Borohidreto complexos de cobre (I) contendo difosfinas. Caracterização espectroscópica e comportamento térmico

Tetrahydroborate complexes of copper (I) with bidentate phosphines, [Cu(η 2-BH 4)(dppm)] (1), [Cu(η 2-BH 4)(dppe)] (2), [Cu(η 2-BH 4)(cis-dppet)] (3) and [Cu(η 2-BH 4)(dppb)] (4) (dppm = bis(diphenylphosphino)methane; dppe = 1,2-bis(diphenylphosphino) ethane; cis-dppet = 1,2-cis(diphenylphosphino)ethene; dppb = 1,4-bis(diphenylphosphino)butane) were prepared and characterized by elemental analysis, infrared spectroscopy, NMR and thermogravimetric analysis. The IR data for 1-4 showed bands typical of a bidentate coordination of BH 4 group to the copper atom and the 31P{ 1H} NMR spectra indicated that the phosphorous atoms are chelating the metal centre. The thermal behavior of the compounds was investigated and suggested that their thermal stability is influenced by the phosphines. Their thermal stability decreased as follows: [Cu(η 2-BH 4)(dppe)] (2) > [Cu(η 2-BH 4)(dppm)] (1) > [Cu(η 2-BH 4)(dppb)] (4) > [Cu(η 2-BH 4)(cis-dppet)] (3). According to thermal analysis and X-ray diffraction patterns all compounds decomposed giving Cu(BO 2) 2, CuO, CuO 2 and Cu as final products.

Preparação e caracterização inicial de complexo de inclusão entre nitrofurazona e 2-hidroxipropil-β-ciclodextrina

Nitrofurazone (NF), 5-nitro-2-furaldehyde semicarbazone, a broad-spectrum antibiotic, has reported toxic effects and low solubility in water. It would be of great interest to form inclusion complexes between NF and a cyclodextrin, to develop more effective and safer antibiotic formulations. This paper focuses on the preparation of inclusion complexes of NF with 2-hydroxypropyl-β- cyclodextrin (HP-β-CD) and their initial characterization by evaluating rates of complex formation, photostability, solubility isotherms, release rate profiles, stoichiometry of the complexes and their morphology, as revealed by scanning electron microscopy. The kinetic tests of complex formation revealed that 17,3 h is enough for stabilization of the NF-cyclodextrin complex. The solubility isotherm studies showed that the isotherm changes from type A to type B, as a function of temperature. The photostability experiments showed that the insertion of the NF in the HP-β-CD cavity protects the drug from photodecomposition. The release kinetic tests showed that the profile of NF release from the complex is altered by the presence of HP-β-CD in the medium. A Job's plot indicated that the stoichiometry of the complex was 1:1 NF:HP-β-CD. The scanning electron micrographs showed changes in the crystal structure of NF in the complex. This study focused on the physicochemical properties of drug-delivery formulations that could potentially be developed into a novel type of therapy with NF.

Exploratory study on sequestration of some essential metals by indigo carmine food dye

Indigo carmine forms a stable complex with different ions, and the stability constant of the complexes were evaluated as log K equal to 5.75; 5.00; 4.89 and 3.89 for complexes with Cu(II), Ni(II), Co(II) and Zn(II) ions, respectively, in 0.1 mol L -1 carbonate buffer solution at pH 10. The interaction between Cu(II) ions and indigo carmine (IC) in alkaline medium resulted in the formation of the Cu 2(IC) complex, measured by the spectrophotometric method, with a stoichiometric ratio between indigo carmine and metal ions of 2:1 (metal-ligand). The reported method has also been successfully tested for determination of copper in pharmaceutical compounds based on copper-gluconate without pre-treatment.

