Synthesis, crystal structure and fluorescence of a new europium complex with 2-bromobenzoate and 2,2′-bipyridine

A new complex of {[Eu2(2-BrBA)6(2,2'-bpy)2]2.CH3CH2OH·H2O} (2-BrBA=2-bromobenzoate; 2,2'-bpy=2,2'-bipyridine) was prepared by solvent method and characterized with X-ray single-crystal diffraction, IR spectroscopy, UV spectrscopy, and fluorescence spectroscopy. The complex crystallized in triclinic crystal system, PT space group, with a=1.17196(4) nm, b=-2.36142(9) nm, c=2.59151(9) nm, a=113.266(2)°, β=101.100(2)°, and γ=94.400(2)°. Two independent dinuclear molecules were contained in the asymmetric unit. The two molecules were similar to each other. Each Eu(Ⅲ) ion was nine-coordinated with seven oxygen atoms from five 2-BrBA ligands and two ni-trogen atoms from 2,2'-bpy molecule. The carboxylate groups acted as bidentate-chelating, bidentate-bridging and chelating-bridging coor-dination modes. The complex adopted a distorted monocapped square-antiprism coordination geometry. Five peaks at 579, 591, 613, 652,and 697 nm appeared in the fluorescence spectrum, corresponding to 5D0→7F0, 5D0→7F1, 5D0→7F2, 5D0→7F3, and 5D0→7F4 transition emis-sions of the Eu(Ⅲ) ion, respectively.     

Facile synthesis of visible light excited La1-xGdxF3: Eu3+ micro-meter sphere using polyvinylpyrrolidone as a template

Lanthanide fluorides exhibited unique luminescent properties in terms of their low phonon energy can restrict the luminescence quenching and extend luminescent lifetimes. Here, a room-temperature co-precipitation method was used to synthesize europium(III) activated La_1-xGd_xF₃ solid phosphors. X-ray diffraction (XRD) data confirmed the crystalline phases of synthesized sample belongs to orthorhombic system. All the as-derived materials exhibited red luminescence (⁵D₀→⁷F₁) under the excitation at longer wavelengths (394 and 466 nm). The powder with the most intense emission was achieved in terms of 10 mol.% doping concentration (Eu content, La/Gd=1/9) and sample sintered at 700 °C. Scanning electron microscopy (SEM) investigated the morphology and crystalline of the samples, showing that many regular and large balls (5-10 μmol/L) were dispersed within the micro-meter scale composites. We proved that the above crystal growth structures were controllable and predicable based on the surface functionalization by polyvinylpyrrolidone ligand.     

Effects of two strategies on afterglow behavior of Lu2O3:Eu single crystal scintillator:Co-doping with Pr3+ and solid solution with Sc2O3

In this paper,effect of two strategies on afterglow behavior of Lu₂O₃:Eu single crystal scintillato r,Pr³⁺ codoping and solid solution with Sc₂O₃,were studied systematically.Two groups of Lu₂O₃:5 at%Eu,x at%Pr(x=0,0.2,0.5,1,2 and 5) and(Lu_1-ySc_y)₂O₃:5 at%Eu(y=0,20 at%,50 at% and 70 at%) single crystals were grown by floating zone(FZ) method in air atmosphere.The structures of ...     

A novel fluorescent sensor for Al~(3+) and Zn~(2+) based on a new europium complex with a 1,10-phenanthroline ligand

A new europium complex Eu(tta)₃Li(la)based on 1,10-phenanthroline derivative(Li=(2-(3,5-dimethoxyphenyl)-1 H-imidazo[4,5-f][1,10]phenanthroline),tta=2-thenoyItrifluoroacetone)was designed and synthesized.Its structure was characterized by¹H and¹³C NMR,elemental analysis,UV-vis,fluorescence spectra and single crystal X-ray diffraction.The crystal of the complex la belongs to monoclinic system with the space group P2_1/n.The europium complex la in the solid and in the solution displays the typical emission of Eu(III)ion centered at 612 nm as a result of the electric dipole transition(⁵D₀-?⁷F₂).It exhibits high quantum yield(20.42%),long lifetime(0.29 ms)and good CIE color coordinate(0.67,0.33)in solid.In addition,the complex shows high sensitivity and selectivity towards Al³⁺and Zn²⁺in methanol solution which can be attributed to the Al³⁺/Zn²⁺cation instead of Eu³⁺in the complex la.The LODs for Al³⁺and Zn²⁺were calculated to be 5.880×10^-7and 7.678×10^-8mol/L,respectively.Besides,the additions of Al³⁺and Zn²⁺express remarkable color changes from red to bright blue and ivory that can be clearly observed by the naked eye respectively.     

