Synthesis and Thermal Decomposition Mechanism of Rare Earth （RE=La, Y, Gd） Salicylates

The rare earth (RE=La, Y, Gd) salicylates were synthesized by the rheological phase reaction method. The complexes were characterized by elemental analysis, infrared spectra (IR), X-ray powder diffraction (XRD) and thermal gravity analysis (TG). They can be represented by general formula RE(HSal)3 (RE=La, Y, Gd; HSal=C6Ha(OH)COO). The crystals of them are monoclinic and have layered structure. The mechanism of thermal decomposition of rare earth salicylates was studied by using TG, DTA, IR and gas chromatography-mass spectrometry (GC-MS). The thermal decomposition of the rare earth salicylates in nitrogen gas proceeded in three stages: firstly, they were decomposed to form RE2(Sal)3 (Sal=C6H4OCOO) and salicylic acid; then, RE2(Sal)3 were decomposed further to form RE2O(CO3)2 and some organic compounds; finally, RE2O(CO3)2 were decomposed to form rare earth metal oxides (RE2O3) and carbon dioxide. The organic compounds obtained from the second step of the reaction are mainly dibenzofuran, xanthenone, 6H-benzo[c]chromen-6-one, 6-phenyl-6H-benzo[c]chromene, and 1,3-diphenyl-1, 3-dihydro-2-benzofuran.     

Highly efficient enrichment and adsorption of rare earth ions (yttrium(III)) by recyclable magnetic nitrogen functionalized mesoporous expanded perlite

A magnetic mesoporous expanded perlite-based (EP_d-APTES@Fe₃O₄) composite was designed and synthesized as a novel adsorbent for enrichment of rare earth ions in aqueous solution. Effect of various factors including the pH of solution, contact time and adsorbent dosage on the adsorption behaviors of yttrium(III) by the EP_d-APTES@Fe₃O₄ nano-material composites from aqueous solution was investigated. The maximum adsorption capacity of the as-prepared materials for yttrium(III) ions was 383.2 mg/g. Among the various isotherm models, the Freundlich isotherm model could well described for the adsorption of the rare earth ions at pH 5.5 and 298.15 K. The kinetic analysis indicated that the adsorption process followed the pseudo-second order kinetics model, and the rate-determining step might be chemical adsorption. Thermodynamic parameters declared that the adsorption process was endothermic. In addition, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and the quantum chemical calculation indicated that the yttrium(III) ions were captured on the EP_d-APTES@Fe₃O₄ surface mainly by coordination with functional group of -NH₂. More importantly, the adsorption-desorption studies indicated that the EP_d-APTES@Fe₃O₄ nano-material composites had a high stability and good recyclability.     

Effect of the rare earth in the perovskite-type mixed oxides AMnO3 (A=Y, La, Pr, Sm, Dy) as catalysts in methanol oxidation

The effect of the rare earth in the perovskite-type mixed oxides AMnO₃ (A=Y, La, Pr, Sm, Dy) on catalytic properties in methanol oxidation was investigated in this work. The perovskites were prepared by reactive grinding in order to enhance the specific surface area in comparison with other classical synthesis procedures. These catalysts were characterized by N₂ adsorption, X-ray diffraction, H₂ temperature-programmed reduction (TPR-H₂), O₂-, CH₃OH- and CO₂-temperature-programmed desorption (TPD). The activity of the five catalysts under study in the methanol oxidation reaction was evaluated. The behaviour of the α-O₂ from the surface of the perovskite was strongly related to the nature of the A-site cation and particularly to its electronegativity but also to its density. Concerning the β-O₂ from the bulk, the rare earth only induces an indirect effect notably due to structural modifications. As suggested in a previous study, the activity in methanol oxidation was directly linked with the surface oxygen density. Under an excess of α-oxygen, the reaction intermediate was found to be a monodentate carbonate that decomposes into CO₂. The stability of monodentate carbonates was also found to be related to the electronegativity of the rare earth during both CH₃OH- and CO₂-temperature-programmed desorption. However, as soon as a lack of α-oxygen was observed in the structure, the dominant reaction intermediate was a bidentate carbonate that induces a consumption of anion vacancies in spite of the production of CO₂. Nevertheless, the accumulation of these carbonates leads to a decrease in the oxidation rate since their desorption requires high temperatures.     

