Superconductivity and Structure of BiSrCaEuCuO Compound

Since the discovery of superconductivity of the BiSrCuO system at 20K, the work of synthesizing high Tc superconductors without rare-earths by adding some elements other than rare-earths in the BiSrCuO system has made a lot of progress. Recently, N. Fukushima et al. have synthesized Bi4Sr4RE2Cu4O16+δ (RE = Nd, Eu or Y) by substituting RE for Ca in the Bi4Sr4Ca2Cu4O16+δ superconductor and revealed that it has a crystal structure identical with this superconductor, but it is an insulator. In this paper, the authors report the superconductivity and structure of the BiSrCaEuCuO compound synthesized by adding 5 at% of rare-earth Eu in the BiSrCaCuO system.

Fluorescence Quenching of a Novel Eu(Ⅲ) Coordination Compound for the Detection of Trace Amounts of Water： Synthesis, Structure and Photoluminescent Property

A novel luminescent coordination compound Eu（TTA）3（DEDAF）（1, TTA = 1,1,1-trifluoro-3-（2-thenoyl）acetone, DEDAF = 9,9-diethyl-4,5-diazafluoren） has been synthesized and fully characterized by infrared spectrum, elemental analysis, UV-vis spectrum, etc. X-ray single-crystal diffraction analysis reveals that compound 1 shows a mononuclear structure with the europium atom in coordinating to one DAF and three TTA ligands. The mononuclear structure units are assembled into a 3-D polymer by hydrogen bonds and π-π interactions. Photoluminescent property of 1 was investigated in detail at room temperature. Complex 1 emits strong red luminescence. However, it could be quenched even by small amount of water. The fluorescence intensity at 614 nm decreases linearly with the water content increasing（vol% in acetonitrile） in the range of 0.025~0.2% under 278 nm excitation. Thermogravimetric analysis has also been studied, which demonstrates good thermal stability of 1.

Non-Isothermal Decomposion Kinetics of Supermolecule Compound [Eu（C10H9N2O4）（C10H8N2O4）（H2O）3]2·phen·4H2O

Europium（Ⅲ） compound with 2-oxopropionic acid salicyloyl hydrazone （C10H10N2O4, H3L） and 1,10-phenanthroline （C12H8N2, phen） has been prepared. A yellow prismatic crystal of the compound was obtained, and the molecule crystallized in the triclinic space group P-1. There are two 9-coordinated complex molecules in every structure unit, where every Eu atom is coordinated by three water molecules and two tridentate C10H10N2O4 ligands, forming two stable pentacycles. The coordination polyhedron around Eu^3＋ was described as a single cap square antiprism. In the crystal cell, there are one free 1,10-phenanthroline and four water molecules. The thermal decomposition of the compound and its kinetics were studied by non-isothermal thermogravimetry. The Kissinger＇s method and Ozawa＇s method were used to calculate the activation energy value of the first-step decomposition. The stages of the decompositions were identified by TG-DTG-DSC curve. The non-isothermal kinetic data were analyzed by means of integral and differential methods. The possible reaction mechanism and the kinetic equations were investigated by comparing the kinetic parameters.

Fluorescence microscopy observation of self-organized microstructure formed by a rare earth compound

The morphologies of monolayers containing Eu(TTA)3Phen (TTA=thenoyltrifluoroace-tone, Phen = 1, 10-phenanthroline) were studied at the air/liquid interface on different subphases by fluorescence microscopy (FM). The composite subphase was the basic premise for the stable existence of the rare earth compound at air/liquid interface. The process that rare earth compound phase changes from liquid expanded state to liquid condensed state corresponded to a plateau in the π-A isotherm. In the pure Eu(TTA)3Phen monolayer, rod domains of Eu(TTA)3Phen formed and packed with no order. In the mixed monolayers with stearic acid (SA), phase transition of SA occurred first and formed domains with an electric gradient field, which induced the rare earth compound to form luminescent ring domains. Influence of intermolecular interaction on the self-organized microstructure was revealed.