Luminescent Properties of Bi-Rare Earth Complexes with m-methylbenzoic Acid and 1,10-phenanthroline

The bi rare earth complexes EuTb( m MBA) 6(phen) 2·2H 2O, TbY( m MBA) 6(phen) 2·2H 2O were synthesized by the reaction of RECl 3 with m methylbenzoic acid and 1,10 phenanthroline in ethanol solution, where m MBA=m methylbenzoate and phen=1,10 phenanthroline. The luminescence properties of the title complexes were studied in comparison with the corresponding complexes Eu 2( m MBA) 6(phen) 2·2H 2O and Tb 2( m MBA) 6(phen) 2·2H 2O respectively. The results indicate that the emission intensity from europium ion can be greatly enhanced by the terbium ion, while the emission from terbium ion was strongly quenched by europium ion in EuTb( m MBA) 6(phen) 2·2H 2O; the emission intensity from terbium ion can be greatly enhanced by yttrium ion in TbY( m MBA) 6(phen) 2·2H 2O. The mechanism about the results was discussed.

Synthesis,structures,thermal and magnetic properties of a series of lanthanide Ln=Sm,Gd,Er,Yb complexes with 4-quinolineacarboxylate

A series of lanthanide binuclear complexes, Ln2（L）6（H2O）4·2H2O（Ln=Sm（Ⅲ）, Gd（Ⅲ）, Er（Ⅲ）, Yb（Ⅲ）, HL=4-quinolinea-carboxylic acid, were synthesized by reactions of corresponding rare earth salts with 4-quinolineacarboxylic acid at room temperature and were characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction.X-ray diffraction analyses showed that they exhibited the same binuclear architecture and crystallized in monoclinic system and P21/c space group.In four complexes, each metal center adopted nine-coordinated mode coordinated by nine O atoms from two H2O molecules and three carboxyls of three ligands, and HL showed three different coordination modes.The variable-temperature magnetic susceptibility showed that complex Gd2（L）6（H2O）4·2H2O performed very weak antiferromagnetic property at low temperature and exchange was almost paramagnetic at high temperature.Complexes Er2（L）6（H2O）4·2H2O and Yb2（L）6（H2O）4·2H2O performed dominating antiferromagnetic coupling.

Synthesis, Structure and Luminescent Properties of Three 1D Chain Rare Earth Complexes

Three 1 D chain coordination polymers [Ln(pydc)2(H2 O)2]n·n Him(Ln = Dy(1), Gd(2), Sm(3), H2 pydc = pyridine-2,5-dicarboxylic acid, Im = imidazole), were solvothermally synthesized by the reaction of pyridine-2,5-dicarboxylic acid(H2 pydc), Ln(Ⅲ) salts and imidazole. They have been characterized by X-ray single-crystal diffraction, IR spectra, TGA analysis and elemental analysis. Structural analyses revealed that complexes 1~3 have similar 1 D chain structures and belong to P1 space group. It is noteworthy that complexes 1~3 exhibited excellent thermal stability and no weightlessness below 117 ℃. Meanwhile, 1 and 3 show characteristic fluorescence of corresponding lanthanide metal ions in solid state at room temperature.

Synthesis and Complexing Properties of Three Aminopolyphosphonic Acids with Rare Earth Ions

Three white crystalline aminopolyphosphonic acids, DTHMP, TTHMP and TPHMP were synthesized by a modified Mannich reaction under gentle conditions. The products were isolated and purified with a SP-Sephadex C-25 column. The acid-base and complexing properties of three aminopolyphosphonic acids with rare earth ions were investigated by means of potentiometric titration in aqueous medium at (25 +/- 0.1) degrees C and ionic strength I = 0.1 mol/L KNO3. The successive protonation constants of ligands and the formation constants of complexes with rare earth elements were obtained. The results show a double-double effect for lgK(MHiL) against atomic number of lanthanide. The properties are advantageous for the separation of the rare earth elements.

