Síntese, caracterização e avaliação da citotoxicidade de complexos de Pd(II) contendo ligantes fosfínicos de N,S - quelantes

Pós-graduação em Química - IQ

Synthesis and thermal behavior study of complexes of the type [Pd(mu-X)(4-eb-p-phen)](2) (X = Cl, Br, I, N-3, NCO, SCN) and 4-eb-p-phen [bis(4-ethylbenzyl)p-phenylenediimine]

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Synthesis and antimycobacterial activity of new pyrazolate-bridged dinuclear complexes of the type [Pd(mu-L)(N-3)(PPh3)](2) (PPh3 = triphenylphosphine; L = pyrazolates)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Study of corrosion resistance of laser welded Au-Pd-Ag-In alloy using electrochemical.

The aim of this work was to evaluate the corrosion resistance of AuPdAgIn alloy, submitted to laser beam welding, in 0.9% NaCl solution, using electrochemical techniques. Measures of the open circuit potential (OCP) versus time were applied to electrochemical experiments, as well as potentiodynamic direct scanning (PDS) and electrochemical impedance spectroscopy (EIS) on AuPdAgIn alloy, submitted to laser beam welding in 0.9% NaCl solution. Some differences observed in the microstructure can explain the results obtained for corrosion potential, Ecorr, and corrosion resistance, Rp. EIS spectra have been characterized by distorted capacitive components, presenting linear impedance at low frequencies, including a non-uniform diffusion. The area of the laser weld presented corrosion potential slightly superior when compared to the one of the base metal. The impedance results suggest the best resistant corrosion behavior for laser weld than base metal region. This welding process is a promising alternative to dental prostheses casting.

The oxidation of hydroxylamine on Pt-, and Pd-modified Au electrodes in aqueous electrolytes: Electrochemical and in situ spectroscopic studies

The electrooxidation of hydroxylamine, NH2OH, in 0.1 M phosphate buffer (PB, pH = 7) on Pt-, and Pd-modified Au electrodes prepared by galvanic displacement of underpotential deposited Cu, was investigated by electrochemical techniques and three and in situ vibrational probes, substrate-induced surface enhanced Raman scattering, SI-SERS, surface enhanced infrared absorption, SEIRAS, and Fourier transform infrared reflection-absorption, IRAS, spectroscopies. Analyses of the results obtained made it possible to identify at low overpotentials, solution phase (sol) and adsorbed (ads) nitric oxide, NO, as well as solution phase nitrous oxide, N2O. As the potential was increased, the peak(s) ascribed to NO(ads) gained in intensity and new features associated with NO2−(ads) and NO2−(sol) were clearly discerned. Further excursion toward higher potentials yielded an additional peak assigned to NO2(ads). This behavior is analogous to that found for bare Au electrodes in a potential region in which the metal is at least partially oxidized under otherwise the same experimental conditions.

Eletro-oxidação de metanol e etanol sobre catalisadores suportados de 'PD''AU'

Pós-graduação em Química - IQ

Desenvolvimento de catalisadores sem platina: estudos comparativos da oxidação de metanol em 'PD''RU'/'C' e 'PT''RU'/'C' em meio alcalino

Pós-graduação em Química - IQ

Synthesis, characterization and thermal behavior of cyclopalladated compounds of the type [Pd{C6H4CH2N(CH3)(2)}(mu-X)](2) (X= Cl, NCO, SCN, CN)

The dimeric compound [Pd(dmba)(μ-Cl)]2 (1) (dmba = N,N-dimethylbenzylamine) reacts with KX, in methanol/acetone, affording the analogous dimeric pseudohalide-bridged species [Pd(dmba)(X)]2 [X = NCO(2), SCN(3), CN(4)]. The compounds were characterized by elemental analysis, infrared spectroscopy, NMR and thermogravimetric analysis. The IR data for 2-4 showed bands typical of coordinated pseudohalide ligands indicating clearly the occurrence of the exchange reaction. Their thermal behavior was investigated and suggested that their thermal stability is influenced by the bridging ligand. The thermal stability decreased in the order [Pd(dmba)(μ-SCN)]2>[Pd(dmba)(μ-Cl)] 2>[Pd(dmba)(;u-NCO)]2>[Pd(dmba)(μ-CN)]2. The X-ray results showed the formation of PdO as final decomposition product. © 1999 Elsevier Science Ltd. All rights reserved.

Compostos de Pd(II) contendo ligantes N,S-doadores: síntese, caracterização e estudo da atividade citotóxica

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Nanopartículas de Pd suportadas em compósitos óxido-carbono: influência das interações metal-suporte na oxidação de etanol em meio básico

Fuel cells powered directly with ethanol (Direct Ethanol Fuel Cell-DEFC) are very attractive for the possibility of using a renewable fuel in the generation of clean energy. However, it is still necessary to deepen the understanding of catalytic processes and their dependence on the catalytic properties. This work proposes to study the catalytic activity of ethanol oxidation in an alkaline medium of Pd nanoparticles supported in carbon oxide hybrids using various transition metal oxides (MoO3, TiO2, WO3 and ZrO2). The materials prepared were characterized by techniques such as X-ray diffraction, transmission electron microscopy (TEM) and X-ray dispersive spectroscopy (EDX) to verify the structure, the distribution of particles in the supports and the presence of Pd on particles oxide. Experiments of X-rays absorption spectroscopy were carried out using soft X-rays (SXS) to evaluate the changes in the electronic properties of the Pd particles caused by interactions with different oxides. Measurements of cyclic voltammetry and potential sweeps of adsorbed CO oxidation allowed evaluating general aspects of the catalysts' electrochemical behavior and determining the electrochemically active area thereof. The catalytic performances of ethanol oxidation in alkaline medium were evaluated by electrochemical techniques (potential scan and chronoamperometry), and showed an improvement in activity with the addition of oxides in material containing only carbon, which was most pronounced for the catalyst containing TiO2. This improvement was predominantly associated with the electronic effects caused by the interaction of Pd on the support, causing a vacancy in the 4d band of Pd which, in turn, produces variations in adsorption energies of the species...