Isoprene polymerization with indolide-imine supported rare-earth metal alkyl and amidinate complexes

Reaction of 7-{(N-2,6-R)iminomethyl)}lindole (HL1, R = dimethylphenyl; HL2, R = diisopropylphenyl) and rare-earth metal tris(alkyl)s, Ln(CH2SiMe3)(3)(THF)(2), generated new rare-earth metal bis(alkyl) complexes LLn(CH2SiMe3)(2)(THF) [L = L-1: Ln = Lu. (1a), Sc (1b); L = L-2 : Ln = Lu (3a), Se (3b)] and mono(alkyl) complexes L-2 Lu-2(CH2SiMe3) (4a). Treatment of alkyl complexes 1a and 4a with N,N'-diisopropylcarbodiimide afforded the corresponding amidinates (LLu)-Lu-1{iPr(2)NC(CH2SiMe3) NiPr2}(2) (2a) and L-2 Lu-2{iPr(2)NC(CH2SiMe3)NiPr2} (5a), respectively.

New rare earth metal bis(alkyl)s bearing an iminophosphonamido ligand. Synthesis and catalysis toward highly 3,4-selective polymerization of isoprene

Newrareearth metal bis(alkyl) complexes [(NPNPh)Ln(CH2SiMe3)(2)(THF) (NPNPh:N(Ph)PPh2=NC6H2Me3-2,4,6; Ln = Sc (3a), Ln = Y (3b), Ln = Lu (3c)) and [(NPNPy)Sc(CH2SiMe3)(2)(THF)1 (NPNPY = N(Py)PPh2=NC6H2Me3-2,4,6) (3d)) have been prepared via protonolysis reaction between rare earth metal tris(alkyl)s and the corresponding iminophosphonamines. Complexes 3a-d are analogous monomers of THF solvate. Each metal ion coordinates to a eta(2)-chelated NPN ligand and two cis-located alkyl groups, adopting tetrahedron geometry.

Age hardening and mechanical properties of Mg-Gd-Er alloy

The Mg-8Gd-0.6Zr-xEr (x = 1, 3 and 5 mass%) alloys were prepared by casting technology, and the microstructures, age hardening behaviors and mechanical properties of alloys have been investigated. Microstructures of the alloys are characterized by the presence of rosette-shaped equiaxed grains. The age hardening behaviors and the tensile properties are enhanced by adding Er element. The maximum aged hardness of Mg-8Gd-0.6Zr-5Er alloy is 97, it is nearly 1.24 times higher than that of Er-free alloy.

Effect of Nd on the microstructure, mechanical properties and corrosion behavior of die-cast Mg-4Al-based alloy

Die-cast Mg-4Al-0.4Mn-xNd(x = 0, 1, 2, 4 and 6 wt.%) magnesium alloys were prepared successfully and influences of Nd on the microstructure, mechanical properties and corrosion behavior of the Mg-4Al-0.4Mn alloy have been investigated. The results showed that with the addition of Nd binary Al2Nd phase and Al11Nd3 phase. which mainly aggregated along the grain boundaries, were formed, and the relative ratio of above two phases was in correlation with the Nd content in the alloy. Meanwhile, the grain sizes were greatly reduced with the increasing Nd content. It was found that due to the addition of Nd both the tensile properties and corrosion resistance were improved substantially.

Regio-regular structure high molecular weight poly(propylene carbonate) by rare earth ternary catalyst and Lewis base cocatalyst

Lewis base modification strategy on rare earth ternary catalyst was disclosed to enhance nucleophilic ability of active center during copolymerization of carbon dioxide and propylene oxide (PO), poly(propylene carbonate) (PPC) with H-T linkages over 83%, and number-average molecular weight (M-n) up to 100 kg/mol was synthesized at room temperature using Y(CCl3OO)(3)-ZnEt2-glycerine catalyst and 1,10-phenanthroline (PHEN) cocatalyst. Coordination of PHEN with active Zinc center enhanced the nucleophilic ability of the metal carbonate, which became more regio-specific in attacking carbon in PO, leading to PPC with improved H-T linkages.

Effects of soil pH and organic matter on distribution of thorium fractions in soil contaminated by rare-earth industries

The labilities of thorium fractions including mobility and bioavailability vary significantly with soil properties. The effects of soil pH and soil organic matter on the distribution and transfer of thorium fractions defined by a sequential extraction procedure were investigated. Decrease of soil pH could enhance the phytoavailability and the potential availability of thorium in soil. Increase of organic matter reduced the phytoavailability of thorium, but enhanced the potential availability of it.

