinc complex, which is neutral in DMSO. The ligand L acts as tridentate and coordinates through nitrogen atom of azomethine group, oxygen atom of keto group ofγ-pyrone ring and oxygen atom of hydrazoic group of benzoyl hydrazine. The 3D molecular modeling and energies of all the compounds are furnished. The biological activity of the ligand and its complexes have been studied on the four bacteriaE. coli, Edwardella, Pseudomonas, andB. subtilisand two fungipencilliumandtricodermaby well disc and fusion method and found that the metal chelates are more active than the free schiff base ligand.

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6

Siraj, I. T. y M. Sule. "Synthesis, characterisation and antimicrobial activities of mixed ligand complexes of Mn (II), Fe (II) and Co(II) containing N,N'-bis (o-anisaldehyde) p-phenylenediamine (tetradentate schiff base) and gylcine". Bayero Journal of Pure and Applied Sciences 11, n.º 1 (11 de octubre de 2018): 32–36. http://dx.doi.org/10.4314/bajopas.v11i1.6.

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Complexes of Mn(II), Fe(II) and Co(II) containing N, N’-bis[o-anisaldehyde]p-phenylenediamine tetradentate Schiff base as primary ligand and glycine as secondary bidentate ligand have been synthesized by reflux in 1:1:1 mole ratio and characterized both analytically and spectroscopically. Molar conductance measurement (69.02 to 86.30Ω–1 cm2 mol–1) of the complexes indicated they are weak electrolyte and magnetic susceptibility measurement shows values in range of 4.53 to 5.59BM indicating their paramagnetism. The infrared data suggested that the Schiff base coordinated via the two nitrogen atoms of the azomethine groups (1628 to 1680 cm-1) and the oxygen atoms of the adjacent methoxy groups (1341 to 1389 cm-1), while glycine coordinated via the nitrogen atom of the amino group (3060-3324 cm-1) and the oxygen atom of the carboxylate anion. Based on the analytical and spectroscopic data the complexes may be assigned an octahedral geometries and molecular formulae of the form [M(L)Gly], where M = Mn, Fe and Co, L=Schiff base and Gly = glycine. The Schiff base and its mixed ligand complexes were screened for antimicrobial activity against Staphylococcus aureus, Escherichia coli, Salmonella typhi, Mucor inducus and Aspergillus fumigatus. The complexes exhibited enhanced antimicrobial activity (10mm to 18mm) at 60 µg/disc as compared to 10mm activity of the uncoordinated Schiff base at the same concentration.Keywords: Mixed ligand complex; Schiff base, Glycine, p-phenylenediamine, o-anisaldehyde

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7

Wagh, Shaila y B. R. Patil. "SYNTHESIS, SPECTRAL, THERMAL AND ANTIMICROBIAL STUDIES OF NEW METAL COMPLEXES OF SUBSTITUTED HYDROXY PROPIOPHENONE". RASAYAN Journal of Chemistry 15, n.º 03 (2022): 1718–27. http://dx.doi.org/10.31788/rjc.2022.1536355.

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A new series of metal complexes of innovative bisketimines (L1 - L5) have been synthesized. Schiff base ligands were synthesized by condensing substituted 2’- hydroxy propiophenone and ethylene diamine. The synthesized Schiff bases act as tetradentate ligands with two nitrogen and two phenolic oxygen groups and co-ordinates with Co (II), Ni (II), Cu (II) and Zn (II) salts. Ligands and their metal complexes have been studied using 1H NMR, IR, UV-Vis and thermogravimetric techniques. The complexes were crystalline, according to the XRD pattern. The thermogravimetric data revealed the thermal stability of the complexes. The study of antibacterial and antifungal activities of the ligands and their metal complexes showed more effectiveness of metal complexes than Schiff base ligands.

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8

Al-Wasidi, Asma S., Ahmed M. Naglah, Mohamed A. Al-Omar, Abdul-Rahman M. Al-Obaid, Eid H. Alosaimi, Nashwa M. El-Metwaly, Moamen S. Refat et al. "Manganese (II), ferric (III), cobalt (II) and copper (II) thiosemicarbazone Schiff base complexes: Synthesis, spectroscopic, molecular docking and biological discussions". Materials Express 10, n.º 2 (1 de febrero de 2020): 290–300. http://dx.doi.org/10.1166/mex.2020.1636.

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Mn(II), Fe(III), Co(II) and Cu(II) Schiff base complexes with general formula ML−2 .nH2O (where M is a respected metal ions and L−2 is the Schiff base). The Schiff base (L = TSCPA) was formed by the condensation of thiosemicarbazide and phthalic anhydride in acetic acid. The microanalytical analysis confirmed the 1:1 (metal: ligand) molar ratio. Magnetic susceptibility and electronic absorption spectra were suggested that the Fe(III) and Co(II) complexes were octahedral structure but the Mn(II) and Cu(II) complexes were tetrahedral geometry. FTIR spectra reveal that the ligand exists, predominantly, as keto form in a solid state but as enol form in the alkaline medium. The coordination between TSCPA chelate and central metal ions take place through nitrogen –NH, sulphur C=S and oxygen –OH groups. Based on the molar conductance measurements the complexes may be formulated as [Mn(L)(H2O)] · 4H2O, [Fe(L)(Cl)(H2O)2] · 2H2O, [Co(L)(H2O)3] · 3H2O and [Cu(L)(H2O)] · 4H2O due to their non-electrolytic behavior. The Schiff base ligand and their metal complexes were screened in vitro against G(+Ve) and G(−Ve) bacteria. This study came after proactive step, which concerning with docking study against pathogen proteins corresponding to microorganisms for bacteria and fungi, which will be scanned in vitro study. Thermogravimetry (TGA) and differential thermogravimetry (DTG) were discussed.

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9

Pająk, Marek, Magdalena Woźniczka, Marta E. Lichawska, Bartłomiej Czerwiński, Jakub Włodarczyk y Jakub Fichna. "Oxygen Binding by Co(II) Complexes with Oxime-Containing Schiff Bases in Solution". International Journal of Molecular Sciences 23, n.º 10 (14 de mayo de 2022): 5492. http://dx.doi.org/10.3390/ijms23105492.

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The present work describes the complexation properties of two oxime-containing Schiff bases (used as ligands), viz. 2-hydroxyimino-N′-[1-(2-pyridyl)ethylidene]propanohydrazone (Hpop) and 2-hydroxyimino-N′-[(pyridine-2-yl)methylidene]propanohydrazone (Hpoa), with Co(II) ions in DMSO/water solution. Volumetric (oxygenation) studies were carried out to determine the uptake of molecular oxygen O2 in the formation of the complexes Co(II)-Hpop and Co(II)-Hpoa. The acquired data can be useful in the development of oxygen bioinorganic complexes of metal ions with Schiff base ligands in solution. Their properties allow them to be used as synthetic oxygen transporters. Moreover, the binding of dioxygen could play an important role in the research of catalytic activity by such systems.

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10

Gao, Jinhao, Shuling Liu, Zhijian Li, Yichuang Xing, Xian Cui y Chao Wang. "Cobalt Phosphide Nanoparticles Synthesized by Solvothermal Phosphidization of Metal-Organic Frameworks for Electrocatalytic Oxygen Evolution". International Journal of Energy Research 2023 (7 de febrero de 2023): 1–12. http://dx.doi.org/10.1155/2023/3893229.

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Active and stable electrocatalysts for oxygen evolution reaction (OER) are crucial in the widespread application of water electrolyzers. Cobalt phosphide nanoparticles (Co-P) with different degrees of crystallinity are synthesized via solvothermal phosphidization of Co metal-organic frameworks and P4 using different solvents. The Co-P can be converted to active OER electrocatalysts in 1 M KOH, with the most active reaching 10 mA cm-2 OER current densities at 270 mV overpotential. The OER intermediate adsorption energy is tuned by the electron interactions in the crystalline/amorphous heterostructured Co-P, which show the highest intrinsic OER activity. After the long-term OER in base, surface phosphides are converted to (oxy)hydroxides that are the active species towards OER.

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11

Wibowo, Atmanto Heru, Anggit Pradifta, Abu Masykur, Ken-ichi Yamashita, Yosuke Tani, Ari Yustisia Akbar y Takuji Ogawa. "Synthesis of Fe(II)/Co(II)-Fused Triphenyl Porphyrin Dimer as Candidate for Oxygen Reduction Reaction Catalyst". Indonesian Journal of Chemistry 21, n.º 4 (29 de julio de 2021): 871. http://dx.doi.org/10.22146/ijc.61671.