Synthesis, crystal structure and characterization of one-dimension complex constructed by terbium（III） and 2-iodobenzoate

The complex of [Tb(2-IBA)₃(H₂O)₂]_n (2-IBA=2-iodobenzoate)was prepared by solvent method from TbCl₃·6H₂O and 2-iodobenzoic acid. The crystal structure was determined with X-ray single-crystal diffraction. The X-ray diffraction analysis indicated that the title complex crystallized in triclinic crystal system and Pī space group. The Tb³⁺ ion was coordinated by six oxygen atoms from five 2-IBA ligands and two oxygen atoms from two water molecules, giving a distorted square-antiprism polyhedral geometry. The carboxyl groups were bonded to the Tb³⁺ ions with bidentate-bridging and bidentate-chelating coordination modes. The adjacent Tb³⁺ ions were linked by two bidentate-bridging 2-IBA ligands, forming 1-D chain structure. The fluorescence spectrum of the complex showed four main peaks at 489, 543, 587, and 618 nm, corresponding to ⁵D₄→⁷F_J (J=6?3) transition emissions of the Tb³⁺ ion, respectively.     

Synthesis and enhanced photoluminescence properties of red emitting divalent ion (Ca2+) doped Eu:Y2O3 nanophosphors for optoelectronic applications

This work presents the synthesis of Y₂O₃:Eu³⁺,xCa²⁺ (x = 0 mol%, 1 mol%, 3 mol%, 5 mol%, 7 mol%, 9 mol%, 11 mol%) nanophosphors with enhanced photoluminescence properties through a facile solution combustion method for optoelectronic, display, and lighting applications. The X-ray diffraction (XRD) patterns of the proposed nanophosphor reveal its structural properties and crystalline nature. The transmission electron microscope (TEM) results confirm the change in the shape of the particle and aggregation of particles after co-doping with Ca²⁺. Fourier transform infrared spectroscopy (FTIR) and Raman vibrations also confirm the presence of Y–O vibration and subsequently explain the crystalline nature, structural properties, and purity of the samples. All the synthesized nanophosphors samples emit intense red emission at 613 nm (⁵D₀→⁷F₂) under excitation with 235, 394 and 466 nm wavelengths of Eu³⁺ ions. The photoluminescence (PL) emission spectra excited with 235 nm illustrate the highest emission peak with two other emission peaks excited with 466 and 394 nm that is 1.4 times higher than 466 nm and 1.9 times enhanced by 394 nm wavelength, respectively. The emission intensity of Y₂O₃:Eu³⁺,xCa²⁺ (5 mol%) is increased 8-fold as compared to Eu:Y₂O₃. Doping with Ca²⁺ ions enhances the emission intensity of Eu:Y₂O₃ nanophosphors due to an increase in energy transfer in Ca²⁺→Eu³⁺ through asymmetry in the crystal field and by introduction of radiative defect centers through oxygen vacancies in the yttria matrix. It is also observed that the optical band gap and the lifetime of the ⁵D₀ level of Eu³⁺ ions in Y₂O₃:Eu³⁺,xCa²⁺ nanophosphor sample gets changed with a doping concentration of Ca²⁺ ions. Nanophosphor also reveals high thermal stability and quantum yield as estimating activation energy of 0.25 eV and 81%, respectively. CIE, CCT, and color purity values (>98%) show an improved red-emitting nanophosphor in the warm region of light, which makes this material superior with a specific potential application for UV-based white LEDs with security ink, display devices, and various other optoelectronics devices.     

Potential application of graphene oxide and Aspergillus niger spores with high adsorption capacity for recovery of europium from red phosphor,compact fluorescent lamp and simulated radioactive waste

The recovery of rare earth elements(REEs) is a global challenge and the mining of rare earths has serious environmental implications due to the toxic waste released post mining.Hence,the rising demand for rare earths and their far reaching electronic applications necessitates an effective strategy to recover the REEs from more viable sources.In this work,the graphene oxide-Aspergillus niger spores(GO-A.niger spores) blend was utilized for adsorptive recovery of a precious rare earth Eu(Ⅲ) and th...     

