镍配合物催化乙烯齐聚和聚合的进展

继SHOP催化体系采用镍配合物催化乙烯齐聚制备端烯烃在研究和应用中获得成功以来,由于后过渡金属上容易产生β-氢消除反应,镍配合物催化乙烯的研究搁置了近二十年。然而,近十年里,镍配合物催化乙烯齐聚和聚合研究再次受到催化剂研究者的重视,进入了飞速发展的新时期。本文综述近三年间这个领域的发展,特别是我国学者在这个领域的贡献,展示了镍配合物在乙烯齐聚和乙烯聚合制备支化聚烯烃中的巨大潜力,促进该领域研究的发展。     

膦酚中性镍催化烯烃聚合及烯烃与极性单体共聚研究进展

烯烃与极性单体共聚制备功能化聚烯烃最为直接,但存在诸多挑战,是聚烯烃领域近20年的研究热点与难点。后过渡金属催化剂在功能化聚烯烃合成上具有优势,已经涌现出了二亚胺、水杨醛亚胺、膦磺酸镍钯经典催化体系;相比之下,膦酚镍催化体系早期关注较少。然而,近期对于膦酚镍催化体系的研究已经揭示,膦酚镍催化体系将是一个极具基础与应用前景的体系。本文总结近5年膦酚镍催化剂的结构特点,综述其在乙烯聚合、乙烯与极性单体共聚合、丙烯与极性单体共聚合方面的重要进展,并总结出膦酚镍催化剂的优势,对极性单体种类、催化剂结构设计、丙烯与极性单体立构规整共聚、聚合反应机理、功能化聚烯烃综合性能进行了展望。     

镍配合物[N,N]NiBr2的合成及其催化乙烯齐聚研究

 吡啶甲醛类化合物与苯胺类化合物缩合形成有机配体［N，N］，\r\n它与金属镍的卤化物NiBr2作用可形成稳定的配合物［N，N］NiBr2．这\r\n种配合物在含铝助催化剂存在下显示出较高的催化乙烯齐聚的活性，所\r\n得乙烯齐聚物具有较高的支化度和较低的α－烯烃含量．实验结果表明\r\n，吡啶环与苯环上的取代基对催化反应的活性具有不同的影响，助催化\r\n剂的种类及用量、反应溶剂和乙烯压力等对该体系的催化反应活性及产\r\n物结构具有直接影响．研究结果表明，通过调节催化聚合反应的工艺条\r\n件，有可能实现控制聚合产物的分子量和分子量分布，以及提高产物中\r\nα－烯烃的含量等．     

ⅣB金属配合物催化烯烃聚合与共聚

在大品种聚烯烃材料中,高附加值聚烯烃通常由乙烯与α-烯烃共聚制备。ⅣB金属配合物能够为烯烃聚合和共聚提供许多催化剂模型;不仅如此,在烯烃聚合机理研究中还可以帮助理解反应中间体和活性物种。针对聚烯烃产业的实用催化剂体系,催化剂不仅满足高的催化活性,而且能够满足升温操作的稳定性。企业的利润需要高附加值聚烯烃,要求催化剂体系能够通过条件变化制得不同性能的聚烯烃材料,而且可以实现乙烯与α-烯烃的共聚。这些对配合物催化剂的需求,在ⅣB金属配合物催化剂中获得了良好地体现;能够在烯烃聚合中获得分子量从低到高的聚合物,也可以进行乙烯与（甚至含有官能团的）α-烯烃共聚制备功能聚烯烃。按照取代基团的分类,本文综述了近年来ⅣB金属配合物催化烯烃聚合与共聚研究的新进展,特别是重点讨论了具有良好热稳定性的配合物催化剂结构变化对于催化活性和聚合性能的影响。     

新型后过滤金属烯烃聚合催化剂——镍系烯烃聚合催化剂

镍系烯烃聚合催化剂是近年来受到广泛关注的一类新型催化剂，是配位催化研究的热点之一。这类催化剂具有高催化活性、单活性中心和良好的分子剪栽性，可以在分子层次上实现烯烃聚合的分子设计与组装。本文介绍了镍系烯烃聚合催化剂的发展和研究概况，并评述了聚合特性及最新研究进展。     

镍螯合物催化乙烯齐聚制低碳α—烯烃

镍螯合物催化乙烯齐聚制低碳α－烯烃刘东兵＊宋焕玲李达刚（中国科学院兰州化学物理研究所兰州７３００００）关键词乙烯，催化齐聚反应，α－烯烃，镍螯合物１９９６－１０－１７收稿，１９９７－０３－１０修回乙烯齐聚所得到的偶碳数α－烯烃是生产各种化工产品和日化...     

