镍系胶体催化丁二烯聚合反应的研究Ⅱ: 催化剂组分的 电导率和紫外光谱

在加氢汽油介质中Ni(naph)~2-Al(i-Bu)~3-(BF~3·OEt~2+n-C~8H~1~7OH)体系为胶体催化剂的基础上,本文从电导率、UV-Vis光谱对催化剂各组分之间的相互作用作进一步的分析。得出催化剂组分以离子对的形式参与反应;Ni^0在Ni(naph)~2-Al(i-Bu)~3陈化液中以团簇粒子形式存在,因吸附Ni^+naph^-而稳定,因加入BF~3·OEt~2而失去稳定性、聚结为胶粒,活性中心位于胶粒表面的观点。     

镍系胶体催化丁二烯聚合反应的研究Ⅱ: 催化剂组分的 电导率和紫外光谱

在加氢汽油介质中Ni(naph)~2-Al(i-Bu)~3-(BF~3·OEt~2+n-C~8H~1~7OH)体系为胶体催化剂的基础上,本文从电导率、UV-Vis光谱对催化剂各组分之间的相互作用作进一步的分析。得出催化剂组分以离子对的形式参与反应;Ni^0在Ni(naph)~2-Al(i-Bu)~3陈化液中以团簇粒子形式存在,因吸附Ni^+naph^-而稳定,因加入BF~3·OEt~2而失去稳定性、聚结为胶粒,活性中心位于胶粒表面的观点。     

镍催化体系合成顺式聚丁二烯的研究——Ⅶ.紫外可见光谱法探讨镍系各组分间的相互作用

环烷酸镍的汽油或甲苯溶液呈亮绿色,根据自旋允许d-d跃迁,在光谱的红和兰区有三个吸收带,其峰值分别是403、680和1170nm,络合物具有八面体构型。在Ni-Al体系中,当Al/Ni摩尔比<0.53,只发生配位体的交换反应,Al/Ni≥0.53,体系中发生还原反应,Ni(II)→Ni(I)→Ni(O)。在Ni-B体系中,只发生配位体交换反应,生成的氟-硼-镍络合物具有和环烷酸镍相类似的d-d吸收带,络合物也具有八面体构型。以上结论与磁化率法的结果一致。     

丁二烯聚合铁系胶体催化剂的相态研究

通过Tyndall效应、电子显微镜观察、超过滤实验和非水体系电导率测定证明 ,Fe(naph) 2 Al(i Bu) 3 CH2 CHCH2 Cl 催化剂在溶有丁二烯的加氢汽油介质中为胶体分散系 ,活性位位于胶粒表面 ,因此是胶体催化剂 .Al(i Bu) 3 以缔合状态存在并解离成离子对 ;它同Fe (naph ) 2 的反应是形成胶核的主要反应 ;与CH2 CHCH2 Cl 反应生成的氯化异丁基铝在胶核表面形成活性位 ;适当过量Al(i Bu) 3 形成双电层 ,使胶粒相对稳定 .催化剂颗粒是无定型的 .催化剂各组分的配比影响胶粒的形态 ,其中以较佳配比所得到的催化剂胶粒较小 ,分布均匀 ,催化活性高 .因是聚结不稳定胶体体系 ,陈化时胶粒迅速聚结长大 ,因而催化活性显著降低     

铜锌催化剂组分间相互作用的研究

本文用ICP、XRD和TPD-MS(O_2)等技术研究了铜锌催化剂组分间的相互作用,发现氧化态Cu-Zn催化剂中部分ZnO熔于CuO中生成了(Cu,Zn)O固熔体。低温变换反应条件下的Cu-Zn催化剂处于还原态,它与氧化态的主要差别在于失去了(Cu,Zn)O的晶格氧。研究了Cu-Zn-Mn催化剂中部分Mn进入ZnO晶格生成(Zn,Mn)O固溶体及其对变换反应活性的影响。本文还用TPD-MS(O_2)技术考察了添加Mn、Al等组分对Cu-Zn催化剂组分间相互作用的影响。     

