Synthesis and Crystal Structure of N-phenylthiocyano-phenylthioformamide-bis （ η5-methylcyclopentadienyl） （tetrahydrofuran） Samarium （Ⅲ）

The insertion reaction of phenyl isothiocyanate into the Ln-S bond was studied. Phenyl isothiocyanate reacted with [(CH3C5H4)2Sm(SPh)(THF)]2 to give the title complex, (CH3C5H4)2Sm[SC(SPh) NPh](THF),in good yield, which was characterized by elemental analyses, IR, ^1H NMR and X-ray structural determination. The crystal structure analysis of complex shows that samarium atom is coordinated by two CH3C5H4 groups, one O atom of THF, and N and S atoms from the SC(SPh)NPh ligand to form a distorted trigonal-bipyramidal geometry.     

Synthesis and characterization of terbium（Ⅲ）-pyromellitic acid（H4L）-1,10-phenanthroline （phen） luminescent complex

The terbium(Ⅲ)-pyromellitic acid(H4L)-1,10-phenanthroline(phen) luminescent complex was synthesized using a co-precipitation method.The chemical composition of the synthesized complex was speculated to be Tb4L3(phen)0.075·10H2O by elemental analysis,inductively coupled plasma-atomic emission spectroscopy(ICP-AES),and Fourier-transform infrared spectroscopy(FT-IR).The X-ray diffraction analytic results indicated that the synthesized complex is a new crystalline complex,whose structure was different from those of other two ligands.The scanning electron microscopy analytic results showed that the product was of spherical crystals with good dispersion property,and the mean diameter of the spheres was about 1-2 μm.The TG-DTA result showed that the complex had good stability below 489 °C.PL spectra showed that the complex emitted characteristic green fluorescence of Tb(Ⅲ) ion under ultraviolet excitation.     

Synthesis, Crystal Structure of [ （MeC5H4）2Ln（μ-OCH2 CH2NMe2 ） ]2 （Ln = Sm, Y, Nd） and Their Catalytic Activity for Ring-Opening Polymerization of ε-Caprolactone

Reaction of (MeC5H4)3Ln with HOCH2CH2NMe2 in tetrahydrofuran (THF) gives the new complexes [ (MeC5H4)2Ln(μ-OCH2CH2NMe2)]2(Ln = Sm, Y, Nd) with nitrogen functionalized μ-alkoxide ligand. The complexes were characterized by elemental analysis and IR, and [ (MeC5H4)2Sm(μ-OCH2CH2NMe2)]2 was structurally characterized by the X-ray diffraction to be a dimer formed by two unsymmetric oxygen bridges. The complex has a tricyclic skeleton with the additional two Sm- N bonds via intmmoleeular coordination of OCH2CH2NMe2. The coordination number of the central metal Sm is nine. The tide complexes show good catalytic activity for ring-opening polymerization of ε-capmlactone.     

Study on the preparation and electrochemical performance of rare earth doped nano-Ni（OH）2

Multiphase nano-Ni(OH)2 doped with Y or La was prepared by supersonic co-precipitation method. The crystal morphology, structure and particle size were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and particle size distribution (PSD). The electrochemical performance of samples was investigated by electrochemical workstation and battery tested system. The results indicated that micro-morphology and grain size were changed with the changing of supersonic power, pH values and doping elements. The morphology of Y doped sample was from the flake-like to the needle-like with the increase of supersonic power; Particles were from quasi-spherical particles into needle-like with the increase of pH values; As the supersonic power increased, the proportion of α-Ni(OH)2 increased initially and then decreased. pH value was very important to the formation of crystalline phase. Lower pH value was beneficial to the formation of α-Ni(OH)2. However, the pH values had a slight effect on the reaction reversibility. Complex electrodes were prepared by mixing 8 wt.% nickel hydroxides with commercial micro-size spherical nickel. The discharge capacity of electrodes increased initially and then decreased with the increase of supersonic power. When the supersonic power was 60 W and the pH value was 9, the sample had the largest dis-charge capacity (358 mAh/g) at 0.5 C rate, which was 122.7 and 76 mAh/g higher than the spherical nickel electrode and La doped sample electrode, respectively.     

