丁二烯聚合镍催化剂的磁性

在通常镍系Ni(naph)_2-Al(i-Bu)_3-BF_3OEt_2和改型镍体系Ni(naph)_2-Al(i-Bu)_2(OR)-BF_3OEt_2中,助催化剂的还原能力顺序为Al(i-Bu)_3>Al(i-Bu)_2(OPhC_8H_(17))>Al(i-Bu)_2(OPhCH_3)>Al(i-Bu)_2(OPh)>Al(i-Bu)_2(OC_8H_7)在Ni(naph)_2-Al(i-Ba)_2(OC_8H_(17))-BF_3OEt_2体系中镍以Ni(Ⅰ)存在为主,其它体系中均Ni(0)和Ni(Ⅰ)共存为特点。Bd的预混能促进各体系中Ni(Ⅱ)→Ni(Ⅰ)的反应。在Ni(naph)_2-Bd-Al(i-Bu)_2(OPh)和Ni(naph)_2-Bd-Al(i-Bu)_2(OPhCH_3)体系中有Ni(0)聚集体,显铁磁性,而其它体系均显顺磁性。     

新型镍催化体系合成Cis-1,4聚丁二烯的研究

本文研究了以加氢汽油为溶剂的Ni(Naph)_2-Al(i-Bu)_2OR-BP_3·OEt_2及Ni(NaPh)_2-Al(i-Bu)_2OAr-BF3·OEt_2两体系对丁二烯的催化聚合活性、聚合物分子量、微观结构等。各种Al(i-Bu)_2OR或Al(i-Bu)_2OAr为助催化剂组成的新型镍催化体系对丁二烯聚合都有较高的催化活性,所得聚合物Cis-1,4含量在96％以上。磁化率和紫外可见光谱研究证明,在Al(i-Bu)_2OR体系中以Ni(Ⅰ)为主及小量未还原的Ni(Ⅱ);Al(i-Bu)_2OAr中Ni(Ⅰ)及Ni(O)共存。     

改型镍体系催化丁二烯顺1,4-聚合活性中心价态的研究

 改型镍系Ni(naph)₂-Al(i-Bu)₂OC₈H₁₇-BF₃·OEt₂的电子顺磁共振谱指出,活性中心主要由Ni(Ⅰ)组成,预混丁二烯能稳定Ni(Ⅰ)和缩短聚合反应的诱导期,但不改变聚合反应的表观活化能。     

SYNTHESIS OF cis-1, 4-POLYBUTADIENE WITH NICKEL CATALYST INVESTIGATIONS ON INTERACTIONS BETWEEN THE CATALYTIC COMPONENTS BY USING UV-VIS SPECTRUM

Ni(Ⅱ) naphthenate in hydrogenated gasoline or toluene will appear light green, which is the result of absorption in the red and blue bands of the spectrum. The three peaks caused by the spin-allowed d-d transitions are 403, 680, and 1170nm respectively, and are similar to those of Ni(H_2O)_6~(+2). The configuration of Ni(Ⅱ) complex is octabedral.In a two-component system of Ni(naph)_2-Al(i-Bu)_3, the naphthenate ligand attached to Ni(Ⅱ) can be exchanged for the alkyl group on tri-isobutylaluminium, if Al(i-Bu)_3/Ni(naph)_2 in a system. containing metalalkyl and naphthenate does not exceed the value of 0.53. At a higher ratio, Al(i-Bu)_3/Ni(naph)_2>0.53, Ni(Ⅱ) is reduced to Ni(Ⅰ) and Ni(O).In a two-component system Ni(naph)_2-BF_3·OEt_2, a part of the naphthenate can be exchanged for halogen. A new Ni(Ⅱ) complex is formed, which consists of three new d-d bands in the region 360-1660 nm.     

