62 resultados para visible bases


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N-Arylamides were exclusively obtained in moderate to good yields from selenium-catalyzed reactions of nitroaromatics with amides in the presence of CO and mixed organic bases Et3N and DBU.

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A novel ZnIn2S4 catalyst synthesized by hydrothermal method shows high and stable photocatalytic activity for water reduction under visible light illumination.

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Y2Ta2O5N2 is presented as a novel photocatalyst with high activity for water splitting under visible-light irradiation in the presence of appropriate sacrificial reagents; the activity for reduction to H-2 is increased by the incorporation of Pt or Ru as a co-catalyst, with a significant increase in production efficiency when both Pt and Ru are present.

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Schiff base compounds refer to the branch of supra-molecules and can be used as sensing material in the construction of potentiometric ion selective electrodes (ISEs). This relatively modern field has been subject to extensive research in the period of 1999-2007 when more than 100 ISEs employing Schiff bases were constructed. The quantitative high-throughput detection of 29 cations and 7 anions has been demonstrated in various scientific branches, such as biomedicine, pharmacy, biochemistry, pharmacology, environmental chemistry, food technology, and agriculture. This review discusses Schiff base compounds and their applications in the design and development of ion selective sensors and microsensors.

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A NADH and glucose biosensor based on thionine cross-linked multiwalled carbon nanotubes (MWNTs) and Au nanoparticles (Au NPs) multilayer functionalized indium-doped tin oxide (ITO) electrode were presented in this paper. The effect of light irradiation on the enhancement of bioelectrocatalytic processes of the biocatalytic systems by the photovoltaic effect was investigated.

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The ligands 4,4,4-trifluoro-1-phenyl-1.3-butanedione (Hbfa) and 1,10-phenanthroline (phen) were used to prepare ternary lanthanide (Ln) complexes [Dy(bfa)(3)phen and Tm(bfa)(3)phen]. Crystal data: Dy(bfa)(3)phen C(42)H(26)FqN(2)O(6)Dy, triclinic, P (1) over bar, a= 9.9450(6) angstrom, b = 14.0944(9) angstrom, c = 14.6043(9) angstrom, alpha = 82.104(1)degrees, beta = 87.006(1)degrees, gamma = 76.490(1)degrees, V = 1971.1(2)angstrom(3), Z = 2; Tm(bfa)(3)phen C42H26F9N2O6Tm, triclinic, P (1) over bar, a = 9.898(5)angstrom, b = 13.918(5)angstrom, c = 14.753(5)angstrom, a = 83.517(5)degrees, alpha = 86.899(5)degrees, gamma = 76.818(5)degrees, V = 1965.3(14)angstrom(3), Z = 2. The coordination number of the central Ln(3+) (Ln = Dy, Tm) ion is eight, with six oxygen atoms from three Hbfa ligands and two nitrogen atoms from the phen ligand.

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CeF3 and CeF3:Tb3+ nanoparticles were prepared by reverse microemulsion with a functional monomer, methyl methacrylate (MMA), as the oil phase, and CeF3:Tb3+/poly (methyl methacrylate) (PMMA) nanocomposites were obtained via polymerization of the MMA monomer. The nanoparticles and nanocomposites have been well characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), low- and high-resolution transmission electron microscope (TEM), selected-area electron diffraction (SAED), thermogravimetric analysis (TGA), UV/vis transmission spectra, photoluminescence excitation, and emission spectra and luminescence decays. The well-crystallized CeF3 and CeF3:Tb3+ nanoparticles are spherical with a mean diameter of 15 nm. They show the characteristic emission of Ce3+ 5d-4f (313 nm, D-2-F-2(5/2); 323 nm, D-2-F-2(7/2)) and Tb3+ D-5(4)-F-7(J) (J = 6-3, with D-5(4)-F-7(5) green emission at 541 nm as the strongest one) transitions, respectively.

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RE3+-activated alpha- and beta-CaAl2B2O7 (RE = Tb, Ce) were synthesized with the method of high-temperature solid-state reaction. Their VUV excitation and VUV-excited emission spectra are measured and discussed in the present article. The charge transfer band of Tb3+ and Ce3+ is respectively calculated to be at 151 +/- 2 and 159 +/- 3 nm. All the samples show an activator-independent excitation peak at about 175 nm and an emission peak at 350-360 nm ascribed to the host absorption and emission band, respectively.

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Phosphors CaYBO4:RE3+ (RE = Eu, Gd, Tb, Ce) were synthesized with the method of solid-state reaction at high temperature, and their vacuum ultraviolet (VUV)-visible luminescent properties in VUV-visible region were studied at 20 K. In CaYBO4, it is confirmed that there are two types of lattice sites that can be substituted by rare-earth ions. The host excitation and emission peaks of undoped CaYBO4 are very weak, which locate at about 175 and 350-360nm, respectively. The existence of Gd3+ can efficiently enhance the utilization of host absorption energy and result in a strong emission line at 314 nm. In CaYBO4, Eu3+ has typical red emission with the strongest peak at 610 nm; Tb3+ shows characteristic green emission, of which the maximum emission peak is located at 542 nm. The charge transfer band of CaYBO4:Eu3+ was observed at 228 nm; the co-doping of Gd3+ and Eu3+ can obviously sensitize the red emission of Eu3+. The fluorescent spectra of CaYBO4:Ce3+ is very weak due to photoionization; the co-addition of Ce3+-Tb3+ can obviously quench the luminescence of Tb3+.