Photophysical properties of a new ternary europium complex with 2-thenoyltrifluoroacetone and 5-nitro-1,10-phenanthroline

A ligand, 5-nitro-1,10-phenanthroline (phenNO2), was synthesized. Its Eu(III) complex with 2-thenoyltrifluoroacetone (HTTA) was prepared and characterized by elemental analysis, IR and 1H NMR spectra. The photophysical properties of the complex were studied in detail by using UV, luminescence spectra, luminescence lifetime and quantum yield. The complex exhibited nearly monochromatic red emission at 612 nm, a remarkable luminescence quantum yield at room temperature (36.0%) upon ligand excitation and a long 5D0 lifetime (458 μs), which indicated that the ligand phenNO2 could sensitize the luminescence of Eu(III) ion efficiently.     

Synthesis,structure and luminescent properties of a new Vernier phase Lu7O6F9 doped by Eu^3＋ as potential scintillator with unique lath tube architecture

To explore novel nano-scintillator with a controllable architecture, pure and Eu3+ doped lutetium oxyfluoride(Lu7O6F9) powder were synthesized by combining mild hydrothermal method and solid state calcination approach. The products were all pure orthorhombic Vernier phase demonstrated by X-ray powder diffraction(XRD). The detailed crystal structure was also studied by Reitveld refinement. Lath-like microcrystals composed of nanoparticles with unique hollow tube of the products were supported by the images of scanning electron microscopy(SEM) and transmission electron microscopy(TEM). Excited by X-ray with W as the target, the pure product showed intense broad emission with the peak at about 400 nm suitable for modern photoelectric multiplier tube(PMT), while the Eu3+ doped sample transferred the incident energy to Eu3+ ions and gave strong 5D0→7Fj(j=0, 1, 2 and 4) emission, which fitted for imaging and labeling measurements. From the luminescent properties, both pure and Eu3+-doped products are potential excellent scintillator for X-ray imaging and other high energy detectors, and the pure product is also a good host candidate for rare earth doping.     

Rare-earth,nitrogen-rich,oxygen heterocyclic supramolecular compounds (Nd,Sm, and Eu): Synthesis,structure, and catalysis for ammonium perchlorate

Three novel rare-earth, nitrogen-rich and oxygen heterocyclic supramolecular complexes, namely [Nd (BTF)₂(H₂O)₅]_n, [Sm(BTF)₂(H₂O)₅]_n, and [Eu(BTF)₂(H₂O)₅]_n, were synthesized. A single crystal was obtained by the solvent evaporation method, and the structure and coordination mode of metal complexes were determined by single crystal X-ray diffraction. Results show that the supramolecular complexes contain many hydrogen bonds and thus have good thermal stability (T_dec > 540 K). The thermal decomposition of ammonium perchlorate (AP) catalyzed by the complexes was investigated by differential thermal analysis, which reveals a pre-eminent catalytic effect on AP. The high temperature decomposition peak of AP can be advanced by nearly 90 K at the amount of added complexes of 10 wt%, and the activation energy of AP descent range is from 70 to 150 kJ/mol. The other properties were fully characterized through elemental analysis and Fourier transform infrared spectroscopy.     

Synthesis,photoluminescence properties and thermal investigation by TG-MS of RE(DAS)_3·xH_2O(RE=Eu~(3+),Tb~(3+))

Rare earth(Ⅲ) diphenyl-4-amine sulfonates(RE(DAS)_3·xH_2O,RE=Eu~(3+),Tb~(3+))phosphors were synthesized by precursor method from barium diphenyl-4-amine sulfonate and rare earth sulfates.FTIR,TG/DSC coupled to mass spectrometry(TG/DSC/MS),X-ray powder diffraction(XPD),scanning electron microscopy(SEM) and photo luminesce nce(PL) spectroscopy were utilized to structurally and morphologically characterize the samples.Thermal decomposition of Eu(DAS)_3·7H_2O and Tb(DAS)_3·2H_2O at 973 K under dynamic air atmosphere results in crystalline Eu_2O_2SO_4 and Tb_2O_2SO_4 materials,respectively.Accordingly,MS spectra reveal the liberation of thermal decomposition products of precursors,largely as CO_2,NO_2 and SO_2 gases.The diphenyl-4-amine sulfonate(DAS) ligand demonstrats a good stabilizing property for Eu~(3+) and Tb~(3+) ions.The Eu(DAS)_3·7H_2O and Tb(DAS)_3·2H_2O compounds display efficient red and green emissions,under UV excitation,arising from the ~5D_0→~7F_J(J=0-4) and ~5D_4→~7F_J(J=0-6) transitions of the Eu~(3+) and Tb~(3+) ions,respectively.     

