血管紧张素Ⅱ(AngⅡ)的溶液构象研究

用固相多肽合成方法合成AngⅡ,并用2DNMR技术测定其在D₂O与DMSO-d₆中的构象.通过偶合常数、ROE效应、化学位移温度系数,确定其二面角约束、距离约束及氢键约束·结果表明,AngI在D₂O与DMSO-d₆中构象极为相近,呈无规卷曲状态,排除了其构象为α螺旋、3₁₀螺旋、β转角、γ转角、平行与反平行β折叠的可能性,且其在水中的构象对温度不敏感.     

异相Ziegler-Natta催化剂的活性中心多分散性(Ⅱ)——4种活性中心的聚合动力学参数

测定了络合Ⅱ型TiCl₃-Al(C₂H₅)₃催化1-辛烯聚合中不同时间的产物分子量分布,用4个Schulz-Flory“最可几”分布函数叠加,较好地拟合了实测分布,从而确定此体系有4种活性中心。从拟合及动力学测定结果确定了4种活性中心的聚合速率、浓度及链增长速率常数、链转移速率常数等,讨论了各活性中心的结构及聚合机理。     

异相Ziegler-Natta催化剂的活性中心多分散性(Ⅰ)——钛催化体系聚合物分子量分布的研究

对TiCl₃及TiCl₄/MgCl₂-Al(C₂H₅)₃(或Al(i-C₄H₉)₃、Al(C₂H₅)₂Cl)催化体系合成的聚辛烯的分子量分布用SchulzeFlory"最可几分布"函数作拟合处理,将各种聚合条件下的实测分布分成了3～5个"最可几分布"的叠加,催化剂结构及聚合条件对这些"最可几分布"峰的位置、大小的影响较有规律,表明每个峰对应于一种活性中心。还测定了聚辛烯各级分的活性中心浓度。对各活性中心的差异作了分析。     

环型高分子链的线团行为(Ⅱ)——环型高分子的沉降系数

本文推导了[η]线/[η]环与S₀环/S₀线和D₀环/D₀线的关系式并通过实验验证了[η]线/[η]环与S₀环/S₀线关系式。     

在线二维液相色谱法同时测定婴幼儿和成人配方营养品中的维生素A、D3和E

建立了在线二维液相色谱同时快速测定婴幼儿配方乳品和成人强化乳品中维生素A、D₃和E含量的方法。首先,依据疏水减法模型,选择C8柱和极性嵌合的反相C18柱分别作为一维和二维分离柱,构成正交分离体系,并均以甲醇、乙腈和水作为流动相,检测波长设为263 nm(维生素D₃)、296 nm(维生素E)和325 nm(维生素A)。采用双三元液相色谱的左泵作为一维分析泵,完成维生素A、E的定量和维生素D₃的净化;根据维生素D₃在一维色谱柱上的保留时间,确定切割时间窗口,并以500 μL定量环收集含有维生素D₃的馏分,由双三元液相色谱的右泵将馏分带到二维色谱柱中,以维生素D₂作为内标物,采用内标法完成维生素D₃的定量分析,整个过程在密闭系统中自动化完成。在上述优化条件下测定了婴幼儿和成人奶粉、奶酪及酸奶等强化乳品中3种维生素的含量。经过1.25 kg/L KOH溶液的热皂化和石油醚的萃取,样品萃取液直接进样分析,得到维生素D₃的加标回收率为75.50%~85.00%,并通过配对t检验法与标准方法测定结果进行比较分析,结果差异无统计学意义,表明本方法可同时快速、准确测定婴幼儿及其他配方营养品中维生素A、D₃、E的含量,提高了样品分析效率。     

