- Magneto-structural study of an oxamato-bridged PdIICo II chain: X-ray crystallographic evidence of a single-crystal-to- single-crystal phase transition
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Two new mononuclear oxamato-containing palladium(II) complexes of formula K2[Pd(opba)]·2H2O (1) and (PPh4) 2[Pd(opba)]·2H2O (2) and the heterodimetallic palladium(II)-cobalt(II) chain {[Co(H2O)2Pd(opba)] ·dmso}n (3) [opba = 1,2-phenylenebis(oxamate), PPh 4+ = tetraphenylphosphonium cation and dmso = dimethyl sulfoxide] have been prepared, and the structures of two of them (compounds 2 and 3) were determined by X-ray diffraction analysis of single crystals. The structure of 2 consists of discrete anions of [Pd(opba)2] 2- and PPh4+ cations. Each PdII ion in 2 is surrounded by two oxamate nitrogen atoms and two carboxylate oxygen atoms in a square-planar surrounding. Compound 3 is a neutral chain with regular alternating PdII and CoII ions, the [Pd(opba)] 2- entity acting as a bis(bidentate) ligand towards trans-diaquacobalt(II) fragments, and dmso molecules of crystallization. Compound 3 exhibits a single-crystal-to-single-crystal phase transition between monoclinic C2/c (α phase) and triclinic P1 (β phase) space groups. Within the α phase the dmso molecule of crystallization is disordered, but it becomes ordered below 215 K in the β phase. The ordering process of the dmso molecule is followed by a reduction in the unit cell volume. The magnetic properties of 3 are barely affected by the structural phase transition, and they indicate an important spin-orbit coupling of the high-spin octahedral CoII ion [α = 1.245, λ =-151 cm -1, Δ = 494 cm-1, the spin Hamiltonian being defined as H =-αλLS + Δ(Lz2-2/3) + βH(-αL + geS)] with an almost negligible intra- [through the diamagnetic square-planar PdII centre] and interchain antiferromagnetic interactions (θ =-0.32 K).
- Oliveira, Willian X. C.,Ribeiro, Marcos A.,Pinheiro, Carlos B.,Nunes, Wallace C.,Julve, Miguel,Journaux, Yves,Stumpf, Humberto O.,Pereira, Cynthia L. M.
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- Preparation of Co2-xZnxMo3O8 mixed crystals with defined composition by chemical vapour transport
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Phase-pure powder samples of Co2-xZnxMo 3O8 mixed crystals were prepared by solid state reactions in evacuated quartz tubes at 1273 K. The lattice parameter were refined from X-ray powder pattern by the Rietveld method. A small but significant change of the lattice parameter of Co2-xZnxMo3O 8 as a function of the zinc content was observed, thus confirming the existence of a complete solid solution series. Single crystals of Co 2-xZnxMo3O8 were grown by means of chemical vapour transport in a temperature gradient 1273 K to 1173 K using NH4Cl or NH4Br as transport agent starting from a source material with a small oxygen excess, corresponding to a formal composition Co2-xZnxMo3O8.1 . The Co/Zn ratio of the obtained Co2-xZnxMo3O 8 single crystals was investigated using EDX measurements.
- Steiner, Udo,Reichelt, Werner,Daminova, Sofia,Langer, Enrico
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- Na10Co4O10, an oligooxocobaltate(II, III) with unusual magnetic properties
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The novel mixed-valent oligooxocobaltate can be synthesized through a direct reaction by the azide/nitrate route. The magnetic properties of the compound are characterized by the strongly distinct hierarchy in the magnetic exchange interactions within the complex anion (see picture).
- Sofin, Mikhail,Guedel, Hans-Ulrich,Bircher, Roland,Peters, Eva-Maria,Jansen, Martin
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- Syntheses, Characterization, and Antibacterial Property of Polynuclear Cobalt(III) and Copper(II) Complexes Derived from Similar Tridentate Schiff Bases
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An end-on azido-bridged trinuclear cobalt(III) complex [Co3(L1)2(μ1,1-N3)4(N3)2(OMe)(MeOH)] (I) and a phenolato-bridged dinuclear copper(II) complex [Cu2(L2)2(NCS)2] (II), where L1 is the deprotonated form of 2-((2-(dimethylamino)ethylimino)methyl)-4-fluorophenol, and L2 is the deprotonated form of 2-((3-(dimethylamino)propylimino)methyl)-4-fluorophenol, have been prepared and characterized by elemental analyses, IR and UV-Vis spectra, and single crystal X-ray diffraction (CIF files CCDC nos. 1023376 (I); 1023377 (II)). The Co atoms in complex I are in octahedral coordination, and the Cu atoms in complex II are in square pyramidal coordination. The antibacterial properties have been tested on some bacteria and yeast.
- Hao
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- Enhancing the electrocatalytic activity of CoO for the oxidation of 5-hydroxymethylfurfural by introducing oxygen vacancies
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The electrochemical oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) is a highly attractive strategy to generate valuable biomass-based oxygenated chemicals. Robust, stable and inexpensive electrocatalysts are crucial for this interesting reaction. In this work, we found that the electrocatalytic performance of cobalt oxide (CoO) could be significantly improved by introducing oxygen vacancies via Se doping. The resulting CoO-CoSe2 with a CoO/CoSe2 molar ratio of 23?:?1 showed excellent performance and stability for the electro-oxidation of HMF to FDCA, and a FDCA yield of 99% could be achieved with a faradaic efficiency of 97.9% at a potential of 1.43 V vs. RHE. A systematic study indicates that the introduction of rich oxygen vacancies could enhance the catalytic activity and the selectivity to FDCA by increasing the electrochemical surface area and reducing charge transfer resistance. As far as we know, this is the first work to develop a highly stable metal oxide as the active component for this reaction.
- Huang, Xin,Song, Jinliang,Hua, Manli,Xie, Zhenbing,Liu, Shuaishuai,Wu, Tianbin,Yang, Guanying,Han, Buxing
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- Non-isothermal dehydration and decomposition of dl-lactates of transition metals and alkaline earth metals: A comparative study
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A comparative study of the non-isothermal decomposition of the dl-lactate hydrates of magnesium, calcium and strontium has been made with that of the dl-lactate hydrates chromium(III), manganese(II), iron(II), cobalt(II), nickel(II), copper(II) and zinc(II) keeping dry air as the purge gas and the heating rate maintained at 10 K min-1. While the dl-lactates of manganese(II), cobalt(II) and copper(II) followed single step decomposition scheme suggesting that dehydration and decomposition steps overlapped, the dehydration steps of the other compounds were distinct. à-T plots of none of the dehydration steps showed any induction period, indicating no physical desorption, nucleation or branching. Neither the à max-values nor the onset temperatures of the dehydration steps did show any pattern. The TG data of the dehydration steps have also been analyzed using the Freeman-Carroll, Horowitz-Metzger, Coats-Redfern, Zsakó, Fuoss-Salyer-Wilson and Karkhanavala-Dharwadkar methods. Values of order of reaction, activation energy and Arrhenius factor have been approximated and compared. There are similarities in the activation energy values for the dehydration steps (-1 in general). It is higher with group 2 metals and lower in transition metals (maximum in magnesium and lowest in chromium and iron lactates). In cases of overlapping of dehydration and decomposition steps, the activation energy values are on the lower side with the same trend (lower in cobalt and copper cases).
- Verma,Verma,Chandra,Bhushan
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- Crystalline nanoflowers with different chemical compositions and physical properties grown by limited ligand protection
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(Figure Presented) A varied bouquet: Crystalline nanoflowers (see picture) of compounds with different chemical and physical properties, for example, In2O3, ZnO, CoO, MnO, and ZnSe, are grown by a new approach, limited ligand protection (LLP). LLP destabilizes the primary nanoparticles and promotes their three-dimensionally oriented attachment into complex nanostructures.
- Narayanaswamy, Arun,Xu, Huifang,Pradhan, Narayan,Peng, Xiaogang
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- Oxygen reduction reaction over (Ba,Sr)6RE2Co4O15-Ba(Ce,Pr,Y)O3composite cathodes for proton-conducting ceramic fuel cells
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In this study, the effect of elemental substitution, especially the Ba/Sr ratio and rare-earth elements, in (Ba,Sr)6RE2Co4O15(RE = La, Pr, Nd, Sm, Gd) and the composite effect with BaCe0.5Pr0.3/
- Eguchi, Koichi,Kamiuchi, Naoto,Kunimoto, Naoki,Manriki, Kohei,Matsui, Toshiaki,Miyazaki, Kazunari,Muroyama, Hiroki
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- Impact of gamma-ray irradiation on some aryl-amide-bridged Schiff-base complexes: spectral, TGA, XRD, and antioxidant properties
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Some aryl amide Schiff base Co(II), Ni(II) and Cu(II) distance between Cu(II) and complexes (1–7) have been obtained and identified by various analytical and spectroscopic tools. To through a light on the probability of structure changes with γ-irradiation, powder samples of complexes 1, 3, 5 and 6 were irradiated with 60Co γ-rays at dose of 100 kGy (hereafter referred to as 1F, 3F, 5F and 6F). Spectral, molar conductance, magnetic susceptibility, thermal, X-ray diffraction and antioxidant activity for the irradiated complexes were gained using similar methods used for the non-irradiated complexes. The data revealed that the irradiated complexes were not seriously affected by the utilized γ-irradiation dose.
- El-Boraey,El-Gammal,Abdel Sattar
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- Environmentally benign benzyl alcohol oxidation and C-C coupling catalysed by amide functionalized 3D Co(II) and Zn(II) metal organic frameworks
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The new 3D metal-organic frameworks (MOFs) [Co(1κN;2κOO′-μ-L)2]n.4n(DMF).1.5n(H2O) (1) and [Zn2(1κN;2κO-μ-L)2(κO4-μ4-BTC)]n.3n(DMF).2n(H2O) (2) [L = 4-(pyridin-4-ylcarbamoyl)benzoate; BTC = benzene-1,3,5-tricarboxylate] have been synthesized from the pyridyl amide functionalized benzoic acid (HL). They were characterized by elemental, FT-IR, powder X-ray and single crystal X-ray diffraction analyses. Topological analysis of 1 discloses a 2,3,7-connected trinodal net with a 4-connected uninodal net with 2-fold interpenetrating networks, whereas that of 2 shows a dia topology. The solid-state photoluminescent properties of HL and 2 were also investigated. The heterogeneous catalytic activity of 1 and 2, under eco-friendly conditions, was assessed in benzyl alcohol oxidation and C-C bond formation model reactions. 1 has good activity in the solvent-free microwave-assisted oxidation of benzyl alcohol to benzaldehyde using tert-butyl hydroperoxide (tBuOOH, TBHP) as oxidizing agent (yields up to 89%). Although with a lower activity, MOF 2 with a redox inactive Zn(II) site, also catalyses such alcohol oxidation, which is explained by DFT calculations according to a mechanism of a similar type to that followed by the peroxidative alkane oxidation. 2 is the most active one in the ambient temperature sonochemical Knoevenagel condensation of benzaldehyde and malononitrile (yields up to 94%) and in the ambient temperature Henry C-C coupling reaction of benzaldehyde with nitroethane in water (yields > 99%), showing appreciable diastereoselectivity towards the syn isomer. The recyclability of catalysts 1 and 2 was evaluated.
- Guedes da Silva, M. Fátima C.,Karmakar, Anirban,Kuznetsov, Maxim L.,Martins, Luísa M. D. R. S.,Novikov, Alexander S.,Paul, Anup,Pombeiro, Armando J. L.
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- Electrochemical investigation on nanoscale CoO as additive to the positive electrodes for Ni/MH rechargeable batteries
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The addition of CoO to the positive electrodes of Ni/MH rechargeable batteries provides excellent performance in terms of specific capacity and mean discharge voltage. CoO increases remarkably the active material utilization due to the formation of CoOOH
- Wu,Tu,Zhang,Huang
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- Thermal behaviour of malonic acid, sodium malonate and its compounds with some bivalent transition metal ions
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Characterization, thermal stability and thermal decomposition of transition metal malonates, MCH2C2O4·nH2O (M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II)), as well as, the thermal behaviour of malonic acid (C3H4O4) and its sodium salt (Na2CH2C2O4·H2O) were investigated employing simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), infrared spectroscopy, TG-FTIR system, elemental analysis and complexometry. The dehydration, as well as, the thermal decomposition of the anhydrous compounds occurs in a single step. For the sodium malonate the final residue up to 700 °C is sodium carbonate, while the transition metal malonates the final residue up to 335 °C (Mn), 400 °C (Fe), 340 °C (Co), 350 °C (Ni), 520 °C (Cu) and 450 °C (Zn) is Mn3O4, Fe2O3, Co3O4, NiO, CuO and ZnO, respectively. The results also provided information concerning the ligand's denticity, thermal behaviour and identification of some gaseous products evolved during the thermal decomposition of these compounds.