Novel lanthanide coordination polymers based on mixed N,O-donor ligands and their visible-light-driven photocatalytic performance

In the present work,we prepared three isostructural lanthanide(Ln) coordination polymers(CPs).namely [Ln(Hhpc)(phen)(NO₃)](Ln=Gd(1),La(2),Y(3),H₃ hpc=5-hydroxy-1 H-pyrazole-3-carboxyIic acid,phen=1,10-phenanthroline) by hydrothermal method.Their structures were characterized by single crystal X-ray diffraction,Fourier transform infrared spectrum,elemental analysis,powder X-ray diffraction and thermal gravimetric analysis.CPs 1-3 are isostrutural and exhibit two-dimensional(...     

Fluorescence and Judd-Ofelt analysis of rare earth complexes with maleic anhydride and acrylic acid

Two kinds of Eu-complexes, Eu(TTA)2(Phen)(AA) and Eu(TTA)2(Phen)(MA) (HTTA=2-Thenoyltrifluoroacetone, Phen=1,10- phenanthroline, AA=acrylic acid, MA=Maleic anhydride), which combined the excellent fluorescence properties of Eu(TTA)2(Phen)(H2O) and the reactivity of acrylic acid and maleic anhydride with radicals, were synthesized. The two complexes were characterized by elemental analysis, infrared (IR) spectra, and X-ray photoelectron spectroscopy (XPS). Based on the data shown from the fluorescent spectra of the Eu-MA and Eu-AA complexes, the ?λ (λ=2 and 4) experimental intensity parameters were calculated. The results demonstrated that the ?2 intensity parameters for the two complexes were smaller than those for the Eu(TTA)2(Phen)(H2O) complex, indicating that a less symmetri- cal chemical environment existed in the complexes. It implied that the radiative efficiency of the 5D0 of these two complexes could be en- hanced by ligand of MA and AA, respectively. The luminescent lifetime of the Eu-AA (τ=7.26×10–4 s) or Eu-MA complex (τ=8.12×10–4 s) was higher than that of the Eu(TTA)2(Phen)(H2O) complex, which was attributed to the substitution of the water molecule (H2O) in Eu(TTA)2(Phen)(H2O) by the MA or AA ligand.     

Metal-organic frameworks of lanthanide iminodiacetates and tartrates:Synthesis,structural characterization and luminescence properties——Commemorating the 100th anniversary of the birth of Academician Guangxian Xu

Two series of lanthanide-containing metal-organic frameworks(Ln-MOFs) of the general formula{[Ln(HIDA)_2 H_2 O]ClO_4·H_2 O}_n(Ln = La(1),Nd(2),Eu(3),Gd(4),Tb(5),Eu:Tb(6);H_2 IDA=iminodiacetic acid) and [Ln(TT)(HTT)(H_2 O)_3]_n(Ln=Eu(7),Gd(8),Tb(9),Dy(10),and Eu:Tb(11);H_2 TT=tartaric acid)were synthesized by reacting Ln(ClO_4)_3 with iminodiacetic acid and L-tartaric acid,respectively.All compounds were structurally characterized by single-crystal X-ray diffraction.Elemental analyses are co nsistent with the corre sponding crystallographically generated formulas.Mo reover,the luminescence properties of both the single and mixed-lanthanide complexes were studied.Near infrared,red,and green emissions that are characteristic of Nd(Ⅲ),Eu(Ⅲ),and Tb(Ⅲ) are observed for 2,3/7,and 5/9,respectively.For the two mixed-lanthanide complex systems 6 and 11,depending on the relative amount of Eu(Ⅲ) and Tb(Ⅲ),the color of emission can be fine-tuned.It is found that a small amount of Eu(Ⅲ) is adequate for the observation of the most intense transition of Eu(Ⅲ).This is believed to be a result of energy transfer from Tb(Ⅲ) to Eu(Ⅲ) within the same complex-a conclusion supported by the significantly shortened lifetime of Tb(Ⅲ) and the accompanying enhanced lifetime of Eu(Ⅲ) in the mixedlanthanide complex with respect to the corresponding values for the pure Tb(Ⅲ) and Eu(Ⅲ) complexes with the same ligand.     