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This paper reports the synthesis of Fe(II)/Co(II) fused triphenyl porphyrin dimers as candidate of hybrid organic metal electrocatalyst. The synthesis was conducted in five-step reactions using the starting materials pyrrole and benzaldehyde. The fuse oxidative reaction was done via free-base form of triphenyl porphyrin to omit metal insertions/removals of intermediate products. This strategy is very beneficial for the synthesis of metal fused triphenyl porphyrin that needs less reactions where phenyliodine(III) bis(trifluoroacetate) (PIFA) was successfully deployed in the oxidative reaction of two free-base triphenyl porphyrins. Here, the comparisons of NMR spectra were presented to see the changes of the starting material to the product. Initial electrochemical tests showed that reduction current of planar structure of Fe/Co fused triphenyl porphyrin dimer was on the potential range at -1.10 V to 0.45 V vs Au. Fe-fused triphenyl porphyrin dimer with 7.58 × 10–4 A (-1.05 V) showed slightly better performance than Co-fused triphenyl porphyrin dimer with 5.67 × 10–4 A (-0.97 V).

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12

Ayuba, Isiyaku, Tajo Siraj Ibrahim, Umar Maigari Aishatu y Magaji Buhari. "Synthesis, characterization and anti-bacterial activity of Schiff Base and its mixed ligand complexes of Cr (II) and Co (II) containing vanillin and 2-aminophenol". Dutse Journal of Pure and Applied Sciences 7, n.º 4a (2 de febrero de 2022): 98–104. http://dx.doi.org/10.4314/dujopas.v7i4a.11.

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Schiff Base are organic ligand that contained azomethine linkage (-HC=N-) which shows biological importance. Schiff Base from vanillin and 2-aminophenol was synthesized in 1:1 mole ratio. The complexes of Cr (II) and Co (II) from Schiff Base in 1:2 mole ratio metal-ligand (M-L) and the mixed ligand complexes from Schiff Base and 2-aminophenol in 1:1:1 mole ratio ligand-metal-ligand(L-M-L) were synthesized and characterized based on solubility, melting point, conductivity, Fourier transform infrared spectroscopy (FTIR) and ultraviolet (UV). The solubility result shows that, dimethyl sulfoxide(DMSO) dissolved all the complexes. The results obtained from melting point, conductivity indicated purity and non-electrolytic of the complexes respectively. In metal complexes, the infrared data showed the ligands is coordinated to the metal ion through azomethine nitrogen, oxygen in methoxyl group and oxygen in phenolic group. In mixed ligand complexes, the infrared data revealed the ligands is coordinated to the metal ion through azomethine nitrogen, oxygen in methoxyl group, oxygen in phenolic group and nitrogen in amino group. The results showed a six coordinate octahedral geometry for these complexes. The ligands and the metal complexes were examined for their antibacterial activity using agar well diffusion method against Escherichia coli, Staphylococcus aureus, streptococcus pyrogens , Klebsiella pneumonia (gram - bacteria), and Bacillus sutilis, Staphylococcus aureus (gram + bacteria). In comparing the results, the complex of Co(HL1)2 has greater zone of inhibition against the tested organism than the free ligands as antibacterial agent.

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13

Knaudt, Jutta, Stefan Förster, Ulrich Bartsch, Anton Rieker y Ernst-G. Jäger. "Catalytic Oxidation of a Trialkyl-Substituted Phenol and Aniline with Biomimetic Schiff Base Complexes". Zeitschrift für Naturforschung B 55, n.º 1 (1 de enero de 2000): 86–93. http://dx.doi.org/10.1515/znb-2000-0114.

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The catalytic oxidation of 2,4.6-tri-tert-butylphenol and 2,4,6-tri-tert-butylaniline with molecular oxygen and tert-butylhydroperoxide was investigated using biomimetic Mn-, Fe- and Co-complexes as catalysts. The catalytic activity and product distribution were determined and compared with those observed in the reactions of the well-known Co(salen) complex

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14

Al- haddad, Mieaad y Layla Ali Mohammed. "Synthesis and Characterization Some Complexes of Mixed Ligand and Study Its Effects as Antioxidant and Anticancer". Journal of Kufa for Chemical Sciences 3, n.º 1 (10 de diciembre de 2023): 250–73. http://dx.doi.org/10.36329/jkcm/2023/v3.i1.11389.

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A series of mixed ligand complexes of Co(II), Ni(II), Cu(II), Zn (II),Cd(II), Fe (III ) andAu(III) were prepared and characterized. A new azo ligand derived from 4-methylimidazole with sulfadiazine and Schiff base derived from 4-(dimethylamino)-2-hydroxobenzaldehyde and 4-amino-3-hydroxy benzene sulfonamide. Ligands structures and their transitional metal mix-ligand complexes were characterized using various analytical techniques, including molar conductance, elemental analysis (C.H.N), electronic spectral, magnetic measurements, 1HNMR, IR spectral studies and mass spectra. The data shows that these complexes have composition of [ML1L2H2O] where M = Co(II), Ni(II), Cu(II), Zn(II) ,Cd(II) and Hg(II). [ML1L2Cl] where M=Fe(III). [ML1L2]Cl2 where M=Au(III). The magnetic susceptibility and electronic spectral data of the complexes indicate that the octahedral geometry of all complexes, except the complex of Au(III) indicates a square plane geometry. The IR results demonstrate that the co-ordination sites are imidazole nitrogen atom and the farthest azo nitrogen atom of L1 as natural bidentate with nitrogen the azomethine and oxygen atoms of Schiff base L4. Azo ligand and Schiff base behave as tridentate manner. All the compounds showed DPPH radical scavenging activity. In general, the results indicated that the complexes have potential and promising anti-oxidant activities.

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15

Akramullazi, Al, Mst Sabiha Sultana, Md Kudrat-E-Zahan, Md Ali Asraf, C. M. Zakaria y Md Faruk Hossen. "Synthesis and Characterization of Novel Schiff Base Complexes of Cu (II), Cd (II), Ni (II), and Co (II) Ions with N'-(4-Nitrobenzylidene) Isonicotinohydrazide". International Research Journal of Pure and Applied Chemistry 25, n.º 3 (2 de mayo de 2024): 55–67. http://dx.doi.org/10.9734/irjpac/2024/v25i3856.

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The Schiff base complexes of Cu (II), Cd (II), Ni (II), and Co (II) ions were synthesized utilizing Schiff base ligand. The Schiff base ligand was produced through the reaction of isoniazid with equimolar quantities of p-nitrobenzaldehyde yielding final product of N'-(4-nitrobenzylidene) isonicotinohydrazide (L). The ligand and its metal complexes were assessed by TLC, melting point determination, conductivity measurement, FTIR spectroscopy, magnetic moment analysis, and UV-Vis spectroscopy. The FTIR spectra revealed that the Schiff base ligand established coordination bonds with the metal ion by utilizing the nitrogen (N) atom of the azomethine group and the oxygen (O) atom of the carbonyl group. All synthesized compounds exhibited cytotoxicity against brine shrimp nauplii, thereby confirming their biological activity. [Ni(L)2] and [Cd(L)2] complexes displayed greater cytotoxic or anticancer efficacy. In addition, the antibacterial efficacy of both ligand and its complexes was investigated against several harmful bacteria. In comparison with the ligand (L), the antibacterial activity of the complexes of [Cu(L)2], [Cd(L)2], and [Ni(L)2] is higher, whereas that of [Co(L)2] is lower.

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16

Łuba, Mateusz, Tomasz Mikołajczyk, Mateusz Kuczyński, Bogusław Pierożyński y Ireneusz M. Kowalski. "Enhancing the Effectiveness of Oxygen Evolution Reaction by Electrodeposition of Transition Metal Nanoparticles on Nickel Foam Material". Catalysts 11, n.º 4 (3 de abril de 2021): 468. http://dx.doi.org/10.3390/catal11040468.

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Electrochemical oxygen evolution reaction (OER) activity was studied on nickel foam-based electrodes. The OER was investigated in 0.1 M NaOH solution at room temperature on as-received and Co- or Mo-modified Ni foam anodes. Corresponding values of charge-transfer resistance, exchange current-density for the OER and other electrochemical parameters for the examined Ni foam composites were recorded. The electrodeposition of Co or Mo on Ni foam base-materials resulted in a significant enhancement of the OER electrocatalytic activity. The quality and extent of Co, and Mo electrodeposition on Ni foam were characterized by means of scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analysis.

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17

Haruna, A., Rumah, M.M., Sani, U. y Ibrahim, A.K. "Synthesis, Characterization and corrosion Inhibition Studies on Mn (II) and Co (II) Complexes Derived from 1-{(Z)-[(2-hydroxyphenyl) imino]methyl}naphthalen-2-ol in 1M HCl Solution". International Journal of Biological, Physical and Chemical Studies 3, n.º 1 (25 de mayo de 2021): 09–18. http://dx.doi.org/10.32996/ijbpcs.2021.3.1.2.

