Oligomerization and Polymerization of Ethylene Initiated by a Novel Ni（II）-Based Acetyliminopyridine Complexes as Single-Site Catalysts

Novel Ni(II)-based acetyliminopyridine complexes 1b, 2b, 3b (1-3b), which are synthesized from ligands 1a, 2a, 3a (1-3a) and [NiCl2(DME)], are suitable precursors for the catalysts that are neces- sary for ethylene oligomerization and polymerization reactions, activated by methylaluminoxane (MAO). The MAO-treated 1-3b presents an active catalytic center, which may oligomerize and polymerize ethylene to produce linear α-olefins and polyethylene, respectively. The molecular weight distributions of oligomers that are obtained are in good agreement with the Schulz-Flory rules for oligomers>C4. The activity of 3b-MAO complex is 6.3E7 g/(molNi·h) at 50 ℃. The activities and molecular weight distributions of oligomers show significant reliance on the structures of catalyst precursors.     

Synthesis, Structure and Catalytic Activity Comparison of Tris- and Tetracoordinated Lanthanide Amides

Tetracoordinated lanthanide amides [(MeaSi)2N]3Ln (μ-C1)Li(THF)3 (Ln=La (1), Pr (2)) were synthesized by the reaction of anhydrous lanthanide(Ⅲ) chlorides LnCl3 (Ln=La, Pr) with 3 equiv, of lithium bis(trimethylsilyl)amide (Me3Si)2NLi in THF, followed by recrystallization from toluene. Sublimation of 1 and 2 afforded the triscoordinate lanthanide amides [(Me3Si)2N]3Ln (Ln=La, Pr). The crystal structure of 2 was determined by X-ray diffraction analysis. The catalytic activity studies show that the tetracoordinate amides can be used as single-component MMA (methyl methacrylate) polymerization catalysts, while the triscoordinate amides showed poor activity on MMA polymerization under the same conditions.     

二氯·{2-乙氧甲酰基-6-[1-[(2,6-二乙基苯)亚胺基]乙基]吡啶}合钴(II)的晶体结构极其对乙烯齐聚的催化活性

利用2,6-二甲基吡啶作为起始物合成了不对称前驱体6-乙酰基-2-乙酯基吡啶，在此基础上合成了单亚胺吡啶配体（5）和相应的Co(II)配合物二氯·{2-乙氧甲酰基-6-[1-[(2,6-二乙基苯)亚胺基]乙基]吡啶}合钴(II)（6）。晶体结构分析表明：配体5作为三齿配体以[N, N, O]原子和两个氯离子与中心钴(II)配位，形成畸变的三角双锥配位环境，其中吡啶氮原子和两个氯原子形成赤道平面。将该钴配合物作为催化剂应用于乙烯的聚合过程，以MAO为助催化剂，在15.5ºC下作用1 h，可达到1.820×10⁴ g/mol-Co∙h∙atm的催化活性。     

Synthesis,Crystal Structure,and Catalytic Performance of 2,6-Bis[1-（2,4,6-trimethylphenylimino）ethyl]pyridine Nickel（II） Complex

A novel nickel（II）-complex Ni[L]Cl2-CH3CN（1） containing the tridentate ligand 2,6-bis[1-（2,4,6- trimethylphenylimino）ethyl]pyridine（L） has been synthesized. The crystal structure of complex 1 was determined by single crystal X-ray diffraction analysis. The catalytic activity of complex 1 for the polymerization of ethylene was studied under activation with methylaluminoxane（MAO）.     

Crystal Structure of [Cd（pom）2Cl2]

ＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｏｆ［Ｃｄ（ｐｏｍ）_２Ｃｌ_２］ＷｕＷｅｎ－Ｓｈｉ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒｙ，Ｈｕａ－ｑｉａｏＵｎｉｖｅｒｓｉｔｙ，Ｆｕｊｉａｎ，Ｃｈｉｎａ，３６２０１１）ＤｏｎｇＭｅｉ－Ｂｉｎ；ＬｉＳｏｎｇ－Ｘｉａ...     

