AlCl_3／SbCl_3引发α－蒎烯阳离子聚合反应──引发活性种本质研究

考察了复合催化剂ＡｌＣｌ_３／ＳｂＣｌ_３的不同配制方法和质子捕捉剂２，６－二异丁基－４－甲基吡啶（ＤＴＢＭＰ）对α－蒎烯阳离子聚合反应的影响。结果表明，ＡｌＣｌ_３和ＳｂＣｌ_３加热熔融复合比简单复合的引发聚合活性更高；ＤＴＢＭＰ对该复合催化剂的聚合反应速率及其产物分子量分布均无明显影响，证明该复合催化剂形成的活性种本质上与质子Ｈ活性种不同，是新型活性种。根据２７ＡｌＮＭＲ对该体系活性种分析结果，认为引发阳离子是［Ｓｂ（Ｖ）Ｃｌ_４］，抗衡阴离子是［Ａｌ_２Ｃｌ_７］     

Cl2／TiCl4体系引发IBVE活性阳离子聚合的研究（Ⅰ）：引…

采用ＵＶ光谱法证明了ＩＢＶＥ／Ｃｌ２／ＴｉＣｌ４／甲苯聚合体系中同时存在着两种引发活性中心及络合竞争，研究了Ｃｌ２／ＴｉＣｌ４和Ｈ２Ｏ／ＴｉＣｌ４络合平衡，求出了２０℃时２ＴｉＣｌ４←Ｃｌ２和ＴｉＣｌ４←Ｈ２Ｏ络合平衡不稳定常数。     

Cu~0/2,2'-联吡啶/CCl_4和CuCl_2/2,2'-联吡啶/偶氮二异丁腈催化引发体系中的苯乙烯“活性”自由基乳液聚合研究

分别以Ｃｕ０／２ ,２′联吡啶（Ｂｐｙ） 和ＣｕＣｌ２／Ｂｐｙ 配合物为催化剂,ＣＣｌ４ 和偶氮二异丁腈（ＡＩＢＮ） 为引发剂,较为详细地研究了苯乙烯的原子转移自由基乳液聚合规律．结果表明：其乳液聚合体系均显示出了“活性”聚合的基本特征,即数均分子量与转化率呈线性关系,但聚合反应一经引发,聚合物的分子量就达数万,且分子量约为理论值的５ 至２０ 倍;Ｃｕ０／Ｂｐｙ／ＣＣｌ４ 体系的ＭＷＤ 与本体聚合相当,而ＣｕＣｌ２／Ｂｐｙ／ＡＩＢＮ 体系的ＭＷＤ 比其本体聚合体系大,最小为１－６４ ;研究Ｃｕ０／Ｂｐｙ／ＣＣｌ４ 体系发现,乳液聚合与悬浮聚合在“活性”特征上没有本质的区别,但两者在动力学上有些差异;跟踪乳液聚合过程中的ｐＨ 值发现,体系中的ｐＨ 值随反应时间的延长呈下降趋势,并可能影响聚合速率．     

SOCl2／SnCl4—DMSO／n—Bu4NCl引发体系苯乙烯活性阳离子聚合反应的研究

研究表明，ＳＯＣｌ２／ＳｎＣｌ４引发体系的苯乙烯聚合反应很快，但所得聚合产物的分子量分布宽（Ｍｗ／Ｍｎ＝４．３７），且其ＧＰＣ曲线呈多重峰；单独加入季铵盐（ｎ－Ｂｕ４ＮＣｌ）或二甲基亚砜（ＤＭＳＯ）可使聚合产物分子量分布明显变窄，并随浓度的增加而加强，但程度有限，不显示活性聚合特征；ＤＭＳＯ和ｎ－Ｂｕ４ＮＣｌ同时加入，表现出协同效应，不仅能保持较高的聚合反应活性，而且产物分子量分布很窄（Ｍｗ／Ｍｎ＝１．２７），分子量随单体转化率增加而增加，且线性关系良好，聚合物链数只与引发剂初始浓度相关，显示活性聚合特征。     