Radical-Bridged Heterometallic Single-Molecule Magnets Incorporating Four Lanthanoceniums

The syntheses and magnetic properties of organometallic heterometallic compounds [K(THF)₆]{Co^I[(μ₃-HAN)RE₂Cp*₄]₂} ( 1-RE ) and [K(Crypt)]₂{Co^I[(μ₃-HAN)RE₂Cp*₄]₂} ( 2-RE ) containing hexaazatrinaphthylene radicals (HAN⋅³⁻) and four rare earth (RE) ions are reported. 1-RE shows isolable species with ligand-based mixed valency as revealed by cyclic voltammetry (CV) thus leading to the isolation of 2-RE via one-electron chemical reduction. Strong electronic communication in mixed-valency supports stronger overall ferromagnetic behaviors in 2-RE than 1-RE containing Gd and Dy ions. Ac magnetic susceptibility data reveal 1-Dy and 2-Dy both exhibit slow magnetic relaxation. Importantly, larger coercive field was observed in the hysteresis of 2-Dy at 2.0 K, indicating the enhanced SMM behavior compared with 1-Dy . Ligand-based mixed-valency strategy has been used for the first time to improve the magnetic coupling in lanthanide (Ln) SMMs, thus opening up new ways to construct strongly coupled Ln-SMMs.     

Removal of phosphate from solution by adsorption and precipitation of calcium phosphate onto monohydrocalcite

The sorption behavior and mechanism of phosphate on monohydrocalcite (CaCO₃?H₂O: MHC) were examined using batch sorption experiments as a function of phosphate concentrations, ionic strengths, temperatures, and reaction times. The mode of PO₄ sorption is divisible into three processes depending on the phosphate loading. At low phosphate concentrations, phosphate is removed by coprecipitation of phosphate during the transformation of MHC to calcite. The sorption mode at the low-to-moderate phosphate concentrations is most likely an adsorption process because the sorption isotherm at the conditions can be fitted reasonably with the Langmuir equation. The rapid sorption kinetics at the conditions is also consistent with the adsorption reaction. The adsorption of phosphate on MHC depends strongly on ionic strength, but slightly on temperature. The maximum adsorption capacities of MHC obtained from the regression of the experimental data to the Langmuir equation are higher than those reported for stable calcium carbonate (calcite or aragonite) in any conditions. At high phosphate concentrations, the amount of sorption deviates from the Langmuir isotherm, which can fit the low-to-moderate phosphate concentrations. Speciation–saturation analyses of the reacted solutions at the conditions indicated that the solution compositions which deviate from the Langmuir equation are supersaturated with respect to a certain calcium phosphate. The obtained calcium phosphate is most likely amorphous calcium phosphate (Ca₃(PO₄)₂?xH₂O). The formation of the calcium phosphate depends strongly on ionic strength, temperature, and reaction times. The solubility of MHC is higher than calcite and aragonite because of its metastability. Therefore, the higher solubility of MHC facilitates the formation of the calcium phosphates more than with calcite and aragonite.     

Oxyhumolite influence on adsorption and desorption of phosphate on blast furnace slag in the process of two-stage selective adsorption of Cu(II) and phosphate

Two-stage adsorption was used for selective removal of Cu(II) and phosphate from aqueous solutions. In the first stage, adsorption of Cu(II) and phosphate on oxyhumolite (OX) was examined. The pseudo second-order equation was found to be the best fit for the kinetic adsorption data. The adsorption capacity of OX for Cu(II) and phosphate depends on the adsorption time, the equilibrium pH influences only the adsorption of Cu(II). The high adsorption efficiency (E = 95 %, pH 3.5, 0.5 g of the solid sorbent and 50 cm³ of the solution, c = 4 mmol dm^?3) of OX for Cu(II) is caused by the presence of humic acids (HA). In the second stage, blast furnace slag (BFS) and activated blast furnace slag (BFS-A) were used to remove phosphates. The presence of OX in the first stage positively influences the adsorption efficiency of sorbents in the second stage due to the soluble humic compounds and residues of humic acids (HA) which support the precipitation of Ca-phosphates on BFS and the ions exchange reactions on BFS-A. Adsorption equilibrium of phosphate on both slags at 298 K can be well described by the Langmuir isotherm equation. Desorption of Cu(II) from OX was around 70 %. The presence of OX in the first stage also influences the desorption of phosphate bound in the second stage. Desorption efficiency of both slags for phosphate was about 60 %.     

