Browsing GI- Quimolmat - Artigos by Issue Date
Now showing items 1-20 of 72
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Peculiarities in the electrical and magnetic properties of cobalt perovskites Ln1−xMxCoO3 (Ln3+: La3+, M2+: Ca2+, Sr2+, Ba2+; Ln3+: Nd3+, M2+: Sr2+)
(Elsevier, 1999-09)We refer here to the electrical and magnetic properties of the Ln1−xMxCoO3 systems (Ln3+: La3+, M2+: Ca2+, Sr2+, Ba2+; Ln3+: Nd3+, M2+: Sr2+), paying special attention to those ferromagnetic compounds that display M–I ... -
Layered LiNi0.5Co0.5O2 cathode materials grown by soft-chemistry via various solution methods
(Elsevier, 2000-07)[Abstract] The lithiated nickel–cobalt oxide LiNi0.5Co0.5O2 used as cathode material was grown at low-temperature using different aqueous solution methods. The wet chemistry involved the mixture of metal salts (acetates ... -
Structural and electrochemical properties of Li-Ni-Co oxides synthesized by wet chemistry via a succinic-acid-assisted technique
(Elsevier, 2001)[Abstract] Lithiated metal oxides LiCo1−yNiyO2 were synthesized by a sol–gel method using succinic acid as chelating agent. Microcrystalline materials were formed by calcination in oxygen at 800°C. The physicochemical ... -
Lithiated cobaltates for lithium-ion batteries: Structure, morphology and electrochemistry of oxides grown by solid-state reaction, wet chemistry and film deposition
(Elsevier, 2001-07)[Abstract] We present the structural (XRD and Raman) and electrochemical properties of various oxides of the cobaltate family (with the α-NaFeO2-type structure) grown by solid-state reaction, wet chemistry and film deposition ... -
IR characterization of Ln2−xSrxCoO4 (x≥1; Ln=La, Nd) oxides
(Elsevier, 2001-07)[Abstract] We have recorded the FTIR spectra of powder samples of Ln2−xSrxCoO4 (Ln=La, Nd) at room temperature. We have identified the infrared active modes (3A2u+4Eu), and analyzed how they change as a function of Ln and ... -
Influence of aluminum doping on the properties of LiCoO2 and LiNi0.5Co0.5O2 oxides
(Elsevier, 2003-01)We have prepared LiCo1−yAlyO2 and LiNi0.5−yAlyCo0.5O2 (0≤y≤0.3) powder samples by a low temperature sol–gel method using succinic acid as chelating agent. We have studied the details of their crystallographic and local ... -
Magnetic and electronic properties of lithium cobalt oxide substituted by nickel
(Elsevier, 2003-02)[Abstract] We measured susceptibility, electron-spin resonance, magnetization and electrical conductivity of LiCo1−yNiyO2 powders synthesized by wet-chemistry method using succinic acid as chelating agent. We found unusual ... -
Synthesis of Acetylhomoagmatine
(Molecular Diversity Preservation International, 2006)The first total synthesis of acetylhomoagmatine, a natural product isolated form the methanolic extracts from the sponge Cliona celata, is performed in four steps in a very high yield. -
LiCo1−yMyO2 positive electrodes for rechargeable lithium batteries: II. Nickel substituted materials grown by the citrate method
(Elsevier, 2006-03)[Abstract] The layered LiCo1−yNiyO2 microcrystalline powders were synthesized by a sol–gel method using citric acid as a chelating agent in the range 0.2 ≤ y ≤ 0.8. Submicron-sized particles of the precursor were obtained ... -
Charge ordering and dielectric properties in the near half-doped Pr0.79Na0.21MnO3 perovskite
(Elsevier, 2008-06)[Abstract] The Pr0.79Na0.21MnO3 perovskite has been prepared in polycrystalline form by a ceramic method. We have carried out its structural characterization by synchrotron X-ray powder diffraction (SXRPD) at room temperature ... -