Wastewater treatment using Fe-doped perovskite manganites by photocatalytic degradation of methyl orange,crystal violet and indigo carmine dyes in tungsten bulb/sunlight

We documented(ⅰ) the decolorization of wastewater in visible light,which contains methyl orange,crystal violet and indigo carmine dyes,using La_0.7Sr_0.3Mn_1-xFe_xO₃(x=0.0,0.05,0.1 and 0.5) manganites and(ⅱ) efficient separation of photocatalysts from water using magnetic field.These ceramic photocatalysts were sintered at 1050℃ for 12 h.Ceramics were characterized by X-ray diffraction(XRD),soft X-ray absorption spectroscopy(SXAS),Fourier transf...     

Preparation,luminescence and photofunctional performances of a hybrid layered gadolinium-europium hydroxide

The design and fabrication of rare earth ions incorporated into the inorganic/organic hybrid materials have attracted growing attention for seeking improved optical properties and photofunctional performances. In this paper, a novel hybrid composite based on the layered rare earth hydroxides was successfully prepared by the ion-exchange and intercalation chemical process. The rare earth elements in the composite contain gadolinium (Gd) and europium (Eu) and the molar ratio of Gd to Eu is kept constant at 1.9 : 0.1. Organic sodium dodecyl sulfonate and dye coumarin-3-carboxyllc acid are simultaneously incorporated into the layered rare earth hydroxides as supporting agent and light-harvesting antenna, respectively. The resulting hybrid layered rare earth hydroxides exhibit the enlarged interlayer distance with about 2.60 nm, and the chemical composition was confirmed through X-ray diffraction, carbon, hydrogen and nitrogen (CHN) elemental analysis, infrared spectroscopy, and thermogravimetric analysis. The layered solid compound shows the characteristic red emission corresponding to the ⁵D₀→⁷F₂ transition of Eu³⁺ ion, and the luminescence intensity of the optimized compound is greatly enhanced as compared to its corresponding nitrate and the hybrid composite without the introduction of dye molecule. The hybrid layered rare earth hydroxides can be exfoliated into bright colloidal solution, which show superior recognition capability to Cu²⁺ ion with the distinct luminescence quenching. The large quenching constant (1.4 × 10⁴ L/mol) and low detection limit (0.35 μmol/L) are achieved for Cu²⁺ ion, implying a “turn-off” fluorescent sensor for Cu²⁺ detection. Moreover, a transparent film was prepared based on the colloidal solution and displays the typical red emission in folded shape. The new hybrid compound with enhanced luminescence and excellent photofunctional performances is expected to be applied in the fields of fluorescent sensing and flexible optical devices.     

Energy transfer and luminescent properties of Tb3+ and Tb3+, Yb3+ doped CNGG phosphors

In this work, calcium niobium gallium garnet (Ca₃Nb_1.6875Ga_3.1875O₁₂ - CNGG) ceramic samples single-doped with Tb³⁺ and co-doped with Tb³⁺ and Yb³⁺ ions were sintered by the solid-state reaction method. The structural characterization of the samples was carried out by X-ray diffraction measurements. The optimal concentration of Tb³⁺ ions corresponding to the maximum luminescence in the green spectral range in CNGG:x at% Tb (x = 0.1, 0.5, 1, 2, 3, 4, and 5) was determined to be 4 at%. The time-resolved luminescence of the ⁵D₄ level (Tb³⁺) in the CNGG:x at% Tb samples was analysed to explore the quenching mechanisms involved in the Tb³⁺ green emission. Co-doped CNGG:4 at% Tb,y at% Yb (y = 0.5, 2, 4, 6, 8, and 10) ceramics were prepared and investigated. It is shown that CNGG:4 at% Tb,y at% Yb phosphors exhibit intense green luminescence under ultra-violet (UV), visible (VIS), and near-infrared (NIR) excitation, thus demonstrating the presence of simultaneous down-conversion (DC) and up-conversion (UC) processes. The dependence of the UC luminescence intensity on the diode laser pumping power was measured and the results indicate a two-photon process based on cooperative energy transfer (CET). Under UV excitation, the lifetime of the ⁵D₄ (Tb³⁺) level slowly increases with increase of Yb³⁺ concentration, suggesting the energy transfer from Yb³⁺ to Tb³⁺ ions, while under NIR excitation, the lifetime of the ⁵D₄ (Tb³⁺) level decreases with increase of Yb³⁺ ions concentration, indicating the presence of a strong energy transfer from Tb³⁺ to Yb³⁺ ions. The highest energy transfer efficiency of ηET ≈42% was determined for the CNGG:4 at% Tb,10 at% Yb sample. The obtained results indicate that CNGG:(Tb³⁺, Yb³⁺) could be efficient new yellowish-green-emitting phosphors.     