Fluorescence Properties of Eu^(3+)/Gd^(3+)/Citric Acid Mixed Complexes Doping in Silicon Rubber Matrix

Series of doped rare earth compiexes-EuxGd(1-x) (CA)3·nH2O (CA = citric acid) were synthesized. Some characterizations were taken for these complexes. The experimental results shows that the doped rare earth complexes have the best fluorescence property when the ratio of Eu and Gd is from 0.7 to 0.3. Silicon rubber-based composites were prepared by mechanical blending the EuxGd(1-x) (CA)3·nH2O and silicon rubber. Then, the fluorescent property of the composites was studied. It is found that the fluorescence intensity of the composites increase linearly with the contents of the rare earth complexes increasing.

Synthesis, Magnetic Property and Crystal Structure of a Ytterbium-Copper Mixed Metal Complex:Yb_2Cu_3L_6·6H_2O (L=O(CH_2COO)_2)

Reaction of hydrated ytterbium nitrate and copper nitrate with diglycolic acid at pH= 7 produced a new Yb-Cu mixed metal complex, Yb2Cu3L6. 6H2O(L= O(CH2COO)2). Complex Yb2Cu3O36C2H36 (Mr= 1437. 23) crystallized in hexagonalP6/mcc (No. 192) with cell parameters of a= 14. 344 (3), c= 15. 470(7) A,V= 2757(2) A 3; Z= 2; F(000) = 1390; Dcalc.= 1- 731 g/cm3 μ(MoKa) =45. 8 cm-1. The final agreernent factors are R= 0. 077 and Rw = 0.089 for 867 observed reflections with I>3δ(I). It has been characterized by elemental analysis, IR spectrum, magnetic measurement and X-ray crystallography. In the complex, the Yb3+ ion is 9-coordinated tothree ether oxygen and six carboxylate oxygen atoms from three ligands, the copper ionis coordinated to four oxygen atoms from four carboxylate groups of four ligands andtwo water molecules. The Yb3+ ions and the Cu2+ ions are connected by the carboxylate groups of the ligands, thus resulting in the formation of the complicated networkstructure.

Magnetocaloric effect and slow magnetic relaxation behavior in binuclear rare earth based RE_(2)(L)_(2)(DMF)4(RE=Gd,Tb,and Dy) complexes

Three binuclear rare earth based complexes combining RE ions with semirigid tricarboxylic ligand(H_(3)L).namely,[RE_(2)(L)_(2)(DMF)_(4)][RE=Gd,Tb,and Dy;H_(3)L=5-((4-Carboxybenzyl)oxy)isophthalic acid;DMF=N,N-dimethylformamide]complexes,were fabricated success fully.The RE_(2)(L)_(2)(DMF)_(4) co mplexe s consist of two central RE ions with the same coordination environment which were connected by two tridentate bridging carboxylic groups and two syn-syn bidentate bridging carboxylic groups originating from the L^(3-)ligands to form the{RE_(2)}dimeric unit,and thus provides the basis for further constructing a dense three-dimensional(3 D)network structure.Moreover,the present RE_(2)(L)_(2)(DMF)_(4) complexes can be described by a topology diagram with the topology point symbol of{4^(2)·6}_(2){4^(4)·6^(2)·8^(7)·10^(2)}.Weak antiferromagnetic(AFM)coupling between the adjacent RE ions for all the present complexes was found according to the magnetic calculations.The observed significant cryogenic magnetocaloric effect(MCE)with the maximum magnetic entropy change-ΔS_(M)^(max) to be 26.3 J/(kg·K)withΔH=7 T in Gd_(2)(L)_(2)(DMF)_(4) complex makes it competitive for the cryogenic magnetic refrigerant.Moreover,the slow magnetic relaxation behavior at 0.2 T dc field with an obvious large U_(eff)/k=45(4)K and τ_(0)=6.5(2)×10^(-10)s was confirmed in Dy_(2)(L)_(2)(DMF)_(4)complex.This work not only provides an effective strategy for obtaining molecular materials with high MCE,but also confirms that tricarboxylate ligands are the ideal choice for constructing stable high dimensional geometric structures.

