Transition Cations
Mostrando 1-12 de 72 artigos, teses e dissertações.
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1. Crystallographic Changes Accompanying the Verwey Transition in a Magnetite from Steatite
The crystallographic structural analysis of the magnetite of a steatite rock at 298 K, (saturation magnetization, σ = 95.0 J T-1 kg-1) showed two cubic networks and, below Verwey temperature (TV ca.120 K) a monoclinic structure, basing on their cell dimensions and different transitional behaviors when reducing the temperature. A monoclinic structure was ide
J. Braz. Chem. Soc.. Publicado em: 2020-09
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2. Relief Position and Soil Properties under Continuous Banana Cropping in Subhumid Climate in Northeast Brazil
ABSTRACT Sequences of thick and eroded soils in hills surfaces are cultivated with banana since the beginning of the last century in the Northeast of Pernambuco (PE), Brazil. Measurements of soil properties depending on soil slope under intensive agricultural cultivation are limited mostly as the pedogenetic approach. This study aimed to identify the dominan
Rev. Bras. Ciênc. Solo. Publicado em: 09/09/2019
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3. Adsorption of Transition Metal Chlorides by Silica with Grafted 1-n-Propyl-3-Methylimidazolium Chloride
Silica with grafted 1-n-propyl-3-methylimidazolium chloride was investigated as adsorbent for the removal of cobalt(II), copper(II), zinc(II), cadmium(II) and mercury(II) chlorides from alcoholic and aqueous solutions. The adsorption proceeds via the formation of metal-chloride anionic complexes detained near the grafted organic cations as counterions. This
J. Braz. Chem. Soc.. Publicado em: 2015-06
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4. Paligorsquita como adsorvente para íons de metais de transição: Estudos cinéticos e do equilíbrio / Paligorsquite as adsorbent for transition metallic ion Kinetic and equilibrium study.
Os argilominerais são silicatos importantes do ponto de vista ambiental, tecnológico e acadêmico, existindo como materiais sintéticos ou naturais. Neste grupo se destaca a paligorsquita, que é um argilomineral de hábito fibroso de estrutura 2:1 de ampla aplicação industrial. Este mineral pode apresentar substituições isomórficas parciais do magné
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 21/12/2011
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5. Gas-phase solvolysis type reactions of SiCl3+ cations
Gas-phase SiCl3+ ions undergo sequential solvolysis type reactions with water, methanol, ammonia, methylamine and propylene. Studies carried out in a Fourier Transform mass spectrometer reveal that these reactions are facile at 10-8 Torr and give rise to substituted chlorosilyl cations. Ab initio and DFT calculations reveal that these reactions proceed by ad
Química Nova. Publicado em: 2010
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6. Investigation of structural, electronic and magnetica properties of Ca2-xLaxFelrO6, Sr2-xLaxFelrO6 e TbMnO3 oxides / Investigação as propriedades estruturais, eletronicas e magneticas dos oxidos Ca2-xLaxFelrO6, Sr2-xLaxFelrO6 e TbMnO3
For many decades the transition metal oxides are subject of great scientific interest because of the wide variety of interesting physical properties and their potential technological applications. More recently, for example, oxides of transition metals with multiferroic properties have been considered as potential magneto-electronic devices. Many transition
Publicado em: 2010
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7. Solvolysis reactions of cation +SiCl3: Experiment and Theory / Reações de solvólise em fase gasosa do cátion +SiCl3: experimento e teoria
Polyhalogenated silicenium ions, X3Si+ (X = F, Cl), are common fragment ions in the mass spectra of polyhalogenated silanes obtained by electron ionization. These ions are powerful electrophiles and are believed to play a role in plasma enhanced corrosion processes and plasma enhanced chemical vapour deposition processes. In this dissertation, we present som
Publicado em: 2010
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8. SÍNTESE E ARRANJOS SUPRAMOLECULARES DE COMPLEXOS BIS(TRIAZENIDO) MACROCÍCLICOS E TRIAZENIDO 1-ÓXIDO COM OS CÁTIONS Cu2+, Ni2+, Cu+, K+. / SYNTHESIS AND SUPRAMOLECULAR ARRANGEMENTS OF BIS(TRIAZENIDE) MACROCYCLIC AND TRIAZENIDE 1-OXIDE COMPLEXES WITH Cu2+, Ni2+, Cu+, K+ CATIONS.
This work elaborates on the determination of crystal and molecular structures of four pro-ligands, emphasizing bis(triazenes), triazene 1-oxide and a new class of bis(triazenes) macrocyclic, and eight complexes involving Cu+, Cu2 +, Ni2 + and K+. Pro-ligands triazenes 1-oxide are relatively small and simple molecules. When they are deprotonated they presen a
Publicado em: 2010
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9. Electrosynthesis and characterizations of polypyrrole-2-carboxylic acid for application as amperometric biosensor constructed in microelectrodes / Eletrossíntese e caracterização de filmes de polipirrol-2-ácido carboxílico para uso em biossensores amperométricos construídos em eletrodos miniaturizados
In this work, we present the electrochemical synthesis of a new conducting polymer derived of polypyrrole (PPI) functionalized by carboxylic group, the polypyrrole-2-carboxylic acid, and its application as amperometric transducer in biosensor by use of polyphenol oxidase (PFO). All the steps of syntheses and characterization of the polymer film in microelect
Publicado em: 2009
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10. Simulação computacional de espectros Raman de líquidos iônicos / Molecular dynamics simulation of Raman spectra of ionic liquids
In this work, theory, experiment and simulation are conjugated to investigate ionic liquids. The observed components in the low frequency part of the spectra (the region between 0 e 200 cm-1) results from the roto-translational dynamics and from inter molecular interactions. In this sense, the vibrational spectroscopies are inserted in the context of techniq
Publicado em: 2008
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11. Catalisadores à base de Cu, Co ou Fe trocados ou suportados em zeólita USY avaliação na redução de NO com CO
The emissions of the nitrogen oxides (NOx) must be hardly reduced in the next years. The catalytic reduction of NO with CO is one of the possible processes with potential to be able to transform those oxides in N2. In that process, supported noble metals have been the most used, however, their low stability in the presence of water steam or SO2, have led to
Publicado em: 2008
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12. Síntese de compostos com potenciais atividades biológicas ou magnéticas
This thesis is divided in two parts and presents the results of our studies on the synthesis and the study of biological or magnetic proprieties of a series of ligands and their transition metal complexes. Firstly we prepared a series of dithiacarboxilic acids and their metal complexes to investigate the biological activity of these compounds against fungi,
Publicado em: 2008