后过渡金属催化烯烃可控/活性聚合的研究进展

烯烃活性聚合由于可以制备出预定分子量的窄分布聚合物,以及各种嵌段共聚物、末端功能化聚合物等而受到广泛关注.过渡金属催化的烯烃配位聚合反应活性高,催化剂性能可通过配体结构的修饰进行调节,聚合物微观结构易于调控,其活性聚合进一步拓展了对烯烃聚合物分子设计的手段,具有重要的意义.除了以钛、锆、钒等为金属中心的前过渡系催化剂之...     

镍配合物催化乙烯低聚/聚合的研究进展

催化乙烯低聚或聚合的镍配合物催化剂研究,不仅帮助提供探索乙烯配位聚合机理的催化剂模型,更为重要的帮助探讨不同催化剂模型下的催化剂活性和选择性,为工业界寻找具有潜在应用价值的高效催化剂奠定基础.同时,利用镍配合物催化剂容易导致所得聚烯烃树脂产生支链的特点,有望制备具有优异性能的支化聚烯烃树脂.本文综述了近年来镍配合物在乙烯低聚或聚合催化剂研究方面的进展,并特别强调了催化剂结构和催化性能之间的内在规律.     

α-二亚胺镍钯配合物合成及催化混合癸烯低聚研究

二亚胺镍钯催化剂具有独特的链行走的特点,通过对催化剂结构设计可以进一步调控其催化性能和链行走过程来制备性能优异的聚烯烃产品.本文合成和表征了莰基骨架的α-二亚胺镍钯配合物,并研究了其在一氯二乙基铝的助催化作用下催化混合癸烯低聚性能.详细探究了催化剂金属中心、溶剂、温度及铝镍比对混合癸烯低聚结果的影响.钯催化剂催化混合癸烯低聚时几乎无活性;而镍催化剂具有较好的催化活性,结合单体的异构化过程线性的单体几乎能完全低聚转化.所得到的产物是高度支化、低分子量的油状聚烯烃产物,并且具有高的黏度指数(>170),低的倾点(<-30℃),在润滑油基础油领域具有良好应用前景.     

Vinyl polymerizations of norbornene catalyzed by nickel complexes with acetoacetamide ligands

On the basis of a remote effect, a series of acetoacetamide ligands and corresponding nickel complexes N‐(R‐phenyl) acetoacetamide Ni(CH₂Ph) (PMe₃) (R = H, 1 ; R = 2‐methyl, 2 ; R = 2,6‐dimethyl, 3 ; R = 2,6‐diisopropyl, 4 ; R = 4‐NO₂, 5 ) were synthesized and characterized. The solid structure of complex 3 was confirmed by X‐ray single‐crystal analysis to be of cis form. ¹H and ³¹P NMR spectroscopy confirmed that cis and trans isomers of nickel complexes were present in solution. Norbornene polymerizations with acetoacetamide nickel complexes activated with modified methylaluminoxane (MMAO) were investigated in detail. Remote steric and electronic effects of acetoacetamide ligand on catalytic activity and molecular weight of polynorbornenes (PNBs) were observed. Characterizations of the obtained PNBs show that the obtained polymer products are non‐crystalline vinylic‐addition polynorbornenes. Copyright © 2013 John Wiley & Sons, Ltd.     

Synthesis and characterization of novel neutral nickel complexes bearing fluorinated salicylaldiminato ligands and their catalytic behavior for vinylic polymerization of norbornene

A series of salicylaldimine‐based neutral Ni(II) complexes (3a–j) [ArN = CH(C₆H₄O)]Ni(PPh₃)Ph [3a, Ar = C₆H₅; 3b, Ar = C₆H₄F(o); 3c, Ar = C₆H₄F(m); 3d, Ar = C₆H₄F(p); 3e, Ar = C₆H₃F₂(2,4); 3f, Ar = C₆H₃F₂(2,5); 3g, Ar = C₆H₃F₂(2,6); 3h, Ar = C₆H₃F₂(3,5); 3i, Ar = C₆H₂F₃(3,4,5); 3j, Ar = C₆F₅] have been synthesized in good yield, and the structures of complexes 3a and 3i have been confirmed by X‐ray crystallographic analysis. Using modified methylaluminoxane as a cocatalyst, these neutral Ni(II) complexes exhibited high catalytic activities for the vinylic polymerization of norbornene. It was observed that the strong electron‐withdrawing effect of the fluorinated salicylaldiminato ligand was able to significantly increase the catalyst activity for vinylic polymerization of norbornenes. In addition, catalyst activity, polymer yield and polymer molecular weight can also be controlled over a wide range by the variation of reaction parameters such as Al:Ni ratio, norbornene:catalyst ratio, monomer concentration, polymerization temperature and time. Copyright © 2008 John Wiley & Sons, Ltd.     