Reversed micellar solubilization extraction and separation of thorium(IV) from rare earth(III) by primary amine N1923 in ionic liquid

The extraction behavior of thorium(IV) sulfate by primary amine N1923 in imidazolium-based ionic liquid (IL) namely 1-octyl-3-methylimidazolium hexafluorophosphate ([C(8)mim]PF6) was systematically studied in this paper. Results showed that the extraction behavior was quite different from that using conventional solvent as diluent. A reversed micellar solubilization extraction mechanism was proposed for the extraction of thorium(IV) by N1923/[C(8)mim]PF6 via slope analysis method and polarized optical microscopy (POM)/transmission electron microscopy (TEM) observation. The salt-out agent, Na2SO4, was demonstrated to prompt this extraction mechanism.

Synthesis and fluorescent property of NH4Y1.9Eu0.1F7 nanoparticles with the temperature effect on the morphology

Sphere NH4Y1.9Eu0.1F7 nanoparticles were successfully synthesized by a hydrothermal method at 180 degrees C for 10 h. SEM and TEM images show the particles are spheres and have lots of hollows in them. The mean particle size is about 60 nm. The shape and size of the particles can be controlled by changing temperature and time of reactants. The luminescent property of the sample indicates that strong emission peaks of the Eu3+ ions are located at about 589 and 612 mm.

Microstructure and mechanical properties of high performance Mg-Gd based alloys

The Mg-12Gd-4Y-2Nd-0.3Zn-0.6Zr (wt.%) alloy was prepared by casting technology, and the structure, age hardening behavior and mechanical properties of the alloy have been investigated. The results demonstrated that the alloy was composed of alpha-Mg matrix, a lot of dispersed Mg24RE5 (RE = Gd/Y/Nd) and Mg5RE precipitates in the as-cast and the T6 state alloys. The alloy exhibited remarkable age hardening response and excellent mechanical properties from room temperature (RT) to 300 degrees C by optimum solid solution and aging conditions. The ultimate tensile strength.

Investigations of the properties of Mg-5Al-0.3Mn-xCe (x=0-3, wt.%) alloys

Mg-5Al-0.3Mn-xCe (x = 0-3, wt.%) alloys were prepared by metal mould casting method. The microstructures and mechanical properties were investigated. The results revealed that the main phases of as-cast Mg-5Al-0.3Mn alloy consist of alpha-Mg matrix and beta-Mg17Al12 phase. With the addition of Ce element, Al11Ce3 precipitates were formed and mainly aggregated along the grain boundaries. The amount of the Al11Ce3 precipitates increased with increasing addition of Ce, but the amount of beta-Mg17Al12 phase decreased. The highest tensile strength was obtained in Mg-5Al-0.3Mn-1.5Ce alloy. The ultimate tensile strength (UTS), yield strength (YS) and elongation at room temperature are 203 MPa, 88 MPa and 20%, separately.

Structure stability and strengthening mechanism of die-cast Mg-Gd-Dy based alloy

Mg-8Gd-1Dy-0.3Zn (wt.%) alloy was prepared by high-pressure die-casting technique. The thermal stability, mechanical properties at temperature range from room temperature to 573 K and strengthening mechanism was investigated. The results showed that the die-cast state alloy was mainly composed of fine cellular equiaxed grain. The fine porosity-free skin region was related to the aggregation of rare earth elements. The long lamellar-shaped stacking compound containing Zn and polygon-shaped precipitate were observed along the grain boundaries. The die-cast sample exhibited high mechanical properties and good thermal stability until 523 K.

Rare Earth Fluorides Nanowires/Nanorods Derived from Hydroxides: Hydrothermal Synthesis and Luminescence Properties

In this paper, we reported the synthesis of nearly monodisperse and well-defined one-dimensional (1D) rare earth fluoride(beta-NaREF4) (RE = Y, Sm, Eu, Gd, Tb, Dy, and Ho) nanowires/nanorods by in situ acid corrosion and anion exchange approach using RE(OH)(3) as precursors via a facile hydrothermal route. X-ray diffraction (XRD), energy-dispersive X-ray (EDX) spectroscopy. scanning electron microscopy (SEM), transmission electron microscopy (TEM). high-resolution transmission electron microscopy (HRTEM), and photoluminescence(PL)spectroscopy were used to characterize the samples. The results show that the as-prepared rare earth fluoride (beta-NaREF4) nanowires/nanorods preserve the basic morphology of the initial RE(OH)(3) precursors.

