[Cp_2Ti(L)X]的ESR谱研究

本文研究了配合物[Cp_2Ti(L)X](Cp:C_5H_5,Me~-C_5H_4,C_5Me_5;L:瞵、异腈、吡啶、胺、一氧化碳等;X:F,Cl,Br,I)的ESR谱,获得了这些配合物的波谱参数。发现在Cl,Br,I三个系列中,g值与钛超精细偶合常数a(Ti)值随L的变化呈线性关系。观测到大量g>g_e的Ti(Ⅲ)配合物的ESR谱,对其规律性进行了探讨。     

2D-NMR测定人参皂苷Rb~1溶液中的三维空间结构

本文用一维和二维NMR归属了人参皂苷Rb~1的质子化学位移, 测定了质子偶合常数, 并用相敏NOESY谱测定了分子中质子间的距离。以所测定的化学位移, 偶合常数和质子间距等NMR结构参数为初始数据, 用自编和改进的分子结构计算程序计算出人参皂苷Rb~1在溶液中的三维空间结构。     

溶液中(RC_2R!'''')CO(CO)(PR_3~'''')_2的配体PR_3~''''之间的交换作用——三跳动力学模型

本文成功地运用了三跳动力学模型,通过相关函数和超精细分裂常数的关系,推出了电子自旋共振波谱的线宽与基本线宽T_(2,0)~(-1)、溶液中各种异构体的超精细分裂常数、配体的交换寿命等之间的关系。求出了在290K温度下(Ph_2C_2)Co(CO)[P(OEt)_3]_2的THF溶渡中P(OEt)_3配体的交换寿命是5.6×10~(-11)秒。     

溶液中(RC2R')Co(CO)(PR″3)2的配体PR″3之间的交换作用——三跳动力学模型

本文成功地运用了三跳动力学模型,通过相关函数和超精细分裂常数的关系, 推出了电子自旋共振波谱的线宽与基本线宽T_(2,0)~(-1)、溶液中各种异构体的超精细分裂常数、配体的交换寿命等之间的关系。求出了在290 K温度下(Ph_2C_2)Co(CO)[P(OEt)_3]_2的THF溶渡中P(OEt)_3配体的交换寿命是5.6×10~(-11)秒。     

光促二氯二茂钛催化丙烯腈聚合的研究

研究了二氯二茂钛催化丙烯腈等单体的本体聚合反应。在光照射下,二氯二茂钛对丙烯腈、甲基丙烯酸甲酯、苯乙烯等单体具有催化聚合活性。光是必要的条件。证明了其聚合反应为游离基机理。计算了丙烯腈的聚合速度、速度常数和反应活化能。     

取代芳基吡唑和取代芳基异噁唑结构的核磁共振波谱表征

用1 H,13 C NMR和多种二维核磁共振谱表征了本系列化合物的结构,完成了1 H和13 C NMR 谱带的归属,测定了氟原子对各质子和碳原子的偶合常数,探讨了影响偶合常数大小的因素.     

5-硝基尿嘧啶电化学还原机理的探讨

本文采用循环伏安法、恒电位电解法结合紫外光谱以及电子自旋共振波谱(ESR)方法对5-硝基尿嘧啶(5NU, 1)在DMSO中Ag-Hg电极上的电化学还原过程进行了研究, 并测定了反应中间物自由基的性质及其动力学规律. 实验结果表明, 1在DMSO中可有二个还原过程. 第一过程为1四电子还原为5-羟胺基尿嘧啶, 反应中所需质子由1提供. 第二个过程为失去质子后形成的阴离子5NU^-(2)在较负的电位下单电子还原为二价阴离子自由基, 后者可用ESR进行现场检测和研究, 其ESR参数分别为: 偶合常数αN=14.6G, αH=5.2G, 自由基g因子, g=2.005. 自由基的衰变反应为夺取1的质子, 反应的速度常数k1=52mol^-^1.dm^3.s^-^1.     

第五、六族元素的有机化合物在有机合成中应用的研究——Ⅶ.三取代环丙烷的质子核磁共振谱研究

本文报道11种三取代环丙烷的质子核磁共振谱及其解析结果.讨论了取代基对化学位移和偶合常数的影响.     

取代芳基吡唑和取代芳基异E唑结构的核磁共振波谱表征

用^1H,^13C NMR和多种二维磁共振谱表征了本系列化合物的结构，完成了^1H和^13C NMR谱带的归属，测定了氟原子对各质子和碳原子的偶合常数，探讨了影响偶合常数大小的因素。     

甲基丙烯酸甲酯增长自由基ESR谱研究

利用高斯分布和构象叠加模型模拟了本体聚合反应全过程增长自由基ESR谱,获得了其构象构成及其随反应的变化,并对产生变化的原因即介质粘度和增长反应对谱的影响进行了讨论。     