Asymmetric fluorination of β-keto esters catalyzed by chiral rare earth perfluorinated organophosphates

Novel chiral rare earth metal complexes bearing perfluorinated binaphthyl phosphate ligand RE[(R)-F₈BNP]₃ (RE = rare earth; F₈BNP = 5,5′,6,6′,7,7′,8,8′-octafluoro-1,1′-binaphthyl-2,2′-diyl phosphate) have been synthesized and used as a catalyst for the asymmetric electrophilic fluorination reaction of β-keto esters. The use of Sc[(R)-F₈BNP]₃ catalyst in combination with 1-fluoropyridinium triflate (NFPY–OTf) as a fluorinating agent was found to give the desired α-fluoro-β-keto esters in high chemical yields and enantiomeric excesses (up to 88% ee) under mild conditions.     

Rare earth ions-enhanced gold nanoclusters as fluorescent sensor array for the detection and discrimination of phosphate anions

The discrimination and detection of phosphate anions have attracted extensive attention due to their important roles in various biological processes. Compared with sensors to detect one individual phosphate at a time, sensor arrays are able to discriminate multiple phosphates simultaneously. In this study, we developed a rare earth ions enhanced AuNCs-based sensor array to achieve facile and rapid identification of phosphate anions (PPi, ADP and ATP). The rare earth ions (i. e., Ce³⁺, Gd³⁺, Tm³⁺ and Yb³⁺) can significantly enhance the fluorescence of AuNCs through aggregation-induced emission effect. And the subsequent addition of phosphate anions can recover the fluorescence of the AuNCs-rare earth ions assembly. Thanks to the different numbers of phosphate group and different steric hindrance effects of phosphate anions, the recovery fluorescence of AuNCs-rare earth ions assembly induced by PPi, ADP or ATP are respectively distinct. Thus the sensor array composed of AuNCs and different rare earth ions is able to distinguish those phosphate anions. Finally, the sensor array was successfully demonstrated to identify the phosphates in blind samples.     

新型层状有机聚合物-无机杂化磷酸铝(AlPS-PVPA)催化剂载体材料的合成及表征

以苯乙烯-苯乙烯基膦酸共聚物、磷酸二氢钠作磷(膦)源,在温和的条件下,通过调节有机膦酸和无机磷酸的比例,合成了一系列不同化学计量比的聚(苯乙烯-苯乙烯基膦酸)-磷酸铝有机聚合物-无机杂化材料。通过FTIR、TG、N2吸附、XRD、SEM和TEM等表征手段对其进行了表征,并提出了其理想的结构模型。结果表明,这类杂化材料具有规则的层状结构和较高的热稳定性,作为催化剂载体具有潜在的应用价值。     

Challenges to develop single-column MA(III) separation from HLLW using R-BTP type adsorbents

In order to directly separate trivalent minor actinides(MA:Am,Cm) from fission products(FP) containing rare earths(RE) in high level radioactive liquid waste(HLLW),the authors have challenged to develop a simplified MA separation process by extraction chromatography using a single column.Attention has been paid to a new type of nitrogen-donor ligands,R-BTP(2,6-bis(5,6-dialkyl-1,2,4-triazin-3-yl) pyridine,R:alkyl group) as an extractant because it shows high extraction selectivity for Am(Ⅲ) over RE(Ⅲ).It is known that the R-BTP ligands show different properties such as adsorbability and stability by having different alkyl groups.Therefore,some novel adsorbents were prepared by impregnating different types of R-BTP ligands(isohexyl-,isoheptyl-and cyheptyl-BTP) and a similar ligand to the R-BTP,ATP(2,6-bis(1-aryl-1H-tetrazol-5-yl)pyridines),into the porous silica/polymer support(SiO2-P particles).This work deals with comparison in adsorption and desorption properties of Am and some FP in HNO 3 solution onto such R-BTP type adsorbents,as well as chemical and radiolytic stability of the adsorbents.Then the possibility of a single-column separation of MA from main FP was pursued by evaluating the results of column experiments using the most promising adsorbent(isohexyl-BTP/SiO2-P) under temperature control.In addition,elution behaviors of U and Pd were also estimated.     