Magnetoelectric behavior in the complex CaMn7O12 perovskite
(Elsevier, 2009)[Abstract] We report a magnetoelectric effect in the double perovskite CaMn7O12, that shows a complex magnetic behavior below 90 K with two magnetic phases coexisting (one ferrimagnetic and the other modulated). A second ... -
A simple solvothermal synthesis of MFe2O4 (M=Mn, Co and Ni) nanoparticles
(Elsevier, 2009-10)[Abstract] Nanoparticles of MFe2O4 (M=Mn, Co and Ni), with diameters ranging from 5 to 10 nm, have been obtained through a solvothermal method. In this synthesis, an alcohol (benzyl alcohol or hexanol) is used as both a ... -
Studies on the power factor of (Ba,Sr)Co2+xRu4−xO11 compounds
(Elsevier, 2011-02)[Abstract] We have prepared polycrystalline single-phase ACo2+xRu4−xO11 (A = Sr, Ba; 0 ≤ x ≤ 0.5) using the ceramic method and we have studied their structure, electrical resistivity and Seebeck coefficient, in order to ... -
Natural Products from Antarctic Colonial Ascidians of the Genera Aplidium and Synoicum: Variability and Defensive Role
(Molecular Diversity Preservation International, 2012)Ascidians have developed multiple defensive strategies mostly related to physical, nutritional or chemical properties of the tunic. One of such is chemical defense based on secondary metabolites. We analyzed a series of ... -
Near Room Temperature Dielectric Transition in the Perovskite Formate Framework [(CH₃)₂NH₂][Mg(HCOO)₃]
(The Royal Society of Chemistry, 2012-05)[Abstract] We report that the hybrid organic–inorganic compound [(CH₃)₂NH₂][Mg(HCOO)₃] shows a marked dielectric transition around Tₜ ∼ 270 K, associated to a structural phase transition from SG R[3 with combining macron]c ... -
Apparent colossal dielectric constants in nanoporous Metal Organic Frameworks
(American Chemical Society (ACS), 2012-05-30)[Abstract] In this work, we show that the hybrid material Co2(1,4-bdc)2(dabco)•[4DMF•1H2O], shows an apparent colossal dielectric constant at room temperature (r5000 at 300 K for =100 Hz). Nevertheless, such response ... -
Coexistence of magnetic and electrical order in the new perovskite-like (C3N2H5)[Mn(HCOO)3] formate
(The Royal Society of Chemistry, 2013-09)[Abstract] In this work we further the structural characterization of the recently discovered (C3N2H5)[Mn(HCOO)3] metal–organic framework with perovskite-like structure, and we present its magnetic and dielectric properties ... -
Dolabelladienols A–C, New Diterpenes Isolated from Brazilian Brown Alga Dictyota pfaffii
(Multidisciplinary Digital Publishing Institute, 2014)[Abstract:]The marine brown alga Dictyota pfaffii from Atol das Rocas, in Northeast Brazil is a rich source of dolabellane diterpene, which has the potential to be used in future antiviral drugs by inhibiting reverse ... -
Transition-metal-free cross-coupling of indium organometallics with chromene and isochroman acetals mediated by BF3·OEt2
(American Chemical Society, 2016)[Abstract] A transition-metal-free coupling of triorganoindium reagents with benzopyranyl acetals mediated by a Lewis acid has been developed. The reaction of R3In with chromene and isochroman acetals in the presence of ... -
Ferrocenylindium reagents in palladium‐catalyzed cross‐coupling reactions: asymmetric synthesis of planar chiral 2‐aryl oxazolyl and sulfinyl ferrocenes
(Wiley, 2017)[Abstract] The preparation of ferrocenylindium species and palladium‐catalyzed cross-coupling reactions for the synthesis of monosubstituted and planar chiral 1,2‐disubstituted ferrocenes is described. Triferrocenylindium ...