Synthesis,structure and olefin polymerization catalysis of nickel(II) complexes bearing N,O-chelate ligands

Four β-ketoimine ligands (two series) were prepared through traditional condensation reactions of β-diketones with 2,6-substituted anilines. Reaction took place only at the cyclohexanone carbonyl rather than at the acetyl or benzoyl carbonyl, even if more than two equivalents of the amines were added. Consequently, four new moisture- and air-stable bis(β-ketoamino)nickel(II) complexes, Ni[2–CH₃C(O)C₆H₈(=NAr)]₂ (Ar?=?2, 6-iPr₂C₆H₃, (1); Ar?=?2, 6-Me₂C₆H₃, (2) and Ni[2–PhC(O)C₆H₈(=NAr)]₂ (Ar?=?2, 6-iPr₂C₆H₃, (3); Ar?=?2, 6-Me₂C₆H₃, (4) were obtained and characterized. The solid-state structures of complex 1, 2 and 3 have been determined by single-crystal X-ray diffraction. Additionally, these complexes can be applied as highly active catalyst precursors for vinyl polymerization of norbornene (NBE) after activation with methylaluminoxane (MAO).     

Synthesis,structural characterization,and ethylene polymerization behavior of (arylimido)vanadium(V) complexes bearing tridentate Schiff base ligands

A series of novel (arylimido)vanadium(V) complexes bearing tridentate salicylaldiminato chelating ligands, V(N‐2,6‐Me₂C₆H₃)Cl₂[(O‐2‐^tBu‐4‐R‐C₆H₃)CH?ND] (R = H, D = 2‐CH₃O? C₆H₄ ( 2a ); 2‐CH₃S? C₆H₄ ( 2b ); 2‐Ph₂P? C₆H₄ ( 2c ); 8‐C₉H₆N (quinoline) ( 2d ); CH₂C₅H₄N ( 2e ); R = ^tBu, D = 2‐Ph₂P? C₆H₄ ( 2f )), were prepared from V(NAr)Cl₃ by reacting with 1.0 equiv of the ligands in the presence of triethylamine in tetrahydrofuran. These complexes were characterized by ¹H, ¹³C, ³¹P, and ⁵¹V NMR spectra and elemental analysis. The structures of 2c and 2f were further confirmed by X‐ray crystallographic analysis. These (arylimido)vanadium(V) complexes are effective catalyst precursors for ethylene polymerization in the presence of Et₂AlCl as a cocatalyst and ethyl trichloroacetate as a reactivating agent. Complex 2c with a ? PPh₂ group in the sidearm was found to exhibit an exceptional activity up to 133800 kg polyethylene/mol_V h for ethylene polymerization at 75 °C, which is one of the highest activities displayed by homogeneous vanadium(V) catalysts at high temperature. Moreover, high molecular weight polymers with unimodal molecular weight distribution can be obtained, indicating the single site behavior of these catalysts. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2633‐2642     

Transfer hydrogenation of ketones catalyzed by nickel complexes bearing an NHC [CNN] pincer ligand

Four NHC [CNN] pincer nickel (II) complexes, [^iPrCNN (CH₂)₄‐Ni‐Br] ( 5a ), [^nBuCNN (CH₂)₄‐Ni‐Br] ( 5b ), [^iPrCNN (Me)₂‐Ni‐Br] ( 6a ) and [^nBuCNN (Me)₂‐Ni‐Br] ( 6b ), bearing unsymmetrical [C (carbene)N (amino)N (amine)] ligands were synthesized by the reactions of [CNN] pincer ligand precursors 4 with Ni (DME)Cl₂ in the presence of Et₃N. Complexes 5a and 5b are new and were completely characterized. The transfer hydrogenation of ketones catalyzed by the four pincer nickel complexes were explored. Complexes 5a and 6a have better catalytic activity than 5b and 6b . With a combination of NaO^tBu/ⁱPrOH/80 °C and 2% catalyst loading of 5a , 77–98% yields of aromatic alcohols could be obtained.     

Synthesis,structure and ethylene polymerization of group 4 complexes with phosphinoamide ligands

Group 4 complexes containing diphosphinoamide ligands [Ph₂PNR]₂MCl₂ (3: R = ^tBu, M = Ti; 4: R = ^tBu, M = Zr; 5: R = Ph, M = Ti; 6: R = Ph, M = Zr) were prepared by the reaction of MCl₄ (M = Ti; Zr) with the corresponding lithium phosphinoamides in ether or THF. The structure of [Ph₂PN^tBu]₂TiCl₂ (3) was determined by X‐ray crystallography. The phosphinoamides functioned as η²‐coordination ligands in the solid state and the Ti? N bond length suggests it is a simple single bond. In the presence of modified methylaluminoxane or i‐Bu₃Al/Ph₃BC(C₆F₅)₄, catalytic activity of up to 59.5 kg PE/mol cat h bar was observed. Copyright © 2005 John Wiley & Sons, Ltd.     

