CATALYTIC COPOLYMERIZATION OF STYRENE AND ETHYLENE BY NEUTRAL NICKEL(Ⅱ) COMPLEXES IN EMULSION

Emulsion copolymerization of styrene and ethylene catalyzed by a series of neutral nickel(Ⅱ) complexes was carried out in an aqueous system to give high-molecular-weight copolymers.The copolymers and emulsions were characterized by an array of techniques including NMR,GPC,TEM,WAXD and DSC.The results indicate that the copolymers obtained are mostly block copolymers of polyethylene with random insertion of styrene units,and their M_W is in the range of 10~5-10~6.By enhancing the electron withdrawing of the s...

2-AMINOMETHYLPYRIDINE NICKEL(Ⅱ) COMPLEXES—SYNTHESIS,MOLECULAR STRUCTURE AND CATALYSIS OF ETHYLENE POLYMERIZATION

A series of new nickel(Ⅱ)complexes with 2-aminomethylpyridine ligands,(2-PyCH_2NHAr)_2NiBr_2(Ar=2,6- dimethylphenyl 2a;2,6-diisopropylphenyl 2b,2,6-difluorophenyl 2c),have been synthesized and used as catalyst precursors for ethylene polymerization in the presence of methylaluminoxane(MAO).The catalysts containing ortho-alkyl-substituents afford high molecular weight branched polyethylenes as well as a certain amount of oligomers.Enhancing the steric bulk of the alkyl substituent of the catalyst resulted in...

Synthesis and Catalytic Activity of Nickel(Ⅱ)and Cobalt(Ⅱ) Complexes Involving Chiral Leucinol

The title nickel complex I and cobalt complex II were obtained separately from the direct reaction of D-（＋）-leucinol with Ni（II） chloride and L-（-）-leucinol with Co（II） acetate tetra- hydrate in anhydrous methanol. The crystal structures of I and II were determined by single-crystal X-ray diffraction and further characterized by elemental analysis and IR. For I： [Ni（C18H45N3O3）]Cl2, orthorhombic, P212121, a = 11.2807（9）, b = 14.7115（11）, c = 16.3580（13） A, V = 2714.7（4） A3, Z = 4, Pcalcd = 1.177 Mg/m3, the final R = 0.0407, and 16539 reflections observed with I 〉 2σ（/）; For II： [Co（C45HI08N6015）], trigonal, R3：H, a = 23.981（3）, b =23.981（3）, c = 10.8925（15） A, γ = 120°, V = 5425.1（14） A3, Z = 3, Pcalcd = 1.002 Mg/m3, the final R = 0.0625 for 16556 observed reflections with I 〉 2σ（I）. The complexes were then used to catalyze the Henry reaction and obtained good catalytic results. The catalytic activity of the complexes was determined by IH NMR. And research is going towards the application to other organic reactions such as cyanosilylation reaction.

Chiral Resolution of β-dl-Phenylalanine Using Chiral Macrocyclic Nickel(Ⅱ) Complexes

The reactions of chiral four-coordinated nickel（Ⅱ） complex [Ni（RR-L）]（ClO4）2/[Ni（SS- L）]（ClO4）2 with β-dl-phenylalanine in acetonitrile/water gave a six-coordinated enantiomer of [Ni（RR-L）（β-d-HPhe）]（ClO4）2（1） and [Ni（SS-L）（β-l-HPhe）]（ClO4）2（2）, respectively（L = 5,5,7, 12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, HPhe = phenylalanine）. Single-crystal X-ray diffraction analyses revealed that the nickel（Ⅱ） atom displays a distorted octahedral coordination geometry by coordinating with four nitrogen atoms of L in a folded configuration, and two carboxylate oxygen atoms of β-d/l-HPhe in cis-position in both complexes. The monomers of [Ni（RR-L）（β-d-HPhe）]2＋ and [Ni（SS-L）（β-l-HPhe）]2＋ are connected through intermolecular hydrogen bonds to generate one-dimensional zigzag chains, respectively. The homochiral natures of 1 and 2 are confirmed by the results of CD spectroscopy.

Ethylene Oligomerization Promoted by Nickel Complexeswith 8-Iminoquinoline Derivatives

A series of 8-iminoquinoline derivatives nickel complexes were synthesized to proceed high activity in ethylene oligomerization.