α-氯代乙苯/TiCl4/Ti(OiPr)4引发β-蒎烯活性阳离子聚合

－４０℃条件下,在ＣＨ２Ｃｌ２溶剂中以α－氯代乙苯为引发剂,ＴｉＣｌ４和Ｔｉ（ＯｉＰｒ）４混合物为Ｌｅｗｉｓ酸活化剂,进行β－蒎烯阳离子聚合,单独使用强的Ｌｅｗｉｓ酸ＴｉＣｌ４时,聚合反应在瞬间完成,聚合产物的分子量分布较宽,添加本身无催化活性的弱Ｌｅｗｉｓ酸Ｔｉ（ＯｉＰｒ）４后,聚合反应减缓且聚合产物的分子量的分布变窄,当Ｔｉ（ＯｉＰｒ）４／ＴｉＣｌ４摩尔比为１／３时,产物的分子量随单体转化率线性增加,且分子量分布较窄,显示出活性聚合特性这种活性聚合特性由单体添加实验进一步得到证实。     

活性自由基聚合法制备以C60封端的聚苯乙烯

通过活性自由基聚合的方法制备了以２,２,６,６－四甲基－４－羟基呱啶氮氧自由基（ＴＥＭＰＯＬ）封端的聚苯乙烯大分子,实验结果证明该反应体系是一个典型的活性自由基聚合体系,同时研究了ＴＥＭＰＯＬ／ＡＩＢＮ的比例及ＡＩＢＮ的含量对聚合反应的影响。用以ＴＥＭＰＯＬ封端的聚苯乙烯和Ｃ６０反应,制得了Ｃ６０的聚苯乙烯高分子衍生物,紫外和ＧＰＣ结果均证明Ｃ６０已连接到聚苯乙烯的长链上,ＧＰＣ的结果还证明,Ｃ６     

由Mg(nBu)2制备的MgCl2载体催化剂的烯烃聚合动力学

讨论了催化剂ＣＤ，ＣＭ和ＣＤ－Ａ的乙烯和丙烯聚合动力学曲线，只有催化剂ＣＤ在丙烯聚合时加入外给电子体其动力学曲线为上升－衰减型，其它均为衰减型，催化剂ＣＤ丙烯聚合活性高于催化剂ＣＭ。丙烯聚合时加入外给电子体使总活性中心浓度降低，但等规中心浓度反应增加。同种载体制备的催化剂ＣＤ和ＣＤ－Ａ载钛过程中加入内给电子体，可使其聚合活性增加，在一定范围内，随Ａｌ／Ｔｉ增加，在一定范围内，随Ａｌ／Ｔｉ增加，催化     

乙烯系自由基聚合阻聚效应（ⅩⅧ）：哌啶氮氧自由基氨基硫…

本文研究了３种１－（芳酰基）－４［４＇－（２，２，６，６－四甲基哌啶）－１－氧自由基］氨基硫脲化合物（ＡＴＳＣＰＯ）分别同通用阻聚剂（ＣＩＨ），如对苯二酚（ＨＱ），苯醌（ＢＱ），吩噻嗪（ＰＴ）及二乙羟胺（ＤＥＨＡ）组成的混合阻聚剂对ＡＩＢＮ引发的ＭＭＡ自由基聚合的影响，研究结果表明：当［ＡＴＳＣＰＰ］／ＣＩＨ＝５：１时，除ＡＴＳＣＰＯ－ＢＱ外，其余阻聚效果均较ＡＴＳＣＰＯ和ＣＩＨ单独用作阻聚剂时高     