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Schiff base derived from the reaction of 2-amino phenol and 2-hydroxy-1-naphthaldehyde and its Co (II), and Mn (II) complexes have been synthesized and characterized by solubility test, melting point/ decomposition temperatures, molar conductance, IR and magnetic susceptibility. The number of ligands coordinated to the metal ion was determined using Job’s method of continuous variation. Their molar conductance values indicate that all the complexes are non-electrolytes. Magnetic moment values of the complexes showed that both Mn (II) and Co (II) are paramagnetic. The spectroscopic data of metal complexes indicated that the metal ions are complexed with azomethine nitrogen and deprotonated oxygen atom. Corrosion inhibition of the schiff base and Mn (II) and Co (II) complexes were evaluated using the weight loss method in a 0.1MHCl solution for copper metal. The inhibition efficiency increased with increasing inhibitors concentration. The negative values of Gibb’s free energy of adsorption (ΔGads) confirmed the spontaneity and physical adsorption of the inhibition process which is inconsistent with Langmuir adsorption isotherm.

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Reddy, Vidyavati, Nirdosh Patil y S. D. Angadi. "Synthesis, Characterization and Antimicrobial Activity of Cu(II), Co(II) and Ni(II) Complexes with O, N, and S Donor Ligands". E-Journal of Chemistry 5, n.º 3 (2008): 577–83. http://dx.doi.org/10.1155/2008/170631.

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The complexes of the type ML2[where M = Cu(II), Co(II), and Ni(II)] L = 1-phenyl-1-ene-3-(2-hydroxyphenyl)-prop-2-ene with 3- substituted-5-mercapto-4-amino-1,2,4-triazoles. Schiff base ligands have been prepared by reacting 3-(2-hydroxyphenyl)-1-phenylprop-2-en-1-one and 3-phenyl/pyridyl-4-amino-5-mercapto-1,2,4-triazoles in an alcoholic medium. The complexes are non-electrolytes in DMF. The resulting complexes were characterized by elemental analysis, magnetic measurements, conductivity measurements and spectral studies. The Schiff base acts as a tridentate dibasic and coordinating through the deprotonated oxygen, thioenolic sulphur and azomethine nitrogen atoms. It is found that Cu(II), Co(II), and Ni(II) complexes exhibited octahedral geometry. The antimicrobial activities of ligands and its complexes were screened by cup plate method.

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Abdullahi, B. L. y I. T. Siraj. "Synthesis, characterization and antimicrobial activities of Schiff base complexes derived from Salicylaldehyde and amino acid (isoleucine)". Bayero Journal of Pure and Applied Sciences 15, n.º 1 (9 de diciembre de 2022): 113–18. http://dx.doi.org/10.4314/bajopas.v15i1.15.

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Complexes of Fe(II), Co(II), Cu(II), and Zn(II) with a Schiff base derived from salicylaldehyde and isoleucine were successfully synthesized. All complexes were distinctly colored and were characterized by molar conductance, magnetic susceptibility, infrared and UV spectroscopy. Infrared spectroscopy shows the Schiff base ligand is coordinated to the central metal ion in a tridentate manner through the N-atom of the azomethine and two oxygen of the phenol and carboxylate. All complexes contain two ligands molecules per metal ion (ML2). An octahedral geometry is proposed for the metal complexes. Antimicrobial study of the complexes was undertaken against five pathogenic bacteria strains and two fungi, mucus species and Aspergillus fumigates. The result reveal that most of the complexes and particularly Co (II) and Zn (II) have a much enhanced activity against Staphyllococcus aureus, Escherichia coli and Klebsiella pneumoniae.

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Do, Jeong, Rama Chava, Namgyu Son, Junyeong Kim, No-Kuk Park, Doyeon Lee, Myung Seo, Ho-Jung Ryu, Jun Chi y Misook Kang. "Effect of Ce Doping of a Co/Al2O3 Catalyst on Hydrogen Production via Propane Steam Reforming". Catalysts 8, n.º 10 (25 de septiembre de 2018): 413. http://dx.doi.org/10.3390/catal8100413.

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We synthesized cerium-doped cobalt-alumina (CoxCey/Al2O3) catalysts for the propane steam reforming (PSR) reaction. Adding cerium introduces oxygen vacancies, and the oxygen transfer capacity of the Ce promoter favors CO to CO2 conversion during PSR, inhibiting coke deposition and promoting hydrogen production. The best PSR activity was achieved at 700 °C using the Co0.85Ce0.15/Al2O3 catalyst, which showed 100% propane (C3H8) conversion and about 75% H2 selectivity, and 6% CO, 5% CO2, and 4% CH4 were obtained. In contrast, the H2 selectivity of the base catalyst, Co/Al2O3, is 64%. The origin of the difference in activity was the lower C3H8 gas desorption temperature of the Co0.85Ce0.15/Al2O3 catalyst compared to that of the Co/Al2O3 catalyst; thus, the PSR occurred at low temperatures. Furthermore, more CO was adsorbed on the Co0.85Ce0.15/Al2O3 catalyst, and subsequently, desorbed as CO2. The activation energy for water desorption from the Co0.85Ce0.15/Al2O3 catalyst was 266.96 kJ/mol, higher than that from Co/Al2O3. Furthermore, the water introduced during the reaction probably reacted with CO on the Co0.85Ce0.15/Al2O3 catalyst, increasing CO2 generation. Finally, we propose a mechanism involving the Co0.85Ce0.15/Al2O3 catalyst, wherein propane is reformed on CoxCey sites, forming H2, and CO, followed by the conversion of CO to CO2 by water on CeO2 sites.

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21

Yin, Huayi y Dihua Wang. "(Invited) Electrochemical Conversion of CO₂ Into Oxygen/ and C/CO in Molten Carbonate". ECS Meeting Abstracts MA2023-01, n.º 56 (28 de agosto de 2023): 2737. http://dx.doi.org/10.1149/ma2023-01562737mtgabs.

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The molten salt CO2 capture and electrochemical transformation (MSCC-ET) process has been demonstrated as an effective approach to capturing and converting CO2 into oxygen and C/CO [1-2]. The effective CO2 capture and electrochemical conversion rely on the high-temperature molten carbonate electrolytes and the cost-effective inert oxygen-evolution anode. In recent years, we have focused on the electrolyte engineering to modulate the reactions at both the cathode and anode as well as the CO2 capture efficiency [3-4]. Besides, we insist on developing iron- and nickel-base oxygen-evolution inert anodes in terms of revealing the fundamental principles and basic guidelines for choosing proper materials and fabrication processes [5]. By doing so, we can prepare functional carbon materials or CO at the cathode with a high current efficiency of over 90%, and produce oxygen at the inert anode. In addition, the kilo-ampere scale electrolyzer was built to produce oxygen, carbon or CO with an energy efficiency of over 50%. Therefore, the molten carbonate CO2 electrolyzer shows its potential to convert CO2 on the Mars to produce oxygen and fuels to support the future exploration of outer space. References [1] H. Y. Yin, D. H. Wang*, et al., Capture and electrochemical conversion of CO2 to value-added carbon and oxygen by molten salt electrolysis. Energy & Environmental Science, 2013, 6: 1538-1545. [2] R. Jiang, M. X. Gao, X. H. Mao, D. H. Wang*. Advancements and potentials of molten salt CO2 capture and electrochemical transformation (MSCC-ET) process, Current Opinion in Electrochemistry, 2019, 17: 38-46. [3] B. W. Deng, J. J. Tang, X. H. Mao, Y. Q. Song, H. Zhu, W. Xiao, D. H. Wang*. Kinetic and Thermodynamic Characterization of Enhanced Carbon Dioxide Absorption Process with Lithium Oxide-Containing Ternary Molten Carbonate, Environmental Science & Technology, 2016, 50(19): 10588-10595. [4] Z. S Yang, B. W. Deng, K. F. Du, H. Y. Yin*, D. H. Wang*, A general descriptor for guiding the electrolysis of CO2 in molten carbonate, 2022, in press. [5] P. L. Wang, K. F. Du, Y. P. Dou, H. Zhu, D. H. Wang*, Corrosion behaviour and mechanism of nickel anode in SO42- containing molten Li2CO3-Na2CO3-K2CO3. Corrosion Science 2022, 166. Figure 1

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22

Shang, Shu, Wei Shao, Xiao Luo, Ming Zuo, Hui Wang, Xiaodong Zhang y Yi Xie. "Facet Engineering in Constructing Lewis Acid-Base Pairs for CO₂ Cycloaddition to High Value-Added Carbonates". Research 2022 (15 de octubre de 2022): 1–9. http://dx.doi.org/10.34133/2022/9878054.

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Cycloaddition of epoxides with CO2 to synthesis cyclic carbonates is an atom-economic pathway for CO2 utilization with promising industry application value, while its efficiency was greatly inhibited for the lack of highly active catalytic sites. Herein, by taking BiOX (X=Cl, Br) with layered structure for example, we proposed a facet engineering strategy to construct Lewis acid-base pairs for CO2 cycloaddition, where the typical BiOBr with (010) facets expose surface Lewis acid Bi sites and Lewis base Br sites simultaneously. By the combination of in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and theoretical calculations, the oxygen atom of the epoxide is interacted with the Lewis acid Bi site to activate the ternary ring, then facilitates the attack of the carbon atom by the Lewis base Br site for the ring-opening of the epoxide, which is the rate-determining step in the cycloaddition reaction. As a result, the BiOBr-(010) with rich surface Lewis acid-base pairs showed a high conversion of 85% with 100% atomic economy in the synthesis of cyclic-carbonates without any cocatalyst. This study provides a model structure for CO2 cycloaddition to high value-added long chain chemicals.