铁系丁二烯聚合胶体催化剂电导率的研究——探讨烷基铝的作用

研究了在２５℃加氢汽油介质中，铁系胶体催化剂［Ｆｅ（ｎａｐｈ）２Ａｌ（ｉ Ｂｕ）３—ＣＨ２ＣＨＣＨ２Ｃｌ］单组分、多组分按不同配比混合，非水体系电导率与浓度的关系，结合Ｔｙｎｄａｌ效应，聚合实验结果，得出Ａｌ（ｉ Ｂｕ）３以缔合状态存在并解离成离子对；它同环烷酸亚铁的作用是形成胶核的主要反应，与氯丙烯反应生成的氯化异丁基铝，在胶核表面参与形成活性中心；由过量Ａｌ（ｉ Ｂｕ）３解离的离子对形成的双电层结构，使胶粒保持相对稳定．催化剂各组分较佳配比对应稳定胶粒的形成；它具有颗粒小、均匀、较高的催化活性．催化体系加入丁二烯引起电导率下降表明活性中心是正离子性的．     

铁体系催化剂制备方式对催化活性影响的研究

通过Ｔｙｎｄａｌ效应，电镜观察，电导率测定，结合聚合实验，发现铁体系催化剂在加氢汽油介质中为胶体催化剂，而且是聚结不稳定胶体体系．催化剂各组分配比，加入顺序影响胶粒的形态，因而影响到催化活性与聚合物微观结构．其中较佳配比，较佳加入顺序（Ｆｅ）∶（Ｃｌ）∶（Ａｌ）＝１∶２．５∶２０，催化剂颗粒比较小，均匀，因而比表面积大，催化活性高，相反其他配比的颗粒大，不均匀，催化活性低．陈化使胶粒聚集变大，故催化活性降低．     

镍系胶体催化丁二烯聚合反应的研究Ⅲ: 催化剂组分的 红外光谱

已知在加氢汽油介质中Ni(naph)~2-Al(i-Bu)~3-(BF~3·OEt~2+n-C~8H~1~7OH)体系为胶体催化剂。本文应用FT-IR谱结合Tyndall效应,电导率,UV-Vis,ESR谱对催化剂各组分的相互作用进行研究。得出Ni(naph)~2被Al(i-Bu)~3还原的主要产物是Ni^0;被(i-Bu)~2AlO(i-Bu)还原的主要产物Ni^+(naph)^-,Ni^0聚结成胶粒(Ni^0)~n,胶粒表面的Ni^0或吸附的Ni^+是活性中心组分,与(i-Bu)~2AlBF~4形成配合物,给出了活性中心模型。丁二烯对形成活性中心无影响,仅起稳定胶粒的作用。     

叠氮化钠与烟草多酚氧化酶相互作用的光谱学研究

N₃^- is a kind of ligand with very strong power for coordination, and is able to bind with many kinds of metal ions or metalloproteins. The metal ions in metalloproteins usually locate at the active site of them, and the combination of other chemical compound(s) to them will cause great influence on the structure and function of them. In addition, the combination can also provide information of the structure of the active site of the enzymes, and that of the higher-order structure of the enzyme. In this paper, we studied the interaction between N₃^- and PPOⅡ from Nicotina Tobacco by the determination of changes in enzymatic activity, UV-Vis, fluorescence spectra and FT-IR. The results showed that N₃^- can activate PPOⅡ with a near linear increase in enzymatic activity to the concentration of N₃^- when the [N₃^-]/[PPOⅡ](molar/molar) is less than or equal to 1.0, and that the enzymatic activity begins to decrease from 1.0 to 4.0; N₃^- didn’t coordinate directly with Cu²⁺ in the active site, but may interact with the side chain groups with positive charges, and further resulted in the increase in α-helix and the slightly decrease in β-turn, random coil and extended chain; the Cu²⁺ may locate deeply in the inner part of PPOⅡ, and coordinates strongly with nitrogen atoms in imidazole of histidine; N₃^- can quench the fluorescence of PPOⅡ, and make the microenvironments of Trp residues more polar after the interaction between N₃^- PPOⅡ.     