新型高活性催化剂乙烯气相聚合的研究（Ⅵ）：锌化合物对催化…

研究了新型高活性乙烯气相聚合催化剂ＴｉＣｌ４、Ｔｉ（ＯＢｕ）４／ＭｇＣｌ２、ＳｉＯ２和ＺｎＣｌ２／醇／ＡｌＲ３体系中ＺｎＣｌ２－ＡｌＥｔ３／ＳｉＯ２重量比和锌化合物含量对气相均聚合的影响，比较了２种不同催化剂Ｃａｔ＃Ａ和Ｃａｔ＃Ｂ的聚合反应力学及性能差异。ｄ ｆ ｃｌｔｉｐ     

异丙醇铝改进的原子转移自由基聚合催化体系

以α 溴代异丁酸乙酯［２ （ＥｉＢ） Ｂｒ］ 为引发剂,溴化亚铜（ＣｕＢｒ）／ 联二吡啶（ｂｐｙ）／ 异丙醇铝［Ａｌ（ＯｉＰｒ）３］ 为复合催化剂,在环己酮溶液中进行了甲基丙烯酸正丁酯（ＢＭＡ） 的原子转移自由基聚合（ＡＴＲＰ） ．研究了异丙醇铝对聚合速率及产物分子量分布的影响．异丙醇铝可与引发剂和聚合物中的羰基配位,使相邻的Ｃ—Ｂｒ 键活化,ＡＴＲＰ 反应可以在较低温度下进行．适量溴化铜的加入,可调节ＡＴＲＰ 活性,可得到分子量可控且分子量分布窄的ＰＢＭＡ（ ＭＷＤ＝ １－３ ～１－５） ．     

开环共聚法合成热可逆共价交联聚醚橡胶

以烷基铝为催化剂,双环戊二烯二甲酸双缩水甘油酯为交联单体,与环氧氯丙烷、环氧乙烷、环氧丙烷进行离子型开环共聚,制得了热可逆共价交联的聚醚橡胶．研究了聚合方法、聚合配方和工艺条件对单体转化率、共聚物组成的影响．通过 Ｉ Ｒ 和 Ｄ Ｓ Ｃ 测定及反应溶解性和高温成型实验,证明了共聚物的结构及共价交联的热可逆转化特性．     

Biomimetic hydrocarbon oxidation catalyzed by nonheme iron(III) complexes with peracids: evidence for an Fe(V)=O species

Mononuclear nonheme iron(III) complexes of tetradentate ligands containing two deprotonated amide moieties, [Fe(Me(2)bpb)Cl(H(2)O)] (3 a) and [Fe(bpc)Cl(H(2)O)] (4 a), were prepared by substitution reactions involving the previously synthesized iron(III) complexes [Et(3)NH][Fe(Me(2)bpb)Cl(2)] (3) and [Et(3)NH][Fe(bpc)Cl(2)] (4). Complexes 3 a and 4 a were characterized by IR and elemental analysis, and complex 3 a also by X-ray crystallography. Nonheme iron(III) complexes 3, 3 a, 4, and 4 a catalyze olefin epoxidation and alcohol oxidation on treatment with m-chloroperbenzoic acid. Pairwise comparisons of the reactivity of these complexes revealed that the nature of the axial ligand (Cl(-) versus H(2)O) influences the yield of oxidation products, whereas an electronic change in the supporting chelate ligand has little effect. Hydrocarbon oxidation by these catalysts was proposed to involve an iron(V) oxo species which is formed on heterolytic O-O bond cleavage of an iron acylperoxo intermediate (FeOOC(O)R). Evidence for this iron(V) oxo species was derived from KIE (k(H)/k(D)) values, H(2) (18)O exchange experiments, and the use of peroxyphenylacetic acid (PPAA) as the peracid. Our results suggest that an Fe(V)=O moiety can form in a system wherein the supporting chelate ligand comprises a mixture of neutral and anionic nitrogen donors. This work is relevant to the chemistry of mononuclear nonheme iron enzymes that are proposed to oxidize organic substrates via reaction pathways involving high-valent iron oxo species.     