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.

Syntheses,crystal structures and magnetic properties of three lanthanide-nitronyl nitroxide complexes

Three new lanthanide-nitronyl nitroxide radical complexes were successfully synthesized with the formula of [Ln（hfac）3（PyNONIT）2]（Ln=Dy（1）, Tm（2）, Ho（3））. All the complexes were isostructural and crystallized in C2/c space group, in which the central metal ions were eight-coordinated in slightly distorted square antiprism coordination geometries（D4d symmetry）. Magnetic studies indicated the existence of antiferromagnetic interaction in complexes 1–3.

Synthesis and luminescent properties of novel pyrazolone rare earth complexes

A novel pyrazolone pyridine-containing ligand, 2,6-bis（1-phenyl-4-ethoxycarbonyl-5-pyrazolone-3-yl）pyridine （H2L） was designed and synthesized from pyridine-2,6-dicarboxylic acid （1）, and its Eu（III） and Tb（III） complexes were prepared. The ligand and complexes were characterized in detail based on FT-IR spectra, ^1H NMR, elemental analysis and thermal analysis, and the formula of Ln2L3·4H2O （Ln=Eu or Tb） of rare earth complexes was confirmed. The UV-vis absorption spectra and photoluminescence properties of the complexes were investigated, which showed that the Eu（III） and Tb（III） ions could be sensitized efficiently by the ligand （H2L） and emit the photolumi- nescence with high intensity, narrow half-peak width, and monochromic light. The results indicated that the complexes showed potential as excellent luminescent materials.

Syntheses of new di-nuclear and tetra-nuclear lanthanide 9-anthracenecarboxylates:Magnetocaloric effect,slow magnetic relaxation and luminescent properties

Lanthanide complex-based materials with magnetic and luminescent properties have received a great deal of attention,owing to their importantly potential applications in diverse fields.In this work,the 9-anthracenecarboxylic acid(9-Haca)as bridging ligand was applied in combination with optically activeπ-conjugated 2,4,6-tri(2-pyridyl)-1,3,5-triazine(tptz)to construct a series of new di-nuclear and tetranuclear lanthanide 9-anthracenecarboxylates[La_(2)(9-aca)_(6)(tptz)_(2)(μ-H_(2)O)]·0.25H_(2)O(1),[Ln_(2)(9-aca)_(6)(tptz)_(2)(H_(2)O)_(2)]·0.5AQ·CH_(3)COOH_(2)H_(2)O[Ln=Sm(2a),Eu(2b),Gd(2c),Tb(2d),Dy(2e),Tm(2f);AQ=9,10-anthracenedione]and[Ln_(4)(9-aca)_(10)(tptz)_(2)(CH3COO)2]·H_(2)O[Ln=Eu(3a),Gd(3b),Dy(3c)].1 displays a di-nuclear centrosymmetric moiety[La_(2)(9-aca)_(6)(tptz)_(2)(μ-H_(2)O)]built up from two complex[La(9-aca)_(2)(tptz)]groups bridged by one H_(2)O molecule and two syn-syn-μ2-η1:η1-9-aca-bridging ligands,while 2a-2f are isostructural and co mprise another di-nuclear centrosymmetric moieties[Ln_(2)(9-aca)_(6)(tptz)_(2)(H_(2)O)_(2)]based on two complex[Ln(9-aca)_(2)(tptz)(H_(2)O)]groups connected by two syn-syn-μ2-η1:η1-9-aca-bridging ligands,3a-3c are isostructural and show tetra-nuclear centro symmetric moieties[Ln4(9-aca)10(tptz)2(CH3COO)2]containing three types of coordination modes of 9-aca-ligands.The present compounds offer the only examples of lanthanide 9-anthracenecarboxylates decorated by optically active tptz.Magnetic investigations of 2a,2c-2f,and 3b-3c indicate that 3c is typical of slow relaxation of the magnetization,while 2c and 3b show significant magnetocaloric effect(MCE)with the value of-ΔSm of 5.26 J/(kg·K)at 4 K and 15.65 J/(kg·K)at 2 K(ΔH=7 T),respectively.The luminescent properties were also studied and reveal that the characteristic luminescent properties of the 7r-conjugated aromatic ligands are introduced into magnetic lanthanide 9-anthracenecarboxylates,simultaneously exhibiting slow magnetic relaxation(or MCE)and luminescent properties.