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23

Ban Mahdi Salih y Muna Abass Hadi. "Synthesis, Identification and Spectral Studies of Some New Schiff base ligand Complexes Contained 3,4-Diaminobenzophenone and pyridoxal hydrochloride Compounds". Journal of Kufa for Chemical Sciences 2, n.º 9 (28 de agosto de 2023): 115–27. http://dx.doi.org/10.36329/jkcm/2022/v2.i9.13290.

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Anew Schiff base ligand. (HMPHM) 3-((4-chlorobenzylidene)amino)-4-((€-(3-hydroxy-5-(hydroxyl methyl)-2-Methyl)puridin-4-yl)methylene)amino)phenyl)(phenyl)methanon has been Prepared from reacting(3-amino-4-(((3-hydroxy-5-(hydroxylmethyl)-2-methylpyridin-4-yl)methylene)amino)phenyl)(phenyl)methanone with P-Chloro benzaldehyde Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Au(III) ions were used to create a new series of chelate complexes. The structures of the new Schiff base ligand and their transition metal complexes were characterized by using Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H-NMR) technique, ultraviolet visible spectroscopy (UV-Vis), mass analysis, molar conductance, and magnetic susceptibility. [(M)(L)2] where M = Co(II), Ni(II), Cu(II), Zn(II), and Cd(II), and [(M)(L)Cl]Cl where M = Au (III). The coordination sites of the Schiff base ligand were revealed by FTIR to be through oxygen of the hydroxyl group, and the nitrogen of azomethine groups. Based on data obtained, the octahedral geometry was suggested for all ligand complexes exception of the Au(III) complex, which had a square planar geometry.

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24

Moosavi, Fatemeh, Mohammad Ebrahim Bahrololoom, Ramin Kamjou, Ali Mirzaei, Salvatore Gianluca Leonardi y Giovanni Neri. "Hydrogen Sensing Properties of Co-Doped ZnO Nanoparticles". Chemosensors 6, n.º 4 (5 de diciembre de 2018): 61. http://dx.doi.org/10.3390/chemosensors6040061.

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In this study, the gas sensing properties of Co-doped ZnO nanoparticles (Co-ZnO NPs) synthesized via a simple sol-gel method are reported. The microstructure and morphology of the synthesized Co-ZnO NPs were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. Co-ZnO NPs were then used for developing a conductometric gas sensor for the detection, at mild temperature, of low concentration of hydrogen (H2) in air. To evaluate the selectivity of the sensor, the sensing behavior toward some VOCs such as ethanol and acetone, which represent the most important interferents for breath hydrogen analysis, was also investigated in detail. Results reported demonstrated better selectivity toward hydrogen of the Co-ZnO NPs sensor when compared to pure ZnO. The main factors contributing to this behavior, i.e., the transition from n-type behavior of pristine ZnO to p-type behavior upon Co-doping, the modification of oxygen vacancies and acid-base characteristics have been considered. Hence, this study highlights the importance of Co doping of ZnO to realize a high performance breath hydrogen sensor.

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25

Baxter, Pamela J., Kyle Garton y Evan D. Kharasch. "Mechanistic Aspects of Carbon Monoxide Formation from Volatile Anesthetics". Anesthesiology 89, n.º 4 (1 de octubre de 1998): 929–41. http://dx.doi.org/10.1097/00000542-199810000-00018.

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Background Desflurane, enflurane and isoflurane can be degraded to carbon monoxide (CO) by carbon dioxide absorbents, whereas sevoflurane and halothane form negligible amounts of CO. Carbon monoxide formation is greater with drier absorbent, and with barium hydroxide, than with soda lime. The mechanism, role of absorbent composition and water, and anesthetic structures determining CO formation are unknown. This investigation examined sequential steps in anesthetic degradation to CO. Methods Carbon monoxide formation from anesthetics and desiccated barium hydroxide lime or soda lime was determined at equimole and equiMAC concentrations. Carbon monoxide formation from deuterium-substituted anesthetics was also quantified. Proton abstraction from anesthetics by strong base was determined by deuterium isotope exchange. A reactive chemical intermediate was trapped and identified by gas chromatography-mass spectrometry. The source of the oxygen in CO was identified by 18O incorporation. Results Desflurane,enflurane,andisoflurane(difluoromethylethyl ethers), but not sevoflurane (monofluoromethyl ether), methoxyflurane (methy-ethyl ether), or halothane (alkane) were degraded to CO. The amount of CO formed was desflurane > or = enflurane > isoflurane at equiMAC and enflurane > desflurane > isoflurane at equimole concentrations. Proton abstraction from the difluoromethoxy carbon was greater with potassium than with sodium hydroxide, but unmeasurable with barium hydroxide. Carbon monoxide formation was correlated (r = 0.95-1.00) with difluoromethoxy (enflurane > desflurane > isoflurane > or = methoxyflurane = sevoflurane = 0) but not ethyl carbon proton abstraction. Deuterium substitution on enflurane and desflurane diminished CO formation. Chemical trapping showed formation of a difluorocarbene intermediate from enflurane and desflurane. Incorporation of H2(18)O in barium hydroxide lime resulted in C18O formation from unlabeled enflurane and desflurane. Conclusions A difluoromethoxy group is a structural requirement for haloether degradation to CO. Results are consistent with initial base-catalyzed difluoromethoxy proton abstraction (potassium > sodium hydroxide, thus greater CO formation with barium hydroxide lime vs. soda lime) forming a carbanion (reprotonated by water to regenerate the anesthetic, hence requirements for relatively dry absorbent), carbanion decomposition to a difluorocarbene, and subsequent difluorocarbene reaction to form CO.

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O. Rajee, A., H. F. Babamale, A. Lawal, A. A. Aliyu, W. A. Osunniran, A. O. Sheriff, M. Lawal y J. A. Obaleye. "Mn(II), Co(II), Ni(II), and Cu(II) complexes of amino acid derived Schiff base ligand: Synthesis, characterization and in-vitro antibacterial investigations". Bulletin of the Chemical Society of Ethiopia 35, n.º 1 (7 de mayo de 2021): 97–106. http://dx.doi.org/10.4314/bcse.v35i1.8.

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Four complexes of Mn(II), Co(II), Ni(II) and Cu(II) with Schiff base ligand (H3L) derived from 2-amino-3-methylbutanoic acid and acetylacetonate were synthesized. All complexes were characterized by elemental analysis, Fourier-transform infrared spectroscopy and electronic spectroscopy. The results confirmed the coordination of the ligand to metals in tridentate fashion via the hydroxyl oxygen, the azomethine nitrogen and the enolic acetylacetonate oxygen. Antimicrobial activities were established for all complexes, free ligand and ciprofloxacin for comparison. Both the ligand and its metal complexes were active against Gram-positive and negative bacterial strains. The Cu(II) complex, showed highest antibacterial activity among the complexes screened. Other complexes displayed considerable antibacterial activity. Octahedral geometry was proposed for the metal(II) complexes with the Schiff base. KEY WORDS: Schiff base, Amino acid, Metal Complexes, Antibacterial agents Bull. Chem. Soc. Ethiop. 2021, 35(1), 97-106. DOI: https://dx.doi.org/10.4314/bcse.v35i1.8

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27

Kumar, Vikas. "Synthesis and characterization of Co (II), Ni (II) and Cu (II) complexes with unsymmetrical tetradentate Schiff base ligand". Research Journal of Chemistry and Environment 28, n.º 2 (28 de diciembre de 2023): 82–85. http://dx.doi.org/10.25303/282rjce82085.

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A novel series of cobalt (II), nickel (II) and copper (II) complexes of unsymmetrical Schiff base ligand 1-(2-hydroxynaphthalideneimino)-2-(5 methoxysalicylidene imino)-4 chlorobenzene-1,2-diamine was synthesised by condensation reaction of 1:1:1 molar ratio of 2-hydroxynaphthalene-1-carbaldehyde, 4-chlorobenzene -1,2-diamine and 5-methoxysalicyidehyde in alcoholic medium. The synthesised ligand and its metal complexes were characterised by elemental analysis, molar conductance measurements, magnetic susceptibility measurements, UV-Vis and infrared spectral data. The molar conductance of synthesised metal complexes in DMSO solution indicates their non-electrolytic nature. The analytical data show the general formula for the complexes to be [M(L)2] where L = Schiff base ligand and M = Co (II), Ni (II) and Cu (II). The spectral data and magnetic moment suggested that Schiff base behaves as a tetradentate ligand, coordinating through azomethine nitrogen and phenolic oxygen atoms to the metal ion. Magnetic susceptibility measurements, UV-Vis and infrared spectral data geometry of metal complexes were proposed to be square planar.