Magnetocaloric effect and magnetic properties of La_（0.9）Ce_（0.1）（Fe_（0.99）Mn_（0.01））_（11.6）Si_（1.4）H_（1.6） compound

Magnetocaloric effect and magnetic properties of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4 and its hydride La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 were investigated. The Curie temperature of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4 was increased by hydrogen absorption. XRD patterns showed that the structure of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 remained NaZn13-type. The Curie temperature (TC) of the sample was increased from 174 K to 331 K. The homogeneity of the hydrogen absorption for La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 was proven very well by the random measurement of DSC. The magnetic entropy △SM of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4H1.6 had peak at 326 K. The peak value of-△SM-was 12.3 and 7.8 J/(kg.K) under magnetic field change of 0-2 T and 0-1 T,respectively,which was comparable with Gd5Si2Ge2. The negative slope and inflection point of the Arrott curve indicated that the first-order magnetic transition of La0.9Ce0.1(Fe0.99Mn0.01)11.6Si1.4 was reserved after hydrogen absorption.     

Synthesis kinetics and thermophysical properties of La_2（Zr_（0.7）Ce_（0.3））_2O_7 ceramic for thermal barrier coatings

La2(Zr0.7Ce0.3)2O7 (LZ7C3) ceramic was synthesized by solid state reaction with La2O3, ZrO2 and CeO2 as starting materials. The synthesis kinetics, phase structure, mass loss and microstructure were studied by thermo gravimetric-different thermal analyzer (TG-DTA), X-ray difference (XRD) and scanning electron microscopy (SEM). The thermal conductivity and thermal expansion coefficient were measured by laser-flash method and pushing-rod method, respectively. XRD results showed that LZ7C3 was a mixture of La2Zr2O7 (LZ, pyro- chlore) and La2Ce2O7 (LC, fluorite). The lowest synthesis temperature and time of LZ7C3 were 1400 oC and 5 h. There were no peaks of La2O3 when the powder granularity was about 0.82 μm in the synthesis process. The atom ratio La:Zr:Ce of prepared LZ7C3 powder was very close to 10:7:3 which was the theory value of LZ7C3. The thermal conductivity of LZ7C3 decreased gradually with the temperature increased up to 1200 oC, and was located within 0.79 to 1.02 W/(m·K), which was almost 50% lower than that of LZ, whereas its thermal expansion coefficient was larger and the value was 11.6×10-6 K-1.     

A novel white-emitting phosphor ZnWO4:Dy3+

A new white luminescent material Dy3+ doped Zn WO4 was synthesized by hydrothermal route followed by calcining process. The phase structure, morphology and luminescent properties of as-synthesized samples were characterized by X-ray diffraction, scanning electron microscopy and fluorescence spectrophotometry, respectively. The results indicated that the sample was pure Zn WO4:Dy3+ only when the p H value of the reaction system was 6. The Zn WO4:Dy3+ sample was composed of spherical particles, and the particle size was about 80–130 nm. The excitation spectrum consisted of a broad band ascribed to the charge transfer transition from oxygen ligand to tungsten ion. The emission spectrum of Zn WO4:Dy3+ was composed of two major parts: the broad band attributing to the intrinsic emission of WO42– and the 4F9/2→6H15/2 transition of Dy3+, and the sharp emission peak corresponding to the 4F9/2→6H13/2 transition of Dy3+. The optimal emission intensity of the Zn1–xWO4:Dy3+x phosphors was realized when x=1.5 mol.%. Moreover, all of the Zn1–xWO4:Dy3+x(x=0.5 mol.%, 1 mol.%, 1.5 mol.%, 2 mol.%) phosphors could exhibit white light emission, which could be potentially applied in white lighting-emitting diodes.     

Shape controlled synthesis and tribological properties of CeVO_4 nanoparticles as lubricating additive

Shape controlled structure of CeVO4 nanocrystals were successfully synthesized via a hydrothermal method from Na3VO4·12H2O and Ce(NO3)3·6H2O. The resulting products were characterized by X-ray powder diffraction (XRD), electron microscopy (SEM) and other techniques. On the basis of the experimental results, CeVO4 nanoparticles exhibited the crystal tetragonal structure and the pH value of solu-tion had an important effect on the crystal structure and morphology of CeVO4 nanoparticles. Furthermore, the tribological properties of CeVO4 nanoparticles as additives in liquid paraffin were evaluated on a four-ball tester. The results indicated that the wear resistance was im-proved by the additive CeVO4 nanoparticles which exhibited very good antiwear and friction reduction performance in wear.     

