Synthesis, Structure, and Luminescent Property of a 3-D Strontium Complex [Sr_3(pda)_2(Hpda)_2(H2O)_2]_n·2nH_2O

The title complex [Sr3（pda）2（Hpda）2（H2O）2]n·2nH2O（H2pda = pyridine-2,6-dicar- boxylic acid） has been prepared under solvothermal conditions. It has been characterized by X-ray single-crystal diffraction, IR and elemental analysis. The crystal belongs to the monoclinic system, space group P21/c with a = 10.3795（8）, b = 9.2225（7）, c = 18.5726（14） , β = 104.377（2）o, V = 1722.2（2） 3, C28H22N4O20Sr3, Mr = 997.36, Z = 2, Dc = 1.923 g/cm3, μ = 4.722 mm-1, F（000） = 984, the final R = 0.0269 and wR = 0.0538. This complex possesses a 3-D structure which is constructed from 1-D chain motifs linked by carboxylate groups. The luminescent property of the title complex has been investigated.

A New 3-D Sr(Ⅱ)Complex:Two-step Solvothermal Synthesis,Structure and Luminescent Properties

The title complex [HSr3（pda）3（H2O）3Cl]n（1, H2pda = pyridine-2,6-dicarboxylic acid） has been prepared under two-step solvothermal conditions. It has been characterized by X-ray single-crystal diffraction, IR, TGA-DSC and elemental analysis. The crystal belongs to the trigonal system, space group R-3 with a = 14.484（2）, b = 14.484（2）, c = 21.970（4） A, γ = 120 o, V = 3991.4（11） A3, C（21）H（16）ClN3O（1）5Sr3, Mr = 848.68, Z = 6, Dc = 2.118 g/cm^3, μ = 6.175 mm-1, F（000） = 2484, the final R = 0.0457 and w R = 0.1139. This complex possesses a 3-D structure constructed from [HSr3（pda）3（H2O）3Cl]2 units and connected by coordinated carboxylate groups of pda2-ligands. The topology symbol of this network is（4^（12）6~3）. Luminescent property of the title complex has been investigated at room temperature.

Nanosized complex fluorides based on Eu^(3+) doped Sr_2LnF_7(Ln=La, Gd)

A simple co-precipitation approach taking place between Ln3＋, Sr2＋ cations and F anions, led to the formation of nanocrystalline Eu3＋ doped Sr2LnF7 （Ln-La and Gd） complex fluorides. The reaction was carried out in the presence of polyeth- ylene glycol, PEG 6000 as a surfactant/surface modifier, providing small size and homogeneity of the products. The synthesized compounds were composed of small nanoparticles with an average size of 15 nm. All obtained Eu3＋ doped compounds exhibited an intensive red luminescence. In the case of gadolinium based compounds, the energy transfer phenomena could be observed from Gd3＋ ions to Eu3＋ ions. In order to study the structure and morphology of the synthesized fluorides, powder X-ray diffraction （XRD） and transmission electron microscopy （TEM） measurements were performed. Also FT-IR spectra of the products were re- corded, revealing the presence of PEG molecules on the nanoparticles suN＇ace. A spectrofluorometry technique was applied to examine optical properties of the synthesized nanoparticles. Excitation and emission spectra as well as luminescence decay curves were measured and analysed. The performed analysis revealed a red luminescence, typical for the Eu3＋ ion situated in the inorganic, highly symmetric matrix. Concentration quenching phenomena and lifetimes shortening, together with an increasing of the Eu3＋ doping level, were observed and discussed. Judd-Ofelt analysis was also performed for all doped samples, in order to support the registered spectroscopic data and examine in details structural and optoelectronic properties of the synthesized nanomaterials.