Synthesis,characterization, and solution redox properties of (trimpsi)M(CO)(2)(NO) complexes [M = V,Nb, Ta; trimpsi = (t)BuSi(CH(2)PMe(2))(3)

Treatment of [Et(4)N][M(CO)(6)] (M = Nb, Ta) with I(2) in DME at -78 degrees C produces solutions of the bimetallic anions [M(2micro-I)(3)(CO)(8)](-). Addition of the tripodal phosphine (t)BuSi(CH(2)PMe(2))(3) (trimpsi) followed by refluxing affords (trimpsi)M(CO)(3)I [M = Nb (1), Ta (2)], which are isolable in good yields as air-stable, orange-red microcrystalline solids. Reduction of these complexes with 2 equiv of Na/Hg, followed by treatment with Diazald in THF, results in the formation of (trimpsi)M(CO)(2)(NO) [M = Nb (3), Ta (4)] in high isolated yields. The congeneric vanadium complex, (trimpsi)V(CO)(2)(NO) (5), can be prepared by reacting [Et(4)N][V(CO)(6)] with [NO][BF(4)] in CH(2)Cl(2) to form V(CO)(5)(NO). These solutions are treated with 1 equiv of trimpsi to obtain (eta(2)-trimpsi)V(CO)(3)(NO). Refluxing orange THF solutions of this material affords 5 in moderate yields. Reaction of (trimpsi)VCl(3)(THF) (6) with 4 equiv of sodium naphthalenide in THF in the presence of excess CO provides [Et(4)N][(trimpsi)V(CO)(3)] (7), (trimpsi)V(CO)(3)H, and [(trimpsi)V(micro-Cl)(3)V(trimpsi)][(eta(2)-trimpsi)V(CO)(4)].3THF ([8][9].3THF). All new complexes have been characterized by conventional spectroscopic methods, and the solid-state molecular structures of 2.(1)/(2)THF, 3-5, and [8][9].3THF have been established by X-ray diffraction analyses. The solution redox properties of 3-5 have also been investigated by cyclic voltammetry. Cyclic voltammograms of 3 and 4 both exhibit an irreversible oxidation feature in CH(2)Cl(2) (E(p,a) = -0.71 V at 0.5 V/s for 3, while E(p,a) = -0.55 V at 0.5 V/s for 4), while cyclic voltammograms of 5 in CH(2)Cl(2) show a reversible oxidation feature (E(1/2) = -0.74 V) followed by an irreversible feature (0.61 V at 0.5 V/s). The reversible feature corresponds to the formation of the 17e cation [(trimpsi)V(CO)(2)(NO)](+) ([5](+)()), and the irreversible feature likely involves the oxidation of [5](+)() to an unstable 16e dication. Treatment of 5 with [Cp(2)Fe][BF(4)] in CH(2)Cl(2) generates [5][BF(4)], which slowly decomposes once formed. Nevertheless, [5][BF(4)] has been characterized by IR and ESR spectroscopies.     

丙烯腈与衣康酸的溶液共聚合

为了获得性能优越的碳纤维,聚丙烯腈（ＰＡＮ）纤维已经成为应用最广泛的前驱体之一［１］．事实表明,碳纤维的性能在很大程度上依赖于前驱体纤维的性能［１］,利用丙烯腈与少量其它单体进行共聚,可使聚合物的力学性能（机械强度、弹性、塑性等）得到明显的改善．由已报道的文章可知,与丙烯腈共聚时所采用的其它单体主要有丙烯酸、甲基丙烯酸、丙烯酸酯、丙烯酰胺、衣康酸等［２～７］,所采用的溶剂主要为二甲基甲酰胺（ＤＭＦ）．对在二甲基亚砜（ＤＭＳＯ）为溶剂中的聚合条件,并未见详细报道．本文以ＤＭＳＯ为溶剂,用偶氮二异丁…     

Crystal Structure of Complex （Et4N）[VFe3S4Cl3（CH3CN）3]

