Polymerization of Styrene and 1,3-Butadiene by Catalyst Systems Based on Calix[4]arene Neodymium Complexes

Polymerization of styrene and 1,3-butadiene were performed by calix[4]arene-neodymium complexes using di-n-butylmagnesium and tri-iso-butylaluminum as cocatalyst respectively. The effect of the substituent groups in calix[4]arene on the catalytic activity was first investigated.

The Synthesis of Neodymium Complexes with Polymers Containing Thiol and Sulphoxide and Their Catalytic Activities

Introduction Polymers containing thiol and sulphoxide which have active—SH and—SO groups respectively, have wide application to biological, pharmaceutical, industrial and other chemical field and—SH and—SO groups are easy to form complexes with metals, so they have aroused an increasing interest of many authors. A large number of functional resins and corresponding metal complexes have been synthesized.

Synthesis and Catalytic Activities of Polymer-Supported Neodymium Complexes——Polymers Containing Thiol and Sulphoxide

The neodymium complexes with crosslinked polystyrene containing -CH2SH and -CH2SOCH3 groups, P-CH2SH . NdCl3 and P-CH2SOCH3. NdCl3, were prepared. P-CH2SH . NdCl3 shows no catalytic activity for butadiene polymerization, while P-CH2SOCH3. NdCl3 can catalyze the polymerization of butadiene. The content of cis-1,4-polybutadiene is more than 95%.

SYNTHESIS AND CHARACTERIZATION OF POLY(STYRENE-co-4-VINYLPYRIDINE) NEODYMIUM COMPLEX

Poly(styrene-co-4-vinylpyridine)-neodymium complexes(NdCl_3·PS4VPY)with variouscontents of the functional group and neodymium have been prepared and characterized.Theinfrared and X-ray photoelectron spectra indicate that uncoordinated 4-vinylpyridine(4VPY)unitsremain in the NdCl_3·PS4VPY complexes.The catalytic behaviour of NdCl_3·PS4VPY was described briefly.

Electronic Structure and Chemical Bonding of a Tetranuclear Neodymium Complex Nd_4O(OR)_4(NR'_2)_6

The nonrelativistic DV-X_α-SCC method was used to study the electronic structure and chemi- cal bonding of tetranuclear neodymium complex Nd_4O(OR)_4(NR′_2)_6,with emphasis on the bonding charac- ter of the central μ_4-O atom and the four Nd atoms.The results of calculation show that the μ_4-O atom uses its sp^3 valence orbitals to contribute four O-Nd bonding MOs with character of multicenter bond apparent- ly.The Mulliken population analysis shows that the overlap population between Nd atoms is almost equal to zero,therefore there is no direct metal-metal bond between Nd atoms.The coordination number of Nd in the complex is discussed briefly.

SYNTHESIS AND STRUCTURE DETERMINATION OF NEODYMIUM COMPLEXES WITH CYCLOHEXANECARBOXYLIC ACID

Two complexes,NdL_3·2C_2H_5OH and NdL_3·2H_2O where L=cyclohexane-carboxylate anion,were synthesized and the structure of the former was determined by the single-crystal X-ray diffration method. The crystal is triclinic,Pspace group with the cell parameters:a=1.2385(6),b=1.2385(6),c=0.9421(5) nm.α=91.69(4)°,β=98.49(4)°,γ=99.16(5)°,Z=2,V=1.436 nm^3.The structure was refined to R value of 0.0866.Each Nd atom is connected with other two Nd atoms by two bidentate and two tridentate carboxyl groups to form a linear polymer.The Nd atom is further coordinated by a chelating carboxyl and two ethanol molecules.So the central atom is nine-coordinated with a distorted monocapped square-antiprism geometry.The infrared spectra and the thermal analysis of the complexes were also studied.

SYNTHESIS AND CRYSTAL STRUCTURE OF NEODYMIUM COMPLEX OF 1-METHYL-1,4,7,10-TETRAAZACYCLODODECANE

The complex [Nd(L)(CH_3CN)(CF_3SO_3)_3] has been synthesized, where L=1-methyl-1,4,7,10-tetraazacyclododecane. The crystal structure of the complex has been determined by a fourcircle X-ray diffractometer to a final R value of 0.0370 and Rw value of 0.0385 respectively. The crystal is triclinic system, space group P1 with a=8.738(2), b=12.870(3), c=12.900(3), α=85.63(2), β=87.25(2), γ=78.30(2)°, V=1415.71(60)~3, Z=2, Dc=1.92g/cm^3. The neodymiumion is eight-coordinated, forming a distorted square antiprism.