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Quadakkers, W. Joe, T. Olszewski, J. Piron-Abellan, Vladimir Shemet y Lorenz Singheiser. "Oxidation of Metallic Materials in Simulated CO₂/H₂O-Rich Service Environments Relevant to an Oxyfuel Plant". Materials Science Forum 696 (septiembre de 2011): 194–99. http://dx.doi.org/10.4028/www.scientific.net/msf.696.194.

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In the present study the oxidation behaviour of a number of candidate alloys for heat exchanging components was investigated in model gas mixtures containing high amounts of CO2 and/or water vapour in the temperature range 550-700°C up to exposure times of 1000 h. During exposure in Ar/CO2 and Ar/CO2/H2O base gas mixtures at 550-650°C the oxidation rates and scale compositions of martensitic 9-12%Cr steels were similar to those previously observed in steam environments. Thin and protective Cr-rich oxide scales which are commonly found during air oxidation was observed locally on the specimens surfaces after oxidation in Ar-(1-3%)O2-CO2. The tendency for protective chromia base scale formation increased when 3% oxygen was added, especially for the 12%Cr steel. When iron base oxide scales were formed on the metal surface, the martensitic steels tended to exhibit carburisation whereby the extent was reduced by increasing the water vapour and oxygen contents. All three studied austenitic alloys exhibited very slow scale growth rates at 550°C, however, at and above 600°C the steels with lower Cr content started to form two-layered iron rich surface oxide scales whereby the outer oxide was prone to spallation upon thermal cycling. The high-Cr austenitic steel 310N and the nickel base alloy 617 formed very thin, Cr-rich oxide scales at all used test temperatures and atmospheres. For those two materials the oxidation behaviour in gases containing water vapour in combination with intentionally added oxygen was affected by formation of volatile chromium oxyhydroxide.

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29

Ceyhan, Tanju, Mustafa Korkmaz, Türker Kutluay y Özer Bekaroğlu. "Synthesis, characterization and EPR spectroscopy of novel s-triazines bearing three oxygen-linked phthalocyanines". Journal of Porphyrins and Phthalocyanines 08, n.º 12 (diciembre de 2004): 1383–89. http://dx.doi.org/10.1142/s108842460400074x.

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Compound 1 (2,4,6-tris(2-oxaphthalonitrile)- s -triazine) has been prepared by the reaction of 4-nitrophthalonitrile and cyanuric acid in dry DMF as the solvent in the presence of K 2 CO 3 as the base. An interesting s -triazine, containing three oxa metal phthalocyanines ( M = Zn , Co or Cu ) has been synthesized from compound 1, 4,5-bis(hexylthio)phthalonitrile and the corresponding anhydrous metal salts ( Zn ( OAc )2, CoCl 2 or CuCl ) by the method of statistically mixed condensation. The new compounds and phthalocyanines were obtained in sufficient purity after successive washings with different solvents and were characterized by elemental analysis, UV-vis, IR, NMR and EPR spectroscopy.

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30

Singh, N. K., Ritu Yadav, M. K. Yadav y Carlos Fernandez. "Effect of Co-substitution on the electrocatalytic properties of Ni1.5Fe1.5O4 for oxygen evolution in alkaline solutions". Journal of New Materials for Electrochemical Systems 20, n.º 3 (27 de julio de 2017): 115–21. http://dx.doi.org/10.14447/jnmes.v20i3.317.

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Some ternary ferrites having composition CoxNi1.5-xFe1.5O4 (0.0 ≤ x ≤ 1.25) have been synthesized by NH4OH co-precipitation method at 11.5 pH. Materials, so obtained, were tested for their electrocatalytic properties towards oxygen evolution reaction (OER) in the form film on Ni-support in alkaline solution. The study showed that the electrocatalytic properties the material increased with partial substitution of Co for Ni in the base oxide (Ni1.5Fe1.5O4). The value being highest with 0.5 mol Co-substitution. At E = 850 mV vs Hg/HgO in 1M KOH at 25 ºC, the electrode showed apparent current density 206.2 mA cm-2, which is about 3 times higher than the base oxide. The Tafel slope values were ranged between 46-82 mV decade-1. A pair of redox peak, an anodic (EPa = 522±28 mV) and corresponding cathodic (EPc= 356±9 mV), was observed in the cyclic voltammetry (CV) study of the material. The thermodynamic parameters namely, standard apparent electrochemical enthalpy of activation ( ), standard enthalpy of activation ( ) and standard entropy of activation ( ) for the oxygen evolution reaction (OER) have also been determined by recording anodic polarization curve in 1M KOH. The value of was observed to be almost similar with each oxide electrode. The values were highly negative and ranged between ~ -165 and ~ -207 J deg-1 mol-1. Phase and morphology of materials have been investigated by using physical techniques X-ray diffraction, infrared spectroscopy (IR) and scanning electron microscope (SEM), respectively.

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Kuate, Maurice, Mariam Asseng Conde, Evans Ngandung Mainsah, Awawou G. Paboudam, Francis Merlin M. Tchieno, Kevin I. Y. Ketchemen, Ignas Tonle Kenfack y Peter T. Ndifon. "Synthesis, Characterization, Cyclic Voltammetry, and Biological Studies of Co(II), Ni(II), and Cu(II) Complexes of a Tridentate Schiff Base, 1-((E)-(2-Mercaptophenylimino) Methyl) Naphthalen-2-ol (H2L1)". Journal of Chemistry 2020 (9 de noviembre de 2020): 1–21. http://dx.doi.org/10.1155/2020/5238501.

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A novel tridentate Schiff base, 1-((E)-(2-mercaptophenylimino) methyl) naphthalen-2-ol (H2L1), was synthesized by the condensation reaction of 2-hydroxy-1-naphthaldehyde with 2-aminothiophenol in absolute ethanol. The resulting ligand was reacted with Co(II), Ni(II), and Cu(II) ions to obtain tetrahedral CoL1, NiL1, and square planar CuL1 complexes. The Schiff base and its metal complexes were characterized using 1H-NMR, microanalysis, FT-IR, UV-visible, and mass spectroscopy (ESI-MS). All the compounds are soluble in DMSO and DMF. Spectroscopic studies show that the ligand coordinates to the metal center through the azomethine nitrogen, naphthoxide oxygen, and thiophenoxide sulfur to form a tridentate chelate system. Conductance measurements show that these compounds are molecular in solution. Cyclic voltammetry studies show Co(III)/Co(II) and Cu(II)/Cu(I) redox systems to be quasi-reversible involving a monoelectronic transfer while Ni(III)/Ni(II) was irreversible. In vitro antibacterial and antifungal activity against five bacterial strains (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Enterococcus faecalis, and Proteus mirabilis) and five fungal strains (Candida albicans, Candida glabrata, Candida tropicalis, Candida krusei, and Candida parapsilosis) showed no antifungal activity but moderate antibacterial activity on E. coli, S. aureus, P. aeruginosa, and P. mirabilis bacterial strains. Antioxidant studies reveal that the ligand and its Cu(II) complex are more potent than Co(II) and Ni(II) complexes to eliminate free radicals.

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Pan, Liao, Meiying Zhang, Lixin Lu, Bingxian Ou y Xi Chen. "A Polyethylene Base Moisture Activating Oxygen Scavenging Film Co-Extruded with Tea Polyphenols-β-Cyclodextrin Inclusion Complex". Materials 13, n.º 17 (1 de septiembre de 2020): 3857. http://dx.doi.org/10.3390/ma13173857.

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Antioxidant packaging is an effective method to protect oxygen-sensitive food from oxidation. In order to concurrently obtain a storage stability and excellent oxygen scavenging of antioxidant film for the high moisture food, a moisture activating oxygen scavenging film was prepared by using tea polyphenols as the oxygen scavenger. The moisture activating function was achieved by introducing the β-cyclodextrin embedding technology, and the tea polyphenols–β-cyclodextrin inclusion complex was co-extruded with low-density polyethylene (LDPE) to improve the storage stability. The results indicate that the tea polyphenols is well embedded by β-cyclodextrin according to the Fourier transform infrared spectra (FT-IR), and a relatively homogeneous dispersion of oxygen scavenger is observed while the oxygen scavenger content is less than 5%. The oxygen scavenging increases with the increase of oxygen scavenger from 1% to 5%, and a maximal oxygen absorption of 0.0150 mol/m2 is exhibited at oxygen scavenger content value of 5%. Then, the oxygen scavenging significantly decrease under the oxygen scavenger content of 7% and 10%. Moreover, the oxygen scavenging amount sharply increase after steeping in water or storage in extremely high humidity of RH 84% while the oxygen scavenging is restrained under RH 32–75%, indicating that the moisture activating oxygen scavenging is functioning. The oxygen scavenging is obvious restrained under low temperature of 4 °C while the oxygen scavenging is activated at 23 °C and 50 °C with similar oxygen scavenging amount. Besides, both of the tensile and heat-sealing strength deteriorative with the increase of oxygen scavenger content, while they are acceptable at oxygen scavenger content of 5%. Finally, the prepared oxygen scavenging film was used for packaging orange juice and received a good antioxidant effect. Thus, the acquired moisture activating oxygen scavenging film has a good stability under regular storage condition, and shows a potentially application for oxygen-sensitive food with high moisture content.