新型卤代3-芳基香豆素的合成及其抗癌活性

以卤代芳基乙酸和2,3,4-三羟基苯甲醛为主要原料,经Perkin缩合和关环反应制得12个含卤素的7,8-二乙酰氧基-3-芳基香豆素化合物（D₁~D₁₂）; D₁~D₁₂经水解反应合成了12个含卤素的7,8-二羟基-3-芳基香豆素化合物（E₁~E₁₂）,除D₂, D₄~D6, E₂, E₄~E₆外均为新化合物,其结构经¹H NMR和MS（EI）表征。采用MTT法研究了D₁~E₁₂对人肺癌细胞株(A549)的体外细胞毒性。结果表明：D₁~E₁₂均表现出不同程度的肿瘤细胞增殖抑制活性（IC₅₀≥192.74 μmol·L^-1）。     

Jahn－Teller变形后C60－的结构和电子光谱

用INDO系列方法对C₆₀^－进行几何构型优化,得到D_3d对称性的构型,表明C₆₀^－确实发生了Jahn-Teller畸变,导致单键变短,双键变长,形成10种键,6种不等同碳原子,并以此构型为基础,计算了C₆₀^－的电子光谱,与实验结果吻合;同时对光谱进行了理论指认;最后对C₆₀^－的3种构型：D_5d,D_3d,D_2h的几何构型、能量、光谱和反应特性进行了分析、比较和总结。     

多体展开势能函数在碳族元素原子簇研究中的应用(Ⅳ)──Si9─Si16原子簇的分子结构与稳定性

多体展开势能函数研究表明,Si₄-Si₁₆原子簇分子间的结构衍生关系为:依次增加一个二配位或三配位的表面原子,分子表面被四元蝶形环Si₄(D_2d)所覆盖;Si_n(n=5-16)结构中多含有Si₅(D_3h)、Si₆(D_2d)区域结构单元,笼状Si₁₀及Si₁₆的表面原子均为三配位或三配位以上,预计Si₅、Si₆、Si₁₀及Si₁₆是硅原子簇碎片化产物分布中丰度较高的序列;在这一范围内的分子结构呈与晶体硅结构(金刚石)无关的密堆积,最高配位数为5,在小于半球的立体角内形成六配位的硅中心,使该簇合物在能量上不稳定。     

顺二氨二水合铂(Ⅱ)与生物膜磷脂反应的核磁共振研究

用NMR法研究了顺二氨二水合铂(Ⅱ)(AAP)与α-二棕搁酸磷脂酰胆碱(DPPC)的相互作用方式,以阐明在顺铂-细胞相互作用中膜磷脂的贡献。¹H及¹³C谱表明,DPPC与AAP在CDCl₃中作用时,铂结合在DPPC的头部并引起DPPC分子中gauche向trans的构象转变。65℃测定DPPC脂质体与AAP在D₂O溶液中反应不同时间后的-N(CH₃)₃、-(CH₂)_n及-CH₃基团¹H的T₁值表明,铂在磷脂上的结合引起的磷脂构象变化会导致膜分子重新装配。     

三维正交群O3-全部正八面体群Oh的V系数

本文讨论了在具有连续群-点群意义的配位场理论方法中,采用O₃⊃O_h⊃D_4h(D_3h)群链计算时的各类耦合系数,并表述成Ⅴ系数的形式,建立了它们与R₃⊃O⊃D₄(D₃)群链的相应系数之间的关系。     

四价钼体系催化丁二烯聚合动力学

本文报导了MoCl₂(n-C₈H₁7O)₂-(i-Bu)₂AlOph体系催化丁二烯聚合动力学研究结果,得到聚合速率方程式R=k(C)_O(2)[M]=k_pa(c)_o(M),表观活化能18.6千卡/摩尔,指数前因子1.6×10¹⁰分^-1,以及不同温度下的催化剂利用率,活性中心浓度,活性中心平均寿命等,还证明了等聚合速率的聚合时间t_O与活性中心平均寿命相近。     