- Caires,Lima,Carvalho,Giagio,Ionashiro
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- Cobalt(II) and copper(II) complexes with carboxylic acids, imidazole, and 2-methylimidazole
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The compositions of [MIm(MeIm) x ]L complexes synthesized by the reaction of cobalt(II) and copper(II) fumarates ML · nH2O with imidazole (Im) and 2-methylimidazole (MeIm) were determined. The thermal decomposition of the salts was a
- Skorik,Filippova,Bukhol'Tseva,Mal'Kov,Kurzina
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- Non-isothermal decomposition of cobalt acetate tetrahydrate
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The non-isothermal decomposition of cobalt acetate tetrahydrate was studied up to 500°C by means of THE, DTG, DTA and DSC techniques in different atmospheres of N2, H2 and in air. The complete course of the decomposition is described on the basis of six thermal events. Two intermediate compounds (i.e.acetyl cobalt acetate and cobalt acetate hydroxide) were found to participate in the decomposition reaction. IR spectroscopy, mass spectrometry and X-ray diffraction analysis were used to identify the solid products of calcination at different temperatures and in different atmospheres. CoO was identified as the final solid product in N2, and Co3 O4 was produced in air. A hydrogen atmosphere, on the other hand, produces cobalt metal. Scanning electron microscopy was used to investigate the solid decomposition products at different stages of the reaction. Identification of the volatile gaseous products (in nitrogen and in oxygen) was performed using gas chromatography. The main products were: acetone, acetic acid, CO2 and acetaldehyde. The proportions of these products varied with the decomposition temperature and the prevailing atmosphere. Kinetic parameters (e.g. E and In A) together with thermodynamic functions (e.g.ΔH, Cp and ΔS) were calculated for the different decomposition steps.
- Mohamed,Halawy,Ebrahim
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- New Mn(II), Co(II), Ni(II) and Cu(II) homoleptic complexes with 6-chloro-5-7-dimethyl-4oxo-4H-chromene-3-carbaldehydes and its heteroleptic complexes with quinoline-8 ol: synthesis, characterization and antimicrobial activity
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In the present study, the synthesis of ligand 6-chloro-5-7-dimethyl-4oxo-4H-chromene-3-carbaldehydes by three steps from the substituted phenol. The formed product in the first step was further processed by fries rearrangement reaction and subsequently Vilsmeier–Haack reaction. Then, its homoleptic and heteroleptic complexes with Mn(II), Co(II), Ni(II) and Cu(II) metal ions by using second ligand quinolin-8-ol were synthesized. The ligand and complexes were characterized by different techniques, such as electron dispersive spectroscopy and elemental analysis (CHN), Fourier transform infrared (FTIR), electronic spectroscopy and magnetic susceptibility, 1H-Nuclear magnetic resonance spectroscopy and mass spectra of ligand, electron spin resonance (ESR), thermogravimetric analysis, powder X-ray diffraction, scanning electron microscopy (SEM) and molar conductivity. The spectroscopic analysis like NMR and the FTIR shows that the both ligands are bidentate in nature. The UV–visible spectra show the homoleptic complex of Cu(II) shows square planer, while M = Ni(II), Co(II) and Mn(II) shows octahedral in nature. While the complexes with heteroleptic ligands from square planer geometry with Cu(II) and Ni(II) while Co(II) and Mn(II) show octahedral geometries. The geometry was also supported by magnetic susceptibility and FTIR spectra. The ESR spectra of Cu(II) complexes shows both are square planer geometry and the G-value was more than 4 indicating the absence of exchange interaction between Cu(II) metal ions in the solid state. The powder X-ray diffraction was used to determine the crystal system of all the complexes, while supporting to this X-ray diffraction the SEM was also taken for the nanostructure of complexes was developed or not. Then, the solution state conductivity of the complexes shows electrolytic in nature. Further, these complexes were evaluated for its antimicrobial activity by agar well diffusion method and structure–activity relationship. The ligands show antimicrobial activity against S.typhi. The Ni(II) does not show antibacterial activity, while complexes Cu(II), Co(II) and Mn(II) shows good activity against the gram-positive and the gram-negative bacteria. The heteroleptic ligand complex (6) of Cu(II) shows higher antifungal activity as compared with Ni(II), Co(II) and Mn(II) complexes.
- Kolhe, Nitin H.,Jadhav, Shridhar S.,Thube, Dilip R.,Takate, Sushma J.,Bankar, Ashok V.,Moharekar, Sanjay T.,Pawar, Hari R.,Moharekar, Shubhangi S.
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- Oxidation of CoO studied with the perturbed angular correlation method
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The substages of the oxidation of CoO have been investigated with the PAC method during isochronal and isothermal annealings at low oxygen activity (10-9 atm). The successive trapping of cation vacancies at the 111In probe atoms up to the formation of spinel-like microclusters has been observed. The results of the PAC experiments are compared with those of X-ray diffraction and RBS analyses and confirmed by a PAC experiment for 111In in Co3O4. A quantitative analysis of the oxidation kinetics in terms of first order rate equations yields an activation enthalpy of ΔH = 0.27(4) eV. It is found that the absorption of oxygen and the formation of vacancies at the surface are the rate controlling processes in this experiment.
- Wegner,Inglot,Lieb
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- Insights into the active sites of ordered mesoporous cobalt oxide catalysts for the total oxidation of o-xylene
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Cobalt oxide is a typical transition metal oxide that exhibits high catalytic activity for the total oxidation of volatile organic compounds. In this study, a reduction process in a glycerol solution was adopted to generate mesoporous CoO (meso-CoO) or CoOx (meso-CoOx) from mesoporous Co3O4 (meso-Co3O4). The obtained samples were rich in Co2+ species and exhibited high catalytic activity for o-xylene oxidation. The meso-CoOx sample with the largest surface Co2+ amount performed the best: The o-xylene conversion at 240?°C was 83%, and the reaction rate over meso-CoOx was nine times higher than that over meso-Co3O4. It is found that the samples with more surface Co2+ species possessed better oxygen activation ability, and the Co2+ species were the active sites that favored the formation of highly active O2? and O22? (especially O2?) species.
- Xie, Shaohua,Liu, Yuxi,Deng, Jiguang,Yang, Jun,Zhao, Xingtian,Han, Zhuo,Zhang, Kunfeng,Dai, Hongxing
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- A Cobalt-Based Metal–Organic Framework as Cocatalyst on BiVO4 Photoanode for Enhanced Photoelectrochemical Water Oxidation
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A metal–organic framework (MOF)-modified bismuth vanadate (BiVO4) photoanode is fabricated by an ultrathin sheet-induced growth strategy, where ultrathin cobalt oxide sheets act as a metal source for the in situ synthesis of Co-based MOF poly[Co2(benzimidazole)4] (denoted [Co2(bim)4]) nanoparticles on the surface of BiVO4. [Co2(bim)4] with small particle size and high dispersion can serve as a promising cocatalyst to accept holes transferred from BiVO4 and boost surface reaction kinetics for photoelectrochemical (PEC) water oxidation. The photocurrent density of a [Co2(bim)4]-modified BiVO4 photoanode can achieve 3.1 mA cm?2 under AM 1.5G illumination at 1.23 V versus the reversible hydrogen electrode (RHE), which is better than those of pristine and cobalt-based inorganic materials-modified BiVO4 photoanodes. [Co2(bim)4], with porosity and abundant metal sites, exhibits a high surface charge-separation efficiency (83 % at 1.2 V versus RHE), leading to the enhanced PEC activity. This work will bring new insight into the development of MOF materials as competent cocatalysts for PEC water splitting applications.
- Zhang, Wang,Li, Rui,Zhao, Xin,Chen, Zhong,Law, Adrian Wing-Keung,Zhou, Kun
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- Spectroscopic and thermal studies of Mn(II), Co(II) and Ni(II) bromide m-methylaniline complexes
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The complexes of the MBr2L2 [M: Mn(II), Co(II) and Ni(II); L: m-methylaniline (mMA)] form have been prepared and characterized by their elemental analyses, thermogravimetric analyses, magnetic moment measurements, UV-vis, IR and Raman spectral studies. Elemental analysis suggests the stoichiometry to be 1:2 (metal:ligand). Thermal decomposition studies, using thermogravimetry show that the intermediate metal complexes are formed for complexes during their decomposition processes, the metal oxide being finally produced in each case. IR and Raman bands of the complexes have been assigned as compared with the free ligand. Coordination effects on the internal modes of mMA have been discussed. A polymeric octahedral geometry around metal ion with bridging bromides has been proposed for the Mn(II) and Ni(II) complexes, while tetrahedral geometry around Co(II) ion with C 2v symmetry is suggested for the Co(II) complex.
- Golcuk,Altun,Kumru
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- A cobalt (II)-based semiconductor complex with two-channel slow magnetic relaxation
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The hydrothermal reaction of 2-methylimidazole (hereafter abbreviated as 2-mim) with cobalt (II) sulfate heptahydrate in methanol affords a novel sulfate cobalt (II) complex with formula [Co(C4H6N2)4](SO4)?(H2O) (1). Its crystal structure was refined from X-ray diffraction data, complemented with the structural information derived from spectroscopic (IR and UV–Vis), thermal data and magnetic measurements. The crystal structure of 1 is made up of isolated [Co(2-mim)4]2+ cations, (SO4)2- anions and lattice water molecules. An extensive network of hydrogen bonds ensures the interconnection of the different entities. Greater knowledge on these interactions has been provided based on the Hirshfeld surface analysis and 2D fingerprint plots. Heating of 1 above 97 °C initiates gradual decomposition stages, which lead to the metal oxide as a final product at 710 °C, as proven by TGA/DSC analysis. A UV–Vis spectroscopy study confirms the tetrahedral environment around the metal. The determined bandgap energy Eg = 2.6 eV from the UV–Vis spectra indicate the interesting semiconducting behavior of our compound. Static magnetic measurements and EPR study revealed the presence of the easy-axis anisotropy with axial term D = –5.45 cm?1 and very small rhombicity, confirmed by the first-principle calculations. Complex 1 behaves as a field-induced single-ion magnet with two relaxation channels. The high-frequency relaxation can be described by the interplay of the two-phonon Orbach and Raman process, the relaxation barrier Ueff = 11.4 cm?1 agrees well with the difference between the two lowest Kramer's doublets.
- ?i?már, Erik,Hchicha, Khouloud,Kliuikov, Andrii,Korb, Marcus,Na?li, Houcine
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- Carboxylate clusters with the M4O4 cubane-like core: Pivalate cocrystal containing CoII and NiII
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Joint thermolysis of the dinuclear pivalate complexes M2(μ- H2O)(μ-Piv)2(Piv)2(HPiv)4 (M = Co (1) and Ni (2), Piv- is the pivalate anion), in decane at 174 °C at the reactant ratio 1: 1 followed by treatment of the dry thermolysis product with methanol afforded crystals of a new cocrystallization product of the molecules containing the heterometallic cubane-like core M4(Co,Ni) O4. According to the X-ray diffraction data and the results of magnetic measurements, inductively coupled plasma atomic emission spectrometry (ICP-AES), and investigations of the solid-state thermal decomposition products, the isolated cocrystallization product has the general formula [Co 1.6Ni2.4(μ3-OMe)4(μ 2-Piv)2(pg2 -Piv)2(MeOH) 4] ?4MeOH (3?4MeOH). Thermolysis of the crystals of the solvate 3?4MeOH is a destructive process accompanied by the intramolecular redox reaction. A mixture of metallic Ni and cobalt oxide (CoO) are the final solid decomposition products of 3 ? 4MeOH in an argon atmosphere, whereas a mixture of the phases NiO, Co3O4, and NiCo 2O4 is formed in air.