Syntheses, Characterization and Crystal Structures of New Nickel Complexes with 2,6-Bis （ imino ） pyridyl Ligands

In the past decade, the imino-complexes based on late transition metal have received significantly increasing attention for their excellent performance in the olefin polymerization area since Brookhart et al. demonstrated that the Ni( Ⅱ ) complexes incorporating with sterically hindered α-diimine ligands could be used in the polymerization of ethylene to form high molecular weight polymers.     

Synthesis and Crystal Structure of （Et4N）2[Pd2（mp）2（mpH）2]

ＳｙｎｔｈｅｓｉｓａｎｄＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｏｆ（Ｅｔ_４Ｎ）_２［Ｐｄ_２（ｍｐ）_２（ｍｐＨ）_２］ＳｈｉＪｉ－Ｃｈｅｎｇ；ＨｕａｎｇＸｉａｏ－Ｙｉｎｇ；ＷｅｎＴｉｎｇ－Ｂｉｎ；ＤｅｎｇＹｕ－Ｈｅｎｇ；ＣｈｅｎｇＣｈａｎｇ－Ｎｅｎｇ；Ｌｉ?..     

Formation and Molecular Structure of an Ion Pair Iron (II) Compound Derived from 2,6‐Bis‐ [1‐(2,6‐dibromophenylimino) ‐ethyl] pyridine and 2‐Acetyl‐6‐[1‐(2, 6‐dibromophenylimino)‐ethyl] pyridine

Two novel tridentate ligands of 2,6‐bis‐[l‐(2,6‐dibromophenylimino) ethyl] pyridine (L₁) and2‐acetyl‐6‐[1‐(2,6‐dibromophenylimino) ethyl] pyridine (L2) have been synthesized. The iron(II) complex of L₁ and L₂ has been characterized with the crystal structure of [Fe(L₁)(L₂)]²⁺ [FeCl₄]² CH₂Cl₂ [monoclinic, P2₁ (#11), a = 1.0562(4), b = 2.0928(4), c = 1.2914(2) nm, β = 100.12°, V = 2.810(1) nm³ D_c = 1.879 g/cm³ and Z = 2].     

Crystallographic report: Bis{4‐[N,N‐bis(2‐cyanoethyl)amino]pyridine} dichlorozinc(II)

In (C₁₁H₁₂N₄)₂ZnCl₂, the zinc(II) center is coordinated by the pyridine nitrogen atoms of two 4‐[N,N‐bis(2‐cyanoethyl)amino]pyridine ligands and two chlorine atoms in a tetrahedral geometry. Copyright © 2004 John Wiley & Sons, Ltd.     

Transition metal complexes bearing 2,6-bis(imino)pyridyl:Synthesis, structure, ethylene polymerization/oligomerization studies

A series of new complexes {2,6-bis[1-((2-methyl-4-methoxyphenyl)imino)ethyl]pyri-dine}MCI2 [M=Fe(Ⅱ) (2), Co(Ⅱ) (3), Ni(Ⅱ) (4), Cu(Ⅱ) (5), Zn(Ⅱ) (6)] have been synthesized. At 25℃, using 500 equiv of methylaluminoxane (MAO), the activities of Fe(Ⅱ), Co(Ⅱ) catalysts can reach 4.02×106 g/mol-Fehatm for ethylene polymerization and 3.98×105 g/mol-Cohatm for ethylene oligomerization. The effects of polymerization conditions such as reaction temperature, Al/M molar ratio and time on the activity of catalyst have been explored.     