“原位”红外光谱追踪反应条件下催化体系的变化

为了观察和监测反应条件下中间产物和催化剂的变化,自行设计并安装了高温高压红外流动池。池体用不锈钢制成,窗口材料为NaCl或CaF₂。它可承受100atm和200℃。整个测量系统包括高压釜、循环泵、红外池等。用Microlab-600型红外分光光度计记录图谱。池内温度和压力与反应釜桐同,可对反应液体、气体或气液混合物进行"原位"追踪。当用铑膦络合物催化剂进行丙烯氢甲酰化反应时,在近于工业反应条件下(t=10O℃,P=17atm,正丁醛溶剂),检测到催化剂母体Rh(acac)(CO)(PPh₃)转化为活性物种RhH(CO)₂(PPh₃)₂;在合成气压力较低时,只转化为RhH(CO)(PPh₃)₃;此活性物种随催化剂失活而消失。催化剂加氧失活后,检测到配位体三苯基膦氧化为氧化三苯基膦,催化剂生成二聚物,丙烯氧化成丙酮,追踪到原料气CO氧化为CO₃的动态过程。本文对"原位"红外光谱实验方法、高温高压红外池作了介绍,并给出有关实验数据和结果。     

KINETICS OF THE ZIEGLER-NATTA POLYMERIZATION OF 1-OCTENE(I)----THE KINETICS OF THE STATIONARY PERIOD

The kinetics of the Ziegler-Natta polymerization of C6~C20 α-defines has been seldom studied,which showed no apparent differences from the kinetics of the polymerization of ethylene and propylene.1-Octene polymerizes in alkanes in a solution state,differing from the slurry polymerization of ethylene.We have found and studied the inordinary kinetics of the polymerization of 1-octene on α-TiCl3-AlEt3[or-Al(i-Bu)3,-AlEt2Cl] catalysts in n-heptane,and have given a primary explanation to this phenomenon.     

含芳香双酯高效催化剂进行丙烯聚合及其动力学的研究

采用多种芳香双酯作为电子给予体制备了丙烯聚合高效催化剂,该催化剂具有高活性、聚合反应平稳、产物等规度高等特征.研究了多种芳香双酯和外加各种烷基硅氧烷对丙烯聚合的作用,测定了聚合反应动力学曲线,确定了聚合动力学方程.用扫描电镜研究了催化剂的形态,表明双酯组份能使催化剂结合得较紧密;对聚合产物的结构用DSD、红外光谱进行了表征.     

Synthesis and structural characterization of cobalt(II) and zinc(II) complexes with 2-(indazol-1-yl)-2-thiazoline (TnInA). X-ray characterization of [CoCl2(TnInA)2] · C2H6O and [(M)(TnInA)2(H2O)2](NO3)2 (M = Co, Zn)

Several complexes of 2-(indazol-1-yl)-2-thiazoline (TnInA) with the divalent ions Co and Zn have been synthesized by the direct combination of the ligand and the metal chloride or nitrate hydrated salts in ethanol. These complexes have been characterized by a variety of physical–chemical techniques. Moreover, the structures of [CoCl₂(TnInA)₂] · C₂H₆O (1) and [(M)(TnInA)₂(H₂O)₂](NO₃)₂ (M = Co, 3; Zn, 4) were determined by single-crystal X-ray diffraction. In all the complexes, the ligand TnInA bonds to the metal ion through the indazole and thiazoline nitrogen atoms. In complex 1 the environment around the cobalt ion may be described as a distorted octahedron with two TnInA ligands and two chlorine ligands. Compounds 3 and 4 are isostructural with a distorted octahedral geometry around the metal center, being linked to two water molecules and two TnInA ligands. However, in complex [ZnCl₂(TnInA)] (2) the zinc atom is four-coordinated with a probable tetrahedral environment with two chloro ligands and one TnInA ligand bonded to the metal ion.     

Bis(di-t-butylphosphino)methane complexes of rhodium: homogeneous alkyne hydrosilylation by catalyst-dependent alkyne insertion into Rh---Si or Rh---H bonds. Molecular structures of the dimer [(dtbpm)RhCl]2 and of the silyl complex (dtbpm) Rh[Si(OEt)3](PMe3)