Novel luminescent europium-centered hybrid material covalently grafted with organically modified titania via 2-substituted imidazophenanthroline for fluorescence sensing

By employing a rational approach,we prepared a novel kind of luminescent europium-centered hybrid material named Eu(tta)_3NCP-TiO_2.The resulting material was characterized by FT-IR spectra,SEM,X-ray diffraction,thermogravimetric analysis,and photoluminescence spectra.The hybrid material features the combined advantages of the europium complex and the titania host,exhibiting not only good thermostability,but also long luminescence lifetime.Owing to the excellent luminescence of this material,the application in detecting organic small molecule solvents and metal ions was explored systematically.Significantly,Eu(tta)_3 NCP-TiO_2 exhibits superior detection for nitrobenzene molecule and Cu~(2+) ion in DMF(N,N-dimethylformamide) medium.Furthermore,the limit of detection(LOD) of Eu(tta)_3 NCP-TiO_2 for nitrobenzene and Cu~(2+) ion can be counted as 5.593× 10~(-5) and 9.566 ×10~(-5) mol/L,respectively.The results demonstrate that Eu(tta)_3 NCP-TiO_2 can serve as an efficient fluorescence probe for the detection of sensing of nitrobenzene and Cu~(2+) ion.     

High thermal stability and blue-violet emitting phosphor CaYAlO4:Ti4+ with enhanced emission by Ca2+ vacancies

Blue-violet light can not only enhance the total content of biomass and glucoside but also enrich the taste of the fruit. Thus, it is meaningful to study the blue-violet luminescent materials for plant cultivation. In this study, titanium (IV) -activated CaYAlO₄ (CYAO) phosphors were synthesized by conventional high-temperature solid–state reaction. X-ray powder diffraction was employed to analyze the crystal-structure of CYAO. It is found that the doped Ti⁴⁺ ions do not change obviously the crystal structure of phosphors. Upon 246 nm excitation, CaYAl_1-xO₄:xTi⁴⁺ phosphors exhibit broad blue-violet emission band peaking at 395 nm, which can be attributed to the charge transfer of Ti⁴⁺–O^2–. Moreover, this phosphor exhibits strong thermal stability. The luminescence emission intensity at 150 °C maintained about 91 mol% of its initial value at room temperature. Additionally, the electron transition process and concentration quenching mechanism of CaYAl_1–xO₄:xTi⁴⁺ are discussed in detail. The excellent luminescent properties indicate that CaYAl_1-xO₄:xTi⁴⁺ phosphor may have promising application in indoor plant cultivation.     

Influence of ligand architecture on the structure of coordination centre in dimeric europium carboxylates with 1,10-phenanthroline

Methods of optical spectroscopy and X-ray crystallography data were used to examine the effect of architecture of carboxylate anions on structure of the Eu³⁺ coordination centre in europium carboxylates with 1,10-phenanthroline Eu(RCOO)₃·Phen. Luminescence spectra of europium acetate, nitropropionate, benzoate, naphthylcarboxylates, phenylacetates, phenoxyacetate, triphenylpropionate were investigated. A few of europium carboxylates with 2,2′-bipyridine Eu(RCOO)₃·Bpy and europium salts Eu(RCOO)₃·nH₂O were also studied. Vibrational IR and Raman spectra of phenylacetate family were analyzed. The crystal structure of nitropropionate Eu(NO₂C₂H₄COO)₃·Phen was solved by X-ray diffraction method. The predominant influence of steric hindrances on Eu³⁺ coordination centre was observed at increase of the size of aromatic fragment of carboxylate anions. It was demonstrated, that introduction of the methylene bridges between the carboxylic group and aromatic rings of ligand weakens the effect of steric factor.