Ring opening polymerization of α‐amino acid N‐carboxyanhydrides catalyzed by rare earth catalysts: Polymerization characteristics and mechanism

Five rare earth complexes are first introduced to catalyze ring opening polymerizations (ROPs) of γ‐benzyl‐L ‐glutamate N‐carboxyanhydride (BLG NCA) and L ‐alanine NCA (ALA NCA) including rare earth isopropoxide (RE(OiPr)₃), rare earth tris(2,6‐di‐tert‐butyl‐4‐methylphenolate) (RE(OAr)₃), rare earth tris(borohydride) (RE(BH₄)₃(THF)₃), rare earth tris[bis(trimethylsilyl)amide] (RE(NTMS)₃), and rare earth trifluoromethanesulfonate. The first four catalysts exhibit high activities in ROPs producing polypeptides with quantitative yields (>90%) and moderate molecular weight (MW) distributions ranging from 1.2 to 1.6. In RE(BH₄)₃(THF)₃ and RE(NTMS)₃ catalytic systems, MWs of the produced polypeptides can be controlled by feeding ratios of monomer to catalyst, which is in contrast to the systems of RE(OiPr)₃ and RE(OAr)₃ with little controllability over the MWs. End groups of the polypeptides are analyzed by MALDI‐TOF MS and polymerization mechanisms are proposed accordingly. With ligands of significant steric hindrance in RE(OiPr)₃ and RE(OAr)₃, deprotonation of 3‐NH of NCA is the only initiation mode producing a N‐rare earth metallated NCA ( i ) responsible for further chain growth, resulting in α‐carboxylic‐ω‐aminotelechelic polypeptides after termination. In the case of RE(BH₄)₃(THF)₃ with small ligands, another initiation mode at 5‐CO position of NCA takes place simultaneously, resulting in α‐hydroxyl‐ω‐aminotelechelic polypeptides. In RE(NTMS)₃ system, the protonated ligand hexamethyldisilazane (HMDS) initiates the polymerization and produces α‐amide‐ω‐aminotelechelic polypeptides. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

K3Ln[OB(OH)2]2[HOPO3]2 (Ln=Yb, Lu): Layered rare-earth dihydrogen borate monohydrogen phosphates

Two isotypic layered rare-earth borate phosphates, K₃Ln[OB(OH)₂]₂[HOPO₃]₂ (Ln=Yb, Lu), were synthesized hydrothermally and the crystal structures were determined by single-crystal X-ray diffraction (R3?, Z=3, Yb: a=5.6809(2) Å, c=36.594(5) Å, V=1022.8(2) ų, Lu: a=5.6668(2) Å, c=36.692(2) Å, V=1020.4(1) ų). The crystal structure can be described in terms of stacking of Glaserite-type slabs consisting of LnO₆ octahedra interlinked by phosphate tetrahedra and additional layers of [OB(OH)₂]^- separated by K⁺ ions. Field and temperature dependent measurements of the magnetic susceptibility of the Yb-compound revealed Curie-Weiss paramagnetic behavior above 120 K (μ_eff=4.7 μ_B). Magnetic ordering was not observed down to 1.8 K.     

Adsorption behavior of trivalent americium and rare earth ions onto a macroporous silica-based isobutyl-BTP/SiO2-P adsorbent in nitric acid solution

To separate minor actinides from high level liquid waste (HLLW) of PUREX reprocessing, a silica-based macroporous isobutyl-BTP/SiO₂-P adsorbent was synthesized by impregnating isobutyl-BTP (2,6-di(5,6-diisobutyl-1,2,4-triazin-3-yl)pyridine) extractant into the macroporous SiO₂-P support with a mean diameter of 60 μm. A partitioning process using extraction chromatography for the treatment of HLLW was designed consisting five separation columns. As a partly work focused on isobutyl-BTP/SiO₂-P separation column, adsorption behavior of ²⁴¹Am and trivalent rare earth (RE) from simulated HLLW onto silica-based isobutyl-BTP/SiO₂-P adsorbent was investigated by batch method. Meanwhile, the chemical and radiolytic stabilities of isobutyl-BTP/SiO₂-P adsorbent against 0.01 M HNO₃ solution and γ-ray irradiation were studied. It was found that isobutyl-BTP/SiO₂-P adsorbent exhibited good adsorption selectivity for ²⁴¹Am over RE(III) in 0.01 M HNO₃ solution and showed weak or no adsorption affinity to light and middle RE(III) groups. In addition, in stability experiments, isobutyl-BTP adsorbent showed excellent stability against 0.01 M HNO₃ solution and γ-ray irradiation over 4 months contact time.     