- Fomina,Dobrokhotova, Zh. V.,Aleksandrov,Kovba,Zhilov,Bogomyakov,Novotortsev,Eremenko
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- The mechanism and kinetics of thermal decomposition of Co3-xNixO4
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Thermal decomposition of Co3-xNixO4, x = 0.1, 0.15 and 0.2, at oxygen pressures 2.7-20.0 kPa at linearly growing temperature was examined. Decomposition of Co3-xNixO4 was found to be mixed-
- Prochowska-Klisch, Barbara,Malecki, Andrzej
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- CoO microspheres and metallic Co evolved from hexagonal α-Co(OH)2 plates in a hydrothermal process for lithium storage and magnetic applications
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CoO microspheres and metallic Co could be successfully synthesized by simply reacting cobalt acetate with a mixture solvent of ethylene glycol and deionized water in a hydrothermal process for different times. As the reaction proceeded, α-Co(OH)2, CoO and metallic Co were produced. To understand the phase evolution processes from α-Co(OH)2 to CoO and then metallic Co, a range of time-dependent experiments were carried out, and the intermediate products obtained at different reaction times were investigated in detail. The investigation revealed that CoO microspheres were actually evolved from α-Co(OH)2 as a precursor. Just elongating the reaction time, CoO microspheres could be further reduced to metallic Co. With a pure ethylene glycol medium for the same reaction, only α-Co(OH)2 could be generated, indicating an important role of water. When the obtained CoO microspheres were used as anode materials for lithium-ion batteries, they delivered a specific capacity of 803 mA h g-1 at 0.1 A g-1 with a retention of 453 mA h g-1 after 70 cycles. Meanwhile, the magnetic properties of the obtained CoO microspheres and metallic Co were investigated, with the CoO microspheres showing an antiferromagnetic behavior and the metallic Co exhibiting ferromagnetic characteristics. This study suggested a novel method for synthesizing CoO with a uniform microsphere morphology and bulk metallic Co easily.
- Ma, Keyuan,Liu,Yuan,Liu,Wang, Jun,Xie,Cheng
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- Effect of the Size and Shape on the Electrocatalytic Activity of Co3O4Nanoparticles in the Oxygen Evolution Reaction
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Co3O4 nanoparticles were size- and shape-selectively synthesized in a solvothermal approach by the thermal decomposition of either cobalt(II) acetylacetonate [Co(acac)2] or cobalt(II) nitrate [Co(NO3)2] in different solvents followed by calcination under air. Spherical, cubic, octahedral, and platelike nanoparticles with narrow size distributions and sizes ranging from 8 to 90 nm were formed in high yield. The nanoparticles were characterized by X-ray diffraction, scanning and transmission electron microscopy, energy-dispersive X-ray analysis, and X-ray photoelectron spectroscopy. The distinctive influence of the size and shape of the nanoparticles on the electrocatalytic activity in the oxygen evolution reaction is also demonstrated.
- Saddeler,Hagemann,Schulz
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- A thermal decomposition study on cobalt(II) complexes of 1,2-di(imino-4′-antipyrinyl)ethane
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The phenomenological, kinetic and mechanistic aspects of thermal decomposition of perchlorate, nitrate, chloride, bromide and iodide complexes of cobalt(II) with the Schiff base 1,2-di(imino-4′-antipyrinyl)ethane (GA) have been studied by TG and DTG analyses. The kinetic parameters like the activation energy, pre-exponential factor and entropy of activation were calculated. The decomposition reactions follow random nucleation with one nucleus on each particle - Mampel model .
- Madhu,Radhakrishnan,Grunert, Matthias,Weinberger, Peter,Linert, Wolfgang
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- Phase equilibria in the La2O3-Ga2O 3-CoO system at 1100°C
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The phase equilibria in the La2O3-Ga 2O3-CoO system have been studied at 1100°C in air, using samples prepared by a standard ceramic processing technique from oxides and by a glycine-nitrate combustion process. The composition ranges and structures of solid solutions in this system have been determined by x-ray powder diffraction: LaGa1-xCoxO3 (0 1-x Ga x O3 (0 4Ga2-xCox O9 (0 1-xGa2+xO4 (-0.20 ≤ x ≤ 0.05). The unit-cell parameters of the solid solutions vary little with composition, in accordance with the small difference in ionic radius between gallium and cobalt. The 1100°C section through the phase diagram of the La2O 3-Ga2O3-CoO system in air is presented.
- Guseva,Cherepanov
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- Thermal, spectral and magnetic properties of 3,5-dimethoxybenzoates of Co(II), Ni(II) and Cu(II)
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The complexes of 3,5-dimethoxybenzoates of Co(II), Ni(II) and Cu(II) have been synthesized as hydrated polycrystalline solids and characterized by elemental analysis, IR, FIR and electronic spectroscopy, magnetic studies and X-ray diffraction measurements. They possess colours typical of the M(II) ions: Cu-blue, Ni-green, Co-pink. The carboxylate groups bind as monodentate or a symmetrical, bidentate chelating or bridging ligands. The thermal stabilities were determined in air. When heated they dehydrate to form anhydrous salts which are decomposed to the oxides of respective metals. The magnetic susceptibilities of the complexes were measured over the range 77-300 K and the magnetic moments were calculated. The results reveal the complexes of Ni(II) and Co(II) to be high-spin complexes and that of Cu(II) to form dimer.
- Ferenc, Wieslawa,Walkow-Dziewulska, Agnieszka,Sadowski
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- Interparticle interactions in composites of nanoparticles of ferrimagnetic (γ-Fe2O3) and antiferromagnetic (CoO,NiO) materials
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The magnetic properties of mixtures of ferrimagnetic γ-Fe 2O3 (maghemite) and antiferromagnetic NiO or CoO nanoparticles have been studied by use of 57Fe Moessbauer spectroscopy, neutron powder diffraction and magnetization measurements. The studies showed that the interaction with antiferromagnetic particles has a significant influence on the magnetic properties of the γ-Fe 2O3 nanoparticles. It was found that mixing the γ-Fe2O3 nanoparticles with NiO nanoparticles resulted in a faster superparamagnetic relaxation and a reduced coercivity compared to a sample consisting solely of γ-Fe2O3 nanoparticles. On the contrary, mixing of γ-Fe2O3 nanoparticles with CoO nanoparticles resulted in a suppression of the relaxation and an increase in coercivity. These results suggest that the properties of the ferrimagnetic γ-Fe2O3 nanoparticles are influenced by the anisotropy of their neighboring antiferromagnetic particles. The dominating type of magnetic interaction between the particles in the composites seems to be exchange interaction between surface atoms of neighboring particles.
- Frandsen,Ostenfeld,Xu,Jacobsen,Keller,Lefmann,Morup
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p. 134416-1-134416-7
(2004)
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- Mesoporous CoO-supported palladium nanocatalysts with high performance for: O -xylene combustion
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The Pd-based catalysts have been widely studied for the combustion of volatile organic compounds, in which the roles of the Pd and the support are still not known clearly. In this study, mesoporous Co3O4 and CoO (i.e., meso-Co3O4 and meso-CoO) were prepared and used as support for the loading of Pd nanoparticles (NPs). The supported Pd samples performed much better than the supports for o-xylene combustion, in which the Pd/meso-CoO sample showed the best catalytic activity (T90% = 173 °C), giving rise to reaction rates at 170 °C 3.5 and 84 times higher than those over the Pd/meso-Co3O4 and meso-CoO samples, respectively. It has been established that the meso-CoO sample possessed strong ability to activate oxygen molecules to the active oxygen species, the loaded Pd NPs in a metallic Pd phase was beneficial for o-xylene adsorption, and the adsorbed o-xylene species could immediately react with the active oxygen species at the interface between Pd NPs and meso-CoO. Therefore, we conclude that the excellent catalytic performance of the Pd/meso-CoO sample was associated with its highly active Pd-CoO interface.
- Xie, Shaohua,Liu, Yuxi,Deng, Jiguang,Yang, Jun,Zhao, Xingtian,Han, Zhuo,Zhang, Kunfeng,Wang, Yuan,Arandiyan, Hamidreza,Dai, Hongxing
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- Cobalt(II) and silver(I) coordination polymers constructed from flexible bis(5,6-dimethylbenzimidazole) and substituted isophthalate co-ligands
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Two coordination polymers, [Co(L1)(IPA] n (1) and {[Ag(L2)(HMIPA)]·H2O} n (2) (H2IPA = isophthalic acid, L1 = 1,2-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene, H2MIPA = 5-methylisophthalic acid, L2 = 1,6-bis(5,6- dimethylbenzimidazol-1-yl)hexane, have been synthesized and characterized by physicochemical and spectroscopic methods, as well as single-crystal X-ray diffraction. In 1, six-coordinated cobalt centers are bridged by L1 and IPA 2- ligands to generate a (4,4) two-dimensional layer. However, complex 2 features a 1D chain structure, which is further extended by O-H···O hydrogen bonding interactions into a 2D supramolecular layer with (63) topology. The fluorescence and thermal gravimetric analysis of both complexes were also explored. Furthermore, the complexes 1 and 2 exhibit remarkable catalytic properties for the degradation of methyl orange dyes in a Fenton-like process.
- Yang, Rui,Van Hecke, Kristof,Yu, Bao Yi,Li, Guang Yue,Cui, Guang Hua
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- Atomically-thin non-layered cobalt oxide porous sheets for highly efficient oxygen-evolving electrocatalysts
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Water electrolysis for hydrogen production requires better catalysts to lower the kinetic barrier of the oxygen evolution reaction. Herein, conceptually-new, noble-metal-free, porous, atomically-thick sheets are first put forward as an excellent platform to promote the oxygen evolution activity through affording abundant catalytically active sites and enhanced two-dimensional conductivity. As an example, the synthetic porous Co 3O4 atomically-thick sheets with a thickness of 0.43 nm and about 30% pore occupancy afford low-coordinated Co3+ atoms to serve as the catalytically active sites, while the obviously increased density of states at the valence band and conduction band edge facilitate fast electron transport along their two-dimensional conducting paths. As a result, the porous, atomically-thick Co3O4 sheets exhibit an electrocatalytic current up to 341.7 mA cm-2, roughly 50-times larger than that of the bulk counterpart and even more strikingly higher than that of most existing reports under similar conditions. This work holds great promise for triggering breakthroughs in the field of electrocatalysis.
- Sun, Yongfu,Gao, Shan,Lei, Fengcai,Liu, Jiawei,Liang, Liang,Xie, Yi
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- Influence of solid corrodents on high-temperature oxidation of cobalt powder
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The oxidation of a fine cobalt powder mixed with solid corrodents was investigated in the air. NaCl, Na2SO4, CaCl2, mixture of NaCl with Na2SO4, mixture of NaCl with MgO, and mixtures of Na2SO4 with V2O5, MoO2 and Fe2O3, respectively, were chosen as corrodents. Thermoanalytical diagrams were recorded within the temperature range from 20 to 1200°C. It was stated that none of the corrodents induced the cobalt oxidation to start at a lower temperature. NaCl and mixture of NaCl with Na2SO4 accelerated the oxidation slightly but addition of MgO stopped this effect.
- Magdziarz,Suliga,Kalicka
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- Reversible single-crystal-to-single-crystal transformation and highly selective adsorption property of three-dimensional cobalt(II) frameworks
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A three-dimensional (3D) coordination polymer, [Co3(L) 2(BTEC)(H2O)2] · 2H2O [1, HL = 3,5-di(imidazol-1-yl)benzoic acid, H4BTEC = 1,2,4,5- benzenetetracarboxylic acid], with tfz-d topology has been hydrothermally synthesized. The framework of 1 has high thermal stability and exhibits single-crystal-to-single-crystal (SCSC) transformations upon removing and rebinding the noncoordinated and coordinated water molecules. X-ray crystallographic analyses revealed that the coordination geometry of Co(II) changes from octahedral to square pyramid upon dehydration, accompanying the appearance of one-dimensional (1D) open channels with dimensions of 2.0 × 2.8 A. The dehydrated form [Co3(L)2(BTEC)] (2) exhibits highly selective adsorption of water molecules over N2,CH 3OH, and CH3Ch2OH, which could be used as sensors for water molecules. Furthermore, the magnetic properties of 1 and 2 were investigated, showing the existence of ferromagnetic interaction between the Co(II) atoms within the trinuclear subunit.
- Su, Zhi,Chen, Min,Okamura, Taka-Aki,Chen, Man-Sheng,Chen, Shui-Sheng,Sun, Wei-Yin
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- Cation distribution in manganese cobaltite spinels Co3-x Mn x O4 (0 ≤ x ≤ 1) determined by thermal analysis
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Thermogravimetric analysis was used in order to study the reduction in air of submicronic powders of Co3-x Mn x O4 spinels, with 0 ≤ x ≤ 1. For x = 0 (i.e. Co3O4), cation reduction occurred in a single step. It involved the CoIII ions at the octahedral sites, which were reduced to Co2+ on producing CoO. For 0 III ions and the second was attributed to the reduction of octahedral Mn4+ ions to Mn3+. From the individual weight losses and the electrical neutrality of the lattice, the CoIII and Mn4+ ion concentrations were calculated. The distribution of cobalt and manganese ions present on each crystallographic site of the spinel was determined. In contrast to most previous studies that took into account either CoIII and Mn3+ or Co2+, CoIII and Mn4+ only, our thermal analysis study showed that Co2+/CoIII and Mn3+/Mn4+ pairs occupy the octahedral sites. These results were used to explain the resistivity measurements carried out on dense ceramics prepared from our powders sintered at low temperature (700-750 °C) in a Spark Plasma Sintering apparatus.