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Nguyen Ngoc, Tue y Trung Nguyen Duc. "Co(II), Cu(II) and Zn(II) complexes of tridentate ONO donor Schiff base ligand: A DFT studies". Vietnam Journal of Catalysis and Adsorption 11, n.º 2 (10 de julio de 2022): 29–33. http://dx.doi.org/10.51316/jca.2022.025.

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A series of Cu(II), Co(II), and Zn(II), mononuclear Schiff base complexes were studied and characterized by DFT calculations. The ligand was derived from the experiment of condensing 5-acetyl-4-hydroxy-2H-1,3-thiazine-2,6(3H)-dione with o-phenylenediamine. The Schiff base ligand has coordination sites on phenolic oxygen, azomethine nitrogen, and amino group nitrogen, where it behaves as a monobasic tridentate. All studied structure was constructed based on the ration 1:1 (metal: ligand) stoichiometry. Except for the Cu(II) complex, which exhibited a square planar arrangement, the metal complexes exhibited octahedral geometry. The Orca quantum program's Density Function Theory (DFT) level was used to optimize the structure and several structural parameters of the ligand and its metal complexes, including total energy, HOMO, LUMO, and dipole moment. Correlations were established between the calculated and experimental data.

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He, Qinggang, Xiao Cheng, Ying Wang, Ruimin Qiao, Wanli Yang y Jinghua Guo. "Electrochemical and spectroscopic characterization of a dicobalt macrocyclic Pacman complex in the catalysis of the oxygen reduction reaction in acid media". Journal of Porphyrins and Phthalocyanines 17, n.º 04 (abril de 2013): 252–58. http://dx.doi.org/10.1142/s1088424612501490.

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The dicobalt complex [ Co2(L2) ] of a Schiff-base pyrrole macrocycle adopts a Pacman structure in solution and the solid state and shows much greater catalytic activity and selectivity for the four-electron oxygen reduction reaction (ORR) than the mononuclear cobalt phthalocyanine (CoPc) counterpart. Soft X-ray absorption spectroscopy (XAS) shows that the Co center in Co2(L2) is of the same valence as mononuclear CoPc . However, the former complex shows higher unoccupied Co 3d density which is believed to be beneficial for electron transfers. Furthermore, the XAS data suggests that the crystal fields for Co2(L2) and CoPc are different, and that an interaction remains between two Co atoms in Co2(L2) . DFT calculations imply that the sterically hindered, cofacial structure of the dicobalt complex is critical for the operation of the four-electron reaction pathway during the ORR.

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35

Nagasawa, iroki y Youichi Yanagawa. "An Analysis of Patients With Carbon Monoxide Poisoning Transported by a Physician-Staffed Helicopter". Academic Journal of Life Sciences, n.º 57 (25 de julio de 2019): 43–47. http://dx.doi.org/10.32861/ajls.57.43.47.

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OBJECTIVE: We retrospectively investigated a series of patients with carbon monoxide (CO) poisoning transported by a physician-staffed helicopter (DH) to seek evidence supporting the daily management of patients with CO poisoning. STUDY DESIGN: Subjects were divided into two groups: the carboxyhemoglobin saturation (SpCO) (+) group, which included patients who had a pulse CO-oximeter attached during transportation; and the SpCO (-) group, which included all other patients. We compared the level of SpCO before and after transportation when the level was noted. RESULTS: The subjects were predominantly middle-aged and male. Seventeen subjects (53.1%) received a diagnosis of CO poisoning based on the situation in which the subjects were found, without the carboxyhemoglobin level being measured. No subjects show deterioration of their condition after transportation, and none ultimately died. The frequency of male gender, normobaric oxygen treatment and return to the base hospital in the SpCO (+) group was significantly greater than in the SpCO (-) group. The SpCO levels after transportation were significantly lower than they had been before transportation. CONCLUSION: This is the first study to show the results of the analysis of patients with CO poisoning transported by the DH. All patients with CO poisoning were safely transported.

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Ali apan, Ali apan, Erdal Canpolat Erdal Canpolat y Henar Sleman and Niyazi Bulut Henar Sleman and Niyazi Bulut. "A Density Functional Theory Study of 3,5-dichlorosalicyliden-p-iminoacetophenone oxime Complexes with Co, Ni, Cu and Zn Metals". Journal of the chemical society of pakistan 41, n.º 5 (2019): 770. http://dx.doi.org/10.52568/000794/jcsp/41.05.2019.

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In this work, new Schiff baz ligand was synthesized by reaction of p-iminoacetophenone oxime with 3,5-dichlorosalicylaldehyde. Metal complexes of Co+2, Ni+2, Cu+2 and Zn+2 acetate metal salts were synthesized with this ligand. The ligand and complexes are characterized in experimental by their elemental analyses, X-ray, 1H-NMR, 13C-NMR, UV-Vis, FT-IR, magnetic susceptibility and thermogravimetric analyses (TGA) and also have been investigated by using quantum mechanical methods. The transition metals are coordinated to the schiff base through the azomethine nitrogen and the carboxyl oxygen atom. Obtained metal complexes were studied the magnetic properties and their geometries were determined. Co+2, Ni+2 and Zn+2 complexes have been found tetrahedral geometry and Cu+2 complex has been found four coordinated geometry.

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Maffi, Lidio, Matteo Paganini, Giuliano Vezzani, Antonios Soumelis, Enrico M. Camporesi y Gerardo Bosco. "Hyperbaric Oxygen Treatment for Carbon Monoxide Poisoning in Italy: Retrospective Validation of a Data Collection Tool for the Italian Registry of Carbon Monoxide Poisonings (IRCOP)". International Journal of Environmental Research and Public Health 17, n.º 2 (16 de enero de 2020): 574. http://dx.doi.org/10.3390/ijerph17020574.

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Background: Carbon Monoxide (CO) poisoning is a frequent cause of intoxication. However, CO poisoning incidence is globally underreported, as well as its features, especially in Italy. The aim of this study was to investigate such characteristics of CO intoxication and foster the creation of the Italian Registry of Carbon Monoxide Poisonings. Methods: A data collection tool was developed and organized in five sections: Patient’s characteristics; CO intoxication modality; emergency medical service and emergency department; hyperbaric facility; outcomes. The tool was validated through a retrospective analysis, including CO intoxicated patients treated in 14 Italian hyperbaric facilities between 2015 and 2016. Results: A total of 1383 patients were included. The high completion ratio (85%) of the collection tool suggests its feasibility in practical terms. CO intoxications were mostly accidental (93.64%) and caused by solid fuel (48.59%). There was not a uniform application of hyperbaric oxygen treatment protocols, but most of the patients were adequately treated at least at 2.5 ATA for more than 60 min (44.97%). Conclusion: This analysis provided new information that was previously unavailable in this country. Furthermore, this tool proved to be a valid base for future registry aiming to consolidate the body of knowledge about CO intoxications in Italy.

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Lin, Xiaoqing, Xinzhe Li, Feng Li, Yiyun Fang, Min Tian, Xingcai An, Yan Fu, Jun Jin y Jiantai Ma. "Precious-metal-free Co–Fe–Ox coupled nitrogen-enriched porous carbon nanosheets derived from Schiff-base porous polymers as superior electrocatalysts for the oxygen evolution reaction". Journal of Materials Chemistry A 4, n.º 17 (2016): 6505–12. http://dx.doi.org/10.1039/c5ta10039a.

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Co–Fe nanoparticles coupled nitrogen-enriched porous carbon (Co_yFe_10−yO_x/NPC) nanosheets were successfully synthesized and used as highly effective electrocatalysts for the oxygen evolution reaction (OER).

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Sree Devi, R. K. y S. SudhaKumari. "Synthesis, Characterization and Antimicrobial studies of Schiff base Ligand from amino acid L-arginine and its Cu(II), Ni(II),Co(II) complexesIJCTR.2019.130201". International Journal of ChemTech Research 13, n.º 2 (2020): 1–8. http://dx.doi.org/10.20902/ijctr.2019.130201.

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Transition metal complexes of Cu(II), Ni(II), Co(II) with a Schiff base Ligand (R,Z)-2-(2-hydroxy-3-methoxybenzylideneamino)-5-guanidinopentanoic acid (HMA-GPA) was synthesized by the condensation of 2-hydroxy-3-methoxybenzaldehyde and L- Arginine. These were characterized by elemental analysis IR, UV, magnetic susceptibility and molar conductivity measurements. The IR spectra of the Ligand HMA-GPA and the metal complexes suggest that the Ligand coordinates the metal ion through azomethine nitrogen, carboxylate Oxygen and Oxygen of the phenolic -OH group. The electronic absorption spectra and magnetic data indicate the Cu(II), Ni(II)complexes to be square planar and Co(II) complex to be octahedral. The metal complexes and the ligand were subjected to antimicrobial studies by Kirby Bayer Disc-diffusion method and found to have significant activity against the selected bacterial and fungal strains under study.