Thermochemical properties of RE (Gly)4 Im (ClO4) 3 2H2O (RE = La,Pr, Nd,Sm, Eu)

The enthalpies of solution in water for five new light rare earth ternary complexes RE(Gly)₄Im(ClO₄)₃ 2H₂O (RE = La, Pr, Nd, Sm, Eu; Gly‐glycine; Im‐imidazole) were measured by means of a Calvet microcalorimeter. The empirical formula of enthalpy of solution (Δ_solH), relative apparent molar enthalpy (πL_i), relative partial molar enthalpy (L_i) and enthalpy of dilution (Δ_dllH_1,2) were drawn up by the data of enthalpies of solution of these complexes. From three plots of the values of standard enthalpy of solution Δ_sol H?, πL_i, L_i) versus the values of ionic radius (r) of the light rare earth elements, the grouping effect of lanthanide was observed, showing that the coordination bond between rare earth ion and ligand possesses a certain extent of the property of a covalent bond. The standard enthalpies of solution in water of similar complexes, Ce(Gly)₄Im(ClO₄)₃.2H₂O were estimated according to the plot of Δ_solH?, versus r.     

Synthesis and application of a macroporous silica-based polymeric octyl(phenyl)-N,N-diisobutylcarbamoylmethylphoshine oxide composite for the chromatographic separation of high level liquid waste

Summary The Minor Actinides Recovery from HLW by Extraction Chromatography (MAREC) process was used mainly for the separation of minor actinides (MAs) and some specific fission products (FPs) from highly active liquid waste (HLW) by the composite CMPO/SiO₂-P of the macroporous silica based polymeric octyl(phenyl)-N,N-diisobutylcarbamoylmethylphoshine oxide (CMPO) and others. In this study a cascade of chromatographic separation was performed on a 3.0M HNO₃ solution containing 5.0 ^. 10^-3M of 13 elements, at 323 K. The cascade consisted of three columns the first and second ones were packed with CMPO/SiO₂-P and the third with SiO₂-P particles. The first column was employed to prepare various eluents containing saturated CMPO. The second column was used for separation into groups. The CMPO of CMPO/SiO₂-P was recovered from the effluent by the third column and a CMPO-free effluent containing minor actinides was obtained. The elements contained in the simulated HLW of 3.0M HNO₃ were separated into (1) a non-adsorption group (Sr, Cs, and Ru etc.), (2) a MA-hRE (heavy rare earth)-Mo-Zr group, and (3) a lRE (light rare earth) group by eluting with 3.0M HNO₃, 0.05M DTPA (diethylenetriaminepentaacetic acid) (pH 2.0) and HNO₃ (pH 3.5), respectively. The resultant MA-hRE-Mo-Zr mixture containing minor actinides was then separated into the groups (1) Pd-Ru, (2) MA-hRE, and (3) Mo-Zr by utilizing 3.0M HNO₃, distilled water, and 0.05M DTPA (pH 2.0) as eluents. More than 92% of CMPO in the MA-hRE containing effluent was adsorbed by SiO₂-P particles. The effectivity and technical feasibility of MAREC process were demonstrated.     

Phosphate uptake behavior and mechanism analysis of facilely synthesized nanocrystalline Zn‐Fe layered double hydroxide with chloride intercalation

Zn‐Fe layered double hydroxide with chloride intercalation (ZFCL) was synthesized by a coprecipitation method at room temperature. ZFCL was characterized by N₂ adsorption‐desorption isotherms, X‐ray diffraction, scanning electron microscope, Zeta‐sizer analyzer, X‐ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The results showed that ZFCL had large surface area and layered structure. The maximum adsorption capacity of ZFCL was 150.6 mg/g at 25°C. That was higher than most other adsorbent which were reported. The kinetic data were described better by the pseudo‐second‐order adsorption kinetic rate model. The adsorption isotherm on the adsorbent was described by Langmuir, Freundlich, and Sips models at pH 6 and followed the fitting order: Sips >Freundlich>Langmuir. Thermodynamic analyses indicated that the phosphate adsorption on ZFCL was endothermic and spontaneous in nature. The sequence of coexisting cations and anions competing with phosphate was Ca²⁺ > Mg²⁺ > Na⁺ and SO₄²⁻ > NO₃⁻ > Cl⁻. ZFCL can be regenerated by the sequential use of NaOH and ZnCl₂. The adsorption capacity remained high as 108.6 mg/g after regeneration of 3 times. The results of zeta potential, Fourier transform infrared spectroscopy, and X‐ray photoelectron spectroscopy analyses indicated that the phosphate adsorption mechanisms involved ion exchange, Zn₃(PO₄)₂ precipitation, and the formation of inner‐sphere complex via replacement of surface hydroxyl groups by phosphate.     

