Research on Chemical Intermediates - Five luminescent ternary and one binary Europium(III) complexes were synthesised with β-keto acid as primary ligand and neocuproine(neo),... 相似文献
Synthesis and photoluminescence behaviour of six novel europium complexes with novel β-hydroxyketone ligand, 2-(4-chlorophenyl)-1-(2-hydroxy-4-methoxyphenyl)ethan-1-one (CHME) and 2,2′-bipyridine (bipy) or neocuproine (neo) or 1,10-phenanthroline (phen) or 5,6-dimethyl-1,10-phenanthroline (dmphen) or bathophenanthroline (bathophen) were reported in solid state. The free ligand CHME and europium complexes, Eu(CHME)3.2H2O [1] Eu(CHME)3.bipy [2], Eu(CHME)3.neo [3], Eu(CHME)3.phen [4], Eu(CHME)3.dmphen [5] and Eu(CHME)3.bathophen [6]were characterized by elemental analysis, FT-IR and 1H-NMR. The photoluminescence emission spectra exhibited four characteristic peaks arising from the 5D0 → 7FJ (J = 1–4) transitions of the europium ion in the solid state on monitoring excitation at λex = 395 nm. The luminescence decay curves of these europium complexes possess single exponential behaviour indicating the presence of a single luminescent species and having only one site symmetry in the complexes. The luminescence quantum efficiency (η) and the experimental intensity parameters, Ω2 and Ω4 of europium complexes have also been calculated on the basis of emission spectra and luminescence decay curves. In addition, the antimicrobial and antioxidant activities were also studied of the investigated complexes. 相似文献
Six crimson samarium (III) complexes based on β-ketone carboxylic acid and ancillary ligands were synthesized by adopting the grinding technique. All synthesized complexes were investigated via elemental analysis, infrared, UV–Vis, NMR, TG/DTG and photoluminescence studies. Optical properties of these photostimulated samarium (III) complexes exhibit reddish-orange luminescence due to 4G5/2?→?6H7/2 electronic transition at 606 nm of samarium (III) ions. Further, energy bandgap, color purity, CIE color coordinates, CCT and quantum yield of all complexes were determined accurately. Replacement of water molecules by ancillary ligands enriched these complexes (S2-S6) with decay time, quantum yield, luminescence, energy bandgap and biological properties than parent complex (S1). Interestingly, these efficient properties of complexes may find their applications in optoelectronics and lighting systems. In addition to these, the antioxidant and antimicrobial assays were also investigated to explore the applications in biological assays.
Europium doped calcium pyrovanadate nanoparticles Ca2V2O7:Eu3+, having a size of 57–63 nm, were synthesized using combustion process. Structure, morphological and optical properties of nanophosphors have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), fluorescence spectrometry (PL) and Fourier transform infra-red (FT-IR) spectroscopy. X-ray studies shows that a pure triclinic Ca2V2O7 phase was obtained at 900 °C temperature. The red emission observed at 620 nm upon excitation at 305 nm is due to hypersensitive transition 5D0 → 7F2 of luminescent activator Eu3+ location at a site with no inversion symmetry in Ca2V2O7 crystal lattice. High luminescent intensity and easy synthesis technique make this red phosphor a promising candidate for application as luminescent materials. 相似文献
Our present technological society needs the assistance of lanthanide luminescence in almost every field to meet the global energy demands. In present research work we have synthesized five (one binary and four ternary) 5-(4-methylphenyl)-2- furoic acid based Eu(III) complexes with ancillary ligands, namely, aqua (H2O), neocuproine (neo), 2, 2’-bipyridyl (bipy), bathophenanthroline (batho) and 1, 10-phenanthroline (phen). The spectroscopic analysis and photophysical features are characterized by the use of different investigative techniques. All the findings obtained from EDAX, elemental (CHN) analysis, FT-IR, NMR, UV–visible spectroscopy declared the coordination of ligand binding sites with the europium ion. These Eu(III) complexes possess good thermal stability and excellent optoelectronic features as predicted with the help of TGA and PL analysis. Diffuse reflectance spectral studies confirm their applications in the wide band gap semiconductors. The Judd–Ofelt analysis and monoexponential behavior of lifetime reveals the existence of asymmetric and single local environment around europium ion. All the complexes show sharp red emission validated by CIE color coordinates, color purity, asymmetric ratio and CCT values. SEM analysis tells that the bulk of these complexes comprised of spherical shaped particles with uniform distribution.
The vanadium–aluminum alloy has been prepared by aluminothermy process. The alloy ingot obtained was refined by electron beam melting and homogenized by vacuum arc melting technique. The refined alloy was crushed into small pieces. These pieces were kept isothermally in a thermobalance attached to the Sieverts apparatus for the hydrogen charging. Reacted fraction α was calculated using isothermal thermo-gravimetry method. The reacted fraction α–t data thus obtained have been linearly fitted over a suitable reaction mechanism function. Rate constants at different temperatures are determined using slope of these linearly fitted curves. Activation energy of hydrogen charging has been calculated using Arrhenius equation. 相似文献
V4Cr4Ti alloy is synthesized by aluminothermy process followed by electron beam refining. Hydrogen absorption characteristics of the alloy have been evaluated by measuring the pressure composition isotherm (PCIT) at 57 °C temperature. Two plateau pressures are observed in the PCIT curve. Substantial decrease in the hydrogen absorption capacity of the alloy as compared to vanadium has been recorded. Hydrogen absorption kinetics of the alloy was investigated in the temperature range of 200–500 °C. Three-dimensional diffusion appears to be the rate controlling step of the hydrogen absorption. The apparent activation energy was calculated as 0.16 eV/atom-hydrogen. 相似文献
BaZrO\(_{3}\):Eu\(^{3+}\) perovskite phosphors were successfully synthesized by employing combustion method. The structure, morphology and optical properties of material have been characterized by X-ray diffraction, scanning electron microscopy and fluorescence spectrometry. The XRD results indicate that crystals of BaZrO\(_{3}\):Eu\(^{3+}\) belongs to cubic perovskite system. The phosphors can be effectively excited by UV light and the emission spectra results indicate that reddish-orange luminescence dominates due to parity allowed magnetic dipole transition \(^{5}\)D\(_{0}\rightarrow ^{7}\)F\(_{1}\) located at 593 nm. The prepared phosphor show remarkable luminescent properties which find applications in field emission displays and plasma display panels. 相似文献
A solution combustion route for the synthesis of Eu3+-activated M2V2O7 (M = Sr, Ba) and their luminescent properties have been investigated. Structure and luminescent characteristics of Sr2V2O7:Eu3+ and Ba2V2O7:Eu3+ nanophosphors have been studied by x-ray diffraction, scanning electron microscopy, transmission electron microscopy, fluorescence
spectrometry and Fourier transform infra-red spectroscopy. The incorporation of Eu3+ activator in these nanoparticles has been checked by luminescence characteristics. These nanoparticles have displayed red
color under a UV source which is due to characteristics transition of Eu3+ from 5D0 → 7F2 at 613 nm in both Sr2V2O7:Eu3+ and Ba2V2O7:Eu3+ nanophosphors. In addition, the optimal Eu3+ - doped contents of Sr2(1-x)Eu2xV2O7 and Ba2(1-x)Eu2xV2O7 nanophosphors for both were 4 mol%. 相似文献