Chaotic diffusion caused by close encounters with several massive asteroids: II. the regions of (10) Hygiea, (2) Pallas, and (31) Euphrosyne

Context. Close encounters with (1) Ceres and (4) Vesta, the two most massive bodies in the main belt, are known to be a mechanism of dynamical mobility able to significantly alter proper elements of minor bodies, and they are the main source of dynamical mobility for medium-sized and large asteroids (D > 20 km, approximately). Recently, it has been shown that drift rates caused by close encounters with massive asteroids may change significantly on timescales of 30 Myr when different models (i.e., different numbers of massive asteroids) are considered. Aims. So far, not much attention has been given to the case of diffusion caused by the other most massive bodies in the main belt: (2) Pallas, (10) Hygiea, and (31) Euphrosyne, the third, fourth, and one of the most massive highly inclined asteroids in the main belt, respectively. Since (2) Pallas is a highly inclined object, relative velocities at encounter with other asteroids tend to be high and changes in proper elements are therefore relatively small. It was thus believed that the scattering effect caused by highly inclined objects in general should be small. Can diffusion by close encounters with these asteroids be a significant mechanism of long-term dynamical mobility? Methods. By performing simulations with symplectic integrators, we studied the problem of scattering caused by close encounters with (2) Pallas, (10) Hygiea, and (31) Euphrosyne when only the massive asteroids (and the eight planets) are considered, and the other massive main belt asteroids and non-gravitational forces are also accounted for. Results. By finding relatively small values of drift rates for (2) Pallas, we confirm that orbital scattering by this highly inclined object is indeed a minor effect. Unexpectedly, however, we obtained values of drift rates for changes in proper semi-major axis a caused by (10) Hygiea and (31) Euphrosyne larger than what was previously found for scattering by (4) Vesta. These high rates may have repercussions on the orbital evolution and age estimate of their respective families. © 2013 ESO.

Nonlinear Optical Properties of Tungsten Lead-Pyrophosphate Glasses Containing Metallic Copper Nanoparticles

We have prepared heavy metal oxide glasses containing metallic copper nanoparticles with promising nonlinear optical properties which were determined by Z-scan and pump-probe measurements using femtosecond laser pulses. For the wavelengths within the plasmon band, we have observed saturable absorption and response times of 2.3 ps. For the other regions of the spectrum, reverse saturable absorption and lifetimes shorter than 200 fs were verified. The nonlinear refractive index is about 2.0 × 10-19 m2/W from visible to telecom region, thus presenting an enhancement effect at wavelengths near the plasmon and Cu+2 d-d band. © 2013 Springer Science+Business Media New York.

Synthesis, characterization, x-ray structure, DNA cleavage, and cytotoxic activities of palladium(ii) complexes of 4-phenyl-3-thiosemicarbazide and triphenylphosphane

Complexes of the type [PdX(PPh3)(1)]X [1 = 4-phenyl-3- thiosemicarbazide; X = Cl- (2), Br- (3), I- (4), and SCN- (5)] have been synthesized and characterized by elemental analyses and IR, UV/Vis, and 1H and 13C NMR spectroscopy. The molecular structure of complex 4 was determined by single-crystal X-ray diffraction. The binding of the complexes with a purine base (guanosine) was investigated by 1H NMR spectroscopy and mass spectrometry, which showed the complexes to coordinate to guanosine through N7. A gel electrophoresis assay demonstrated the ability of 2-5 to cleave DNA plasmid. All the complexes were tested in vitro by means of the MTT assay for their cytotoxicity against two murine cell lines, LM3 (mammary adenocarcinoma) and LP07 (lung adenocarcinoma), and compared with cisplatin. Complexes 2-5 exhibited good cytotoxicity that surpasses that of cisplatin in the case of LM3. A series of thiosemicarbazide/phosphane palladium(II) complexes have been synthesized and fully characterized. These complexes are able to cleave DNA plasmid and show cytotoxicity against adenocarcinoma (mammary LM3 and lung LP07), surpassing the cytotoxicity of cisplatin in the case of LM3. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis, cytotoxic activity and DNA interaction of Pd(II) complexes bearing N′-methyl-3,5-dimethyl-1-thiocarbamoylpyrazole

A new series of complexes of general formulae [PdX2(tmdmPz)] {X = Cl (1), Br (2), I (3), SCN (4); tmdmPz = N′-methyl-3,5-dimethyl-1- thiocarbamoylpyrazole} have been synthesized and characterized by elemental analysis, molar conductivities, IR, 1H and 13C{ 1H} NMR spectroscopy. In these complexes, the tmdmPz coordinates to Pd(II) center as a neutral N,S-chelating ligand. The geometries of the complexes have been optimized with the DFT method. Cytotoxicity evaluation against LM3 (mammary adenocarcinoma) and LP07 (lung adenocarcinoma) cell lines indicated that complexes 1-4 were more active than cisplatin. The binding of the complexes with a purine base (guanosine) was investigated by 1H NMR and mass spectrometry, showing that the coordination of guanosine occurs through N7. Electrophoretic DNA migration studies showed that all of them modify the DNA tertiary structure. © 2013 Elsevier Ltd. All rights reserved.