- Bordeneuve,Rousset,Tenailleau,Guillemet-Fritsch
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- Polymer complexes. LXIX. Some divalent metal(II) polymer complexes of potentially bidentate monomer N-[4-(5-methyl-isoxazol-3-ylsulfamoyl)-phenyl]-acrylamide: Synthesis, spectroscopic characterization, thermal properties, antimicrobial agents and DNA studies
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Monomer of N-[4-(5-methyl-isoxazol-3-ylsulfamoyl)-phenyl]-acrylamide (HL) and some transition metal polymeric complexes of the general formula {[M(HL)(OH2)2(OCOCH3)2] xH2O}n (M = Co(II), x = 2; Ni(II), x = 3; Mn(II), x = 2) and [Cd(HL)2(OCOCH3)2] were synthesized and characterized by elemental analysis, IR, UV spectroscopy, conductance measurements, magnetic susceptibility, thermogravimetric analyses and X-ray diffraction analysis. In all polymer complexes, the spectral data revealed that the ligand act as bidentate neutral molecule and coordinate to metal ion through enolic sulphonamide OH and isoxazol-N. In all polymer complexes, the spectral data revealed that the ligand act as bidentate neutral molecule and coordinate to metal ion through enolic sulphonamide OH and isoxazol-N. The molar conductance data revealed that the polymer complexes are non-electrolytes while UV-vis and magnetic measurements data have been shown that the polymer complexes have octahedral geometry. All the studies revealed coordination six for the metals in all the polymer complexes and octahedral structures were suggested. The inhibitive effect of HL against C38 steel was investigated in 2?M HCl solution (tafel polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) methods). The type of HL is mixed inhibitor whose adsorption habit onto C38 steel.
- El-Sonbati,Diab,Morgan, Sh.M.,Eldesoky,Balboula
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- Fractal porosity in metals synthesized by a simple combustion reaction
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A simple modification of a combustion method has been used for the production of ultraporous metals in air. Nitrates of different metallic elements were reacted with glycine as a reducing fuel. The glycine to nitrate ratio can be simply used to control the formation of oxides or, in the case of fuel-rich mixtures, the formation of metals such as Ni, Co, Cu or Ag. Furthermore, the metallic monoliths obtained present a remarkable porosity of fractal nature (from macro to nano scales) with pores ranging from many microns down to at least 5 nm. This exceedingly simple approach shows the way for the design and synthesis of complex porous microstructures of metals for the wide variety of applications where interface optimization is crucial.
- Gomez-Romero, Pedro,Fraile, Julio,Ballesteros, Belen
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- Hexagonal nanoplates of NiO/CoO/Fe2O3 composite acting as an efficient photocatalytic and electrocatalytic water oxidation catalyst
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A unique hexagonal sheet-shaped NiO/CoO/Fe2O3 composite with irregularly shaped nanoparticles was fabricated for the first time through a simple co-precipitation and hydrothermal method. The NiO/CoO/Fe2O3 composite was characterized by numerous techniques (TEM, HRTEM, PXRD, EDX, ICP-AES, BET, and XPS) to confirm its structure and composition. This structure of the NiO/CoO/Fe2O3 composite may enhance the photocatalytic and electrocatalytic performance for water oxidation. Compared with NiO, CoO and Fe2O3, the NiO/CoO/Fe2O3 composite exhibits a lower overpotential and a much smaller Tafel slope of 49 mV dec-1 for water oxidation. At the same time, the composite possesses beneficial ferromagnetic properties and superior stability; thus, it can be used repeatedly without any loss in activity.
- Zhao, Yukun,Zhang, Yan,Ding, Yong,Chen, Mindong
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- A thermal analysis study of some transition-metal dithizonates
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Solid dithizonates of Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II), have been prepared. Thermogravimetry (TG), derivative thermogravimetry (DTG), differential scanning calorimetry (DSC), X-ray diffraction powder patterns and elemental analysis have been used to characterize and study the thermal stability and thermal decomposition of these compounds.
- Chahud,Carvalho Filho,Fernandes,Zuanon Netto,Ionashiro
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- TG-MS and TG-FTIR studies of imidazole-substituted coordination compounds: Co(II) and Ni(II)-complexes of bis(1-methylimidazol-2-yl)ketone
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Co(II) and Ni(II) coordination compounds with bis(1-methylimidazol-2-yl) ketone (BIK) of general formula M(BIK)2X2 (M = Co or Ni; X = Cl or NO3) were synthesized and characterized by elemental analysis, by UV-vis and FTIR spectroscopies. Following our previous thermoanalytical studies on imidazole-substituted coordination compounds, the thermal behavior of the synthesized complexes was investigated by TG and DTG techniques: the thermal profile is always characterized by three substantial consecutive releasing steps for all the three complexes and the releasing supposed behavior is confirmed by EGA analysis (TG-MS and TG-FTIR). In particular, the first step is ascribed to the release of the two anions, followed by the loss of four methyl groups (side chains of the ligand) and two bridge-carbonyl groups. The residual Cobalt or Nickel tetra-imidazole complex decomposes in a final step to give the metal oxide as the final residue.
- Materazzi,Vecchio,Wo,De Angelis Curtis
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- Structural and thermal studies of some aroylhydrazone Schiff's bases-transition metal complexes
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Cobalt(II), nickel(II) and copper(II) complexes of some aroylhydrazone Schiff's bases derived from isoniazide (hydrazide of isonicotinic acid) with p-hydroxybenzaldehyde; 2,4-dihydroxybenzaldehyde or 2-hydroxy-1-naphthaldehyde are prepared and characteriz
- El-Boraey
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- Redox reaction and gas phase precipitation in the system In/Mn/O
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The oxidation of manganese metal with In2O3 occurs at approximately 973 K in evacuated silica ampoules. Thereby, the vapour transport species In2O(g) is being formed, which decomposes to indium metal and In2O3 at lower temperatures. Thermodynamic data as well as a description of the transport mechanism is given.
- Moeller, Angela,Schmidt, Peer,Fastje, Oliver
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- Synthesis, characterization, molecular docking, thermal degradation studies and biological screening of N-{[2-(pyridin-4-ylcarbonyl)hydrazinyl]carbonothioyl}furan-2-carboxamide and its Mn(II), Ni(II), Co(II), Cu(II) and Zn(II) complexes
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N-{[2-(Pyridin-4-ylcarbonyl)hydrazinyl]carbonothioyl}furan-2-carboxamide and its complexes with Ni(II), Co(II), Cu(II), Zn(II) and Mn(II) ions have been synthesized. The structure of the synthesized compounds was elucidated by elemental analysis, conductivity measurements, UV-visible, FT-IR, 1H NMR, powder XRD and thermal analysis studies. Most of metal complexes have exhibit thermal degradation between 80-750 °C and the powder X-rays diffraction data suggest that all the synthesized metal complexes were in nano crystalline phase. The computational molecular docking has been studied using Hex molecular modeling package version 8.2. The three dimensional structure of E. coli MurBenzyme (PDB code 2MBR) was used in microbial activity. The metal complexes showed comparable E total values with the standard drug tetracycline. The antioxidant and antimicrobial activity of prepared compounds indicate agreeable results versus bacterial strains three Gram-positive bacteria; S. aureus, S. pyogenes and P. acnes and three Gram-negative bacteria; E. coli, K. terrigena and K. pneumonia. The antifungal activity gave good results against fungal strains C. albicans, C. neoformans and Trichosporon.
- Yuvaraj,Parameshwara Naik,Krishnamurthy,Venkatesh,Mohammed Shafeeulla,Manjuraj,Venugopal
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- Cytotoxic effects, microbiological analysis and inhibitory properties on carbonic anhydrase isozyme activities of 2-hydroxy-5-methoxyacetophenone thiosemicarbazone and its Cu(II), Co(II), Zn(II) and Mn(II) complexes
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Metal complexes of thiosemicarbazones have been receiving considerable attention in biological applications such as antimicrobial and anticancer therapies. In this work, Co(II), Zn(II) and Mn(II) complexes of 2-hydroxy-5-methoxyacetophenone thiosemicarbazone (HMAT) were synthesized for the first time and characterized by EPR, FT-IR, NMR, UV–Vis spectroscopies, TG/DSC and elemental analysis. X-ray powder diffraction analysis was carried out for Zn(II) complex. HMAT and its Cu(II), Co(II), Zn(II) and Mn(II) complexes were tested as enzyme inhibitory agents. All compounds are effective inhibitor of cytosolic carbonic anhydrase I and II isoforms (hCA I and II) enzymes. IC50 values of HMAT and its Cu(II), Co(II), Zn(II) and Mn(II) complexes were determined as 93.35, 324.46, 25.67, 1.06 and 22.36?μM for CA I isozyme and 99.02, 86.64, 57.76, 10.34 and 36.48?μM for CA II isozyme, respectively. The evaluation of potential cytotoxic effects of the compounds was performed against normal epithelial breast mammary gland CRL-4010, estrogen-positive low metastatic MCF-7 and triple negative highly metastatic MDA-MB-231 breast adenocarcinoma cell lines by MTT assay. The results showed that the tested metal complexes have high cytotoxic effects than their ligand molecule. In particular, the Cu(II) complex displayed preciously high cytotoxic properties different from the others. Given these facts, the Cu(II) complex could be debated as potential chemotherapeutic molecule against drug-resistant breast cancer cells. Minimum inhibitory concentrations of the compounds against the test organisms were also detected for the microbiological analysis.
- Ucar, Asuman,Findik, Mukerrem,Kuzu, Muslum,Pehlivanoglu, Suray,Sayin, Ulku,Sayin, Zafer,Akgemci, Emine Guler
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- Study of the mixed conducting SrFeCo0.5Oy ceramic membrane material by in-situ neutron powder diffraction
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Dense ceramic tubes of the multi-phase mixed ionic/electronic conductor SrFeCo0.5Oy have been synthesized by solid-state reaction, and the stability of its component phases studied using in-situ neutron diffraction over the oxygen pa
- Mitchell,Richardson,Murphy,Ma,Balachandran,Hodges,Jorgensen
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- Three new coordination compounds based on 2-phenyl-4-quinolinecarboxylic acid and nitrogenous neutral ligands: Syntheses, structural features, and properties
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Solvothermal reactions of 2-phenyl-4-quinolinecarboxylic acid (Hpqba) with CdII, CoII, ZnII and/or 4,4′-bipyridyl (4,4′-bipy), 1,4-bis(imidazol-1-ylmethyl)benzene (biyb), 2,2′-bipyridyl (2,2′-bipy) afford three new coordination compounds of stoichiometries [Cd(pqba)2(4,4′-bipy)] (1), [Zn(pqba) 2biyb] (2), and [Co3(pqba)6-(2,2′-bipy) 2] (3). Compounds 1-3 were characterized by elements analysis, IR spectroscopy, thermogravimetry, and single-crystal X-ray diffraction study. Compound 1 has a two-dimensional structure, whereas compound 2 consists of a one-dimensional (1D) network, which is further expanded by π·· ·π stacking interactions to form a 3D supramolecular structure. Complex 3 also exhibits a 3D supramolecular structure completely based on π···π stacking interactions. The pqba ligands adopt μ1-k1,k1, μ1-k1, μ2-k1,k1, and μ2-k 1,k2 coordination modes for compounds 1, 2, and 3. The fluorescence properties were examined on compounds 1 and 2 in the solid state at room temperature. Magnetic susceptibility measurements indicate that in complex 3 antiferromagnetic coupling between adjacent CoII ions exist. Copyright
- Hou, Xiang-Yang,Wang, Xiao,Fu, Feng,Wang, Ji-Jiang,Tang, Long
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- KINETICS OF THERMAL DECOMPOSITION OF Co3O4 POWDER AND SINGLE CRYSTALS.