改性镍系催化体系各组分反应的红外光谱研究

用红外光谱法研究了Ni(naph)_2-TIBA·DBMP-BF_3·OEt_2催化丁二烯聚合中催化剂组分之间的反应。发现TIBA与DBMP反应主要产生iBu_2AlOAr,它可延缓Ni(I)的继续被还原,从而提高了活性中心Ni(Ⅰ)的稳定性,使产物分子量大大提高,而凝胶含量降低。还根据DBMP与TIBA、Ni(naph)_2与TIBA·DBMP及BF_3·OEt_2反应产物的分析数据,推测了活性中心的结构。     

二氯-α、ω-双二苯膦代烷合镍对丙烯双聚反应的催化行为

本工作研究了双配位配体的氯化镍络合物对丙烯双聚的催化行为,设计了对称的双膦配体Ph_2P(CH_2)nPPh_2及不对称的双膦配体和膦氮配体。论文中合成了三种d、ω-双二苯膦代烷配体Ph_2P(CH_2)_2PP_2,(dPPe),Ph_2P(CH_2)_4PPh_2,(dPPb),Ph_2P(CH_2)_0PPh_2,(dPPh),以及相应的氯化镍络合物Ni(dppe)Cl_2(Ⅰ),Ni(dPPb)Cl_2     

两个固相合成异核金属簇合物Ni_2Nb_2Te_4和Ni_2Ta_2Te_4的合成与晶体结构分析

本文通过高温固相反应得到标题所示的两个异核金属簇合物,两种晶体系异质同晶,空间群为C_v-Pma2;晶胞参数分别为(Ⅰ):a=7.955(1),b=6.258(1),c=7.203(2);(Ⅱ):a=7.914(1),b=6.237(1),c=7.236(1);Z=2。在簇单元Ni_2M_2T_(10)中,2个Ni和2个M原子成菱形排布,Ni—Ni和Ni—M之间存在金属—金属相互作用。每个金属原子周围最近邻的Te原子均按畸交四面体与金属原子配位,簇合物的结构式可写成[Ni_2M_2(μ_4-Te)_(6/3)(μ_4-Te)_(4/2)]_∞。簇单元之间通过簇间较弱的金属—金属键以及共有Te原子相互联结成平行于ab面的二维网状结构。晶体显示出较强的各向异性导电性。     

用量子化学方法研究Ni(DMG)_2络合物的电还原机理

本文用自旋非限制的INDO量子化学方法,研究了Ni(DMG)_2,[Ni(DMG)_2]~-和[Ni(DMG)_2]~(2-)的电子结构,结果表明:在Ni(DMG)_2络合物电还原时,第一个电子是和Ni的d轨道相互作用,第二个电子是和N的p轨道相互作用,该结果与我们的电化学实验结果基本一致。     

ELECTROREDUCTION MECHANISM OF Ni(DMG)-2 COMPLEX STUDIED WITH QUANTUM CHEMICAL METHOD

The electronic structures of the species Ni(DMG)_2, (Ni(DMG)_2)~- and (Ni(DMG)_2)_(2-) have been studied by INDO quantum chemical method. The results have clearly shown that in the first stage of the electroreduction of Ni(DMG)_2, one electron interacts with the d orbitals on the nickel atom, while in the further stage the second electron interacts with the p orbitals on the nitrogen atoms. It conforms with our electrochemical experimental studies which showed that not only Ni(Ⅱ) is reduced but also DMG is catalytically reduced during the reduction of Ni(DMG)_2.     

环氧化物稀土络合催化开环聚合动力学研究

用膨胀计方法研究环氧丙烷、环氧氯丙烷在稀土络合催化剂 Nd(P_(204))_3-Al(i-Bu)_3-H_2O作用下的聚合反应动力学,表明聚合反应速度对催化剂浓度及单体浓度均呈一级关系。环氧丙烷、环氧氯丙烷开环聚合反应活化能分别为61.3kJ/mol和48.9kJ/mol。在同样的聚合反应条件下,环氧氯丙烷聚合反应速度大于环氧丙烷聚合反应速度。 研究还发现,催化剂组成摩尔比Al/Nd及H_2O/Al对聚合反应速度均有一定影响;各种稀土元素络合催化剂催化活性顺序为:Nd>La>Dy>Yb>Eu;稀土络合物中配体对活性的影响为:acac>P_(204)>P_(507)>naph;烷基铝的影响为:Al(i-Bu)_3>AlEt_3。     