Synthesis, crystal structures, antimicrobial, antifungal and antituberculosis activities of mixed ligand silver(I) complexes

The biological activity of some new mixed silver-phosphane-thio-ligand complexes, with 1:1:2, 1:1:1 and 1:2:1 (Ag:phospine:ligand) compositions, have been examined. Ten compounds were prepared using a series of silver(I) salts [AgX, where X = NO3, ClO4, PF6 and Br], tertiary phosphines and the ligands thi-osemicarbazide, 2-(propan-2-ylidene) hydrazinecarbothioamide, and thiazolidine-2-thione. The syntheses were carried out under ambient conditions, and the ten complexes obtained were found to be light stable. All 10 compounds were characterized by elemental analysis, FTIR, and NMR spectroscopy, whereas nine compounds were characterized by X-ray diffraction analysis. The anti-proliferative activities were evaluated by minimum inhibitory concentration (MIC: lg/mL) in an aqueous suspension system and they all show promising potential activity against selective strains of Gram-positive and Gram-negative bacteria, fungous and Mycrobaterium tuberculosis H37Rv. © 2013 Elsevier Ltd. All rights reserved.

Caracterização e dinâmica de metais em rios da Bacia Hidrográfica do Turvo/Grande. -

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

Síntese, caracterização e estudo do comportamento térmico dos 2-metoxibenzoatos de Mn(II), Co(II), Ni(II), Cu(II) e Zn(II) no estado sólido

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Complexos de zinco(II), de európio(III) e heterobimetálico com os ácidos tiofeno 2 e 3-carboxílico. Síntese, caracterização e propriedades luminescentes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Complexos contendo o ligante 2 - Mercaptopiridina derivados da série '[RUCL IND. 3(NO)(P-P)]'

Pós-graduação em Química - IQ

Temporary occlusion of the inferior lacrimal punctum and canaliculi of dogs with n-butyl-cyanoacrylate and 2-octyl-cyanoacrylate

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

Coordinative versatility of a Schiff base containing thiophene: Synthesis, characterization and biological activity of zinc(II) and silver(I) complexes

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

2 '-Deoxyguanosine, 2 '-deoxycytidine, and 2 '-deoxyadenosine adducts resulting from the reaction of tetrahydrofuran with DNA bases

A recent study showed that tetrahydrofuran (THF), a widely used solvent, is carcinogenic in experimental animals. Despite its carcinogenic activity, there is a paucity of information regarding cellular toxicity, biomolecular damage, and genotoxicity induced by THF. We describe here the structural characterization of adducts produced by the reaction of oxidized THF with 2'-deoxyguanosine (dGuo-THF 1 and dGuo-THF 2), 2'-deoxyadenosine (dAdo-THF), and 2'-deoxycytidine (dCyd-THF). Adducts were isolated from in vitro reactions by reverse-phase HPLC and fully characterized on the basis of spectroscopic measurements. The stable derivatives obtained by the reduction of adducts with NaBH4 ( the case of dGuo-THF 1, dCyd-THF, and dAdo-THF) and the stable adduct dGuo-THF 2 were used as standards for optimization of chromatographic separations for adduct detection in DNA through HPLC/ESI/MSMS. Using this methodology, we successfully detected the four adducts in calf thymus DNA reacted with oxidized THF. The present study also provides evidence that rat liver microsomal monooxigenases oxidize THF to the reactive electrophilic compounds that are able to damage the DNA molecule, as indicated by a significant increase in adduct dGuo-THF 1 level when NADPH was added to the THF/ microsomes/dGuo incubation mixtures. Our data point to DNA-THF adducts as possible contributing factors to the toxicological effects of THF exposure.