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Kinetics of thermal decomposition in vacuum of Co//3O//4 powder as well as single crystals has been investigated. Discrepancies with the results of previous authors have been discussed. Decomposition of Co//3O//4 proceeds through formation of a compact layer of CoO and hence diffusion is the rate-limiting factor. THe experimental curves alpha (t) can be described for 0. 05 less than alpha less than 0. 85 using a modified Ginstling-Brounshtein equation: 1 minus 2 alpha /3 minus (1 minus alpha )**2**/**3 equals kt**n where the activation energy varies with the degree of decomposition.
- Malecki,Tareen,Doumerc,Rabardel,Launay
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- Antibacterial and anticorrosion behavior of bioactive complexes of selected transition metal ions with new 2-acetylpyridine Schiff base
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Successful preparation of Schiff base 4-(4-aminophenoxy)-N-(1-(pyridin-2-yl)ethylidene)aniline derived from refluxing of 4,4-oxydianniline with 2-acetylpyridine within 2?h in 1:1 molar ratio was performed. Different transition metal complexes were synthesized by reacting metal chlorides with the formed ligand in 1:1 molar ratio. Structural features of the complexes were obtained from different tools such as infrared (IR), 1H-nuclear magnetic resonance (1H-NMR), ultraviolet–visible (UV-vis), molar conductivity, thermogravimetric (TG)/differential thermogravimetric (DTG), microanalysis, and mass spectrometry. All complexes had an octahedral structure and Schiff base acted as a neutral bidentate ligand that linked to metal centers via N-azomethine and N-pyridine atoms. Cr(III), Fe(III), and Ni(II) complexes were electrolytes while other complexes were nonelectrolytes. The molecular structure of Schiff base was optimized theoretically and its HOMO and LUMO energies were dictated by B3LYP/DFT calculations. The in vitro antibacterial activity versus some selected bacteria species showed that all prepared compounds were biologically active except Fe(III) complex against certain species and Co(II) complex had the highest biological activity values. Molecular docking was used to determine effective binding modes between ligand and its [Co(L)(H2O)2Cl2]·4H2O complex with active sites of 4WJ3, 4ME7, 4K3V, and 3T88 receptors. The strongest binding of Co(II) complex was with the 4ME7 receptor with lowest binding energy value ?25.4?kcal mol?1. Schiff base as corrosion inhibitors for mild steel in 1.0-M HCl had been investigated using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PP), and electrochemical frequency modulation (EFM). The results showed that the inhibitor acts as a mixed-type inhibitor. The inhibition efficiency increases with increasing inhibitor concentration to its maximum of 97.5% at 1?×?10?3?M solution. The adsorption model obeys the Langmuir isotherm, and Gibbs free energy was around ?40 kJ/mol, indicating that it is spontaneously and chemically adsorbed on the surface. SEM/EDX results proved the sticking of a barrier film on the mild steel sample.
- Ashmawy, Ashraf M.,Deghadi, Reem G.,Elsharkawy, Ahmed E.,Mohamed, Gehad G.
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- Band-gap engineering in novel delafossite-type multicomponent oxides for photocatalytic degradation of methylene blue
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A series of novel mixed oxides with honeycomb layered structure viz. delafossite-type Na3M2SbO6 (where M = Cu; Ni; Cu, Ni; Cu, Ni, Co; Cu, Ni Co, Fe; Cu, Ni Co, Fe, Mn) were synthesized by a facile method. The synthesis involved heating of the metal precursors at 1100 °C followed by air quenching. The structure was analogous to that of Na3Ni2SbO6 (space group: C2/m). The effect of increased entropy on the Jahn-Teller distortion effect, as previously reported in M = Cu system, was evident from the X-ray diffraction (XRD)/Rietveld structural analysis. The as-synthesized oxides showed photocatalytic activity as confirmed by the degradation of methylene blue. This was correlated to a drop in the optical band-gap from 2.41 to 1.96 eV on increasing the number of elements as well as its effect on the band energies are proposed here.
- Adigilli, Harish Kumar,Borse, Pramod H.,Gupta, Jyoti,Joardar, Joydip,Karati, Anirudha,Parida, Tripta
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- A novel high entropy spinel-type aluminate MAl2O4(M = Zn, Mg, Cu, Co) and its lithiated oxyfluoride and oxychloride derivatives prepared by one-step mechanosynthesis
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For the first time, a spinel-type high entropy oxide (Zn0.25Cu0.25Mg0.25Co0.25)Al2O4 as well as its derivative lithiated high entropy oxyfluoride Li0.5(Zn0.25Cu0.25Mg0.25Co0.25)0.5Al2O3.5F0.5 and oxychloride Li0.5(Zn0.25Cu0.25Mg0.25Co0.25)0.5Al2O3.5Cl0.5 are prepared in the nanostructured state via high-energy co-milling of the simple oxide precursors and the halides (LiF or LiCl) as sources of lithium, fluorine and chlorine. Their nanostructure is investigated by XRD, HR-TEM, EDX and XPS spectroscopy. It is revealed that incorporation of lithium into the structure of spinel oxide together with the anionic substitution has significant effect on its short-range order, size and morphology of crystallites as well as on its oxidation/reduction processes. The charge capacity of the as-prepared nanomaterials tested by cyclic voltammetry is found to be rather poor despite lithiation of the samples in comparison to previously reported spinel-type high entropy oxides. Nevertheless, the present work offers the alternative one-step mechanochemical route to novel classes of high entropy oxides as well as to lithiated oxyfluorides and oxychlorides with the possibility to vary their cationic and anionic elemental composition.
- Da Silva, Klebson Lucenildo,Kolev, Hristo,Lisnichuk, Maksym,Porodko, Olena,?epelák, Vladimír,Fabián, Martin,Girman, Vladimír,Vinar?íková, Monika,Zukalová, Markéta
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- Theoretical and Experimental Evaluation of the Reduction Potential of Straight-Chain Alcohols for the Designed Synthesis of Bimetallic Nanostructures
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Recently, the development of bimetallic nanoparticles with functional properties has been attempted extensively but with limited control over their morphological and structural properties. The reason was the inability to control the kinetics of the reduction reaction in most liquid-phase syntheses. However, the alcohol reduction technique has demonstrated the possibility of controlling the reduction reaction and facilitating the incorporation of other phenomena such as diffusion, etching, and galvanic replacement during nanostructure synthesis. In this study, the reduction potential of straight-chain alcohols has been investigated using molecular orbital calculations and experimentally verified by reducing transition metals. The alcohols with a longer chain exhibited higher reduction potential, and 1-octanol was found to be the strongest among alcohols considered. Furthermore, the experimental evaluation carried out via the synthesis of metallic Cu, Ni, and Co particles was consistent with the theoretical predictions. The reaction mechanism of metallic particle formation was also studied in detail in the Ni-1-octanol system, and the metal ions were confirmed to be reduced via the formation of nickel alkoxide. The results of this investigation were successfully implemented to synthesize Cu-Ni bimetallic nanostructures (core-shell, wire, and tube) via the incorporation of diffusion and etching besides the reduction reaction. These results suggest that the designed synthesis of a wide range of bimetallic nanostructures with more refined control has become possible.
- Ishijima, Masanao,Matsumoto, Takatoshi,Cuya Huaman, Jhon L.,Shinoda, Kozo,Uchikoshi, Masahito,Matsuo, Kohei,Suzuki, Kazumasa,Miyamura, Hiroshi,Balachandran, Jeyadevan
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p. 9432 - 9441
(2021/05/06)
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- Novel n-octadecylcarboxamide CoPc: amperometric detections for bioanalytes using modified GCE
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Here, we are reporting cobalt(II) phthalocyanine (CoPc) containing the active catalyst for the electrochemical investigations of bioanalytes. The synthesized tetra-n-octadecylcarboxamide cobalt(II) phthalocyanine was characterized by FT-IR, UV, TGA, mass and powder XRD analysis. In the present work, the synthesized complex was characterized by cyclic voltammetry and shows the redox behaviour corresponding to central metal (Co+II/Co+I) of the complex. Three biomolecules are well separated by their oxidation peaks in simultaneous detections of AA, DA and UA at 170, 350 and 550?mV with increasing high positive peak current. The low detection limit of AA, DA and UA was 40, 30 and 30?μmol by CV methods. The modified tetra substituted CoODAPc/GCE exhibits an excellent electrocatalytic activity, stability, high sensitivity, good linearity and selectivity without losing its catalytic activity and proves to be a versatile chemical sensor for commercial pharmaceutical samples, vitamin C tablets and dopamine injections. Graphic abstract: [Figure not available: see fulltext.]
- Mounesh,Venugopal Reddy,Nagaraja
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p. 2945 - 2956
(2021/02/22)
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- Enhancement of propane combustion activity over CoO: Xcatalysts by introducing C2-C5diols
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A series of nanocrystalline CoOx catalysts were synthesized by a citric acid complexation strategy. The effects of C2-C5 diols (including ethylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,5-pentadiol) on catalyst structure and propane combustion performance were investigated. The results showed that the structure of CoOx transformed from pure Co3O4 to mixed-phase CoO-Co3O4 with a larger surface area and smaller crystallite size after the introduction of diol compounds. Importantly, diol compounds effectively weaken the Co-O bond strength in nanocrystalline CoOx and enhance the activity of oxygen species, thus effectively degrading propane. Due to the weakest Co-O bond strength, excellent oxygen species activity, abundant oxygen vacancies, and the strongest redox ability, the catalyst prepared by adding 1,3-propanediol (Co-PDO) exhibited the best catalytic activity (T90 = 227 °C). Moreover, the increase in pore size, surface Co2+ and oxygen vacancy content of Co-PDO in the 40 h stability test can compensate for the loss of activity caused by the decrease in specific surface area, thereby maintaining stable catalytic activity.
- Liu, Zhao,Cheng, Lijun,Zhangxue, Shiyun,Huang, Min,Zeng, Jia,Yuan, Shanliang,Bo, Qifei,Zhang, Biao,Jiang, Yi
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p. 8795 - 8805
(2021/05/25)
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- Utilization and simulation of innovative new binuclear Co(ii), Ni(ii), Cu(ii), and Zn(ii) diimine Schiff base complexes in sterilization and coronavirus resistance (Covid-19)
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This article aimed at the synthesis and molecular docking assessment of new diimine Schiff base ligand, namely 2-((E)-(2-((Z)-2-(4-chlorophenyl)-2-hydroxyvinyl)hydrazono) methyl)-6-methoxyphenol (methoxy-diim), via the condensation of 1-(4-chloro-phenyl)-2-hydrazino-ethenol compound with 2-((E)-(2-((Z)-2-(4-chlorophenyl)-2-hydroxy vinyl) hydrazono)methyl)-6-methoxyphenol in acetic acid as well as the preparation of new binuclear complexes of Co(ii), Ni(ii), Cu(ii), and Zn(ii). The following synthesized complexes were prepared in a ratio of 2:1 (metal/ligand). The 1H-NMR, UV-Vis, and FTIR spectroscopic data; molar conductivity measurements; and microanalytical, XRD, TGA/DTG, and biological studies were carried out to determine the molecular structure of these complexes. According to the spectroscopic analysis, the two central metal ions were coordinated with the diamine ligand via the nitrogen of the hydrazine and oxygen of the hydroxyl groups for the first metal ions and via the nitrogen of the hydrazine and oxygen of the phenol group for the second metal ions. Molecular docking for the free ligand was carried out against the breast cancer 3hb5-oxidoreductase and the 4o1v-protein binding kidney cancer and COVID-19 protease, and good results were obtained.
- Alam, Kehkashan,Alsanie, Walaa F.,Gaber, Ahmed,Kobeasy, Mohamed I.,Refat, Moamen S.,Zakaria, Rozan
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p. 772 - 784
(2021/07/13)
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- Label-free and visible-light driven photoelectrochemical sensor with CuCo2O4@CoO Core-shell hybrid rod as photoanode for selective sensing diclofenac
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Diclofenac (DCF), the non-steroidal anti-inflammatory drugs (NSAIDs), remaining in environment as a heavily pollutants, the development of rapid and accurate method for sensing trace level DCF is urgent. Herein, a novel photoelectrochemical (PEC) sensing platform with CuCo2O4@CoO core-shell hybrid rods as photoanode was developed for rapidly sensing DCF without any additional recognition units. The Cu-based composite show specific interaction with carboxyl and imino group, it could selective absorbing and sensing DCF from other coexisting NSAIDs such as ibuprofen (IB), ketoprofen (KP) and flurbiprofen (FP) based on chelating ability and electrochemical activity. The synergistic effect of the well design core-shell structure combining close-connected heterojunction could enhance the sensitivity of the PEC sensor. The PEC response of the sensor was found to be linearly proportional to the concentration of DCF in the range from 10 nmol L-1 to 500 μmol L-1. The detection limit (3S/N) is 6.5 nmol L-1. The application of PEC sensor was evaluated by the determination of DCF in environment water samples, the spiked recoveries are in the range from 86.0 to 115.8%. The relative standard deviation (RSD) value of reproducibility and repeatability are less than 4.3 and 3.9%, showing excellent sensitivity, good reproducibility, repeatability and high stability. This strategy opens up a new avenue for the constructed high sensitivity and high selectivity PEC sensor.