ABSORPTION SPECTRA OF 4f ELECTRON TRANSITIONS OF NEODYMIUM COMPLEX WITH 8-HYDROXYQUINOLINE AND OCTYLPHENOL POLY(ETHYLENEGLYCOL)ETHER

In this paper the absorption spectra of 4f electron transitions of the neodymlum complex with 8-hydroxyquinoline and octylphenol poly(ethyleneglycol)ether have been studied. The marked intensification of the band at low octylphenol poly(ethyleneglycol)ether concentration is found normally at 575 nm, and its resolution into three sharp bands centering at 572, 580 and 584 nm. The absorbances of the absorption maxima are 3.5 (at 572 nm), 7.2 (at 580 nm) and 10.2 (at 584 nm) times greater than that of the chloride.

Synthesis and Crystal Structure of Neodymium Complex [Nd(C_6H_4OHCHNC_2H_4NCHC_6H_4OH)(NO_3)_3(CH_3SOCH_3)]

The title complex was obtained by reaction of hydrated neodymium(Ⅲ) nitrate with N,N-disalicyclideneethylenediamine in DMSO. The complex [Nd(C_6H_4OHCHNC_2H_4NCHC_6H_4OH)(NO_3)_3(CH_3SOCH_3)] crystallizes in monoclinic system, space group- P2_1/n, a=9.663(2), b=16.610(6),c=16.322(5),β=102.77(2)°,V=2555(3),M_r=676.71,Z=4,Dx=1.759 gcm-3. The coordination number of Nd(Ⅲ) is 9 with the geometry of a monocapped square antiprism.All of coordination atoms are oxygen atoms from three bidentate nitrate groups, two dischiff base molecules and one DMSO molecule.

Synthesis and Crystal Structure of Neodymium Complex[Nd (C_(18)H_(20)N_2O_4) (NO_3)_3]

The title complex (Nd (C18H20N2O4) (NO3)3] was prepared and char-acterized by X-ray diffraction. The complex crystallizes in monociinic system, spacegroup P21/n, a= 14. 220(5) A, b= 11. 777(3) A, c= 14. 812(4) A, β= 105. 28(3)°, V= 2393(2) A3, Mr= 658. 63, Z=4, Dx= 1. 828 g/cm3, F(000) = 1308, thefinal R= 0. 053, Rw= 0. 065. In the complex the coordination number of Nd(Ⅲ) is 10with the geometry of a bicapped square antiprism. All of the coordination atoms areoxygen atoms.

Polymerization of isoprene catalyzed by neodymium heterocyclic Schiff base complex

Neodymium-based heterocyclic Schiff base complex was prepared and applied for the coordination polymerization of isoprene. This complex polymerized isoprene to afford products featuring high cis-1,4 stereospecificity （ca. 95%） and high molecular weight （ca, 10^5） in the presence of the triisobutyl aluminium （AliBu3） as cocatalyst, The microstructure of obtained polyisoprene was investigated by FTIR, 1^H NMR. Two different kinds of active centers in the catalyst system were examined by GPC method.

Highly Cis-1,4 Selective Polymerization of Conjugated Dienes Catalyzed by ^-heterocyclic Carbene-ligated Neodymium Complexes

Neodymium complexes containing N heterocyclic carbene(NHC)ligands,NdCl5[1,3,R(NCH=)2C]-THF,(Nd1:R=2,6-Pr2C6H3,x=0;Nd2:R=2,6-Et2C6H3,x=1;Nd3:R=2.4,6-Me3C6H2,x=1)were synthesized and employed as precatalysts for the coordination polymerization of conjugated dienes(butadiene and isoprene).In combination with trisobutylaluminium(TIBA),Nd1 promoted butadiene polymerization to produce extremely high cis-1,4(up to 99.0%)polybutadienes with high molecular weight(Mw=250-780 kg·mol 1).The Nd1/TIBA catalytic system also exhibited both high catalytic activity and cis-1,4 selectivity(up to 97.8%)for isoprene polymerization.The catalytic activity,molecular weight and molecular weight distribution of resulting polydienes were directly influenced by Al/Nd molar ratio,aging method,and polymerization temperature.Very interestingly,the high cis-1,4 selectivity of the catalyst towards butadiene and isoprene kept almost unchanged under different reaction conditions.The cis-1,4 polyisoprenes with high molecular weight(Mw=210-530 kg·mol 1)and narrow molecular weight distribution (Mw/Mn=1.9-2.7)as well as high cis-1.4 selectivity(-~97%)could be synthesized by using the aged Nd1/TIBA catalytic system in the presence of isoprene(100 equivalent to Nd)at low AlNd molar ratios of 6-10.Polyisoprenes with low molecular weights(Mw=12-76 kg·mol-7)and narrow molecular weight distributions (Mw/Mn=1.7-2.6)were obtained by using Nd2 and Nd3 as precatalysts,indicating that the molecular weight of resulting polyisoprenes can be adjusted by changing the substitutes of ligand in Nd complex.