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40

Hosny, Nasser, Reyad Ibrahim y Ahmed El-Asmy. "Spectral, thermal, optical and biological studies on (E)-4-[(2-hydroxyphenyl)imino]pentan-2-one and its complexes". Journal of the Serbian Chemical Society 81, n.º 1 (2016): 57–66. http://dx.doi.org/10.2298/jsc150201058h.

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Metal complexes derived from the reaction of Cu(II), Co(II), Ni(II) and Zn(II) acetates and (E)-4-(2-hydroxyphenylimino)pentan-2-one (H2L) have been synthesized and characterized by elemental analyses, MS, IR, UV-Vis., 1H NMR, thermal analyses (TGA and DTG) and magnetic measurements. In all complexes except for Zn(II) complex, the Schiff base ligand acts as a mono-negative tridentate (NOO) donor, through the azomethine nitrogen, the hydroxyl oxygen and the enolic carbonyl oxygen. The structure of the Cu(II) complex is square-planar, the Co(II) is octahedral while, the Ni(II) and Zn(II) are tetrahedral. The optical band gap measurements indicated a semi-conducting nature of these complexes. The biological activities have been screened against two bacteria and two fungi. Some of the studied complexes showed activity against bacteria and fungi.

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41

Shekhawat, A. S., N. P. Singh y N. S. Chundawat. "Synthesis, Characterization and Biological Activities of Schiff's Base Metal Complexes Derived from Hydroxy Trizene and Aromatic Aldehyde". Journal of Scientific Research 14, n.º 1 (1 de enero de 2022): 387–94. http://dx.doi.org/10.3329/jsr.v14i1.54814.

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Schiff's bases are one of the important classes of the ligands, which are obtained by the condensation of amine and aromatic aldehyde. The metal complexes of Schiff's bases are widely considered because they show excellent biological activities. Such as antimicrobial, antitumor, antibacterial, and anti-fungal properties. The present studies deal with synthesis and characterization of Schiff's base transition metal complexes synthesized from general formula (ML) M=Co(II) and Cu(II); L = Schiff's base ligand derived from hydroxy trizene and aromatic aldehyde. The Synthesized complexes were characterized by physical and spectral analysis such as FTIR, 1HNMR, and XRD. They were also tested in vitro biological activities. The Schiff base behaves as a bidentate ligand with O and N donors and binds to metal ions via hydroxy group oxygen and azomethane nitrogen. The Schiff's base ligands and Metal complexes' structure was confirmed by modern instrumental techniques viz, FTIR and 1HNMR. The in-vitro antibacterial studies were carried out against S. aureus, E. coli, and P. Aeruginosa and anti-fungal activities C.albicans, A. clavatus. The result shows that the complexes have excellent biological activities.

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42

Yu, Anthony S., Tae-Sik Oh, Ran Zhu, Alexa Gallegos, Raymond J. Gorte y John M. Vohs. "Surface modification of La0.8Sr0.2CrO3−δ–YSZ dual-phase membranes for syngas production". Faraday Discussions 182 (2015): 213–25. http://dx.doi.org/10.1039/c5fd00007f.

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Oxygen permeation fluxes were studied in Mixed Ionic and Electronic Conducting (MIEC) membranes based on composites of 40 vol% La_0.8Sr_0.2CrO₃ (LSCr) and 60 vol% yttria-stabilized zirconia (YSZ), using ambient air and flowing CO to establish a P(O₂) gradient. The ambipolar conductivity of the dense LSCr–YSZ composite was determined for membranes with dense layers that were 115 μm and 650 μm thick. Other parts of the investigation focused on how modifications to the surface on the CO side affected the fluxes. Using a porous LSCr–YSZ composite on the surface as the base case, oxygen fluxes were shown to increase dramatically upon addition of 5 wt% CeO₂ as a catalyst and an additional increase was observed with 1 wt% Pt. Changes in the structure of the porous composite LSCr–YSZ surface to improve connectivity of the YSZ phase also led to large increases in the oxygen fluxes.

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43

Gokulnath, G., P. Anitha, R. Manikandan y C. Umarani. "Synthesis, Spectral Characterization and Biological Evaluation of Metal Complexes of 2-Thioxoquinoline Aminophenol". Asian Journal of Chemistry 33, n.º 6 (2021): 1439–46. http://dx.doi.org/10.14233/ajchem.2021.23233.

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A series of novel 2-thioxoquinoline aminophenol Schiff base based Co(II), Ni(II), Cu(II) and Zn(II) metal complexes [M(L)2], (M = Co2+, Ni2+, Cu2+ & Zn2+; L = 2-thioxoquinoline aminophenol) were synthesized and characterized by elemental analysis and spectral studies (FT-IR, UV-Vis, 1H NMR, ESR and ESI-Mass). All experimental results showed that in these metal complexes, the central metal atom was coordinated by oxygen, nitrogen and sulfur donor atoms of deprotonated Schiff base. Further, the ligand and its metal(II) complexes were screened against Gram-positive (Staphylococcus aureus), Gram-negative (Escherichia coli) bacteria and fungus (Candida albicans) strains. in vitro Anticancer activity of ligand and its metal(II) complexes were also screened against HeLa cells (Human cervical cancer cells).

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44

Jiang, Jian, Yao Liu, Bo Liu, Yijin Wang y Zhonglu You. "Synthesis, Crystal Structures and Urease Inhibition of Zinc Complexes Derived from 4-Chloro-2-(((2-(pyrrolidin-1-yl) ethyl)imino)methyl)phenol". Acta Chimica Slovenica 70, n.º 1 (20 de marzo de 2023): 139–47. http://dx.doi.org/10.17344/acsi.2022.7969.

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Three new zinc(II) complexes, [Zn3(μ2-η1:η1-OAc)2(μ2-η2:η0-OAc)2L2] (1), [Zn3(μ2-η1:η1-OAc)2(μ1,1-N3)(N3)L2] (2), [Zn2(μ1,3-N3)(N3)(H2O)L2] (3), with the Schiff base ligand 4-chloro-2-(((2-(pyrrolidin-1-yl)ethyl)imino)methyl)phenol (HL) have been synthesized and characterized by elemental analysis, IR and UV-Vis spectroscopic studies. Crystal structures of the complexes were confirmed by single crystal X-ray diffraction. Complex 1 is a bidentate acetato, monoatomic bridging acetato, and phenolato co-bridged trinuclear zinc compound. The Zn atoms are in octahedral and square pyramidal coordination. Complex 2 is a bidentate acetato, end-on azido, and phenolato co-bridged trinuclear zinc compound. The Zn atoms are in trigonal bipyramidal and square pyramidal coordination. Complex 3 is an end-to-end azido bridged dinuclear zinc compound. The Zn atoms are in square pyramidal and trigonal bipyramidal coordination. The Schiff base ligands in the complexes coordinate to the Zn atoms through the phenolate oxygen, imino nitrogen and pyrrolidine nitrogen. The complexes have interesting inhibitory activity on Jack bean urease, with IC50 values of 7.1–15.3 μmol·L–1.

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45

Basim H. Al-Zaid y Najat J. Al-Obaidi. "Synthesis and Spectral Studies of Cr(III), Mn(II), Co(II), Ni(II), Cu(II) and Cd(II) Complexes with New Bidentate (N,O) Schiff Base Ligand bearing an Oxime functional group". Journal of the College of Basic Education 20, n.º 86 (2 de febrero de 2023): 939–48. http://dx.doi.org/10.35950/cbej.v20i86.9733.

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The new Schiff base ligand has been prepared viacondensation reaction of o-aminoacetophenonoximeand3-Ethoxysalicylaldehyde. This ligand has been characterized by different techniques such as, (IR, U.V-Vis) spectroscopy, (1H, 13C) NMR spectra, GC-Mass spectrum and micro-elemental analysis. Its Cr(III), Mn(II), Co(II), Ni(II) and Cu(II) complexes prepared and characterized by (IR, U.V-Vis) spectroscopy, magnetic susceptibility, conductivity measurements and atomic absorption. The ligand acts as monobasic bidentate with (N,O) set donar and coordinates through phenolic group oxygen atom and imine azomethine nitrogen atom. Octahedral geometry structure proposed to Cr(III), Mn(II), Cu(II) and Cd(II) show, while tetrahedral and square planar structures were proposed to complexes of Co(II) and Ni(II), respectively.

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46

Gose, Ramamohan, Raju A. Jaya, N. Nagaraju y J. Sreeramulu. "Biological Studies and Spectroscopic investigation of 4-Methyl Benzylimine Schiff Base Metal Complexes". Research Journal of Chemistry and Environment 27, n.º 4 (15 de marzo de 2023): 39–45. http://dx.doi.org/10.25303/2704rjce039045.