1　ＩＮＴＲＯＤＵＣＴＩＯＮＳｉｎｃｅ1980,ｍａｎｙＶ/Ｆｅ/Ｓｈｅｔｅｒｏｍｅｔａｌｌｉｃｓｕｌｆｕｒｃｌｕｓｔｅｒｃｏｍｐｏｕｎｄｓｈａｖｅｂｅｅｎｒｅｐｏｒｔｅｄ.ＲａｕｃｈｆｕｓｓｅｔａｌｏｂｔａｉｎｅｄｔｗｏｋｉｎｄｓｏｆＶ/Ｆｅ/Ｓｃｏｍｐｏｕｎｄｓ[1]ｕｓｉｎｇ(ＣＨ3Ｃ5Ｈ4)2Ｖ2Ｓ4ａｓａｎｏｒｇａｎｏｍｅｔａｌｌｉｃｌｉｇａｎｄ,ｏｎｅｉｓ(ＭｅＣｐ)2Ｖ2Ｆｅ2(ＮＯ)2Ｓ4ｗｉｔｈａｃｕｂａｎｅｌｉｋｅｓｔｒｕｃｔｕｒｅａｎｄａｎｏｔｈｅｒｉｓ(ＭｅＣｐ)2Ｖ2Ｓ4Ｆｅ(ＮＯ)2ａｎｄ(ＭｅＣｐ)2Ｖ2Ｓ4…     

Density functional theoretical study of a series of binary azides M(N3)n (n = 3, 4)

Geometrical structures of a series of binary azides M(N3)n (M = elements in groups 3 and 13 (n = 3) and in groups 4 and 14 (n = 4)) were investigated at the B3LYP/6-311+G level of theory. Our calculations found that binary group 3 triazides M(N3)3 (M = Sc, Y, La) and binary group 4 tetraazides M(N3)4 (M = Ti, Zr, Hf) turn out to be stable with all frequencies real having a similar linear M-N-NN structural feature, as previously reported for M(N3)4 (M = Ti, Zr, Hf). However, binary azides of group 13 M(N3)3 (M = B, Al, Ga, In, Tl) and group 14 elements M(N3)4 (C, Si, Ge, Sn, Pb) with bent M-N-NN bond angles differ obviously from binary group 3 and 4 azides in geometrical structure. These facts are mainly explained by the difference in electronic density overlap between the central atom and the alpha-N atoms of the azido groups. Two lone-pair electrons on the sp hybridization alpha-N atoms in the binary group 3 and 4 azides donate electron density into two empty d orbitals of the central transition metal atom and a pair of valence bonding electrons, resulting in the alpha-N atoms acting as a tridentate ligand. The sp2 hybridization alpha-N atoms of the binary group 13 and 14 azides only give one valence electron to form one valence bonding electron pair acting virtually as monodentate donors.     

Kinetics of the thiazolium ion-catalyzed benzoin condensation.

The formation of benzoin (Ph-CHOH-CO-Ph) from two molecules of benzaldehyde, catalyzed by 3-benzyl-5-(2-hydroxyethyl)-4-methylthiazolium bromide in methanol buffered with Et(3)N/Et(3)NH(+)Cl(-) has been studied. Initial-rate studies at various concentrations of PhCHO (0.1-1.7 M) showed that the reaction is close to being first order in PhCHO. Following the reaction in deuteriomethanol, (1)H NMR spectroscopy allowed rate constants for all three kinetically significant steps to be determined. These show that all three steps are partially rate-determining. A normal deuterium kinetic isotope effect for the overall reaction (k(H)/k(D) approximately 3.4) is observed using PhCDO, and a large inverse solvent isotope effect (k(D)/k(H) approximately 5.9) is observed using deuteriomethanol, consistent with the kinetic scheme presented here.     