Study on Polymerization of 4-Vinylpyridine by Neodymium Complex Catalyst

Polymerization of 4-vinylpyridine by complex catalyst of neodymium chloride was studied. The influence of Al/Nd (molar ratio), concentration of catalyst, reaction time and temperature on polymerization of 4-vinylpyridine was investigated. The results show that different kinds of ligand in the rare earth complex have an effect on the catalytic activity of the complex. The catalytic activity of the rare earth complex is higher than that of simple rare earth chloride. The catalytic activity of polymer-supported catalyst is higher than those of the similar small molecular system.

Synthesis and Crystal Structure of Neodymium Complex with Glycine [Nd(Gly)(H_2O)_7]Cl_3

The title complex [Nd(Gly)(H 2O) 7]Cl 3 was synthesized and its crystal structure was determined by X ray diffraction to obtain a final R value of 0 026 0 and a wR value of 0 086 8. The crystal is of monoclinic system with a space groug Pm . Every two neodymium ions in the crystal are connected with a carboxyl group to form a polymeric chain molecule. And each neodymium ion is further coordinated with seven oxygen atoms from water molecules. The counter ion(Cl -) is non coordinated to fill up the space between the polymeric chains. So the Nd 3+ cation is nine coordinated and the coordination polyhedron is a trigonotetradecahedron. In addition, there exists the mirror symmetry in the complex.

Synthesis and Study of Antidiabetic Properties of the Neodymium Complexes with N^5-[o-（un）Substituted Benzoyl]-N^1,N^1 - dimethylbiguanide

N^1,N^1-Dimethylbiguanide hydrochloride （HDMBG,HCl） was introduced as an oral glucose-lowering agent to treat non-insulin dependent diabetes mellitus. In this paper, two solid complexes-trichlorotris（N^5-benzoyl-N^1,N^1-dimethylbiguanidato）neodymium, [Nd（BDMBG）3Cl3）, and chlorobis-[N^5-（o-carboxybenzoyl）-N^1,N^1- dimethylbiguanidato]neodymium, [Nd（CDMBG）2Cl], were synthesized and characterized by elemental analyses, fluorescence spectra, IR, UV, DG, DTA etc. Biological testings were conducted by diabetic rats and ESR. The results showed that both the antidiabetic activity and the inhibition rates （Ih） to superoxide anion free radical （O2） on lipid are in the order as follows： Nd（SDMBG）3 [tris（N^5-salicyloyl-N^1,N^1-dimethylbiguanidato）neodymium]〉 Nd（CDMBG）2Cl≈HDMBG·HCl 〉Nd（BDMBG）3Cl3. It was concluded that different substituents at the o-position of the benzoyl group may affect these two kinds of behaviour to a great extent.

Synthesis and Structural Characterization of a Cyano-bridged Dinuclear Neodymium(III)-iron(III) Complex [Nd(DMSO)_5(H_2O)_2](μ-CN)[Fe(CN)_5]

A new neodymiumIII-ironIII complex [Nd(DMSO)5(H2O)2](μ-CN)[Fe(CN)5] (DMSO = dimethyl sulfoxide) has been synthesized by the grinding reaction method. The crystal belongs to monoclinic, space group P21/m with a = 8.859(4), b = 13.684(5), c = 12.290(4) ?, ?= 91.85(2)o, C16H34FeN6NdO7S5, Mr= 782.88, V = 1489(1) ?3, Z = 2, Dc = 1.746 g/cm3, S = 0.906, μ(MoKa) = 2.606 mm-1, F(000) = 788, R = 0.0646 and wR = 0.1654. The slightly distorted square-antiprism eightfold-coordinated Nd(III) and approximately oriented octahedrally sixfold- coordinated Fe(III) are linked by a cyano-bridge group to construct a dinuclear compound. The [Nd(DMSO)5(H2O)2](μ-CN)[Fe(CN)5] species are held together via hydrogen bonds to form a three-dimensional framework.