Nickel Complexes Bearing Bidentate SchifF Base as Ethylene Oligomerization Catalysts

Several nickel complexes [N,N]NiBr_2, in which [N,N] indicates bidentatenitrogen-containing ligands (1: [N,N]=N-(2,6-diisopropylphenyl)pyridine-2-carboxaldimine(C_(18)H_(22)N_2); 2: N-(2,6-diisopropylphenyl)-6-methylpyridine-2-carboxaldimine (C_(19)H_(24)N_2);3: N-(2,4,6-trimethylphenyl)pyridine-2-carboxaldimine(C_(15)H_(16)N_2); 4:N-(2,4,6-trimethylphenyl)-6-methylpyridine-2-carboxaldimine (C_(16)H_(18)-N_2) were synthesized.Some of the nickel complexes exhibit high activity for ethylene oligomerizatiori in the presence ofan organoaluminum activator. The main factor affecting the activity and the structure of oligomersis the steric effect of substituents on [N,N] ligands. Methylaluminoxane (MAO) -activated catalystsshowed higher activities and produced oligomers with higher molecular weight than Et_2AlCl-activatedones. The oligomerization in toluene rather than hexane results in much higher activity, and theoligomers produced in toluene have relatively high molecular weight. With activation of MAO orEt_2AlCl, the [N,N]NiBr_2 system tended to produce highly branched oligomers with low α-olefincontent, but the α-olefin content could be increased by changing the reaction conditions.

Syntheses, Crystal Structures and Photoluminescence Properties of Cadmium(Ⅱ) and Nickel(Ⅱ) Complexes with 2-(2-Benzimidazolyl)quinoline

Two novel complexes, [Cd2（BMQU）2Cl4] （1） and [Ni（BMQU）2HPO4]·1.5H2O （2） （BMQU = 2-（2-benzimidazolyl）quinoline）, were synthesized by the hydrothermal method and characterized by elemental analysis, IR, and TG-DTG. The crystal structures were determined by single-crystal X-ray diffraction. Both 1 and 2 crystallize in the triclinic system, space group P . The data for 1： a = 0.8342（7）, b = 0.9226（9）, c = 1.0646（8） nm, α = 90.819（2）, β = 97.466（2）, γ = 98.280（2）°. The Cd（Ⅱ） is coordinated with three chlorine atoms and two nitrogen atoms of a BMQU molecule, generating a distorted square-pyramidal geometry. The dinuclear Cd（Ⅱ） complex is formed by two chlorine bridge bonds, and the one-dimensional chain structure is constructed with the hydrogen bond N-H…Cl and π-π stacking interaction. The data for 2： a = 1.2251（1）, b = 1.2451（1）, c = 1.2868（1） nm, α = 107.510（2）, β = 98.630（1）, γ = 109.921（2）°. The Ni（Ⅱ） is coordinated with four nitrogen atoms of two BMQU molecules and two oxygen atoms of a HPO42-, forming a distorted-octahedral geometry. The two-dimensional layer structure is formed by the hydrogen bonds and π-π stacking interaction between neighboring molecules. Complex 1 shows a strong blue fluorescence emission （λmax= 456 nm） at solid state.

MAGNETIC INVESTIGATION OF THE NICKEL COMPLEXES OF MULTI－SULFUR 1．2－DITHIOLATES

The magnetic susceptibility of (Bu4N)(NI(MEDT)2) and (Bu4N)(Ni(PHDT)2)(MEDT:5-methyl-6-hydro-1, 4-dithiin-2, 3-dithiolate, PHDT: 5-phenyl-6-hydro-1.4-dithiin- 2,3-dithiolate) was measured in the temperature range of 75-300K. The magnitudeof magnctic moments is consistent,with a doublet state arising from Ni(Ⅲ).Antiferromagnetic properties were discussed in consideration of molecularstructure.

Syntheses, Characterization and Magnetism of μ-2-Chloroterephthalato Nickel (Ⅱ) Binuclear Complexes

Three new nickel(Ⅱ) binuclear complexes, namely,[Ni_2(CTPHA)(Phen)_4](ClO_4)2·4H_2O (complex 1 ), [Ni_2(CTPHA) (Nphen)_4](ClO_4)_2·2H_2O(complex 2 ) and [Ni2 (CTPHA)(Bpy)4] (ClO4)2 (complex 3 ). (CTPHA = 2-chloroterephthalate . Phen=1, 10-phenanthroline, Nphen=5-nitro-1, 10-phenanthroline, Bpy=2, 2-bipyridyl), have been synthesized and characterized by elemental analysis, IR, molar conductance and electronic spectra. These complexes are proposed tohave extended Z-chloroterephthalato-bridged structure and to consist of two nickel(Ⅱ). The variable-temperature magnetic susceptibilities of complex 1 were measuredover 4. 2～300 K and the data were fitted by least-squares to a susceptibility equationderived from the Hamiltonian operator, giving the exchange integral ZJ=1. 6 cm-1, which indicate a very weak antiferromagnetic interaction between nickelf (Ⅱ) ions.