Metallacyclic mechanism of the addition polymerization of norbornene involving Ni(I) and Ni(III) complexes

The catalytic system Ni(COD)₂/BF₃·OEt₂ is highly active in the addition polymerization of nor-bornene (NB). Its activity, which is up to 1930 (kg NB) (mol Ni)⁻¹ h⁻¹, is higher than the activity of the other known nickel complex catalysts. Another advantage of this system over the latter is that it contains a smaller proportion of a Lewis acid (5 molar parts or below) and no conventional stabilizing organoelement ligands. The activity of this system in NB polymerization has been investigated by Fourier-transform IR spectroscopy. According to EPR data, NB polymerization is accompanied by the formation of low-spin complexes of trivalent nickel, which result from the oxidative addition of the monomer to univalent nickel complexes. A metallacyclic mechanism involving Ni(I) and Ni(III) complexes is suggested for NB polymerization.     

Ni(II) and Fe(II) complexes based on bis(imino)aryl pincer ligands: synthesis, structural characterization and catalytic activities

Bis(imino)aryl NCN pincer Ni(II) complexes 2,6-(ArN=CH)(2)C(6)H(3)NiBr (1: Ar = 2,6-Me(2)C(6)H(3); 2: Ar = 2,6-Et(2)C(6)H(3); 3: Ar = 2,6-(i)Pr(2)C(6)H(3)) were prepared via the oxidative-addition of Ni(0)(Ph(3)P)(4) with bis(N-aryl)-2-bromoisophthalaldimine. These nickel complexes were characterized by NMR and elemental analyses. Their solid molecular structures were established by X-ray diffraction analyses. The nickel metal centers adopt distorted square planar geometries with the bromine atoms acting as one coordinate ligands. The NCN pincer Fe(II) complexes 2,6-(ArN=CH)(2)C(6)H(3)Fe(μ-Cl)(2)Li(THF)(2) (4: Ar = 2,6-Me(2)C(6)H(3); 5: Ar = 2,6-Et(2)C(6)H(3); 6: Ar = 2,6-(i)Pr(2)C(6)H(3)) were synthesized by lithium salt metathesis reactions of the ligand lithium salts with FeCl(2). X-ray structure analyses of 4 and 5 revealed that the Fe(II) complexes are hetero-dinuclear with the iron atoms in trigonal bipyramidal environments. When activated with MAO, the nickel complexes are active for norbornene vinyl polymerization but are inert for butadiene polymerization. The Fe(II) complexes show moderate activities in butadiene polymerization when activated with alkylaluminium, affording the cis-1,4 enriched polymer.     

镍系催化丁二烯聚合条件的新探索

通过改变环烷酸镍─三异丁基铝─三氟化棚乙醚络合物［（Ni（naph）2－Al（i－Bu）3－BF3OEt2）］体系中催化剂的配比，丁二烯浓度，聚合温度等聚合条件，考察了它们对适宜Al／B比活性范围的影响，结果表明：采用固定Ni变Al或者固定Al变Ni两种方式改变Al／Ni摩尔比，都能有效地调节适宜Al／B比范围，并认为目前工业生产顺丁橡胶的配方中Al／Ni＝4是太低的，有必要适当加以提高；丁二烯浓度太低时，适宜Al／B比范围很窄，从提高聚合活性和聚合速率来看，适当地提高丁二烯浓度是有益的；在一定范围内改变聚合温度，对适宜Al／B比范围没有明显影响。     

