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排序方式: 共有358条查询结果,搜索用时 31 毫秒
71.
Ana Maria Rocco Daniel Perrone Moreira Robson Pacheco Pereira 《European Polymer Journal》2003,39(9):1925-1934
Blends of poly(ethylene oxide) (PEO) of high molecular weight with poly(bisphenol A-co-epichlorohydrin) (PBE) with high epoxy equivalent were studied spectroscopically, thermally and morphologically. As similar systems of low molecular weight, a single Tg was observed for all blends, indicating miscibility. A progressive decrease in the degree of crystallinity and in the size of the PEO spherulites as the PBE is added is also observed. Quantitative analysis from FTIR spectra provided determination of specific interactions between the constituents and their variation with PEO content. Simulations were performed utilising the spectra of the pure polymers to confirm that the observed changes in the experimental spectra of the blends were due to interaction between the polymers. 相似文献
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Pereira RV Garcia Ferreira AP Gehlen MH 《The journal of physical chemistry. A》2005,109(27):5978-5983
A new fluorochromic dye was obtained from the reaction of 9-aminoacridine with ethyl-2-cyano-3-ethoxyacrylate. It displays complex fluorescence that is ascribed to normal emission from the acridine chromophore in addition to excited-state intramolecular charge transfer (ESICT) formed upon light excitation. The analysis of the fluorescence decays in different solvents reveals two short-lived components in the range of 80-450 ps and 0.7-3.2 ns, ascribed to the formation and decay of the intramolecular charge transfer (ICT) state, in addition to a third component of about 9.0 ns, which is related to the normal emission from the acridine singlet excited state, probably in an enol-imine tautomeric form. The ICT emission is readily quenched by water addition to polar solvents, and this effect is ascribed to changes in the keto-amine/enol-imine equilibrium of this fluorochromic dye. 相似文献
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Davet Aline Carvalho Joo Luiz S. Dadalt Robson C. Vituoso Suzane Dias Josiane F.G. Miguel Marilis D. Miguel Obdlio G. 《Chromatographia》2009,69(2):245-247
This study proposes an RP 18 LC method for the analysis of some common nitrogen-containing compounds. This method has used the ionic pair concept in the mobile phase with sulfuric acid and lauril sodium sulfate in its composition. N-Methyltyramine and hordenine have been identified for the first time in this species.
相似文献78.
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Dr. José García-Calvo Dr. Jonathan A. Robson Prof. Dr. Tomás Torroba Prof. Dr. James D. E. T. Wilton-Ely 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(62):14214-14222
A series of new ruthenium(II) vinyl complexes has been prepared incorporating perylenemonoimide (PMI) units. This fluorogenic moiety was functionalised with terminal alkyne or pyridyl groups, allowing attachment to the metal either as a vinyl ligand or through the pyridyl nitrogen. The inherent low solubility of the perylene compounds was improved through the design of poly-PEGylated (PEG=polyethylene glycol) units bearing a terminal alkyne or a pyridyl group. By absorbing the compounds on silica, vapours and gases could be detected in the solid state. The reaction of the complexes [Ru(CH=CH-PerIm)Cl(CO)(py-3PEG)(PPh3)2] and [Ru(CH=CH-3PEG)Cl(CO)(py-PerIm)(PPh3)2] with carbon monoxide, isonitrile or cyanide was found to result in modulation of the fluorescence behaviour. The complexes were observed to display solvatochromic effects and the interaction of the complexes with a wide range of other species was also studied. The study suggests that such complexes have potential for the detection of gases or vapours that are toxic to humans. 相似文献