煤炭液化复合铁系催化剂的研究

用微型高压釜,以杂酚油为溶剂,在反应温度400℃,氢初压6.08MPa,反应时间30分钟的条件下,研究了多种含铁矿物质、复合铁系催化剂对煤炭液化的催化效果。并用高压DTA技术进一步证实了复合铁系催化剂的良好液化加氢活性。     

VB6与不同CopC作用的光谱研究

在室温, pH 7.4, 10mmol?L-1 Hepes缓冲溶液条件下, 通过紫外差光谱,荧光光谱法研究了apoCopC、CuN-CopC与Ag+的结合性质,进一步研究了apoCopC、 CuN-CopC、CopC-AgC 和CuN-CopC-AgC 与 Vitamin B6 作用的超分子行为. 结果表明：在 apoCopC与Ag+剂量比为1:1时,Ag+可以占据apoCopC蛋白C端的Cu+ 结合位点,结合常数为(1.68±0.33)×104mol?L-1. apoCopC结合不同的金属离子后,与Vitamin B6结合位点数明显减少.     

聚合物担载胶态钯催化剂的制备及其催化加氢性能研究

合成了一系列不溶性交联聚合物担载的胶态钯催化剂;用红外光谱、X射线衍射分析、扫描电镜等对催化剂进行了表征。用这些催化剂在80～100℃、氢压196.133×10~4Pa、苯-无水乙醇中进行了环十二碳三烯等不饱和化合物的催化加氢反应。考察了催化剂的活性、选择性、重复使用性能及反应条件对催化剂性能的影响。     

Electrochemical and Spectroscopic Studies on the Interaction of Gallocyanine with DNA

The interaction of gallocyanine (GC) with double‐stranded DNA (dsDNA) in pH 3.5 Tris‐HCl buffer solution was investigated by electrochemical methods and spectrophotometric methods as well. In the potential scan range of ‐0.25 ? +0.18 V(vs. SCE), GC had a couple of well‐defined redox peaks at ‐0.022 V and ‐0.069 V on a cyclic voltammogram at the scan rate of 100.0 mV/s, respectively. After the addition of dsDNA into the GC solution, the redox‐peak currents decreased obviously and the peak potentials shifted positively. The results demonstrated that GC binding to DNA was caused by intercalation. Electrochemical parameters such as the electron number (n), the charge transfer coefficient (α) and the electrochemical reaction standard rate constant (k_s) were calculated and compared in the absence and presence of dsDNA. Almost unchanged values of the electrochemical parameters after adding dsDNA showed that non‐electroactive complexes were formed when GC interacted with DNA. The results indicated that the decrease of the redox‐peak currents was caused by the decrease of the free concentration of GC in the reaction solution. The binding constant and binding ratio were investigated by spectrophotometric methods. DNA concentration can be determined by the decrease of the peak current of GC. The linear range for dsDNA was in the range of 1.45 × 10^?7 ? 1.45 × 10^?6mol/Land 1.45 × 10^?6 ? 1.45 × 10^?5 mol/L, respectively with the linear regression equation as Δi_P (10^?7 A) = 0.037 + 0.018C (10^?7mol/L), and Δi_P (10^?7 A) = 0.25 + 0.041C (10^?6mol/L), respectively, and the detection limit (3σ) was 1.13 × 10^?7 mol/L.     