Synthesis and Crystal Structure of Bis-{N-[2-(6-ethylpyridyl)]-salicylideneiminato} Cobalt(Ⅱ)

1 INTRODUCTION The Schiff bases derived from salicylaldehyde and 2-aminopyridine derivatives have been used as potentially terdentate ligands[1]. Yamada and Yam- anouchi have synthesized the type of ML2nH2O complexes (M = CoⅡ, NiⅡ, CuⅡ, ZnⅡ or PdⅡ)[     

Tuning Bis(imino)pyridyl Iron‐Catalyzed Ethylene Oligomerization by Modification of MAO with p‐BrPhOH

To reduce the simultaneous production of insoluble polymers during the bis(imino)pyridyl iron‐catalyzed ethylene oligomerization, in this study, p‐BrPhOH (4‐bromophenol) has been chosen as the most optimal modifier for the production of linear α‐olefins. It is found that the polymer share in the total products is largely reduced with the use of p‐BrPhOH as the modifier. The catalytic system also possesses a high activity with the liquid production maintained high level of linearity. Moreover, the introduction of p‐BrPhOH promoted the high‐temperature stability of the catalytic system, leading to the enhanced oligomerization activity as the catalytic system can catalyze ethylene oligomerization at higher temperatures. A characterization of the catalytic system with electron paramagnetic resonance shows that introduction of p‐BrPhOH significantly inhibits the formation of ferric ions, which can be the main active centers responsible for generating undesired insoluble polymers, thus this can largely retard the production of insoluble polymers during ethylene oligomerization.     

Synthesis and Characterization of {2-Formyl-6-[1-(2,4,6-trimethylphenyl)]-4- chlorophenoxy}_2Ni and Its Ethylene Oligomerization

1 INTRODUCTION Late-transition metal complexes as catalysts for ethylene oligomerization and polymerization have become an intense research subject[1]. Nickel com- plexes are in hot point due to the significant achieve- ments of academic research[2, 3] and industrial appli- cations[4, 5]. The nickel complexes with bidentate [P,O] ligands were industrialized as the SHOP pro- cess for α-olefins[4]. It is supposed that late transition metal complexes have a strong propensity of under- goi…     

含氟苯基水杨醛亚胺配体的中性镍络合物的合成、表征及对乙烯齐聚的催化活性

合成了一系列含N-氟苯基-水杨醛亚胺配体的中性镍络合物，并对代表性的络合物4进行了X-ray晶体结构分析以进一步确证其结构。这种中性镍络合物在助催化剂烷基铝氧烷(MAO)的作用下，具有较高的催化乙烯齐聚的活性和对C₆烯烃的选择性，催化活性高达4.22×l05 g o1igomers/(mol Ni•h)，对C6烯烃的选择性达到94％。     

Crystallographic report: Tris{2‐[2‐(1‐methyl)imidazolyl]methyliminoethyl}aminezinc(II) dihexafluorophosphate

The cation in the title compound has crystallographic threefold symmetry. The zinc atom is in a distorted octahedral geometry, being coordinated by three nitrogen atoms of the imine and three nitrogen atoms of imidazole. Copyright © 2004 John Wiley & Sons, Ltd.     

Synthesis and coordination chemistry of the PPN ligand 2‐[bis(diisopropylphosphanyl)methyl]‐6‐methylpyridine

The synthesis and crystal structure of the multidentate PPN ligand 2‐[bis(diisopropylphosphanyl)methyl]‐6‐methylpyridine (L ), C₁₉H₃₅NP₂, are described. In the isostructural tetrahedral Fe and Co complexes of type LM Cl₂ (M = Fe, Co), namely {2‐[bis(diisopropylphosphanyl)methyl]‐6‐methylpyridine‐κ²P ,N }dichloridoiron(II), [FeCl₂(C₁₉H₃₅NP₂)], and {2‐[bis(diisopropylphosphanyl)methyl]‐6‐methylpyridine‐κ²P ,N }dichloridocobalt(II), [CoCl₂(C₁₉H₃₅NP₂)], the ligand adopts a bidentate P ,N‐coordination, whereas in the case of the octahedral Mn complex {2‐[bis(diisopropylphosphanyl)methyl]‐6‐methylpyridine‐κ²P ,P ′}bromidotricarbonylmanganese(I), [MnBr(C₁₉H₃₅NP₂)(CO)₃], the ligand coordinates via both P atoms to the metal centre.