Fluorescence determination of europium with pyridine-2,4,6-tricarboxylic acid

Europium can form a stable chelate with pyridine-2,4,6-tricarboxylic acid (PTA) with a ratio of 1:1 in aqueous. The system, having the maximum excitation and emission wavelengths at 311.0 nm and 616.3 nm, separately, shows a constant fluorescence intensity in the pH range of 11.0-12.0. The method has high selectivity and sensitivity as well as low effect from foreign ions. The optimum determinate conditions were obtained. The fluorescence intensity is a linear function of Eu3+, concentration in the range of 0.0029-1.5200 mu g center dot mL(-1) and the limit of detection is 2.90 ng center dot mL(-1).

Two Novel Lanthanide Coordination Polymers with Differently Bridging Pyridine-2,4,6-tricarboxylate Ligand

Two new lanthanide-pyridinetricarboxylic complexes formulated as [Lu（pyta）（H2O）3]（1） and [La（pyta）· （H2O）2]-1.SH2O（2） were synthesized through hydrothermal reactions of LuC13 or La（NO3）y6H2O with pyridine-2,4,6-tricarboxylic acid（H3pyta）, respectively, and characterized by X-ray crystallography. Complex 1 crystal- lized in the monoclinic system with space group P21/n, a=1.01930（12） nm, b=0.73423（9） nm, c=1.45449（17） Mm, β=94.734（2）° V=1.0848（2） nm3, Z=4. Complex 2 crystallized in the monoclinic system with space group P21/c, a=0.68474（8） nm, b=1.20982（15） nm, c=1.36063（17） nm, β=99.823（2）°, V=l.1106（2） nm3, Z=4. The overall structure of complex 1 consists of 2D binuclear Lu2（pyta）4-based grid coordination layers which are further extended into a 3D supramolecular architecture via hydrogen bonding interactions. With different coordination modes of the pyta ligand, complex 2 is a 3D porous network comprised of La-carboxylate framework.

Two New Iron Coordination Polymers Based on Fe-pyta Chains Incorporating Pyridine-2,4,6-tricarboxylate

Reaction of FeCIz＇6H20, pyridine-2,4,6-tricarboxylic acid（H3pyta） and NaOH in the hydrothermal system at 185 ℃ resulted in the formation of 1D coordination polymer[Fe（Hpyta）（H2O）2]（1） based on Fe-Hpyta chains. When the abpt[abpt=-4-amino-3,5-bis（4-pyridyl）-l,2,4-triazole] ligand was employed in the reaction system, a 3D supramolecular porous network （H2bpt）[Fe（pyta）（H2O）2]·4H2O（2） was obtained. The framework was constructed with negative （Fe-pyta） chains and the positive H3bpt^＋ in situ, formed from the abpt reagent, to form 1D channels filled with guest water molecules via hydrogen-bonds. X-Ray diffraction crystal structure analysis shows that complex 1 crystallized in the monoclinic system, space group C2/c, a=1.1490（5） nm, b=0.9008（4） nm, c=1.0058（5） nm, B=107.254（9）°, V=0.9942（8） nm3, Z=4; and complex 2 crystallizes in the triclinic system, space group P1 with a=0.90392（11） nm, b=0.96027（11 ） nm, c=1.55540（18） nm, a=73.558（2）°,B= 86.126（2）°,r= 68.745（2）°, V=1.2059（2） nm^3 and Z=2.

Mixed Rare-Earth Complexes of Eu（Ⅲ） and Y（Ⅲ） with Pyridine-2,4,6-tricarboxylic Acid and Their Photoluminescent Properties

A series of rare-earth luminescent complexes {[Eu（pta）（H2O）3]·H2O}n（1, H3pta=pyridine-2,4,6-tricarboxylic acid） and {[EuxY（1-x）（pta）（H2O）3]·H2O}n（2-10） have been synthesized. Complexes 1 and 8 were determined by single-crystal X-ray diffraction, while other complexes were characterized by powder X-ray diffraction, displaying the similar structural mode. The luminescent properties of complexes 1--10 were investigated and the results show that the emission intensities of mixed rare-earth complexes 2--10 are the same or even higher than that of homometallic complex 1 with the increasing Y（Ⅲ） ions.

Synthesis,Structure and Near-infrared Photoluminescent Property of a Tetranuclear Er(Ⅲ) Complex

A tetranuclear erbium complex with pyridine-2,4,6-tricarboxylic acid（H3ptc）, [Er4（ptc）4（H2O）18]·6H2O（1）, has been synthesized by hydrothermal method. The complex crystallizes in triclinic system, space group P1, with a = 7.620（2）, b = 10.459（3）, c = 17.418（5） A, α = 92.351（5）, β = 92.080（5）, γ = 95.627（4）°, V = 1379.1（7）A3 and Z = 2. One Er（III） cation is eight-coordinated and the other is nine-coordinated. The complex exhibits characteristic luminescence of erbium cation in near-infrared region upon the excitation of UV-rays. Furthermore, a three-dimensional supramolecular complex was formed by weak hydrogen bonds among the tetranuclear units.