Transition Metal
Mostrando 1-12 de 362 artigos, teses e dissertações.
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1. New Europium(III)-TTA Complex Containing 2-Pyrrolidone as Coligand to Application as Luminescent Sensor: PbII and Ethanol in Gasoline
This work describes the synthesis and application of an europium(III) complex, [Eu(TTA)3(2-pyr) (H2O)], containing 2-thenoyltrifuoroacetonate (TTA) and 2-pyrrolidone (2-pyr) as ligands, obtained as white solid and soluble in ethanol. In solution, the complex showed red emission, characteristic of the EuIII emission in the solid state (λexc = 375 nm and λem
Journal of the Brazilian Chemical Society. Publicado em: 2022
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2. Adsorption of Calcium(II), Cadmium(II) and Copper(II) Ions from Water by Prepared Silicon-Aluminum-Zirconium Oxide Using Sol-Gel Process
Ternary oxide silica-alumina-zirconia (SiO2/Al2O3/ZrO2) obtained by the sol-gel process was applied as novel adsorbent of ions in aqueous solution. Batch isotherms were performed using standard CuII, CdII and CaII solutions at variable pH and different concentrations. Adsorption capacity was best at weakly acidic pH. The maximum adsorption capacities were 2.
J. Braz. Chem. Soc.. Publicado em: 2021-07
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3. Ferrimagnetic to paramagnetic transition and dielectric relaxation in Ni1-xZnxFe2O4 ferrites
Abstract The spinel ferrite system Ni1-xZnxFe2O4 (x=0-0.7, Δx=0.1) was prepared by wet chemical co-precipitation method using sulfates of respective metal ions. The electrical resistivity and dielectric properties of the prepared samples have been studied as a function of temperature, frequency, and Zn content (x). The DC resistivity (ϱ) was measured in th
Cerâmica. Publicado em: 2021-06
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4. RECENTES APLICAÇÕES DO ORGANOFOTOCATALISADOR 1,2,3,5-TETRAQUIS(CARBAZOL-9-IL)-4,6-DICIANOBENZENO EM TRANSFORMAÇÕES QUÍMICAS
Ruthenium and iridium polypyridine complexes are among the most employed photocatalysts described in literature. The broad applicability is due to the redox potentials and long half-life times of the excited state which these molecules presented. The pursuit for metal-free alternatives has been intensified in the last few years, therefore, many organic fluor
Quím. Nova. Publicado em: 2021-03
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5. Shortcomings in the training program of medical residency during the COVID-19 pandemic in Brazil. How will they be repaired?
Ruthenium and iridium polypyridine complexes are among the most employed photocatalysts described in literature. The broad applicability is due to the redox potentials and long half-life times of the excited state which these molecules presented. The pursuit for metal-free alternatives has been intensified in the last few years, therefore, many organic fluor
Rev. Bras. Ginecol. Obstet.. Publicado em: 2021-03
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6. EVALUATION OF THE RELATIVE PROTECTION FACTOR OF ROSEMARY EXTRACT IN BIODIESEL IN THE PRESENCE OF TRANSITION METAL IONS
Biodiesel contains unsaturated methyl esters making it susceptible to oxidation reaction. Among the factors that cause oxidative instability is the contamination by transition metal ions that in small quantities catalyze the oxidation reaction. The objective of this work was to evaluate the relative protection factor of rosemary extract, in biodiesel, in the
Quím. Nova. Publicado em: 2020-09
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7. RAMAN STUDIES OF BIS(PHENYLTERPYRAZINE)IRON(II) AND SUPRAMOLECULAR SPECIES WITH PENTACYANIDOFERRATE(II) IONS
The chemistry and spectroscopy of the iron(II) phenylterpyrazine complex, [Fe(phtpz)2]2+, were investigated in comparison with the analogous phenylterpyridine species, Fe(phtpy)2]2+, and the results indicated a strong electronic delocalization on the Fe(II) terimine chromophore encompassing the lateral pyrazyl groups. The delocalized nature of the molecular
Quím. Nova. Publicado em: 05/12/2019
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8. Aplicação do Formalismo CTP em uma Ação com Operador Pseudo-Diferencial
Resumo O formalismo CTP (closed-time-path) é uma ferramenta matemática para calcular funções de Green em sistemas físicos. A principal vantagem desta técnica é a de que, ao contrário do formalismo de Feynman, o formalismo CTP pode ser aplicado em sistemas fora do equilíbrio. Por outro lado, em física da matéria condensada, alguns modelos não loca
Rev. Bras. Ensino Fís.. Publicado em: 25/11/2019
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9. New Strategies in Enantioselective Hydrogenation on Supported Transition Metal Catalyst: Effects of Metal Sintering and Support Swelling
The effect of noble metal catalysts supported on an ionic exchange resin for the enantioselective hydrogenation of ethyl pyruvate to ethyl lactate was studied. High activity and moderate enantioselectivity levels were obtained. Pt was the best enantioselective metallic phase, followed by Pd and Au; Rh was the less enantioselective metallic phase. The effect
J. Braz. Chem. Soc.. Publicado em: 12/08/2019
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10. IRON OXIDE AND Fe2O3/Al2O3 USED TO CATALYZE REMOVING HYDROGEN FROM TAIL CHLORINE AT LOW TEMPERATURE
The transition metal oxide, such as iron oxide and Fe2O3/Al2O3 is cheap and industrialized that are widely used to catalyze the reaction of chlorine and oxygen with hydrogen in mixture gas to remove hydrogen from tail chlorine at low temperature. The reaction gas was prepared by the same composition with industrial tail chlorine, namely Cl2 (65% ~ 80%), O2 (
Quím. Nova. Publicado em: 02/05/2019
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11. Exploring the metallochromic behavior of pentacyanidoferrates in visual, electronic and Raman spot tests
Abstract: Pentacyanidoferrate(II) complexes of aromatic N-heterocycles, such as 4-cyanopyridine, exhibit characteristic colors and strong metallochromism associated with the donor-acceptor interactions of the metal ions with the cyanide ligands. In the presence of transition metal ions insoluble polymeric complexes are formed, displaying bright yellow, red,
An. Acad. Bras. Ciênc.. Publicado em: 25/04/2019
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12. Mechanical characterization of PM aluminum composites by small punch test
ABSTRACT In this work Small Punch Test (SPT) was applied to study the mechanical behavior of ultrafine-grained Al-Al2O3metal matrix composites (MMCs) fabricated in situ via powder metallurgy route (HITEMAL®). Such MMCs show attractive mechanical properties, enhanced creep performance and increased thermal stability at elevated temperatures, not normally ass
Matéria (Rio J.). Publicado em: 19/07/2018