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181.
182.
Heloisa Beraldo Ricardo F. F. da Costa Rejane Lima Geraldo M. de Lima Ivana S. Lula Bernard Mahieu 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):2455-2463
The reaction of tin(IV) tetrachloride with 3-formylpyridine semicarbazone and different 3-formylpyridine thiosemicarbazones produces [Sn(HL)CL 3 ][SnCl 5 ] where HL stands for the neutral ligand. The tin(IV) complexes were characterized using a variety of spectroscopic techniques. Coordination through the pyridine nitrogen occurs in all cases. Solvation studies in DMSO indicated that dissociation of the ligands and their complete replacement by solvent molecules occurs. 相似文献
183.
Ray L. Frost Yunfei Xi Ricardo Scholz Andrés López Fernanda M. Belotti Mário L. S. C. Chaves 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):1526-1534
Abstract The metal lithium is very important in industry, including lithium batteries. An important source of lithium besides continental brines is granitic pegmatites as in Australia. Lithiophilite is a lithium and manganese phosphate with chemical formula LiMnPO4 and forms a solid solution with triphylite, its Fe analog, and belongs to the triphylite group that includes karenwebberite, natrophilite, and sicklerite. The mineral lithiophilite was characterized by chemical analysis and spectroscopic techniques. The chemical is: Li1.01(Mn0.60, Fe0.41, Mg0.01, Ca0.01)(PO4)0.99 and corresponds to an intermediate member of the triphylite-lithiophilite series, with predominance of the lithiophilite member. The mineral lithiophilite is readily characterized by Raman and infrared spectroscopy. 相似文献
184.
Alma Viso Roberto Fernández de la Pradilla Ana García Carlos Guerrero-Strachan Marta Alonso Mariola Tortosa 《Phosphorus, sulfur, and silicon and the related elements》2013,188(5-6):1229-1234
Abstract Readily available p-tolylsulfinimines undergo highly stereoselective [3 + 2] cycloadditions with azomethine ylides generated from α -iminoesters and LDA to produce N-sulfinylimidazolidines. In the presence of Lewis acids, p-tolylsulfinimines react with glycine iminoester enolates to produce N-sulfinylimidazolidines, after cyclization of open chain intermediates. These mechanistically diverse processes take place with excellent regio-, stereo-, and facial selectivities, and the latter is opposite to most known reactions involving sulfinimines. Some of the resulting imidazolidines have been transformed into examples of a novel class of nonsymmetrical vicinal diamines using reductive and/or hydrolytic protocols. 相似文献
185.
Elena O. Alonso Maria E. R. Marcondes Vicente G. Toscano 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4)
Abstract As part of our continuing interest in the mechanistic photochemistry of phosphonium salts (Toscano et al., Chez. Commun., 567 (1973); J. Phys. Chem., 83(9), 1213 (1979)) we have investigated the photodecomposition (313 nm irradiation) of (1-naphthyl-methyl) triphenylphosphonium (I) chloride and tetrafluoroborate in deaerated isopropanol: 相似文献
186.
Luis Alvarez Thon Carlos Bustos Fernando Diaz‐Marín Maria Teresa Garland Ricardo Baggio 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(1):101-104
The title compound, C17H10F5N5O2, is described and compared with its 4‐nitrophenyl isomer [Bustos, Sánchez, Schott, Alvarez‐Thon & Fuentealba (2007). Acta Cryst. E 63 , o1138–o1139]. The title molecule presents its nitro group split into two rotationally disordered components, which in conjunction with the rotation of the `unclamped' rings constitute the main molecular differences. Packing is directed by a head‐to‐tail type `I' C—F...F—C interaction, generating double‐chain strips running along [100]. These substructures are interlinked by a variety of weak F...F, O...F, F...π and O...π interactions. 相似文献
187.
Luis Alvarez‐Thon Carlos Bustos Katherina Espinoza‐Santibaez Maria Teresa Garland Ricardo Baggio 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(10):1200-1204
The title compound, C17H11F5N4O, is described and compared with two closely related analogues in the literature. There are two independent molecules in the asymmetric unit, linked by N—H...O hydrogen bonds and π–π interactions into dimeric entities, presenting a noticeable noncrystallographic C2 symmetry. These dimers are in turn linked by a medium‐strength type‐I C—F...F—C interaction into elongated tetramers. Much weaker C—H...F contacts link the tetramers into broad two‐dimensional substructures parallel to (101). 相似文献
188.
The self-assembly and bioactivity of the peptide–polymer conjugate DGRFFF–PEG3000 containing the RGD cell adhesion motif has been examined, in aqueous solution. The conjugate is designed to be amphiphilic by incorporation of three hydrophobic phenylalanine residues as well as the RGD unit and a short poly(ethylene glycol) (PEG) chain of molar mass 3000 kg mol−1. Above a critical aggregation concentration, determined by fluorescence measurements, signals of β-sheet structure are revealed by spectroscopic measurements, as well as X-ray diffraction. At high concentration, a self-assembled fibril nanostructure is revealed by electron microscopy. The fibrils are observed despite PEG crystallization which occurs on drying. This suggests that DGRFFF has an aggregation tendency that is sufficiently strong not to be prevented by PEG crystallization. The adhesion, viability and proliferation of human corneal fibroblasts was examined for films of the conjugate on tissue culture plates (TCPs) as well as low attachment plates. On TCP, DGRFFF–PEG3000 films prepared at sufficiently low concentration are viable, and cell proliferation is observed. However, on low attachment surfaces, neither cell adhesion nor proliferation was observed, indicating that the RGD motif was not available to enhance cell adhesion. This was ascribed to the core–shell architecture of the self-assembled fibrils with a peptide core surrounded by a PEG shell which hinders access to the RGD unit. 相似文献
189.
This work presents an automatic system, based on an electronic tongue, for resolution of mixtures of three pesticides. Inhibition detections were performed during the steady state of biosensors response. Three biosensors were built using two enzymes, electric eel (EE), genetically-modified Drosophila melanogaster (B131), and electric eel co-immobilized with drosophila melanogaster (BH). Calibrations curves for paraoxon, dichorlvos, and carbofuran were performed in the ranges 0.4–50.4 µM, 0.01–1.01 µM, 0.01–0.41 µM with LOD of 3.91 × 10?8, 6.30 × 10?11, and 5.84 × 10?10, respectively. An artificial neural network (ANN) was used to model the combined response of three pesticides. A set of 19 mixtures were prepared in order to train the artificial neural network, the modeling was validated with a set of 6 spiked samples of river water. The error and recovery yields were found in consistent with expected values. 相似文献
190.
Anderson Hollerbach Klier Ricardo José Alvea Maria Auxiliadora Fontes Prado José Dias de Bouza Filho Norma Beatriz D'accorso 《合成通讯》2013,43(23):4361-4374
The synthesis of 5-[6′-deoxy-(1′,2′:3′,4′-di-O-isopropylidene-α-D-galactopyranos-6′-yl)]tetrazole and its reaction with acetic anhydride and 1,2:3,4-di-O-isopropylidene-6-O-(4-toluenesulfonyl)-α-D-galactopyranose are described. 相似文献