SYNTHESIS AND CHARACTERIZATION OF BIS-[2-[[(2-ALKOXYPHENYL)IMINO]METHYL]-PHENOLATO-O,N,O]NICKEL(II)COMPLEXES AND THEIR NORBORNENE POLYMERIZATION

A series of salicylaldimines, synthesized in high yield via microwave-assisted condensation of salicylaldehyde and 2-alkoxyaniline were allowed to react with nickel chloride to form six-coordinated nickel complexes. These nickel complexes were carefully characterized, and the solid structure of la was elucidated by X-Ray diffraction. Activated with MAO, the nickel complexes showed good activity for homopolymerization of norbornene. Reaction parameters, such as the ratio of nickel precursor to MAO, monomer concentration, reaction time and the reaction temperature, as well as the nature of the ligands were found to have significant effects on the catalytic activity and some properties of the resulting polynorbornene.

Syntheses and Magnetism of μ-1, 3, 5-Benzenetricarboxylato Trinuclear Manganese(Ⅱ) and Nickel(Ⅱ)Complexes

Two new manganese(Ⅱ ) trinuclear complexes and two new nickel (Ⅱ) trinuclear compIexes, namely, [Mn3 (BZT ) (Phen )6] (ClO4 )3 (complex 1 ), [Mn (BZT)· (Nphen )6] (ClO4 )3 (complex 2), [Ni3 (BZT) (Phen)6] (ClO4 )3· 5H2O (complex3) and [Ni3 (BZT ) (Nphen )6] (ClO4 )3 (complex 4 ) (BZT = 1, 3, 5-benzenetricarboxylato, Phen = 1, 10-phenthroline, Nphen = 5-nitro-1, 10-phenanthroline )have been synthesized. The complexes were characterized using elemental analysis,IR and electronic reflection spectra. These complexes are proposed to have extended 1, 3, 5-benzenetricarboxylato-bridged structure and to consist of three manganese (Ⅱ) or three nickel(Ⅱ). The X-band ESR spectra of the complex 1 and complex 2were recorded at room temperature. The variable-temperature magnetic susceptibilities of complex 1 and complex 3 were measured over 4. 2-300 K. According to experimental results of the variable-temperature magnetic susceptibility, the magnetic interaction between the paramagnetic centers is too weak to be detected using the usual magnetic susceptibility technique.

Supramolecular Formation via Hydrogen Bonding in Copper and Nickel Complexes with 2-Hydroxynicotinic Acid

Two complexes, Cu（HnicO）2 1 and Ni（HnicO）2（H2O）2 2 （H2nicO = 2-hydroxynicolinic acid）, were synthesized by hydrothermal reactions and structurally characterized. Complex 1 crystallizes in monoclinic, space group P21/n, with a = 8.314（7）, b = 6.275（4）, c = 11.283（7）A, β = 98.32（3）°, V = 582.5（7）A^3, Z = 2, Mr = 339.74, Dc = 1.937 g/cm3, F（000） = 342, μ = 1.908 mm^-1, S = 1.097, the final R = 0.0284 mad wR = 0.0781 for 1177 observed reflections with Ⅰ 〉 2σ（Ⅰ）. Complex 2 crystallizes in monoclinic, space group P21/c, with a = 7.438（5）, b = 12.22（1）, c = 7.537（5）A,β = 100.07（3）°, V= 674.3（8）A3, Z = 2, Mr = 370.95, Dc = 1.827 g/cm^3, F（000） = 380, = 1.487 mm^-1, S = 1.041, the final R = 0.0335 and wR = 0.0779 for 1202 observed reflections with I 〉 2σ（Ⅰ）. There are extended 3D framework structures in complexes 1 and 2 due to the N-H…O and C-H…O hydrogen bonds. The copper atom in 1 has square planar coordination, while the nickel atom in 2 adopts octahedral coordination geometry. The TG curve shows that complex 2 is stable in solid state to 150 ℃.

Syntheses and Structures of Two Macrocyclic Nickel(Ⅱ) Complexes Bridging Benzene Polycarboxylic Acid

Two complexes with formulas [Ni L][（Ni L）（IPA）2]·8H2O（1） and [（Ni L）（H2O）2] [（Ni L）（PMA）]·4H2O（2）（L = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane,IPA2– = isophthalic anion,PMA4– = 1,2,4,5-benzenetetracarboxylic anion） were synthesized and characterized by elemental analyses and IR spectra.The crystal structures were determined by X-ray diffraction.In complex 1,the [Ni L]^2＋ bridged IPA^2– to give [（Ni L）（IPA）2]^2– monomer,and the [Ni L]^2＋ bridged PMA4– to form a one-dimensional chain [（Ni L）（PMA）]n^2n– in complex 2.The [Ni L]^2＋ and [（Ni L）（IPA）2]^2–/[（Ni L）（PMA）]^2– are connected through intermolecular hydrogen bonding to generate three-dimensional supramolecular structures.