- Jiang, Manci,Wang, Qiong,Zhang, Lei
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- Synthesis, Structure, DFT, and Biological Activity of Metal Complexes of Norfloxacin and Metformin Mixed Ligand
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Abstract: A new series of mixed ligand metal complexes has been synthesized by the reaction of Co(II), Ni(II), Cu(II), Zr(IV), Pd(II), and Cd(II) with norfloxacin (NOR) and metformin hydrochloride (MF) in 1 : 1 : 1 molar ratio. The complexes have been characterized by FT-IR, UV-Vis, and 1H NMR spectra, TG/DTG and elemental analysis, molar conductance, and magnetic susceptibility data. According to FT-IR, NOR chelates with metal ions as a bidentate ligand via one oxygen of the carboxylate group and pyridone oxygen, and MF chelates with metal ions via two imine groups. Complexes have been identified as electrolytes. Electronic and magnetic data have indicated the octahedral structure for all complexes except square planar Pd(II) complex. Antibacterial and antifungal activities of the compounds have been tested against several species, and have indicated higher inhibition against micro-organisms for the metal complexes than the mixed ligands.
- Abbass, L. M.,El-Shwiniy, W. H.,El-Telbany, M.,Sadeek, S. A.,Zordok, W. A.
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p. 1774 - 1782
(2021/11/01)
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- Comprehensively Probing the Contribution of Site Activity and Population of Active Sites toward Heterogeneous Electrocatalysis
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Due to the enormous demand for clean energy generation and for efficient energy storage, developing green and storable energy has become an urgent task. This subject, thus, stimulates studies on the improvement of new electrocatalysts. Specifically, through improving the population of active sites and/or the activity of individual sites, the performance of the catalysts can be significantly improved. However, clarifying the contribution of these two factors is still ambiguous and must be done with great care. To allow researchers in related fields to present their findings objectively, having a clear insight into the electrocatalytic activity is indispensable. In this study, a series of cobalt-based pre-electrocatalysts are taken as an example to examine their corresponding oxygen evolution reaction (OER) behaviors. Wherein, the three important metrics – electrochemical active surface area (ECSA)/roughness factor (RF), Tafel slope, and turnover frequency (TOF) – are used to profile the population of active sites of electrocatalysts and the activity of related individual sites. The results indicate the correction of OER behavior by ECSA/RF manifests the more accurate identification of OER activity. Meanwhile, the timing to obtain RF/ECSA significantly influence such an evaluation. Altogether, a fair benchmarking is proposed for the comparison between the activities of electrocatalysts.
- Chen, Hsiao-Chien,Chen, Tai-Lung,Lin, Sheng-Chih,Hsu, Chia-Shuo,Chan, Ting-Shan,Liao, Mei-Yi,Chen, Hao Ming
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p. 1926 - 1933
(2020/02/27)
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- Fabrication of Dandelion-like p-p Type Heterostructure of Ag2O@CoO for Bifunctional Photoelectrocatalytic Performance
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A novel three-dimensional purple dandelion-like hierarchical Ag2O@CoO heterojunction with an appropriate redox potential was constructed by chemical precipitation of Ag2O nanoparticle on flower-like CoO. By feat of this hierarchical structure, the Ag2O@CoO photocathode showed significantly high photoelectroreduction activities toward p-nitrophenol (p-NP) and Cr(VI). The high performance of Ag2O@CoO was mainly attributed to the specific structural characteristics and synergistic effect of each chemical component. This hierarchical structure could effectively increase the specific surface area, provide more exposed active edges, and be beneficial for multiple light reflection/scattering channels and light utilization efficiency. The introduction of Ag2O optimized the composition and further improved the band structure, resulting in an improved separation of photogenerated electrons and holes. The unique photocathode achieves a removal efficiency of 86% for photoelectrocatalytic p-NP degradation after 120 min and 95% for Cr(VI) after 40 min under visible light irradiation with excellent stability. This research provided a simple way for the synthesis of photoelectrocatalytic material with potential applications in the field of environmental governance with visible light illumination.
- Yang, Lijun,Hu, Yandong,Su, Mingming,Zhang, Lei
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p. 12357 - 12365
(2020/11/03)
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- Nano-Azo Ligand and Its Superhydrophobic Complexes: Synthesis, Characterization, DFT, Contact Angle, Molecular Docking, and Antimicrobial Studies
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Metal complexes of the 2,2'-(1,3-phenylenebis(diazene-2,1-diyl))bis(4-aminobenzoic acid) diazo ligand (H2L) derived from m-phenylenediamine and p-aminobenzoic acid were synthesized and characterized by different spectral, thermal, and analytical tools. The H2L ligand reacted with the metal ions Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) as 1: 1 stoichiometry. All complexes displayed an octahedral geometry according to the electronic and magnetic moment measurements. The IR spectra revealed the binding of the azo ligand to the metal ions via two azo nitrogen atoms and protonated carboxylate O in a neutral tetradentate manner. Both IR and 1H NMR spectra documented the involvement of the carboxylate group without proton displacement. The thermal studies pointed out that the complexes had higher thermal stability comparable with that of the free ligand. SEM images revealed the presence of the diazo ligand and its Cd(II) complex in a nanostructure form. The contact angle measurements proved that the Cd(II) complex can be considered as a superhydrophobic material. The molecular and electronic structure of H2L and [Cd(H2L)Cl2].H2O were optimized theoretically, and the quantum chemical parameters were calculated. The biological activities of the ligand, as well as its metal complexes, have been tested in vitro against some bacteria and fungi species. The results showed that all the tested compounds have significant biological activities with different sensitivity levels. The binding between H2L and its Cd(II) complex with receptors of the crystal structure of S. aureus (PDB ID: 3Q8U), crystal structure of protein phosphatase (PPZ1) of Candida albicans (PDB ID: 5JPE), receptors of breast cancer mutant oxidoreductase (PDB ID: 3HB5), and crystal structure of Escherichia coli (PDB ID: 3T88) was predicted and given in detail using molecular docking.
- Mahmoud, Walaa H.,Mohamed, Gehad G.,Refaat, Ahmed M.
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- Spectral and biological studies: Co(II), Ni(II), Cu(II), Zn(II) and Pd(II) complexes of 5-methyl-4-{(3-fluoro-4-methoxybenzylidiene)amino}-3-thiol-1,2,4-triazole
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A series of metal-complexes of Co2+, Ni2+, Cu2+, Zn2+ and Pd2+ with new Schiff base named 5-methyl-4-((3-fluoro-4-methoxybenzylidiene)-amino)-3-thiol-s-triazole have been synthesized and characterized. Schiff base is formed by the condensation of 3-fluoro-4-methoxy-benzaldehyde and 4-amino-3-mercapto-5-methyl-1,2,4-triazoles (AMMT). After synthesis, Schiff base is characterized by IR and NMR techniques. Metal complexes are characterized by different techniques as IR, NMR, ESR, electronic and fluorescence. Elemental analysis and magnetic measurements of metal complexes have also been carried out. Using different techniques, tentative geometry for newly synthesized complexes have been proposed i.e. square planar for copper and palladium complexes and octahedral for rest of the metal complexes. The biological activities of all the metal complexes of this series are also examined.
- Sharma, Amit,Singh, Kiran,Siwach, Preeti
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p. 3157 - 3164
(2021/01/06)
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- Lead(II)oxidotellurates(VI)with double perovskite structures
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Pb2BTeO6 (B = Co, Mn, Cd, Ca)and Pb7.47Sr3.53Te4O23 were synthesized by solid state reactions, starting from TeO2, and precursors of lead(II)oxide and the respective metal oxides. Structure determinations from single crystal X-ray data at room temperature revealed that Pb2CoTeO6 and Pb2CoTeO6 adopt the B site ordered cubic double perovskite aristotype (Z = 4, Fm3ˉm)whereas Pb2CdTeO6 and Pb2CaTeO6 crystallize as hettotypes thereof, with a reduction of the space group symmetry to C2/c and P21/c, respectively. Differential scanning calorimetry and temperature-dependent X-ray powder diffraction revealed reversible phase transitions around 270 °C for Pb2CdTeO6 and 225 °C for Pb2CaTeO6 to the cubic aristotype as the high-temperature phase. Pb7.47Sr3.53Te4O23 is a representative of a solid solution M11Te4O23 (M = Pb, Sr)with Sr2+ and Pb2+ cations occupationally disordered at the same sites in the cubic structure (Z = 8, Fm3ˉm). Its crystal structure can be described as an eightfold superstructure with all axes doubled in relation to the fully ordered double perovskite structure, and with cation vacancies at one of the B sites, anion vacancies at one of the O sites, and an additional O site in the structure. The relationships between the aristotype structure and the different hettotypes (Pb2CdTeO6, Pb2CaTeO6 and M11Te4O23 (or M2.75TeO5.75 with Z = 32))are concisely described with the aid of group-subgroup relations.
- Artner, Christine,Weil, Matthias
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- Synthesis-Controlled Polymorphism and Magnetic and Electrochemical Properties of Li3Co2SbO6
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Li3Co2SbO6 is found to adopt two highly distinct structural forms: a pseudohexagonal (monoclinic C2/m) layered O3-LiCoO2 type phase with honeycomb 2:1 ordering of Co and Sb, and an orthorhombic Fddd phase, isostructural with Li3Co2TaO6 but with the addition of significant Li/Co ordering. Pure samples of both phases can be obtained by conventional solid-state synthesis via a precursor route using Li3SbO4 and CoO, by controlling particle size, initial lithium excess, and reaction time. Both phases show relatively poor performance as lithium-ion battery cathode materials in their as-made states, but complex and interesting low-temperature magnetic properties. The honeycomb phase is the first of its type to show A-type antiferromagnetic order (ferromagnetic planes, antiferromagnetically coupled) below TN = 14 K. Isothermal magnetization and in-field neutron diffraction below TN show clear evidence for a metamagnetic transition at H ≈ 0.7 T to three-dimensional ferromagnetic order. The orthorhombic phase orders antiferromagnetically below TN = 112 K and then undergoes two more transitions at 80 and 60 K. Neutron diffraction data show that the ground state is incommensurate.
- Brown, Alex J.,Xia, Qingbo,Avdeev, Maxim,Kennedy, Brendan J.,Ling, Chris D.
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p. 13881 - 13891
(2019/10/16)
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- Transition metal complexes of nano bidentate organometallic Schiff base: Preparation, structure characterization, biological activity, DFT and molecular docking studies
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An organometallic NO-bidentate Schiff base, (2-(1-((1-carboxyethyl)imino)ethyl) cyclopenta-2,4-dien-1-yl)(cyclopenta-2,4-dien-1-yl) iron (HL) was synthesized by condensation of 2-acetylferrocene with amino acid alanine. Then its octahedral Cr (III), Mn (I
- Mahmoud, Walaa H.,Deghadi, Reem G.,El Desssouky, Maher M.I.,Mohamed, Gehad G.
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- Synthesis, spectral characterization, docking analysis, DNA binding/cleavage, antimicrobial and cytotoxic activity of new dimeric antipyrine-Schiff base metal complexes
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In the present study, a new series of novel Schiff base ligand derived from (furan-2-carbaldehyde and 4-aminoantipyrine) and dimeric metal(II) complexes with the composition of [MLCl2]2, where M=Cu(II), Co(II), Ni(II) and Zn(II) have been synthesized and characterized by elemental analysis, magnetic susceptibility, molar conductivity measurements, FT-IR, UV-visible, 1H NMR, 13C NMR, EPR, MS (ESI), XRD, SEM and EDX studies. The spectral data recommend that the dimeric metal complexes embrace octahedral geometry around the central metal ions. The DMF solutions of the dimeric metal complexes demonstrate the lower molar conductance values which might be due to the non-electrolytic nature of the complexes (5.67-13.24 ?-1 mol-1 cm-2). The biological studies involved are DNA interaction (binding and damage) antimicrobial, anti-proliferative and molecular docking. DNA interaction of these complexes carried out with using calf thymus DNA (CT-DNA) by electronic absorption titration, viscometric measurement which revealed that the synthesized dimeric complexes interact with DNA through intercalative binding mode. A gel electro-phoresis assay testifies the ability of complexes to cleave supercoiled pUC19 DNA in the presence of hydrogen peroxide as an activator. The synthesized compounds were initiated from their biological perspective. The antimicrobial assay indicates that dimeric complexes are good antimicrobial agents. Besides, in vitro antiproliferative activity of dimeric complexes were investigated on MCF-7, Hep G2, HBL-100 cell lines using an MTT assay. In addition, the molecular docking study was accomplished to considerate the nature of binding of the synthesized compounds with protein and DNA.