The homogeneous, Rh-catalysed hydrosilylation of but-2-yne with triethoxysilane has been studied. All rhodium complexes employed as catalyst precursors contain ^tBu₂PCH₂P^tBu₂ (“dtbpm”) as a chelating ligand. The crystal and molecular structure of the dimer [(dtbpm)RhCl]₂ (10) has been determined by X-ray diffraction. Complex 10 is shown to be a sluggish catalyst in hydrosilylation reactions of hex-1-ene, whereas but-2-yne is hydrosilylated more rapidly. A much more efficient and highly selective catalyst is 10 with added PPh₃, equivalent to the use of monomeric (dtbpm)RhCl(PPh₃). (E)-2-Triethoxysilylbut-2-ene is formed exclusively and with high turnover numbers in this case. For both 10 and its PPh₃ derivative, the 14-electron fragment [(dtbpm)RhCl], formed by dissociation processes, is the most likely active intermediate in a Harrod-Chalk-type catalytic cycle. The PPh₃ dissociation equilibrium has been studied in detail for (dtbpm)RhCl(PPh₃) and its thermodynamic parameters have been determined. With rhodium alkyl complexes as catalyst precursors, a different type of alkyne hydrosilylation catalysis, involving direct alkyne insertion into the Rh---Si bond of an intermediate rhodium silyl complex, (dtbpm)Rh[Si(OEt)₃](PMe₃) (14), has been found. Complex 14 was synthesized independently from (dtbpm)RhMe(PMe₃) and characterized by X-ray diffraction. It is an equally active catalyst itself, yielding (E)-2-triethoxysilylbut-2-ene as the major product (90%) from but-2-yne and HSi(OEt)₃ (turnover number 1000 per 30 min). The insertion step of the alkyne into the Rh---Si bond of 14 and the formation of two stereoisomeric rhodium vinyl complexes were established independently for MeO₂CCCCO₂Me as a more reactive alkyne substrate. A catalytic cycle is proposed for this unprecedented hydrosilylation reaction. The synthesis of the ν³-benzyl complex (dtbpm)Rh(η³-CH₂C₆H₅) (23) is described. This compound allows an alternative, more efficient access to the new silyl complex (dtbpm)Rh[Si(OEt)₃](PMe₃).     

Silsesquioxane Chemistry, 4.: Silsesquioxane Complexes of Titanium(III) and Titanium(IV)

Reaction of the incompletely condensed silsesquioxane derivative Cy₇Si₇O₉(OH)₃ (1) with Ti(OEt)₄ affords the dimeric titanasilsesquioxane [(Cy₇Si₇O₁₂)Ti(μ-OEt)(EtOH)]₂ (13) in 81% yield. The known titanasilsesquioxane [Cy₇Si₇O₁₁(OSiMe₃)]₂Ti (18) has been prepared through a modified procedure starting from titanium tetraalkoxides. Novel oxotitanium silsesquioxane derivatives are obtained from reactions of titanocene dihalides with Cy₇Si₇O₉(OH)₂(OSiMe₃) (14). Cp₂TiCl₂ yields dinuclear (μ-O)[{Cy₇Si₇O₁₁(OSiMe₃)}TiCp]₂ (19), while with Cp^*₂TiCl₂ the trinuclear titanacycle Cp^*₂Ti₃O₃[Cy₇Si₇O₁₁(OSiMe₃)]₂ (20) is obtained. In addition, a new synthetic route to model compounds for titanium catalysts immobilized on silica has been developed. Disilylated Cy₇Si₇O₉(OH)(OSiMe₃)₂ (15) cleanly reacts with the ‘tucked-in’ fulvene complex Cp*Ti(C₅Me₄CH₂) to give the titanium(III) silsesquioxane Cp*₂Ti[Cy₇Si₇O₁₀(OSiMe₃)₂] (21). In a similar manner treatment of Cp*Ti(C₅Me₄CH₂) with Cy₇Si₇O₉(OH)₂(OSiMe₃) (14) affords the mono(pentamethylcyclopentadienyl) complex Cp*Ti[Cy₇Si₇O₁₁(OSiMe₃)][Cy₇Si₇O₁₀-(OH)(OSiMe₃)] (22) which is an advanced model compound for a catalytically active titanium center on a silica surface. The molecular structures of these titanium silsesquioxane derivatives have been determined by X-ray diffraction analyses.     