Nickel Group Complexes With Thiolate or/and Phosphine Ligands.Synthesis and X-ray CrystalStructure of 〔Ni_2(pdt)_2 (PEt_3)_2〕

The reactions of nickel group M2+ with thiolate and phosphine inMeOH yield mononuclear and binuclear complexes. Ni2 (PEt3 ), (pdt )2 (pdt = 1, 2propanedithiolate) was synthesized and analyzed by single crystal X--ray diffractionmethod. The complex is monoclinic with space group P21 /c, Mr= 566. 16 a = 18. 737(5), b=9. 906(4), c= 14. 540(10) A; V=2697. 65 A3, Dc = 1. 394 g/cm3 for Z=4; the final R(Rw) = 0. 062(0. 072). The complex is a dimer, where the Ni atoms arelinked by two sulphur atoms from SC3H6S2- (pdt2- ) ligands and each Ni atom is fourcoordinated by one P and three S atoms with distorted square--planar geometry. The Ni--Ni distance is 3. 025 .A, the average Ni--S, Ni--P distances are 2. 187 and 2. 194A, respectively.

Syntheses and Crystal Structures of Two Nickel(Ⅱ) Complexes [Ni(dmpzm)_2(L)]Cl·nH_2O (L=HCO_2,OAc;n=2,3;dmpzm=1,1'-Methylenebis(3,5-dimethyl-1H-pyrazole))

Reactions of NiCl2-6H2O with dmpzm and formic or acetic acid at PH = 7 produced the two title compounds, [Ni（dmpzm）2（HCO2）]Cl·2H2O 1 and [Ni（dmpzm）2（OAc）]C2·H2O 2 （dmpzm = 1,1 ＇-methylenebis（3,5-dimethyl-lH-pyrazole））. 1 and 2 were characterized by elemental analysis, IR spectra, and thermogravimetric analysis. 1 crystallizes in the orthorhombic system, space group Pcca with a = 18.700（2）, b = 8.6843（9）, c = 18.098（2）A, V= 2939.1（5）A^3, Z = 4, Dc = 1.319 g/cm^3, T = 193 K, C23H37CINsNiO4, Mr = 583.75, F（000） = 1232, p（MoKa） = 0.792 cm^-1, S = 1.079, R = 0.0772 and wR = 0.1958 for 2265 observed reflections with I〉 2σ（I）. 2 crystallizes in the orthorhombic system, space group Pcca with a = 17.011（3）, b = 18.630（4）, c = 19.300（4）A, V = 6117（2）A^3, Z = 8, Dc = 1.337 g/cm^3, T= 193（2） K, C24H41C1N8NiO5, Mr = 615.79, F（000） = 2608, μ（MoKa） = 0.768 cm^-1, S = 1.059, R = 0.0518 and wR = 0.1109 for 5124 observed reflections with I 〉 2σ（I）. The Ni atoms in 1 or 2 are chelated by two dmpzm ligands and one formate or acetate anion, forming slightly distorted octahedral geometries. In the crystals of 1 or 2, intermolecular hydrogen bonding interactions result in the formation of 2D hydrogen-bonded frameworks.

Kinetics and Vapor Pressure Studies of bis(<i>N</i>-alkyl-2-hydroxonapthaldimine)nickel (II) (<i>N</i>-R = methyl to pentyl) Complexes

The complexes of bis[N-alkyl-2-hydroxonapthaldimine]nickel(II) (N-alkyl = methyl, ethyl, propyl, butyl or pentyl) were synthesized and their volatilization in N2 atmosphere was demonstrated by the TG-based transpiration technique. The equilibrium vapor pressure of the complexes over a temperature span of 470 - 590 K was determined by adapting a horizontal dual arm single furnace thermoanalyser as a transpiration apparatus. It yielded as 153.1 (±1.9), 122.9 (±0.3), 147.6 (±10.7), 151.8 (±10.9) and 114.7 (±5.3) k·Jmol–1 respectively. The entropies of vaporization for these complexes as calculated from the intercept of the linear fit expressions were found to be 319.7 (±3.9), 229.9 (±5.8), 317.8 (±17.2), 319.7 (±19.1) and 254.6 (±9.6) Jmo–1·K–1 respectively. The non-isothermal vaporization activation energy was determined from Arrhenius and Coats-Redfern methods.