Evaluation of phosphate removal from water by calcined-LDH synthesized from the dolomite

In the present study, the characteristics of the adsorption of phosphate on calcined layered double hydroxides (LDHs) from aqueous solution were evaluated under laboratory conditions. The anionic clays were Mg₃pH₁₀-LDH synthesized by co-precipitation and D ₁pH₁₀-LDH synthesized from the dolomite. The equilibrium isotherm showed that the uptake of phosphate ion by Mg₃pH₁₀(500)-LDH was in agreement with the Langmuir and Freundlich equations; the Langmuir model gave a better fit to the experimental data than the Freundlich one. The equilibrium isotherm showed, however, that the adsorption of the phosphate on D₁pH₁₀(500)-LDH was accompanied with precipitation reac tion of the phosphate salts. A mechanism proposed for the removal of phosphate ion has been confirmed by X-ray diffraction and FT-IR spectroscopy.     

Studies on Polarographic Adsorptive Wave of the System of the Rare Earth (III)-Copper(Ii)-M-Trifluomethyl Chlorophosphonazo

Abstract

A new heteronuclear complex, rare earth (III)-copper (II)-m-trifluomethyl chlorophosphonazo (CPA-mCF₃) system for determining trace rare earth ions is presented. In a medium of 0.02mol/L NH₄Cl,1. 0×10^?3mol/L Cu(II),1.0×10^?5 mol/L CPA-mCF₃, a very sensitive polarographic adsorptive wave is observed by using a single sweep oscillopolarograph at about –0.83V (vs. Ag/AgCl). The linear relationship between the peak current and the concentration of rare earth exists from 6. 0×10^?9 to 1. 0×10^?6 mol/L. The detection limit of rare earth is down to 2. 0×10^?9 mol/L for Tm³⁺. This method has been applied to determine trace RE in several samples of Chinese tea. The results are satisfactory. The composition of the complex is detected as RE (II): Cu (II): CPA-mCF₃ = 1: 1: 2.     

Further Results on Behaviors of Rare Earth Metal Ions in Centrifugal Partition Chromatography with DI(2-Ethylhexyl) Phosphoric Acid

Abstract

In centrifugal partition chromatography (CPC) of rare earth metal ions (RECl₃) by the use of di(2-ethyl-hexyl)phosphate (D2EHPA) as “separator” in the stationary phase, effects of number of microcells and stationary solvent were investigated for improving separation. By increasing the number of microcells from 1200 (3 cartridges) to 2400 (6 cartridges), the peak resolution value (R) for the separation of PrCl₃ versus NdCl₃ was improved from 0.37 to 0.62. Heavier RE ions (ErCl₃ and YbCl₃) was able to separate almost completely by using CHCl₃ as stationary solvent. This result suggests that by adjusting these two factors, in addition to adjusting [HC1] in the mobile phase (previously reported), almost whole series of adjacent couples of RE ions will be effectively separated by CPC with acidic D2EHPA. In contrast, neutral tri-n-butyl phosphate (TBP) was found to be a poor separator.     

Structures and luminescent properties of Sm(III) and Dy(III) coordination polymers with 2,4,6-pyridinetricarboxylic acid

Two rare earth coordination compounds with 2,4,6-pyridinetricarboxylic acid (H₃pta) have been synthesized by the hydrothermal method; the formula is {[RE(pta)(H₂O)₃]?·?H₂O} _n [RE?=?Sm (1) and Dy (2)]. Complexes 1 and 2 are crystallized in the monoclinic crystal system with P2₁/c space group. X-ray structure analyses show the two complexes have the same structure. Each pta^3? connects three rare earth ions. Both the Sm(III) and Dy(III) complexes exhibit characteristic luminescence in the visible region upon excitation with UV-rays.