Self-assembly of an Unprecedented Cynao-bridged One-dimensional 4f-3d Complex[Eu(DMF)4(H2O)2Cr(CN)6] H2O

Recently, there has been considerable interest in cyano-bridged lanthanide(Ⅲ) hexacyanometalate(Ⅲ) complexes LnM(CN)₆·nH₂O (M=Fe, Cr and Co) because of their potential as catalytic, semiconductive, and magnetic materials.^[1-8] In this study, we employed N,N-dimethylformamide (DMF) as a hybrid ligand to construct a bimetallic complex[Eu(DMF)₄(H₂O)₂Cr(CN)₆]·H₂O. It was synthesized as yellow crystals by the self-assembly of anhydrous EuCl₃ and (Bu₄N)₃[Cr(CN)₆] in MeOH and DMF. Single-crystal X-ray diffraction analysis shows that it consists of a cyano-bridged chain structure. The Eu atom is eight-coordinate with a distorted bicapped square antiprism geometry. Six oxygen atoms of two water molecules and four DMF molecules and two nitrogen atoms of the bridging CN ligands are bound to Eu with the Eu-O distance ranging from 2.368(7) to 2.447(8) Å. The bridging cyanides coordinate to the Europium(Ⅲ) ion[N(l)-Eu=2.543(9) Å and N(3)-EuA=2.543(8) Å] in a bent fashion with the bond angles of 164.0(9) for C(1)-N(1)-Nd and 155.1(7)。for C(3)-N(3)-EuA (A denotes the symmetry transformation:-x+l,y-l/2,-z+3/2). Each Cr(CN)₆ coordinates to two Eu(Ⅲ) ions using two cis cyanide ligands, while each Eu(DMF)₄(H₂O)₂ group connects two Cr(CN)₆ moieties in a cis fashion, giving rise to an unprecedented chain structure. Crystal data:monoclinic, space group P2₁/c, a=13.151(2), b=12.905(2), c=19.186(2) Å, β=109.70(1)°, V=3065.5(7) ų,Z=4, ρ_obs=1.531 Mg m^-3, S=1.024,R1=0.0540, R_w=0.1616.     

CRYSTAL STRUCTURE OF A HETERONUCLEAR LANTHANIDE COMPLEX OF ERBIUM-YTTRIUM AND GLYCINE[ErY(GlY)_6(H_2O)_4](ClO_4)_65H_2O

The title complex [ErY(Gly)_6(H_2O)_4](ClO_4)_6 5H_2O has been synthesized.Its crystalstructure has been determined by X-ray diffraction method.The crystal is triclinic with space groupP1.The unit cell parameters are as follows:a=11.518(4),b=14.105(7),c=15.530(6) ,α=96.61(3),β=102.74(3),γ=105.70(3)°,V=2327.7(17) ~3,Z=2,Dc=2.091g/cm~3.The structure has been refinedto a final R of 0.0785.The crystal is an infinite chain complex,in which four carboxyl groups fromglycine molecules bridge the Er(Ⅲ)and Y(Ⅲ)ion,other two carboxyl groups bridge two adjacentEr(Ⅲ)or two Y(Ⅲ)ions.     

Synthesis and Fluorescence of a New Active Material for Electrochemiluminescent Sensor:Ru(phen)2[phen-NHCO(CH2)4Br](PF6)2

Recently, much attention has been paid to Ru(II) complexes because of their excellent properties of photochemistry, phtophysis. Bis(2,2'-bipyridine)[4-methyl-4'-(6-bromohexyl)-2,2'-bipyridine] ruthenium(II) perchlorate has been used as an active material for electrochemiluminescent (ECL) sensor for selective detection of oxalic acid.It is known that ECL efficiency of Ru(phen)₃²⁺ is much higher than that of Ru(bpy)₃²⁺. In order to make out more efficient ECL sensor, we have designed and synthesized a new Ru(II) complex, Ru(phen)₂[phen-NHCO(CH₂)₄Br](PF₆)₂.