Two Nickel(Ⅱ) Complexes Constructed by Novel Bis(3-methoxy-2-pyridyl)ether-6,6′-dicarboxylic Acid Ligand:Lattice Water Control of Structure

Under given conditions, two complexes of [Ni（H20）2BEDA]·2H2O 1 and [Ni（Py）2- BEDA]·6H2O 2 （BEDA = bis（3-methoxy-2-pyridyl）ether-6,6′-dicarboxylic acid） have been synthesized and characterized by elemental analysis and X-ray single-crystal diffraction. Crystal data for 1： C14H18NiN2O11, monoelinic C2/c, a = 14.3844（17）, b = 12.9900（15）, c = 9.6309（11） A, β = 104.3350（10）°, V= 1743.5（4） A3, Z = 4, Dc= 1.711 g/cm^3, F（000） = 928, μ = 1.179 mm^-1, Mr= 449.01, the final R = 0.0228 and wR = 0.0625. Crystal data for 2： C24H32NiN4O13, triclinic P1, a = 9.423（2）, b = 11.863（3）, c = 13.089（3） A, α = 91.511（3）, β = 92.465（3）, γ = 100.696（2）°, V = 1435.6（6） A^3, Z = 2, Dc= 1.488 g/cm^3, F（000） = 672, μ = 0.748 mm^-1, Mr= 643.25, the final R = 0.0400 and wR = 0.0975. Interestingly, in the two complexes, lattice water molecules dominate its crystal structures. Therefore, extensive intermolecular hydrogen bonds assemble 1 and 2 into 2D extended sheets and a 3D open framework, respectively. Furthermore, water molecules present in 2 are associated to form water clusters.

Synthesis and Characterization of Dipeptide Schiff Base Complexes of Copper(Ⅱ), Zinc(Ⅱ), Nickel(Ⅱ) and Cobalt(Ⅱ)

A new Schiff base (LK) obtained from 2, 4, -dihydroxybenzaldehyde and glycly-DL- phenylalanine reacted with Cu(II), Zn(II), Ni(II) and Co(II) to yield new complexes. The complexes were characterized by elemental analyses, molar conductance, 1H NMR DTA, TG, IR and UV spectroscopy. In these complexes the ligand is coordinated to the metal through its phenolic oxygen, carboxyl oxygen, imino nitrogen and amide nitrogen. All complexes are non-electrolytes and four coordinated with 1:1(metal; ligand) stoichiometry. The probable structure of the complexes is suggested

Simple Preparation of Halogen-Substituted <i>α</i>-Diimine Nickel Complexes Immobilized into Clay Interlayer as Catalysts for Ethylene Oligo-/Polymerization

In the practical use for the production of the α-olefins, it is highly desired to develop a novel heterogeneous catalyst system. The metal complexes immobilized into the clay interlayers show a great potential as heterogeneous catalysts due to their excellent processability. In this study, nine types of heterogeneous procatalyst Ln/Ni2+-micas were synthesized via a one-pot preparation method, which includes both the condensation reaction of the ligand derivatives and the intercalation of the ligands into the Ni2+ ion-exchanged fluorotetrasilicic mica interlayer. The ligand structures of the prepared procatalysts were [Ln: R-N = C(Nap)-C(Nap) = N-R] [(Nap = 1,8-naphthdiyl) (L1, R = 2-MePh;L2, R = 2-FPh;L3, R = 2-BrPh;L4, R = 4-MePh;L5, R = 4-FPh;L6, R = 4-BrPh;L7, R = 2,4-F2Ph;L8, R = 2,4-Br2Ph;L9, R = 2,6-F2Ph). At 50℃ and 0.7 MPaethylene pressure, the triisobutylaluminum-activated L1-L6/Ni2+-mica showed a catalytic activity for the ethylene oligo-/polymerization in the range of 334 - 549 g-ethylene&bull;g-cat–1&bull;h–1. A high catalyst activity was obtained when the substituent having a larger steric bulk than that of a methyl substituent was introduced at the ortho-position of the aryl rings. The introduction of the fluorine substituent as a strong electron-withdrawing group to the para-position also increased the catalytic activity. The L2, L4, L5, and L6/Ni2+-micas showed moderate selectivities to oligomers consisting of C4-C20 in the range of 19.9 - 41.6 wt% at 50℃. The calculated Schulz-Flory constants α based on the mole fraction of C12 and C14 were within 0.61 - 0.78.