Hydrothermal synthesis, crystal structure and magnetic properties of a Dy~Ⅲ-Fe~Ⅲ heteronuclear complex

A new 3d-4f heteronuclear complex [Fe（phen）3]2[FeDy（H2O）（tiron）3]·6H2O （1,Na2H2tiron=disodium 4,5-dihydro-xybenzene-1,3disulfonate） was synthesized by the hydrothermal reaction. The complex crystallized in the cubic system, space group P213 with the cell parameters：a=2.18786（14）nm, V=10.4727（12）nm3 , Z=4, F（000）=4720, R1=0.0493, wR2 =0.1165, S=1.05. In each [FeDy（H2O）（tiron）3]6-unit, it was revealed that the Fe3＋ ion was in a FeO6 distorted trigonal anti-prism coordination polyhedron completed by six phenolate O atoms from three tiron 4- ligands, while Dy3＋ in a DyO7 distorted monocapped trigonal anti-prism coordination polyhedron completed by three phenolate μ2-O atoms and three O atoms from sulfonate groups of three ligands and one O atom from water. The magnetic properties of the complex was determined in the range of 2-300K, indicating the antiferromagnetic interaction between the central DyIII-FeIII ions.

New Rare Earth（Ⅲ） Complexes with H2tmtaa

A series of Ln（tmtaa）（Htmtaa）·CH2Cl2 （Ln = Sm, Tb, Er and Yb） complexes were prepared and characterized by infrared spectra, mass spectra and molecular electronic spectroscopy as well as DSC measurement. A sandwich structure containing all the eight nitrogen atoms of tmtaa and Htmtaa was proposed for these complexes. X-ray photoelectron spectra （XPS） of these complexes revealed that four nitrogen atoms of both tmtaa and Htmtaa were chemically equivalent to each other, respectively. The acidic hydrogen of Htmtaa did not bind specifically to any nitrogen atom of Htmtaa, but was shared by all the four nitrogen atoms. The magnetic properties of these complexes were found to be in good agreement with their theoretical values.

Synthesis and luminescent properties of terbium complex with 2-amino-4-chlorobenzoic acid

A novel complex [Tb（L）_2（H_2O）_3·H_2O]（where L=2-amino-4-chlorobenzoic acid） was synthesized and characterized by a series of analysis. The molecular formula of complex was confirmed by Fourier transform infrared（FT-IR） spectroscopy and thermogravimetric/differential thermogravimetric（TG-DTG） measurements. The optical properties of complex was measured by ultraviolet spectroscopy（UV） and fluorescence spectroscopy（FS）. The results indicated that Tb^（3＋） in the complex was coordinated by ligand, and the complex emitted bright yellow-green luminescence with main peak at 548.8 nm with excitation at 369.4 nm.

Dopamine-containing gadolinium complex as magnetic resonance imaging contrast agent

Gadolinium diethylenetriamine-pentaacetic bisdopamide （Gd-DTPA-2DA） was synthesized by the incorporation of dopamine to diethylenetriaminepentaacetic acid （DTPA） and further reaction with gadolinium chloride. In vitro and in vivo properties were also evaluated. Gadolinium complex Gd-DTPA-2DA possessed higher relaxation effectiveness and less cytotoxicity to HeLa cells than that of Gd-DTPA. Moreover, Gd-DTPA-2DA greatly enhanced the contrast of MR images of the brains, provided prolonged intravascular duration, and pro- duced highly contrasted visualization of the brain.