丁二烯催化环化三聚中多金属的协同效应

研究了第二过渡金属化合物对ＴｉＣｌ４／ＡｌｅＴ１．４６ｃＬ１．５４催化丁二烯环化三聚的多金属协同效应。结果表明，极少量的第二过渡金属化合物，如Ｃｒ，（ａｃａｃ）３，Ｍｎ（ａｃａｃ）３，ＮｉＣｌ２，ＺｒＣｌ４等加入ＴｉＣｌ４／ＡｌＥｔ１．４６Ｃｌ１．５４体系后不同程度地提高了丁二烯环化三聚的选择性，并改变了体系的最大速率和催化剂效率。     

Combined polymerization catalysis of nickel complex and zirconocene for branched polyethylene

The polymerization behavior of 2-(2′-pyridyl) quinoxaline nickel dibromide/Cp₂ZrCl₂/MAO system was investigated in three ways: the Ni catalyst was added first, followed by addition of Zr catalyst (method I); the Ni and Zr catalysts were added simultaneously (method II); and the Zr catalyst was added first, followed by addition of Ni catalyst (method III). Results of GC-MS, GPC,¹³C NMR and DSC investigations indicated that the properties of resulting polyethylene were greatly varied by changing feeding orders of the two catalysts. Decreasing Ni/Zr molar ratio or increasing polymerization temperature gave corresponding polyethylenes with less branches and higher melting point. Compared to the procedure using Cp₂ZrCl₂ catalyst only, the activity of Zr catalyst in those combined system decreased because of the competition of ethylene between the [Ni−C] and [Zr−C] active centers. In addition, other zirconocenes were also employed as copolymerization catalysts in the combined system with nickel complex. compared to Cp₂ZrCl₂ case, the ethyl-bridged Zr catalyst performed better for polymerization of ethylene while the Si-bridged Zr catalyst showed better copolymerization ability.     

双吡唑亚胺镍/甲基铝氧烷催化降冰片烯的聚合

合成了两种双吡唑亚胺镍配合物: 双-N-(苯基-1-3,5-二甲基吡唑基亚甲基)苯基亚胺二溴化镍(Cat.1)和双-4-甲氧基-N-(苯基-1-3,5-二甲基吡唑基亚甲基)苯基亚胺二溴化镍(Cat.2). 研究了Cat.1/MAO和Cat.2/MAO催化体系对降冰片烯(NBE)单体聚合的催化性能, 考察了各种聚合条件, 如温度、Al/Ni摩尔比及催化剂浓度对降冰片烯的催化效率、单体转化率、聚合物分子量及分子量分布的影响. 研究结果表明, Cat.1/MAO和Cat.2/MAO催化体系对降冰片烯聚合具有较高的催化效率, 可达到105 g PNBE/(mol Ni)数量级, 所得聚降冰片烯(PNBE)的重均分子量在105以上, 分子量分布指数在2左右. 聚合产物的1H NMR和FTIR谱分析结果表明, 该聚合反应是以单体的乙烯基加成聚合机理进行的.     

双膦胺镍/甲基铝氧烷催化降冰片烯聚合研究

合成了一种双膦胺镍配合物N,N-双(二苯膦基)-对甲氧基苯胺二氯化镍(PNP-Ni),研究了PNP-Ni/甲基铝氧烷(MAO)体系使降冰片烯(NBE)单体按乙烯基加成聚合的催化性能,考察了各种聚合条件如温度、Al/Ni比及催化剂浓度对催化效率、单体转化率、聚合物分子量及分子量分布的影响.结果表明,该催化体系具有较高的催化效率,可达到105g PNBE/(mol Ni)数量级,所得可溶性聚合产物聚降冰片烯(PNBE)重均分子量可高达1×106以上,分子量分布窄(Mw/Mn<2).该PNBE具有很好耐热性能,其玻璃化转变温度Tg高于300℃.通过对聚合产物1H和13C-NMR分析表明,该聚合反应是单体按乙烯基配位聚合机理进行的,聚合产物PNBE的3种立体构型含量分别为[mm]=53%,[mr]=39%,[rr]=8%.