Synthesis, characterization and antitumor activity of rare earth （Y, La） substituted phosphotungstates containing 5-fluorouracil

Two rare earth substituted Keggin-type phosphotungstates containing 5-fluorouracil,K10C4H4FN2O2Y(PW11O39)2·10H2O(FYPW) and K9(C4H4FN2O2)2La(PW11O39)2·18H2O(FLaPW)were synthesized in aqueous solution,and the structures were characterized by Fourier transform infrared spectroscopy(FT-IR),element analysis,inductively coupled plasma spectrometry(ICP),X-ray powder diffraction(XRD) and 1 H nuclear magnetic resonance(NMR).Thermal analysis showed that the decomposition processes of the two compounds could be divided into three steps,the loss of crystal water,the decomposition of 5-fluorouracil unit and the decomposition of Keggin-type polyanions. The in vitro cytotoxicities against HEK 293,HeLa and HepG-2 cells were studied by methyl thiazolyl tetrazolium(MTT)assay.The results showed that FYPW and FLaPW had higher antitumor activities than 5-fluorouracil,C4H4FN2O2H2PW12O40·8H2O and rare earth substituted polyoxometalates K11Ln(PW11O39)2·nH2O(Ln=Y,La).It was concluded that introducing 5-fluorouracil and rare earth(Y or La)into its structure was a considerable way to enhance antitumor activities of polyoxometalates.     

Synthesis and luminescence properties of a novel red Sr3Bi（PO4）3：Sm^3＋ phosphor

A series of Sr3Bi1-x(PO4)3: xSm3+phosphors were prepared by solid state method at 1250 °C for 4 h. X-ray diffraction (XRD) indi-cated that the sample was of a pure phase of Sr3Bi(PO4)3. The main excitation peaks were located at 343 (6H5/2→4H9/2), 360 (6H5/2→4D3/2), 373 (6H5/2→6P7/2), 400 (6H5/2→4F7/2), 414 (6H5/2→6P5/2) and 467 nm (6H5/2→4I13/2). The main emission were located at 563 (4G5/2→6H5/2), 599 (4G5/2→6H7/2), 646 (4G5/2→6H9/2) and 708 nm (4G5/2→6H11/2). The intensest emission was excited by 400 nm. We studied the effect of differ-ent doping concentrations of Sm3+ activator on the luminescence properties and found that the luminescent intensity first increased with Sm3+ concentration increasing, and then decreased. The luminescent intensity had the best value when x=0.04. The chromaticity coordinates of the sample Sr3Bi0.96(PO4)3:0.04Sm3+ were (x=0.57, y=0.36), and the lifetime was 2.12 ms.     

Syntheses,characterization, and luminescence of two lanthanide complexes [Ln2（acetate）6（HeO）4]·4H2O （Ln=Tb（1）, Sm（2））

Two dinuclear compounds [Ln2（acetate）6（H2O）4]-4H2O （Ln=Tb（1）, Sm（2）） were obtained by the hydrothermal reaction of Ln2O3 with malonic acid at 150 ℃. Both compounds were characterized by elemental analyses, infrared spectra, and single crystal X-ray diffraction. The results showed that complexes 1 and 2 were isomorphous and crystallize in triclinic space group P 1. The coordination geometry around Ln（Ⅲ） ions in the complexes 1 and 2 was a distorted tricapped trigonal prism with a nine coordination. In the crystal, the molecular organization was further stabilized by well-defined weak hydrogen bonding interactions between the neutral dinuclear molecular units that led to the formation of a three-dimensional network. The fluorescence properties of the two complexes 1 and 2 in organic solvents were also studied. The results show that the ligand acetate favored energy transfer to the emitting energy level of Tb（Ⅲ） in complex 1. Some factors that influence the fluorescent intensity were also discussed in the article.     

Synthesis and Structural Characterization of Erbium Complex with Tripodal Ligand, N, N, N＇, N＇ N＂ N＂-Hexaisopropyl-2,2＇, 2＂-Nitrilotris （2,1-ethoxy） triacetamide （L）

A new tripodal ligand, N, N, N‘, N‘, N“, N“-hexaisopropyl-2, 2‘, 2“-nitrilotris (2, 1-ethoxy)-triacetamide (L) and its new erbium picrate complex were prepared. The structure of the complex was determined by Xray crystal structure analysis. The result reveals that the Er^3 is encapsulated by the three arms of the tripodal ligand, and nine-coordinated by the bridged-head nitrogen atom, all ether oxygen atoms and carbonyl oxygen atoms of the ligand, and two oxygen atoms of the bidentate picrate. The coordination polyhedron is a distorted monocapped square antiprism.     