Rare-earth metal complexes stabilized by amino-phosphine ligand. Reaction with mesityl azide and catalysis of the cycloaddition of organic azides and aromatic alkynes

Stoichiometric reactions between mesityl azide (MesN(3), Mes = 2,4,6-C6H2Me3) and amino-phosphine ligated rare-earth metal alkyl, LLn(CH2SiMe3) (2)(THF) (L = (2,6-C6H3Me2)NCH2C6H4P(C6H5)(2); Ln = Lu (1a), Sc (1b)), amide, LLu(NH(2,6-(C6H3Pr2)-Pr-i))(2)(THF) (2) and acetylide at room temperature gave the amino-phosphazide ligated rare-earth metal bis(triazenyl) complexes, [L(MesN(3))]Ln[(MesN(3))-(CH2SiMe3)](2) (Ln = Lu (3a); Sc (3b)), bis(amido) complex [L(MesN3)] Lu[NH(2,6-C6H3 Pr-i(2))](2) (4), and bis(alkynyl) complex (5) (L(MesN(3))Lu (C CPh)(2))(2), respectively. The triazenyl group in 3 coordinates to the metal ion in a rare eta(2)-mode via N-beta and N-gamma atoms, generating a triangular metallocycle. The amino-phosphazide ligand, L(MesN(3)), in 3, 4 and 5 chelates to the metal ion in a eta(3)-mode via N-alpha and N-gamma atoms. In the presence of excess phenylacetylene, complex 3a isomerized to 3', where the triazenyl group coordinates to the metal ion in a eta(3) mode via Na and Ng atoms.

Highly 3,4-Selective Polymerization of Isoprene with NPN Ligand Stabilized Rare-Earth Metal Bis(alkyl)s. Structures and Performances

Deprotonation of (ArNHPPh2NAr2)-N-1 (H[NPN](n), n = 1 - 10) by Ln(CH2SiMe3)(3)(THF)(2) (Ln = Lu, Y, Sc, Er) generated a series of rare-earth metal bis(alkyl) complexes [NPN](n)Ln(CH2SiMe3)(2)(THF)(2) (1-10), which under activation with [Ph3C][B(C6F5)(4)] and AliBu(3) were tested for isoprene polymerization. The correlation between catalytic performances and molecular structures of the complexes has been investigated. Complexes 1-5 and 8, where Ar-1 is nonsubstituted or ortho-alkyl-substituted phenyl, adopt trigonal-bipyramidal geometry. The Ar-1 and Ar-2 rings are perpendicular in 1-4 and 8 but parallel in 5. When Ar-1 is pyridyl, the resultant lutetium and yttrium complexes 9a and 9b adopt tetragonal geometry with the ligand coordinating to the metal ions in a N,N,N-tridentate mode, whereas in the scandium analogue 9c, the ligand coordinates to the Sc3+ ion in a N,N-bidentate mode. These structural characteristics endow the complexes with versatile catalytic performances, With increase of the steric bulkiness of the ortho-substituents Ar-1 and Ar-2, the 3,4-selectivity increased stepwise from 81.6% for lutetium complex 1 to 96.8% for lutetium complex 6 and to 97.8% for lutetium complex 7a. However, further increase of the steric bulk of the ligand led to a slight drop of 3,4-selectivity for the attached complex 5 (95.1%).

Synthesis, photoluminescence, thermoluminescence and dosimetry properties of novel phosphor KSr4(BO3)(3):Ce

Polycrystalline powder sample of KSr4(BO3)(3) was synthesized by high-temperature solid-state reaction. The influence of different rare earth dopants, i.e. Tb3+, TM3+ and Ce3+, on thermoluminescence (TL) of KSr4(BO3)(3) Phosphor was discussed. The TL, photoluminescence (PL) and some dosimetric properties of Ce3+-activated KSr4(BO3)(3) phosphor were studied. The effect of the concentration of Ce3+ on TL intensity was investigated and the result showed that the optimum Ce3+ concentration was 0.2 mol%. The TL kinetic parameters of KSr4(BO3)(3):0.002 Ce3+ phosphor were calculated by computer glow curve deconvolution (CGCD) method. Characteristic emission peaking at about 407 and 383 nm due to the 4f(0)5d(1) -> F-2((5/2),(7/2)) transitions of Ce3+ ion were observed both in PL and three-dimensional (3D) TL spectra. The dose-response of KSr4(BO3)(3):0.002 Ce3+ to gamma-ray was linear in the range from 1 to 1000 mGy. In addition, the decay of the TL intensity of KSr4(BO3)(3):0.002 Ce3+ was also investigated.