Quantum Chemistry Based Computational Study on the Conformational Population of a Neodymium Neodecanoate Complex

The title complex is widely used as an efficient key component of Ziegler-Natta catalyst for stereospecific polymerization of dienes to produce synthetic rubbers. However, the quantitative structure-activity relationship（QSAR） of this kind of complexes is still not clear mainly due to the difficulties to obtain their geometric molecular structures through laboratory experiments. An alternative solution is the quantum chemistry calculation in which the comformational population shall be determined. In this study, ten conformers of the title complex were obtained with the function of molecular dynamics conformational search in Gabedit 2.4.8, and their geometry optimization and thermodynamics calculation were made with a Sparkle/PM7 approach in MOPAC 2012. Their Gibbs free energies at 1 atm. and 298.15 K were calculated. Population of the conformers was further calculated out according to the theory of Boltzmann distribution, indicating that one of the ten conformers has a dominant population of 77.13%.

Crystal Structure and Raman Spectrum of Neodymium（Ⅲ） Complex of p－Aminobenzoic Acid and 1，10－Phenanthroline

Crystal structure of tetra(1,10-Phenanthroline)neodymium (Ⅲ) tetra(4-aminobenzoate)-hydrate, [Nd(p-ABA)4·2Phen]H+3O·2Phen (p-ABA:p-aminobenzoate,Phen:1,10-phenanthroline) has been determined by X-ray diffraction.The complex crystallizes in monoclinic, space group C2/c.The cell dimensions are a=1.9067 (5) nm,b=1.9192 (3) nm,c=2.0190 (4) nm,β=117.25 (2) °.V=6.568 (3) nm3, Mr= 1428.63,Z=4 and Dx= 1.45 g·cm-3.The coordination number of Nd atom is 10, and the coordinated polyhedron around the Nd atom is distorted trigonal prism.

Synthesis and Crystal Structure of Neodymium Heteropolymolybdate Complex Na_4(NH_4)_(10)[Nd_4 Mo_(29)O_(100)(H_2O)_(16)]·34H_2O

Single crystals of the title complex Na4 (NH4)10[Nd4Mo29O100(H2O)16]·34H2O obtained from the reaction of (NH4)6Mo7O24 and Nd (NO3)3, crystallize in themonoclinic, space group C2/c, with a= 19. 556(8), b= 43. 22 (2), c= 20. 389 (7) A,β= 117. 43(3)°, V= 15297(10) A3, Z=4, Dc= 1. 331g· cm-3, F(000) =5824, μ=1. 875 mm-1, final R(wR) = 0. 0816 (0. 2039) for 6128 unique intensity data [I≥2σ(I)]. In the molecule, each Nd heteroatom is coordinated by nine oxygen atoms with amono-capped square-antiprism configuration[1], while the Mo (VI) ions have severaldifferent coordination numbers (4, 5 and 6) with different configurations such as tetra-hedron, distorted square pyramid and octahedron respectively.

Synthesis of Poly[6-(2,6-bis(1＇-methylbenzimidazolyl)pyridin-4-yloxy)hexyl acrylate](PBIP) and Magnetic Property of Its Neodymium Complex(PBIP-Nd^(3＋))

Homopolymer（PBIP） containing 2,6-bis（1＇-methylbenzimidazolyl）pyridine（Me BIP） ligands in the side chain was synthesized by RAFT polymerization and its kinetics was studied. Polymeric complex PBIP-Nd^3＋ was prepared by chelating PBIP with lanthanide ion Nd^3＋. The homopolymers and PBIP-Nd^3＋ complex were investigated by NMR, FTIR, GPC and TGA. The optical property of PBIP-Nd^3＋ complex was characterized by UV-Vis spectroscopy. The magnetic property of PBIP-Nd^3＋ complex was measured as a function of temperature（5 K to 300 K） and as a function of field（-3.98×10^6 A/m to 3.98×10^6 A/m）. These results indicated that PBIP-Nd^3＋ complex is paramagnetic.