稀土N-苯基邻氨基苯甲酸-1,10-邻菲咯啉二元、三元配合物的合成、表征及其光物理性质

合成了几种新型的稀土（钆，铕，铽）的Ｎ－苯基邻氨基苯甲酸－１，１０－邻菲咯啉的二元、三元配合物．以元素分析、红外光谱和紫外光谱进行了表征，确定了组成．同时以低温磷光光谱确定了配体的三重态能级为２４３３０ｃｍ－１，研究了配体与稀土离子的能级匹配．详细讨论了配合物的光物理性质如发光性能和配体与稀土离子之间以及有机配体之间的分子内能量传递机制，结果发现，铽的Ｎ－苯基邻氨基苯甲酸－１，１０－邻菲咯啉配合物的发光性能良好．

稀土3,4-呋喃二甲酸,1,10-二氮杂菲配合物的光物理性质

研究了稀土Ｇｄ３＋、Ｅｕ３＋、Ｔｂ３＋的３，４呋喃二甲酸，１，１０二氮杂菲（Ｐｈｅｎ）配合物的合成、红外光谱、紫外光谱及光物理性质。详细讨论了配合物的分子内能量传递过程。发现分子内能量传递效率依赖于稀土中心离子的共振发射能级与配体最低三重态能级之间的相对位置。

稀土、2,2’-联吡啶、邻氨基苯基苯甲酸配合物合成、光谱表征及荧光性质

2,2’-联吡啶(bipy)、邻氨基苯基苯甲酸(HL)与稀土离子(RE=Tb,Eu,Sm,Nd)合成了固体稀土配合物。用元素分析、摩尔电导、紫外光谱、红外光谱、差热-热重分析和荧光光谱,对配合物的组成进行了确定和表征,并对TbL3和TbL3·bipy·3H2O的荧光性能进行了测试和讨论。TbL3·bipy·3H2O的荧光强度比TbL3的荧光强度强。

铕(Ⅲ)-对茴香酸-邻菲罗啉三元配合物的合成及谱学性质

本文合成了ＥｕＬ３·ｐｈｅｎ·Ｈ２Ｏ（Ｌ＝对茴香酸根，ｐｈｅｎ＝邻菲罗啉）固体配合物，对所合成的配合物进行了元素分析，摩尔电导，ＩＲ，ＵＶ，ＮＭＲ等测试。

铕-樟脑酸-1,10-菲咯啉配合物的合成及发光性质

实验合成了稀土铕 樟脑酸 1,10 菲咯啉二元、三元配合物 ,通过元素分析、1 HNMR、中红外光谱、拉曼光谱 ,确定了配合物的组成为Eu2 (CA) 3·2H2 O ,Eu2 (CA) 3(phen) 2 (CA :樟脑酸根 ,phen :1,10 菲咯啉 ) ,另外 ,又合成了铕、镧混配的上述配合物 ,通过三维荧光光谱确定最佳激发波长为 310nm ,最强荧光波长为6 12nm ,即在 310nm光的激发下 ,发射光谱显示Eu3+ 的特征发射光谱 ,产生 7条谱带 ,分别是 5D0 7F0 (5 79nm) ,5D0 7F1 (5 94nm) ,5D0 7F2 (6 12 ,6 2 0nm) ,5D0 7F3(6 5 0nm) ,5D0 7F4 (6 89,6 97nm) ,其中7F2 和7F4能级发生了分裂。对荧光强度的研究表明 ,镧的掺入并没有降低铕的荧光强度 ,说明镧对铕的荧光发射有增强作用 ,但发射峰的位置基本不变。