- Alaghaz, Abdel-Nasser M.A.,Alturiqi, Amani S.,Ammar, Reda A.,Zayed, Mohamed E.
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p. 199 - 212
(2018/12/11)
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- Bimetallic nanoparticle decorated perovskite oxide for state-of-the-art trifunctional electrocatalysis
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The development of stable ABO3 type perovskite oxides with trifunctional electrocatalytic activity is an arduous task. Such a feat is achieved by exsolution of the B-site cations to bimetallic nanoparticles (NPs) decorated on the perovskite surface. Sr0.95Nb0.1Co0.9-xNixO3-δ (0.1 ≤ x ≤ 0.4) was prepared by calcination at 1000 °C and treated under 10% H2/N2 to create -2, -3 mA cm-2 and -10 mA cm-2 for the OER, ORR and HER, respectively at pH 14. In terms of pH universality, HER overpotential is redressed to 183 mV at pH 0. The improved catalytic activity as compared to several reported perovskite oxide and non-perovskite based systems could be attributed to the simultaneous regulation of an optimal eg orbital filling, cation vacancies at catalytically active B-sites, lower metal-oxygen bond hybridization, oxygen non-stoichiometry, surface oxygen vacancies, and ionic and charge-transfer abilities.
- Islam, Quazi Arif,Majee, Rahul,Bhattacharyya, Sayan
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supporting information
p. 19453 - 19464
(2019/08/28)
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- Sustainable fixation of CO2 into epoxides to form cyclic carbonates using hollow marigold CuCo2O4 spinel microspheres as a robust catalyst
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The present work demonstrates the chemical fixation of CO2 for the synthesis of organic carbonates using mesoporous hollow marigold CuCo2O4 spinel microspheres as a catalyst prepared using the solvothermal method. The synthesized microspheres were characterized using contemporary analytical and spectroscopic tools. The CuCo2O4 spinel microspheres with the best morphological behaviour obtained after solvothermal treatment for 3 h were employed as a heterogeneous catalyst for the solvent-free conversion of epoxides and CO2 to generate cyclic carbonates. As a result, the model reaction of styrene oxide and CO2 revealed 94% conversion, 88% yield and 94% selectivity towards styrene carbonate in the presence of TBAI as a base under mild reaction conditions (80 °C, 20 bar, 3 h). Notably, the enhanced catalytic activity was attributed to the cooperative effect of the exposed Lewis acidic sites of CuCo2O4 and the efficient basic nature of TBAI. The effects of different reaction variables such as catalyst loading, temperature, pressure and time were investigated and discussed. Additionally, the effect of different bases was also experimentally determined. Further, the substrate scope using the CuCo2O4 and TBAI catalytic system revealed good performance towards CO2 fixation with a variety of terminal and internal epoxides. The catalyst was easily separated out after the reaction and tested for its recyclability. Results showed good recyclability up to five cycles without a substantial loss of catalytic activity. Based on the results obtained from XPS, XRD, and TPD and the available literature, an effort to predict a plausible mechanism was made in order to support the cycloaddition reaction. The present protocol is the first report of hollow marigold CuCo2O4 spinel microspheres as an outstanding and efficient catalyst with high selectivity towards fixation of CO2 into epoxides for cyclic carbonate formation.
- Prasad, Divya,Patil, Komal N.,Bhanushali, Jayesh T.,Nagaraja, Bhari Mallana,Jadhav, Arvind H.
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p. 4393 - 4412
(2019/08/22)
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- Synthesis, characterization, and in vivo anti-cancer activity of new metal complexes derived from isatin-N(4)antipyrinethiosemicarbazone ligand against ehrlich ascites carcinoma cells
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The current study aimed to synthesize new metal coordination complexes with potential biomedical applications. Metal complexes were prepared via the reaction of isatin-N(4)antipyrinethiosemicarbazone ligand 1 with Cu(II), Ni(II), Co(II), Zn(II), and Fe(III) ions. The obtained metal complexes 2-12 were characterized using elemental, spectral (1H-NMR, EPR, Mass, IR, UV-Vis) and thermal (TGA) techniques, as well as magnetic moment and molar conductance measurements. In addition, their geometries were studied using EPR and UV-Vis spectroscopy. To evaluate the in vivo anti-cancer activities of these complexes, the ligand 1 and its metal complexes 2, 7 and 9 were tested against solid tumors. The solid tumors were induced by subcutaneous (SC) injection of Ehrlich ascites carcinoma (EAC) cells in mice. The impact of the selected complexes on the reduction of tumor volume was determined. Also, the expression levels of vascular endothelial growth factor (VEGF) and cysteine aspartyl-specific protease-7 (caspase-7) in tumor and liver tissues of mice bearing EAC tumor were determined. Moreover, their effects on alanine transaminase (ALT), aspartate transaminase (AST), albumin, and glucose levels were measured. The results revealed that the tested compounds, especially complex 9, reduced tumor volume, inhibited the expression of VEGF, and induced the expression of caspase-7. Additionally, they restored the levels of ALT, AST, albumin, and glucose close to their normal levels. Taken together, our newly synthesized metal complexes are promising anti-cancer agents against solid tumors induced by EAC cells as supported by the inhibition of VEGF and induction of caspase-7.
- El-Saied, Fathy,El-Aarag, Bishoy,Salem, Tarek,Said, Ghada,Khalifa, Shaden A.M.,El-Seedi, Hesham R.
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- Metal complexes of novel Schiff base derived from iron sandwiched organometallic and 4-nitro-1,2-phenylenediamine: Synthesis, characterization, DFT studies, antimicrobial activities and molecular docking
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The condensation of 2-acetylferrocene with 4-nitro-1,2-phenylenediamine in a 1:1 molar ratio, resulting in formation of a novel bi-dentate organometallic Schiff base ligand (L), (2-(1-((2-amino-5-nitrophenyl)imino)ethyl)cyclopenta-2,4-dien-1-yl)(cyclopenta-2,4-dien-1-yl)iron. Also, its Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes have been synthesized. The stoichiometric ratios of the prepared compounds were estimated using elemental analysis (C, H, N, M), molar conductivity, FT-IR, UV-Vis, 1H-NMR, SEM and mass spectral analysis. Furthermore, their TG and DTG properties were studied. The geometrical structure of the complexes was found to be octahedral. From spectral analysis, the Schiff base coordinated to metal ions through the azomethine and amine groups. DFT-based molecular orbital energy calculations of the synthesized ligand have been studied, in which the ligand was theoretically optimized. The Schiff base and its metal complexes have been screened for their antimicrobial activities against different bacterial and fungal species by using disc diffusion method. The anticancer activities of the ligand and its metal complexes have also been studied towards breast cancer (MCF-7) and human normal melanocytes (HFB-4) cell lines. Molecular docking was also used to identify the interaction between the Schiff base ligand and its Cd(II) complex with the active site of the receptors of breast cancer mutant oxidoreductase (PDB ID: 3HB5), crystal structure of Staphylococcus aureus (PDB ID: 3Q8U) and yeast-specific serine/threonine protein phosphatase (PPZ1) of Candida albicans (PDB ID:5JPE).
- Mahmoud, Walaa H.,Deghadi, Reem G.,Mohamed, Gehad G.
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- Complex salts of Pd(ii) and Pt(ii) with Co(ii) and Ni(ii) aqua-cations as single-source precursors for bimetallic nanoalloys and mixed oxides
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A series of highly soluble double complex salts [M′(H2O)6][M′′(NO2)4]·2H2O (M′ = Ni, Co; M′′ = Pd, Pt) have been synthesized, studied and used as single-source precursors for bimetallic nanoalloys and metal-oxide composites. According to the results of simultaneous thermal analysis-mass spectrometry (STA-MS), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), thermolysis of the compounds in diverse atmospheres (O2, He, and H2), delafossite-type mixed oxides M′′CoO2/(NiO + M′′O), metal-oxide composition M′O + M′′ and bimetallic solid solution M′0.5M′′0.5, respectively. In an H2 atmosphere an instant isolation of the equiatomic solid solution occurs at lower than 200 °C with simultaneous reduction of noble and ignoble metals. The bimetallic products can be superstructurally ordered at higher temperatures. The solubility of precursors in organic solvents allows carrying out an impregnation of the salts inside multiwalled carbon nanotubes; subsequent heating in H2 yields intercalated nanoparticles of ~2-4 nm in size.
- Zadesenets, Andrey V.,Filatov, Evgeniy Yu.,Plyusnin, Pavel E.,Asanova, Tatyana I.,Korolkov, Ilya V.,Baidina, Iraida A.,Shlyakhova, Elena V.,Asanov, Igor P.,Korenev, Sergey V.
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p. 8843 - 8850
(2018/06/08)
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- Four supramolecular transition metal(II) complexes based on triazole-benzoic acid derivatives: crystal structure, Hirshfeld surface analysis, and spectroscopic and thermal properties
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Four new complexes [M(3-tba)2(H2O)4] (1–3) and [Co(4-tba)2(H2O)4] (4) {M = Zn (1), Ni (2), Co (3), 3-Htba = 3-(1H-1,2,4-triazol-1-yl)benzoic acid, 4-Htba = 4-(1H-1,2,4-triazol-1-yl)benzoic
- Wang, Da-Wei,Wang, Tao,Du, Lin,Zhou, Jie,Yan, Tong,Zhao, Qi-Hua
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p. 1013 - 1023
(2018/02/19)
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- Thermodynamics of Sr2NiMoO6 and Sr2CoMoO6 and their stability under reducing conditions
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The values of standard enthalpy of formation at 298.15 K and 1 atm for the double perovskites Sr2NiMoO6 and Sr2CoMoO6, measured by means of drop solution calorimetry, were found to be -2418.1 ± 12.4 and -2422.9
- Sereda,Tsvetkov,Sednev,Druzhinina,Malyshkin,Zuev, A. Yu.
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p. 20108 - 20116
(2018/08/16)
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- Two luminescent cobalt(II) coordination polymers for selective sensing of MnO4? in water
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Two luminescent Co(II)-based coordination polymers (CPs) with the formulae of [Co(L1)(1,4-ndc)·H2O]n (CP 1) and [Co2(L2)(1,4-chdc)2]n (CP 2) (L1 = 1,1′-(1,4-butanediyl)bis(5,6-dimethylbenzimidazole), 1,4-H2ndc = 1,4-naphthalenedicarboxylic acid, L2 = 1,1′-(1,4-butanediyl)bis(2-methylbenzimidazole), 1,4-H2chdc = 1,4-cyclohexanedioic acid) have been synthesized. Both CPs were characterized by single-crystal X-ray diffraction, thermogravimetric analysis, elemental analysis, IR spectroscopy, and powder X-ray diffraction. CP 1 reveals a 2D 3,5L2 framework, while CP 2 has a 2D (4,5)-connected 4,5L51 network. Both CPs are luminescent and can be employed for the selective detection of free MnO4? in water.
- Zhao, Xiao-Xue,Qin, Zhan-Bin,Li, Yue-Hua,Cui, Guang-Hua
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p. 597 - 604
(2018/05/28)
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- Synthesis, characterization, DFT and antimicrobial study of Co(II), Ni(II), Cu(II) and Zn(II) complexes of novel schiff base ligands derived from 3-Amino-1,2,4-Triazole-5-Thiol
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Two novel Schiff base ligands are prepared by condensing 2-hydroxy-4-methoxybenzaldehyde with 3-Amino-1,2,4-Triazole-5-Thiol (HL1) and 2-hydroxy-3-methoxybenzaldehyde with 3-Amino-1,2,4-Triazole-5-Thiol (HL2). The ligands were synthe
- Prakash, Ajay,Malhotra, Rajesh
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p. 2781 - 2787
(2018/11/20)
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- Low Temperature Formation of Ruddlesden–Popper-Type Layered La2CoO4±δ Perovskite Monitored via In Situ X-ray Powder Diffraction
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In this contribution low temperature formation of Ruddlesden–Popper (RP)-type layered La2CoO4±δ perovskite was optimized via in situ X-ray powder diffraction (XRPD). Starting from LaCoO3 a stoichiometric transformation to La2CoO4±δ and CoO can be achieved by controlled reduction with H2. The challenge of this reaction is the use of appropriate amounts of H2 in a defined temperature region. If the amount of H2 is too high, complete reduction of the perovskite occurs. If temperatures are not appropriate, intermediate phases seem to hinder the transformation to La2CoO4±δ or lead to a complete decomposition to simple oxides. Based on in situ XRPD experiments, the temperature window and required amount of H2 for the transformation of LaCoO3 to La2CoO4±δ were determined. Systematic experiments reveal that 650 °C is the optimal temperature for the complete transformation of LaCoO3 into La2CoO4±δ and CoO/Co0. The information was then transferred to realize bulk synthesis of La2CoO4±δ at 650 °C in a tube furnace without extended heat treatments at elevated temperatures.
