967 resultados para tin(II) complexes


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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

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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The cct isomers [RuCl 2(CO) 2(PPh 3) 2] (1) and [RuCl 2(CO) 2(AsPh 3) 2] (2) were synthesized from [RuCl 3(PPh 3) 2DMA]DMA and [RuCl 3(AsPh 3) 2DMA]DMA, respectively. The complexes were characterized by elemental analysis, IR and UV-vis spectroscopy and their molecular structures were found to be cis-cis-trans isomers by X-ray crystallography. Cyclic voltammetry data show that the tripenylphosphine stabilizes better the ruthernium(II) complex than the tripenylarsine ligand. © 1994.

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This work deals with the synthesis, spectroscopic characterization of mono and polynuclear Pd(II) compounds obtained from the reaction between [PdCl2(MeCN)2] precursor and imidazolidine-2-thione (L1) and benzimidazoline-2-thione (L2). The interaction between [PdCl2(MeCN)2] and imidazolidine-2-thione, in the 1:2 molar ratio, using MeOH as solvent, yielded compound [Pd2Cl4(L1)4]Cl2 (1) whereas the complex [Pd2Br4(L1)4]Br2 (2) was obtained from the reaction between 1 and Br- ions. Binuclear compounds of general formulae [Pd2(L2)4]X23/2 MeOH {X= Cl-(3), Br-(4)} were synthesized using benzimidazoline-2-thione as ligand, employing the same procedure used in the synthesis of 1 and 2, respectively. The new complexes 1-4 are crystalline, air stable and soluble in methanol and dmso. The compounds were characterized by elemental analysis, IR spectroscopy, ESI/MS mass spectrometry and thermogravimetry. Coordination of the ligands L1 and L2 via sulphur atom was evidenced by the shift of the CS band (~499 cm-1, 1 and 2; ~620 cm-1, 3 and 4) to lower frequencies in comparison with those found in the free ligands (510 cm-1, L1; 660 cm-1, L2), indicating the weakening of the CS bom after coordination. ESI/EM mass spectra (positive mode) of the complexes 1-4 allowed atribute the molecular formulae [Pd2X4(L1)4]X2 {X= Cl-(1), Br-(2)} and [Pd2(L2)4]X2 {X= Cl-(3), Br-(4)} by the appearance of the peaks at m/z 794,61 [(1) + MeOH]+, m/z 836,77 [(2) - 2H - L1]+, m/z 810 [(3) - 2Cl]+, m/z 810 [(4) - 2Br]+. The TG-DTA curves showed that the complexes 1 and 2 are thermally stable up to 212 and 169º C, respectively, and further decompose to metallic palladium at 527º C (1, obt. 28,46 %; calcd. 27,88%) and 895º C (2, obt. 22,85 %; calcd. 22,62%). Compounds 3 and 4 exhibited an initial mass loss of ~5% between 25 -146º C related to the release of metanol molecules. The complexes 3...Fujimura Leite.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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OBJECTIVE: To analyze major histocompatibility complex expression in the muscle fibers of juvenile and adult dermatomyositis. METHOD: In total, 28 untreated adult dermatomyositis patients, 28 juvenile dermatomyositis patients (Bohan and Peter's criteria) and a control group consisting of four dystrophic and five Pompe's disease patients were analyzed. Routine histological and immunohistochemical (major histocompatibility complex I and II, StreptoABComplex/HRP, Dakopatts) analyses were performed on serial frozen muscle sections. Inflammatory cells, fiber damage, perifascicular atrophy and increased connective tissue were analyzed relative to the expression of major histocompatibility complexes I and II, which were assessed as negatively or positively stained fibers in 10 fields (200X). RESULTS: The mean ages at disease onset were 42.0 +/- 15.9 and 7.3 +/- 3.4 years in adult and juvenile dermatomyositis, respectively, and the symptom durations before muscle biopsy were similar in both groups. No significant differences were observed regarding gender, ethnicity and frequency of organ involvement, except for higher creatine kinase and lactate dehydrogenase levels in adult dermatomyositis (p<0.050). Moreover, a significantly higher frequency of major histocompatibility complex I (96.4% vs. 50.0%, p<0.001) compared with major histocompatibility complex II expression (14.3% vs. 53.6%, p = 0.004) was observed in juvenile dermatomyositis. Fiber damage (p = 0.006) and increased connective tissue (p<0.001) were significantly higher in adult dermatomyositis compared with the presence of perifascicular atrophy (p<0.001). The results of the histochemical and histological data did not correlate with the demographic data or with the clinical and laboratory features. CONCLUSION: The overexpression of major histocompatibility complex I was an important finding for the diagnosis of both groups, particularly for juvenile dermatomyositis, whereas there was lower levels of expression of major histocompatibility complex II than major histocompatibility complex I. This finding was particularly apparent in juvenile dermatomyositis.