邻二取代苯电化学氧化聚合的实验及理论计算研究

用电化学阳极氧化方法尝试了一系列邻二取代苯衍生物的聚合反应,结果表明在三氟化硼乙醚(BFEE)溶液中邻苯二酚(oHDB)、邻二甲氧基苯(oDMOB)、1-羟基-2-甲氧基苯(HMOB)能够电化学聚合并获得聚合物,而其它邻二取代苯单体无法用此方法获得聚合物.NMR分析和理论研究证明oHDB、oDMOB、HMOB的聚合位点发生在(C4,C5)位.用密度泛函理论对单体进行分子轨道和负电荷密度分析,表明邻二取代苯单体进行电化学氧化聚合并获得聚合物满足至少两个条件,即聚合位点HOMO-LUMO满足轨道对称性匹配且能隙最小;负电荷密度绝对值高于某一临界值(估计为|0.09|).     

Comparative study of dielectric,mechanical, and nuclear magnetic relaxations of linear polyethylene. I. Broad-line NMR investigation of the fine structure of the α and γ loss bands observed by dielectric and mechanical measurements

Detailed investigation of the linewidth, second moment, and mobile fraction by straightline decomposition of NMR spectra of linear polyethylene from ca. ?160 to ca. 100°C reveals five molecular processes denoted γ₁, γ₂, β, α′, and α. Relaxation maps show that the γ₁, γ₂, and β processes correspond to the dielectric and mechanical relaxations given the same names, while the α and α′ processes correspond respectively to the mechanical α₂ process due to molecular motion in the interior of crystals and to the dielectric α process. Close relations are found between the mass fractions of protons for the γ₁ and β processes and also between those for the γ₂ and α′ processes. From the effects of diluent on these processes and the annealing-time dependence of mass fractions of protons, the γ₁, and β processes are attributed to two modes of molecular motion in an interlamellar amorphous region, while the γ₂ and α′ processes are attributed to motions in the lamellar surface layers. The surface-layer thickness obtained by applying the two-phase model for the data on mobile fraction agrees quite well with that reported in the literature. The Bergmann–Nawotki three-component analysis of NMR spectra and symmetric-line decomposition for determining mobile fraction are shown to be unsuitable for studying the fine structure of the α and γ loss bands.     

Dynamics of proton tautomerism in 2,5-dihydroxy-p-benzoquinone: A 13C NMR and CNDO study

The temperature and solvent dependence of the ¹³C NMR spectra of 2,5-dihydroxy-p-benzoquinone have been investigated. The variations of the line shapes are analyzed in terms of chemical exchange of the two equivalent intramolecular hydrogen bonds. The interpretation of the rate parameters suggests an interconversion mechanism in which the two hydroxylic protons move in a two consecutive step mechanism. This is supported by the shape of the potential surface for the motion of the hydroxylic protons, calculated by CNDO.     

Wide-line proton magnetic resonance spectra of some celluloses

Characteristic wide-line proton magnetic resonance absorption spectra of a number of representative cellulose preparations have been obtained in the dry state and after addition of about 7% water. Line widths, second moments, spin-spin and spin-lattice relaxation times have been determined. The second moment of the absorption curve of dry cellulose was found to correlate well with the crystalline fraction for most specimens. A technique is described for determining the number of water-cellulose protons exchanging relative to the number of cellulose protons not exchanging. The reduction in absorption line width observed when water is added to cellulose is shown to be quantitatively consistent with such a proton exchange phenomenon.     

单体组成对甲基丙烯酸甲酯/丙烯酸丁酯RAFT共聚合转移常数的影响

采用Z基团为—CH2C6H5的RAFT试剂为链转移剂,AIBN为引发剂,60℃下进行甲基丙烯酸甲酯/丙烯酸丁酯(MMA/BA)的本体RAFT共聚合,并用GPC法测算不同单体组成下低聚物RAFT的链转移常数(Ctr).实验表明,对BA的均聚合,Ctr高达116,但对MMA的均聚合,Ctr约为0.1.在共聚体系中,Ctr与fMMA之间为非线性关系,随着fMMA的增加呈下降趋势.Ctr随单体组成的变化规律可以很好地解释不同单体组成下RAFT共聚合中分子量及其分布随转化率变化的规律.     

水溶性荧光共轭聚合物MPS-PPV的聚合新方法及其荧光波长调控研究

在NaOH/C_2H_5OH/DMF液中,实现了水溶性阴离子荧光共轭聚合物聚-[5-甲氧基-2-(3-磺酰化丙氧基)-1,4-苯撑乙烯](MPS-PPV)单体的快速聚合并提高了聚合产率.通过改变溶液中NaOH的浓度,实现了聚合物荧光发射波长的调控.对聚合物进行了元素分析、红外光谱以及分子量的表征,并探讨了不同聚合条件下得到的MPS-PPV的荧光和紫外光谱变化.研究了过氧化氢对MPS-PPV荧光发射波长及强度的影响,据此可测定过氧化氢.与单纯依赖荧光强度变化的过氧化氢检测法比,此法具有更高的选择性,为基于荧光聚合物的新型传感器研制提供了新思路.     