Studies on Interaction Between Gallocyanine and DNA

IntroductionConsiderable attention has been focused onnew DNA- binding and DNA- modifying agents fromnatural ones to wholly synthetic designs due totheir usage as probes of deciphering the structureand the function of nucleic acids and as potentialchemotherapeutic agents[1— 4] . The application ofthose molecules must be based on the preciseunderstanding of the structural details about thebinding of the agents with the target molecule,double- helical DNA. The interaction of smallmolecules …     

用荧光光谱和紫外-可见差谱研究抗体-卟啉的相互作用

meso-四(α,α,α,α-O-苯乙酰苯)卟啉与其单克隆抗体1F2结合后,产生显著的增色效应,反映了卟啉与抗体之间刚性紧密的结合,在抗体中的抗原结合部位存在芳香族氨基酸.用同步荧光光谱结合荧光猝灭法得到抗体抗原结合部位的芳香族氨基酸主要为色氨酸和酪氨酸,但酪氨酸的残基数要少于色氨酸.卟啉与抗体的结合比为1:1,解离常数(2.084±0.246)×10^-10mol/L,可见卟啉与McAb₁F₂有很高的亲和力.     

Cu(phen)2+2和Cu(bpy)2+2与6-巯基嘌呤、腺嘌呤相互作用的研究

在ｐＨ为７．０的磷酸盐缓冲溶液中，用荧光光谱、紫外光谱、电化学及紫外光谱电化学等方法研究了铜配合物与６－巯基嘌呤、腺嘌呤的相互作用．结果表明，Ｃｕ（ｐｈｅｎ）２＋２和Ｃｕ（ｂｐｙ）２＋２与６－巯基嘌呤、腺嘌呤发生了相互作用，但作用程度不同．根据荧光光谱实验数据计算出Ｃｕ（ｐｈｅｎ）２＋２和Ｃｕ（ｂｐｙ）２＋２与６－巯基嘌呤、腺嘌呤的配位比均为１∶１；它们与６－巯基嘌呤作用的配位常数分别为２．２３×１０４Ｌ／ｍｏｌ和６．１１×１０４Ｌ／ｍｏｌ；与腺嘌呤作用的配位常数分别为１．９５×１０４Ｌ／ｍｏｌ和５．１２×１０４Ｌ／ｍｏｌ．电化学实验也获得了相近的结果．这为解释Ｃｕ（ｐｈｅｎ）２＋２和Ｃｕ（ｂｐｙ）２＋２与ＤＮＡ的作用机理及作用部位提供了有益的信息     

吡虫啉与牛血红蛋白相互作用的光谱研究

利用紫外可见光谱和荧光光谱研究了在生理pH值条件下农药吡虫啉与牛血红蛋白(BHb)的相互作用。实验结果表明:吡虫啉分子与BHb发生反应生成复合物,导致BHb内源荧光的猝灭,该猝灭属于静态猝灭。测定了不同温度下该反应的表观结合常数、结合位点数及结合热力学参数,热力学参数的变化表明上述作用过程是一个熵增加、自由能降低的自发分子间作用过程,吡虫啉与BHb之间以静电和疏水作用力为主;并用同步荧光光谱法探讨了吡虫啉对BHb构象的影响。     

Influence of Sedimentation on Crystallization of Charged Colloidal Particles

The method of density matching between the solid and liquid phases is often adopted to effectively eliminate the effect of sedimentation of suspensions on dynamic behavior of a colloidal system. Experiments on crystallization of charged colloidal microspheres with di-ameter of 98 nm dispersed in density-matched and -unmatched media (mixtures of H₂O and D₂O in proper proportion) are compared to examine the influence of sedimentation. Reflection spectra of colloidal suspensions were used to monitor the crystallization process. Results showed that the crystal size of the density-unmatched (namely, in the presence of sedimentation) sample grew faster than that of the density-matched (in the absence of sedi-mentation) case at the initial stage of the crystallization, and then the latter overtook and outstripped the former. To explain these observations, we assume that in the settling of crystals sedimentation facilitates result in more particles getting into the crystal structures. However, as the crystals increase to varying sizes, the settling velocities become large and hydrodynamic friction strips off some particles from the delicate crystal structures. Overall, the sedimentation appears to accelerate the crystal size growth initially and then retard the growth. In addition, the crystal structures formed under microgravity were more closely packed than that in normal gravity.