Synthesis of novel zirconium complexes bearing mono‐Cp and tridentate Schiff base [ONO] ligands and their catalytic activities for olefin polymerization

A series of novel zirconium complexes {R²Cp[2‐R¹‐6‐(2‐CH₃OC₆H₄N?CH)C₆H₃O]ZrCl₂ ( 1 , R¹ = H, R² = H, 2 : R¹ = CH₃, R² = H; 3 , R¹ = ^tBu, R² = H; 4 , R¹ = H, R² = CH₃; 5 , R¹ = H, R² = n‐Bu)} bearing mono‐Cp and tridentate Schiff base [ONO] ligands are prepared by the reaction of corresponding lithium salt of Schiff base ligands with R²CpZrCl₃·DME. All complexes were well characterized by ¹H NMR, MS, IR and elemental analysis. The molecular structure of complex 1 was further confirmed by X‐ray diffraction study, where the bond angle of Cl? Zr? Cl is extremely wide [151.71(3)°]. A nine‐membered zirconoxacycle complex Cp(O? 2? C₆H₄N?CHC₆H₄‐2? O)ZrCl₂ ( 6 ) can be obtained by an intramolecular elimination of CH₃Cl from complex 1 or by the reaction of CpZrCl₃·DME with dilithium salt of ligand. When activated by excess methylaluminoxane (MAO), complexes 1–6 exhibit high catalytic activities for ethylene polymerization. The influence of polymerization temperature on the activities of ethylene polymerization is investigated, and these complexes show high thermal stability. Complex 6 is also active for the copolymerization of ethylene and 1‐hexene with low 1‐hexene incorporation ability (1.10%). Copyright © 2006 John Wiley & Sons, Ltd.     

Ethylene polymerization catalyzed by substituted pyrazole nickel complexes

(Pyrazole)nickel dibromide complexes, (3,5-Me₂pz)₂NiBr₂ (1), (3-Mepz)₄NiBr₂ (2), (pz)₄NiBr₂ (3) and (3,5-^tBu₂pz)₂NiBr₂ (4), were prepared by the reaction of the appropriate pyrazole with (DME)NiBr₂. Solid-state structures of these complexes show a direct relation between the steric bulk of the pyrazole ligand and structure, with more bulky ligands forming four-coordinate complexes (1 and 4) whereas the less bulky ligands formed six-coordinate complexes (2 and 3). Activation of selected complexes (1 and 3) with methylaluminoxane (MAO) produced species that catalyzed the polymerization of ethylene to form high density polyethylene.     

Effect of ligand backbone substituents of nickel α‐diimine complexes on livingness/controllability of olefin polymerization: Competition between monomer isomerization and propagation

Four α‐diimine nickel complexes [(Ar? N?C(R)? C(R)?N? Ar)NiBr₂; R?H, CH₃, cyclohexane‐1,2‐diyl, naphthalene‐1,8‐diyl, Ar?2,6‐i‐Pr₂‐C₆H₃‐) were investigated in propene and hex‐1‐ene polymerization to identify the limits of backbone substituent R size needed to provide living/controlled α‐olefins polymerization by the sufficient suppression of β–H elimination transfer. Propagation kinetics measurements, molar mass on monomer conversion dependencies and reinitiation tests were used to evaluate the livingness of hex‐1‐ene polymerization. Interestingly, living/controlled hex‐1‐ene polymerization was observed in the case of all diimine derivatives including the one bearing only hydrogen atom in backbone positions. Unexpectedly, in the case of catalysts bearing H and CH₃ backbone substituents, we observed the unusual isomerization of hex‐1‐ene into internal hexenes in parallel with its polymerization. Nevertheless, by subtracting the amount of monomer consumed in isomerization side reaction, polymerization still keeps the features of living/controlled process. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3193–3202     

Structures and styrene polymerization activities of a series of nickel complexes bearing ligands of pyrazolone derivatives

A series of nickel complexes with β‐ketoamine ligands based on pyrazolone derivatives were synthesized by condensing pyrazolone with aniline, 2‐chloroaniline or naphthylamine and then reacting the produced β‐ketoamine with nickel halide. The solid‐state structures of these three complexes were determined by single‐crystal X‐ray diffraction. The bis(β‐ketoamine)nickel complexes are all air‐stable and can act as highly active catalyst precursors for styrene polymerization with activation of methylaluminoxane under mild reaction conditions. The activity of the catalyst for styrene polymerization is as high as 2.10 × 10⁵ g polymer/mol Ni h. Both steric and electronic effects were found to be important and influential for catalytic activity. Copyright © 2005 John Wiley & Sons, Ltd.