Crystal Structure and Polymerization Activity of Bromo-（2-diphenylphosphino-N-（2-oxybenzylidene）-aniline）-nickel

The title compound,bromo-（2-diphenylphosphino-N-（2-oxybenzylidene）-aniline）- nickel,was synthesized by simple condensation of 2-diphenylphosphino-N-（2-oxybenzylidene）- aniline with NiBr2·6H2O and characterized by elemental analysis,IR spectra and single-crystal X-ray diffraction. The crystal belongs to the triclinic system,space group P1 with a = 9.756（2）,b = 10.232（2）,c = 13.313（3）A,α = 95.09（3）,β = 102.48（3）,γ = 95.45（3）o,V = 1283.5（4） A^3,C29H23BrNNiO2P,Mr = 587.07,Z = 2,Dc = 1.519 g/cm^3,λ（MoKα） = 0.71073 A,F（000） = 596 and μ = 2.402 mm^-1. The structure was refined to the final R = 0.0408 and wR = 0.0965 for 4507 observed reflections （I 〉 2σ（I））. Intermolecular π-π interactions （with distances of about 3.705 A） are pronounced in the crystal structure. Under methylaluminoxane （MAO） activation,the title compound was able to catalyze norbornene polymerization,exhibiting good polymerization activities.     

M(S)2(I)2 (M=Zn,Cd) and Hg(S)3I Coordination Environment of Transition Metal Complexes – Synthesis,Spectral, and Single Crystal X‐ray Structural Investigations

Three new transition metal complexes [Zn(bipyrtds)I₂]( 1 ), [Cd(bipyrtds)I₂] ( 2 ) and [Hg(pipdtc)I]( 3 ) (where bipyrtds = bipyrrolidine thiuamdisulfide and pipdtc = piperidinecarbodithioate) were prepared by the reaction of the corresponding biscarbodithioates with iodine and were characterized by elemental analysis, IR and NMR spectra. The structures of all the three complexes were determined by single crystal X‐ray crystallography. Compounds 1 and 2 contain four coordinated metal atoms and both Zn^II and Cd^II complexes are isostrucutral. Interestingly, complex 3 was found to contain effectively four coordinated mercury atom as a dimer with a relatively long Hg‐S (3.084Å) bond. The IR studies are in keeping with the observed thioureide distances. ¹H NMR spectra of 1 and 2 show clear differences in environments of α‐ and β‐CH₂ protons. However, in 1 a broad signal was observed at 4.02 ppm for α‐protons and a multiplet at 2.10 for β‐protons. For 2 , two triplets appeared at 4.26 and 4.03 ppm for α‐protons and two quintets appeared in the range of 2.18 and 2.28 ppm for β‐protons. Complex 3 gave three sets of signals. Variation of stereochemical environment with respect to α and β protons of the rings is very clearly observed in the NMR spectra.     

自聚集在纳米金粒上的烷基硫醇单分子层的NMR驰豫时间研究

通过质子的自旋-晶格驰豫时间（T_1）、自旋-自旋驰豫时间（T_2）研究烷基 巯基[X(CH_2)_nS-]单分子层保护的纳米金粒中配体分子的运动。本研究涉及两种 典型配体：CH_3(CH_2)_7SH和Py(CH_2)_(12)SH及该两配体的不同配比的测合配体 。实验监测了配体中不同位置的质子的NMR驰豫时间随空间距离及配体比例改变的 变化情况。不同位置的质子,因主要影响因素的不同,表现出各自特殊的运动特征 。配体与金粒配位后,2,3位T_1,T_2值减少,1,4位T_1,T_2值增加。混合配体 中Py(CH_2)_(12)SH含量增加,1,2,3位T_1,T_2值都会减小;而4位T_1值减小, T_2值却增加;不同位置T_1,T_2值变化快慢有别。2位因其特殊位置,在配体配比 PY:C_8 = 1:1[PY代表Py(CH_2)_(12)SH,C_8代表CH_3(CH_2)_7SH]时,分子运动最 自由。实验结果显示T_1总是大于T_2,这说明配体处于低频运动区。     

STUDY ON THE MECHANISM OF 1-OCTENE ZIEGLER-NATTA POLYMERIZATION BASED ON THE NUMBER OF ACTIVE CENTERS

The number of active centers (C_p)-t and k_p-t profiles of Solvay type TiCl_3 - AlR_3 (R=C_2H_5, i-C_4H_9) or Stauffer AA TiCl_3-Al (C_2H_5)_3 catalyzed 1-octene polymerization were determined by using an acetyl chloride quenching method as well as kinetic data. The results show that in the studied systems k_p decreases when C_p increases, indicating the presence of two or more types of different active centers. The C_(p~(-t)) plots of the Solvay TiCl_3-AlR_3 systems show the presence of both stable active centers and unstable centers which decay in the polymerization process. The phenomena are explained based on a model of active center plurality. The increases of C_p in the induction periods are also discussed.