SYNTHESIS AND STRUCTURE OF[Et_4N]_3[FE_3(SPh)_3Br_3Cl_3]

<正> The title compound was synthesized and its structure solved. The formula is [Et4N]3[Fe3(SPh)3Br3Cl3]. M=1231.95, monoclinic, space group C2/c, a=24.569(4), b=13.504(2), c=18.348.(3)A, β=110.78(1)°, V=5691(3)A3, Z=4, Dm= 1.41, Dc=1.44-g/cm3. The flat structure of the anion has. a planar [Fe3S3] ring and three phenyl groups. Statistical distribution of chlorine and bromine atoms on two sides of the [Fe3S3] plane results in a C2 symmetry of the anion.     

Molybdenum-iron-sulfur clusters of nuclearities eight and sixteen, including a topological analogue of the P-cluster of nitrogenase

Transformations of the edge-bridged double cubane cluster [(Cl4cat)2(Et3P)2Mo2Fe6S8(PEt3)4] (1) under reducing conditions have been investigated as synthetic approaches to the clusters of nitrogenase. Cluster 1 is a versatile precursor to different Mo-Fe-S cluster types. The reaction system 1/K(C14H10) in THF yields the reduced cluster [(Cl4cat)2(Et3P)2Mo2Fe6S8(PEt3)4]1- (2), which as its crystalline Et4N+ salt retains the edge-bridged structure of 1. X-ray structural and M?ssbauer spectroscopic results indicate an unsymmetrical electron distribution with localized [MoFe3S4]2+,1+ cubane-type units. The system 1/2K(C14H10)/2HS- in THF/acetonitrile affords [(Cl4cat)4(Et3P)4Mo4Fe12S20K3(DMF)]5- (3), whose structure was determined as the Ph3PMe+ salt. The cluster consists of two isostructural Mo2Fe6S9 fragments connected by two mu 2-S bridges. Three potassium ions are bound between the two fragments. In each fragment, the iron atoms are present in tetrahedral FeS4 and the molybdenum atoms in octahedral MoO2PS3 coordination units, and two MoFe3(mu 3-S)3 cuboidal units are bridged by a common mu 6-S atom. The fragments have idealized mirror symmetry and are isostructural with two of the fragments present in the previously reported high-nuclearity cluster [(Cl4cat)6(Et3P)6Mo6Fe20S30]8- (4) (Osterloh, F.; Sanakis, Y.; Staples, R. J.; Münck, E.; Holm, R. H. Angew. Chem., Int. Ed. Engl. 1999, 38, 2066). On the basis of overall shape, atom connectivities, and metric features, the Mo2Fe6S9 fragment is a topological analogue of the P-cluster of nitrogenase in the PN (reduced) state. A third cluster type, formed as a minor byproduct in the reaction system leading to 2, was crystallographically identified as [(Cl4cat)2(Et3P)2Mo2Fe6S8(PEt3)4]4-, whose core is made up of two MoFe3(mu 3-S)3 cuboidal units bridged by two mu 2-S atoms and connected by a direct Fe-Fe bond. Full structural details and the redox properties of 2 and 3 are reported.     

含8-羟基喹啉类配体的新型钛配合物[O,N]CpTiCl_2的合成及其催化乙烯聚合研究

茂金属催化烯烃聚合的活性中心被认为是1 4电子结构的金属阳离子配合物 [Ｃｐ2 ＭＲ]+ (Ｒ为烷基 ) ,并且金属中心的Ｌｅｗｉｓ酸性和周围茂配体的空间构型对其催化活性及聚合产物的结构有直接的影响[1,2 ] .然而 ,茂金属须大量ＭＡＯ存在下才能显示高活性 ,并且其稳定性较差 ,这都一定程度上限制了茂金属催化剂的实际应用 .近几年来 ,将含非环戊二烯基配体的金属配合物应用于烯烃均相聚合的研究大量出现[3] ,其中非环戊二烯基配体有含氮化合物[4～ 9] 和含氧化合物[10～ 15] 等 ,这些非茂配合物可催化乙烯或丙烯聚合 ,但活性一般较低 .茂金…