Activity improvement of Pt/C catalysts by adding CeO2 nanoparticles

Carbon-supported platinum catalysts were prepared by NaBH4 reduction of metal precursors and the CeO2 nanoparticles were pre-pared by citric acid sol-gel method.The structure and morphology of two kinds of nanoparticles were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM),respectively.The Pt particles were uniformly dispersed on the carbon surface and showed the rod-like morphology.The CeO2 was spherical in shape.The appropriate amount of CeO2 nanoparticles was added into Pt/C sys-tems to improve activity of the catalysts.Several electrochemical techniques such as cyclic voltammogram (CV),chronoamperometry (I-t) and electrochemical impedance spectroscopy (EIS) were used to investigate the properties of CeO2-Pt/C catalysts for methanol electrooxidation in 1 mol/L CH3OH+0.5H2SO4 aqueous solutions.The results revealed that compared with Pt/C catalysts CeO2-Pt/C exhibited a higher activity and stability for methanol electro-oxidation.Moreover,the effect of CeO2 content on the activity of Pt/C catalysts was discussed in detail.     

Nanocrystalline La2Mo2O9 and Its Characterization

In this work, both the thermal expansion and electrical conductivity of nanocrystalline La2Mo2O9 were studied.The nanocrystalline powder of La2Mo2O9 was obtained by sol-gel method, and with the help of SHP (superhigh pressure)up to 4.5 × 104 atm at 700 ℃ for a short time, and the nanocrystalline powder was densified without obvious particle size growth. The electrical conductivity of nanocrystalline La2Mo2O9 was one orderof magnitude lower than that of the microcrystalline sample at the same temperature. Owing to the phase transition, the microcrystalline La2Mo2O9 has an abrupt increase of thermal expansion with a peak value of 48 × 10-6 K-1 at 556 ℃. For the nanocrystalline material, the peak value increases to 112 × 10-6 K-1 at 520 ℃. On the other hand, above 600 ℃ the significant growth of particle size of the nanocrystalline La2Mo2O9 was observed, accompanying by a tremendous increase of thermal expansion with a peak value of third higher than that of La2Mo2O9.     

Influence of iron on phase and magnetic property of the LaFe_（11.6）Si_（1.4） compound

The phase relation, microstructure, Curie temperatures, hysteresis, and magnetocaloric effects of LaFex*11.6Si1.4 (x=0.96, 0.98, 1.0, and 1.02) compounds prepared by arc-melting and then annealed at 1423 K (1.5 h)+1523 K (4.5 h) were investigated. The main phase was NaZn13-type phase, the impurity phases included a small amount of α-Fe and LaFeSi phase in four samples. The crystal cell parameters of 1:13 phase increased from 1.1433(5) to 1.1454(4) nm with x increasing from 0.96 to 1.02, respectively. All samples kept the typical first-order magnetic transition. The increase of Fe strengthened IEM behavior, and led to the remarkable enhancement of MCE effect and negative slopes in Arrott plots around TC. The maximum ΔSM (T, H) under a low magnetic field (0-2 T) was 15.3, 16.8, 17.9, and 24.7 J/kg K with increasing of Fe content from x=0.96 to 1.02, respectively.     

Solvent extraction of neodymium（III） from acidic nitrate medium using Cyanex 921 in kerosene

The extraction of neodymium(Ⅲ) from acidic nitrate medium was investigated using Cyanex 921 as extractant in kerosene. The metal concentration in the aqueous phase before and after extraction was determined spectrophotometrically by Arsenazo Ⅲ method. The complete equilibration was achieved in 15 min. The effects of shaking time, nitric acid concentration, nitrate concentration, extractant concentration, and temperature on the extraction were studied. The extraction of Nd(Ⅲ) was found to increase very slowly with increase in concentration of HNO3 in the range of 0.001-0.008 mol/L and then decreased when 0.01 mol/L HNO3 was used. The percentage of extraction was increased with increase in nitrate concentration from 0.01-0.45 mol/L and then decreased when nitrate concentration increased to 0.5 mol/L. Quantitative extraction of Nd(Ⅲ) (98%) was obtained from the aqueous phase containing 0.001 mol/L HNO3 and 0.1 mol/L KNO3 using 0.5 mol/L Cyanex 921. On the basis of slope analysis, the extracted complex in the organic phase was proposed to be Nd(NO3)3.2Cyanex 921. The extraction of Nd(III) was found to increase with increase in concentration of metal ion in the range of 0.001-0.05 mol/L from 0.001 mol/L HNO3 and 0.1 mol/L KNO3 with 0.1 mol/L Cyanex 921. The percentage of extraction of neodymium was found to decrease with increase in temperature. From temperature variation studies, the negative value of △H indicated the extraction reaction to be exothermic and the negative value of △S indicated the formation of a stable complex. Almost 100% Nd(Ⅲ) was recovered from the fully loaded organic phase using 0.002 mol/L H2SO4 and 0.01 mol/L HCl.     