- Ortatatl?, ?eyma,Ternieden, Jan,Weidenthaler, Claudia
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p. 5238 - 5245
(2019/01/04)
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- Standard enthalpy of reaction for the reduction of Co3O4 to CoO
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Two different high-temperature calorimetry methods were used to determine the enthalpy of reaction for the reduction of Co3O4 to CoO. This reaction is particularly interesting for assessing the thermodynamics of the first step of the
- Mayer,Cupid,Adam,Reif,Rafaja,Seifert
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p. 109 - 118
(2017/04/21)
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- Si/Co-CoSi2/reduced graphene oxide ternary nanocomposite anodes for Li-Ion batteries with enhanced capacity and cycling stability
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Silicon (Si) is a promising anode material for high-performance Li-ion batteries (LIBs), but it undergoes rapid capacity fading through severe volumetric expansion during Li insertion/extraction. Although alloying Si with various metal sources has been pursued to mitigate the structural deterioration, the resulting materials have shown the intrinsic problem of low electrical conductivity. To address this conflicting issue, here we describe a novel ternary nanocomposite of Si/Co-CoSi2/reduced graphene oxide (rGO) made using a facile process of mechanical mixing of Si nanoparticles, Co3O4 microparticles, and rGO nanosheets, followed by carbothermal reduction. Specifically, rGO, which has high electrical conductivity and structural integrity, could work as both a conductive matrix and a reducing agent in forming the Co-CoSi2 phase inside the Si domains during thermal treatment. The proposed ternary nanocomposites exhibited a noteworthy specific capacity of 952 mA h g?1 with 79.3% capacity retention after 80 cycles at a current density of 100 mA g?1. We attribute the improved electrochemical performance to the increased structural stability offered by the Co-CoSi2 phase and the interconnected conductive framework of the rGO nanosheets. Therefore, we expect our design process for Si/Co-CoSi2/rGO ternary nanocomposites to be applicable to other materials that can eventually be used as high-performance anodes for the next generation LIBs.
- Park, A Reum,Nam, Myeong Gyun,Kim, A-Young,Kim, Kwang Su,Sher Shah, Md. Selim Arif,Lee, Jun Young,Kim, Woo-Jae,Lee, Joong Kee,Yoo, Pil J.
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p. 1134 - 1142
(2017/07/22)
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- Synthesis, spectroscopic, and thermal investigations of metal complexes with mefenamic acid
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The novel metal complexes with empirical formulae M(mef)2·nH2O (where M = Mn(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II); mef is the mefenamic ligand) were synthesized and characterized by elemental analysis, molar conductance, FTIR-spectroscopy, and thermal decomposition techniques. All IR spectra revealed absorption bands related to the asymmetric (as) and symmetric (s) vibrations of carboxylate group. The Nakamoto criteria clearly indicate that this group is bonded in a bidentate chelate mode. The thermal behavior of complexes was studied by TGA methods under non-isothermal condition in air. Upon heating, all compounds decompose progressively to metal oxides, which are the final products of pyrolysis. Cu(II), Zn(II), and Cd(II) complexes were also characterized by the coupled TG-FTIR technique, which finally proved the path and gaseous products of thermal decomposition. Additionally, the coupled TG-MS system was used to determine the principal volatile products of thermolysis and fragmentation processes of Mn(mef)2·3H2O and Co(mef)2·2H2O.
- Kafarska, Karolina,Gacki, Micha?,Wolf, Wojciech M.
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- Preparation, infrared emissivity and thermochromic properties of Co doped ZnO by solid state reaction
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In this paper, green Zn1-xCoxO nanopowders were synthesized via solid-state reaction at different calcination temperatures. The effects of sinterring temperature on structure, morphologies, color and infrared emissivity was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), UV–visible absorption spectroscopy, Raman spectroscopy and IR-2 dual-band infrared emissometer, respectively. The results show that the as-synthesized samples have hexagonal wurtzite structure and meantime the peaks of the secondary phase, Co3O4, were observed when the sinterring temperature is below 900 °C. The sintering temperature plays a vital important role in crystallite sizes, lattice parameters, volume of the unit cell as well as microstructure. According to the EDS results, Zn ions were substituted by the Co ions in the ZnO lattice where Co ions present in the +2 state indicated via XPS analysis. Additionally, UV–visible absorption spectra shows that absorption edge have a red shift while the corresponding energy band gap of the semiconductor nanoparticles decrease with the increasing sintering temperature, which affects the thermochromic characteristics of materials significantly. The infrared emissivity is related to the microstructure, grain size, conductivity and lattice vibration.
- Zhu, Yongmei,Xu, Guoyue,Guo, Tengchao,Hou, Haili,Tan, Shujuan
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p. 105 - 115
(2017/05/31)
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- Novel mixed-ligand complexes of coumarilate/N,N′-diethylnicotinamide with some transition metals: Synthesis and structural characterization
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Coordination complexes of transition metal cations (CoII, NiII, CuII and ZnII) containing coumarilate and N,N′-diethylnicotinamide were synthesized. The structural characterization and thermal behaviour analysis
- Da?l?, ?zge,K?se, Dursun Ali,Avc?, Gül?in Alp,?ahin, Onur
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p. 1389 - 1402
(2017/08/16)
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- A robust anionic pillared-layer framework with triphenylamine-based linkers: Ion exchange and counterion-dependent sorption properties
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A new anionic pillared-layer cobalt(ii) metal-organic framework combining 4,4′,4′′-nitrilotribenzoic acid (H3ntb) as a linker and terephthalic acid (H2bdc) as a pillar-ligand with the formula {((CH3)2NH2)2[Co3(ntb)2(bdc)]}n (JUMP-1, JUMP = Jena University Magnetic Polymer) has been solvothermally synthesized and characterized. The crystal structure of JUMP-1 was determined to belong to the orthorhombic space group Cmca. It displays a three-dimensional (3D) framework for which the topological analysis revealed a 3,8-connected net with a tfz-d topology. The 3-connected organic node is linked to an 8-connected secondary building unit composed of a linear trinuclear cobalt(ii) cluster with a mixed arrangement of coordination geometries (Td-Oh-Td) leading to two-dimensional layers which are further linked by terephthalic acid to give the pillared-layer arrangement. The magnetic properties are characterized by an antiferromagnetic coupling between a central octahedrally coordinated cobalt(ii) ion and two outer tetrahedral cobalt(ii) centers, whereas only a very weak inter-cluster coupling is observed. Moreover, a moderate zero-field splitting is detected for the tetrahedral cobalt(ii) ions. The organic counterions could successfully be exchanged by lithium ions under retention of the anionic 3D network leading to JUMP-1(Li). For both compounds JUMP-1 and JUMP-1(Li), N2 and CO2 adsorption isotherms were measured. The pore distribution analyses revealed improved microporosity for the lithium exchanged MOF.
- Akintola, Oluseun,Ziegenbalg, Sven,Buchholz, Axel,G?rls, Helmar,Plass, Winfried
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p. 2723 - 2732
(2017/07/10)
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- Studies on some metal complexes of a quinoxaline?based unsymmetrical ONNO donor ligand: Synthesis, spectral characterization, thermal, in vitro biological and DFT studies
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Abstract: Co(II), Ni(II), Cu(II) and Zn(II) complexes of an unsymmetrical tetradentate ONNO donor ligand, 3-(-(3-(-1-(2-hydroxyphenyl)ethylideneamino)propylimino)methyl)quinoxalin-2(1H)-one (L) have been synthesized and characterized by elemental analysis, molar conductance, magnetic susceptibility measurements, FTIR, UV–Vis., mass and 1H NMR spectral studies. ESR spectra of the Cu(II) complex under room (300?K) and liquid nitrogen temperature (77?K) were also recorded. Thermal behavior of the newly synthesized ligand and its metal complexes was assessed by TG–DTG analysis. All the complexes are found to be mononuclear. Crystallinity, average grain size and unit cell parameters were determined from powder X-ray diffraction study. Electrochemical behavior of the compounds was examined by cyclic voltammetry technique. The in vitro antimicrobial screening of the unsymmetrical ligand and corresponding metal chelates was tested against some bacterial strains (E. coli, K. pneumoniae, S. pneumoniae and S. aureus) and fungal strains (A. niger, A. flavus, P. chrysogenum and R. stolonifer). The in vitro antioxidant and anticancer activities of the compounds were also evaluated. DFT studies were done to optimize the structure of the compounds and to calculate nonlinear optical properties of the compounds. Graphical Abstract: [Figure not available: see fulltext.]
- Dhanaraj, C. Justin,Johnson, Jijo
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p. 1845 - 1862
(2017/02/10)
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- Coordination chemistry of Cu(II), Co(II), Zn(II) and Ag(I) complexes of isomeric pyridine 2- and 4-carboxamides and their biological activity evaluation
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Eight complexes of Cu(II), Co(II), Zn(II) and Ag(I) with rarely studied ligands, N,N-diisopropyl/butylpicolinamide (L1/L2), and N,N-diisopropyl/butylisonicotinamide (L3/L4), have been synthesized and characterized spectroscopically, and their molecular and crystal structures have been reported. Diverse coordination modes of these positional isomers have been discovered, discussed and compared with the limited available literature in light of their respective convergent and divergent nature. All the complexes show stable and extended 1D, 2D or 3D coordination/H-bonded networks owing to a large number of weak C–H?O/X and other intermolecular interactions. Further, the ligands as well as the metal complexes have been evaluated for their antimicrobial activity and have turned out to be potent antimicrobial agents.
- Lumb, Isha,Sran, Balkaran Singh,Sood, Henna,Arora, Daljit Singh,Hundal, Geeta
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p. 153 - 166
(2017/03/09)
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- Rigid versus semi-rigid bis(imidazole) ligands in the assembly of two Co(II) coordination polymers: structural variability, electrochemical properties and photocatalytic behavior
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The hydrothermal reactions of 1,2,4,5-cyclohexanetetracarboxylic acid (H4L) with CoCl2·2H2O and rigid or semi-rigid bis(imidazole) ligands were able to generate two Co(ii) coordination polymers (CPs), {[Co5(L)2(1,4-bimb)(μ3-OH)2(H2O)8]·2H2O}n (1), {[Co(L)0.5(1,4-bib)]·H2O}n (2) (1,4-bimb = 1,4-bis(imidazol-1-ylmethyl)benzene, 1,4-bib = 1,4-bis(1H-imidazol-1-yl)benzene). CPs 1 and 2 were structurally characterized by elemental analysis, IR spectroscopy, X-ray powder diffraction and single crystal X-ray diffraction. CP 1 features a 3D 3,3,4,4,5-connected framework with an unprecedented {42·8·102·12}{43·6·86}2{43}2{46}2{62·8}2 topology, which represents the first example of CPs with such a topology. CP 2 possesses a three-fold interpenetration 3D framework with mog topology. The distinct structures of the two CPs may result from diverse coordination modes of the (L)4- ligands and different structural characteristics of rigid or semi-rigid N-donor ligands. The thermal stabilities, photoluminescence properties and electrochemical behavior in the solid state for CPs 1 and 2 have been investigated. The photophysical studies indicated that CPs 1 and 2 are potential semiconductive materials. Moreover, both CPs 1 and 2 show high photocatalytic efficiency for the degradation of methylene blue (MB) under UV light irradiation and exhibit good stability and recyclability. A possible photocatalytic mechanism is speculated by introducing t-butyl alcohol (TBA) as a widely used ?OH scavenger.
- Cui, Jing-Wang,Hou, Suo-Xia,Van Hecke, Kristof,Cui, Guang-Hua
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supporting information
p. 2892 - 2903
(2017/03/11)
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