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Primary benzyl amines are highly important building blocks in the pharmaceutical and polymer industry. A new Schiff base ligand named (4-Methyl benzyl 2-Hydroxy 5-NitroAceto) imine was prepared through condensation reaction of 4-Methyl Benzyl amine and 2-hydroxy 5-Nitro Acetophenone in 1:2 molar ratios. The new ligand was characterized by spectral techniques. The coordination behaviour of a series of transition metal ions named Mn(II), Co(II), Zn(II) and Cd(II) with the newly prepared Schiff base ligand is reported. From IR spectra, it was observed that the ligand is a neutral bidentate ligand which coordinates to the metal ions through protonated phenolic oxygen, azomethine nitrogen and nitrogen atom of NH2 group. The molecular structures of the Schiff base ligand and its metal complexes were optimized theoretically. The synthesized ligand and its complexes were screened for antimicrobial activities against bacterial species. It was found that the compounds have shown activity against the organisms like Candida albicans, Bacillus subtilis and Salmonella typhi.

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Sanin, Vitalii V., Maksym I. Aheiev, Yury Yu Kaplanskii, Pavel A. Loginov, Marina Ya Bychkova y Evgeny A. Levashov. "The Effect of Dopants on Structure Formation and Properties of Cast SHS Alloys Based on Nickel Monoaluminide". Materials 16, n.º 9 (22 de abril de 2023): 3299. http://dx.doi.org/10.3390/ma16093299.

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Alloys based on NiAl-Cr-Co (base) with complex dopants (base+2.5Mo-0.5Re-0.5Ta, base+2.5Mo-1.5Re-1.5Ta, base+2.5Mo-1.5Ta-1.5La-0.5Ru, base+2.5Mo-1.5Re-1.5Ta-0.2Ti, base+2.5Mo-1.5Re-1.5Ta-0.2Zr) were fabricated by centrifugal SHS metallurgy. The phase and impurity compositions, structure, mechanical properties, and the mechanism of high-temperature oxidation at T = 1150 °C were studied; the kinetic oxidation curves, fitting equations and parabolic rate constant were plotted. Al2O3 and Co2CrO4 were the major phases of the oxidized layer. Three layers were formed: I—the continuous Al2O3 layer with Co2CrO4 inclusions; II—the transitional MeN-Me layer with AlN inclusions; and III—the metal layer with AlN inclusions. The positive effect of thermo-vacuum treatment (TVT) on high-temperature oxidation resistance of the alloy was observed. The total weight gain by the samples after oxidative annealing decreased threefold (from 120 ± 5 g/m2 to 40 ± 5 g/m2). The phases containing Ru and Ti microdopants, which reduced the content of dissolved nitrogen and oxygen in the intermetallic phase to the values ∑O, N = 0.0145 wt.% for the base+2.5Mo-1.5Ta-1.5La-0.5Ru alloy and ∑O,N = 0.0223 wt.% for the base+2.5Mo-1.5Re-1.5Ta-0.2Ti alloy, were identified by transmission electron microscopy (TEM). In addition, with the significant high-temperature oxidation resistance, the latter alloy with Ti had the optimal combination of mechanical properties (σucs = 1644 ± 30 MPa; σys = 1518 ± 25 MPa).

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48

Yurchenko, D., L. Oleksenko, N. Maksymovych, G. Fedorenko y I. Matushko. "CARBON MONOXIDE ADSORPTION SEMICONDUCTOR SENSOR CREATED ON THE BASE OF THE NANOSIZED MATERIAL Pt/SnO2". Bulletin of Taras Shevchenko National University of Kyiv. Chemistry, n.º 1(55) (2018): 70–72. http://dx.doi.org/10.17721/1728-2209.2018.1(55).18.

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Nanosized material SnO2 was obtained by a sol-gel technique to create a sensor purposed for determination of carbon monoxide concentration in air. Platinum was added to the nanosized tin dioxide by a wet impregnation method using H2PtCl6 solution. According to TEM data the average size of the SnO2 particles in the obtained nanosized tin dioxide was equal to 10–11 nm. Sensor nanomaterials based on SnO2 and Pt/SnO2 powders which were sintered at 620°C in air atmosphere consisted of spheric particles with average sizes 20 and 14–15 nm, correspondingly. Phase compositions of the obtained nanomaterials were studied by the XRD method. Only a phase of cassiterite was detected for the nanomaterials with and without platinum. The absence of any reflexes of platinum-containing phases in the diffraction pattern of Pt/SnO2 is most likely due to the low content of platinum in the material. It was shown that dopping the nanosized SnO2 materials by platinum lead to increase their catalytic activities in the reaction of CO oxidation: the temperature of practically complete conversion of CO using Pt/SnO2 catalyst was equal to 110°С. The sensor created on the base of Pt/SnO2 nanomaterial was found to be more sensitive to CO than the one created without platinum in the range of its heater power consumption 0.25–0.45 W. High catalytic activity of the Pt/SnO2 nanomaterial in the reaction of CO oxidation is a reason of such sensor sensitivity increase. The dependence of the sensitivity of the sensor on the heater power consumption has a maximum that can be explained by the change of the amount of oxygen chemisorbed on the sensor gas sensitive layer when the sensor temperature is increased. The maximal sensor sensitivity to CO is γ = 10 at the optimal heater power consumption of the sensor (0.3 W). The created sensor to CO based on the nanomaterial Pt/SnO2 was found to be very fast. The response time of the sensor (τ0,9) was equal to 4,5 sec and the relax time (τrelax) was equal to 9.8 sec. It was shown that the created sensor based on nanomaterial Pt/SnO2 has high sensitivity to carbon monoxide and possess good dynamic properties, which makes the sensor to be promising for usage it in gas analytical devices purposed for determination of CO in air.

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Rasoulnia, Payam, Robert Barthen, Kati Valtonen y Aino-Maija Lakaniemi. "Impacts of Phosphorous Source on Organic Acid Production and Heterotrophic Bioleaching of Rare Earth Elements and Base Metals from Spent Nickel-Metal-Hydride Batteries". Waste and Biomass Valorization 12, n.º 10 (1 de marzo de 2021): 5545–59. http://dx.doi.org/10.1007/s12649-021-01398-x.

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AbstractThis study investigated heterotrophic bioleaching of rare earth elements (REEs) and base metals from spent nickel-metal-hydride (NiMH) batteries. Furthermore, the impacts of phosphorous source [Ca3(PO4)2, KH2PO4 and K2HPO4] and its concentration on organic acid production by Gluconobacter oxydans and Streptomyces pilosus were evaluated. Phosphorous source affected microbial acid production and metal leaching. Among the studied phosphorous sources, use of K2HPO4 resulted in highest organic acid production by both bacteria. Increasing K2HPO4 concentration from 2.7 to 27 mM enhanced pyruvic acid production by S. pilosus from 2.2 to 10.7 mM. However, no metal was leached from the spent NiMH batteries with S. pilosus using either one-step, two-step or spent-medium bioleaching. With G. oxydans, highest gluconic acid concentration of 45.0 mM was produced at the lowest K2HPO4 concentration of 2.7 mM. When using two-step bioleaching with G. oxydans, higher leaching efficiencies were obtained for base metals (88.0% vs. 68.0% Fe, 41.5% vs. 35.5% Co, 18.5% vs 16.5% Ni), while more REEs were leached using spent-medium bioleaching (9.0% vs. 6.0% total REEs). With both bioleaching methods, base metals leaching was faster than that of REEs. Surplus of phosphorous should be avoided in bioleaching cultures as precipitation especially with REEs is possible. Graphic Abstract

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Coetsee, Theresa y Frederik De Bruin. "Application of Unconstrained Cobalt and Aluminium Metal Powders in the Alloying of Carbon Steel in Submerged Arc Welding: Thermodynamic Analysis of Gas Reactions". Applied Sciences 12, n.º 17 (25 de agosto de 2022): 8472. http://dx.doi.org/10.3390/app12178472.

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The application of cobalt and aluminium powders in unconstrained format, not as metal powder in tubular wire nor as pre-alloyed powder, is used in this work to simplify weld metal alloying. The objective of this study is to demonstrate the application of unconstrained cobalt and aluminium powders in Submerged Arc Welding SAW to alloy the weld metal and to control the weld metal oxygen content. Aluminium powder is used to control the oxygen potential at the weld pool-slag interface in order to prevent oxidation of cobalt. The results presented here show that with the addition of Aluminium powder, 70% yield of Cobalt was achieved from the cobalt powder to the weld metal. The carbon steel base-plate material and weld wire materials combination were alloyed to 5.3% Co and 4.2% Al, whilst controlling the weld metal total oxygen content to 230 ppm. Thermodynamic analysis is applied to investigate the possible chemical interaction reactions between Co and Al compounds, as well as the role of the reactions on Co yield to the weld pool. The application of unconstrained metal powders ensures productivity gains in the overall SAW process because the time consuming and expensive manufacturing of alloyed wire and alloyed powder are eliminated.

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