Surface-effect on detection ability of fluorescent Eu(btc) metal-organic frameworks to metal ions

Eu(btc)metal organic frameworks(MOFs)were prepared by co-precipitation method via 1,2,4-benzenetricarboxylic acids(H3btc)connecting with Eu³⁺ions,and the morphology was controlled from compact spherical to irregular honeycomb by adjusting the pH of reaction solutions.The luminescence properties of Eu(btc)MOFs are found to be related to the surface morphology of products,and the compact spherical one performs stronger emission intensity.The sensing ability of Eu(btc)MOFs to 11 kinds of metal ions was investigated and a prominent quenching effect occurrs in Fe³⁺,or Ni²⁺solutions.Based on UV—vis absorption analysis,an“ion-fence”model presents the competition to absorb exciting light between Eu(btc)MOFs and adsorbed metal ions.Based on Stern-Volmer equation,the Eu(btc)detection is found with higher Ksv value and a lower detection limit.Meanwhile,a higher sensing efficiency is confirmed in the Eu(btc)MOFs with loose honeycomb due to aggravating porous surface offering much more sites for metal ions.     

Polymerization of Dimethylaminoethyl Methacrylate Catalyzed by Substituted Indenyl Lanthanide（Ⅱ） Complexes

The polymerization of dimethylaminoethyl methacrylate （DMAEMA） catalyzed by the 1-cyclopentylindenyl lanthanide （Ⅱ） complex （1-C5H9C9H6）2Yb （THF）2 was investigated. The results indicated that the complex （1- C5H9C9H6）2Yb （THF）2 as a single component catalyst showed high activity. The conversion of the polymerization and the molecular weight of the polymer were affected by temperature, time, amount of catalyst and solvent in the polymerization process. The catalytic activity of （1-C5H9C9H6）2Yb （THF）2 enhanced significantly when a small amount of polar solvent THF was added into the polymerization system in which toluene was selected as the solvent. The optimal temperature of polymerization was about 0 ℃. Other modified substituted indenyl lanthanide （Ⅱ） complexes also showed good catalytic activity. The order of catalytic activity of the complexes was as follows： （1-C5H9C9H6）2Sm（THF）≈ （1- C2 H5 C9H6 ）2 Sm（THF）2 〉 （1 -C5 H9 C9 H6 ）2 Yb（THF）2 〉 （1 -PhCH2 C9 H6 ）2 Sm（THF）2. The steric regularity of p oly （dimeth- ylaminoethyl methacrylate） （PDM AEM A） was characterized by 1H NM R spectra. The polymerization provided syndio- tacticity-rich PDM AEM A. The molecular weight and the molecular weight distribution of PDM AEM A were measured by gel permeation chromatography.     

Synthesis, characterization and thermostability of tris（2,2,6,6-tetramethyl-3,5- heptanedionato）yttrium（III）

The metal-organic chemical vapor deposition (MOCVD) technique is a promising process for high temperature superconductor YBa2Cu3O7-δ(YBCO) preparation. In this technique, the purity, evaporation characteristics and thermostability of adopted precursors will decide the quality and reproducible results of YBCO film. In the present report, tris(2,2,6,6-tetramethyl-3,5-heptanedionato)yttrium(III)(Y(TMHD)3) was synthesized by the interaction of yttrium nitrate hydrate with TMHD in methanol solution, and its structure was identified by FTIR, 1 H NMR, 13C NMR and EI-MS spectroscopy. Subsequently, the thermal property and the kinetics of decomposition were systematically investigated by non-isothermal thermogravimetric analysis methods (TGA) at different heating rates in streams of N2,and the average apparent activation energy of evaporation process was evaluated by the Ozawa, Kissinger and Friedman methods. The possible conversion function was estimated through the Coats-Redfern method to characterize the evaporation patterns and followed a phase boundary reaction mechanism by the contracting area equation with average activation energy of 88.9kJ/mol.     

Oxidative dehydrogenation of ethane over RE-NiO （RE=La, Nd, Sm, Gd） catalysts

RE-NiO(RE=La,Nd,Sm,Gd) catalysts were prepared by a modified sol-gel method and characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM),BET surface area analysis,H 2 temperature-programmed reduction(H 2-TPR),and O 2 temperature-programmed desorption(O 2-TPD).The oxidative dehydrogenation of ethane(ODHE) to ethylene was applied to evaluate catalytic performance of the samples.The results showed that the doping of RE affected the physicochemical properties of the catalysts.The strong interaction between Gd and NiO played an important role in the lessened reducibility and the distribution of adsorbed oxygen species,consequently influenced the catalytic performance.The best yield to ethylene of 29% was obtained over the Gd-NiO catalyst with an ethane conversion of 56%.