2,3'-联吡啶还原合成毒藜碱、安那他品和异毒藜碱

本论文从2，3'-联吡啶出发，利用两个吡啶环上氮的反应活性差异，选择性合成了单烷基盐1-甲基-2，3，-联吡啶盐、1-甲基-1，一氧-2，3，-联吡啶盐和1'-甲基／节基2，3气联吡啶盐，还原单烷基盐合成了天然生物碱毒黎碱、安那他品和异毒黎碱及其衍生物：对异毒黎碱的合成由还原N，-节基盐后脱节基简化为一步实现还原和脱节基直接得到异毒黎碱。通过用（R）-BINOL和（S）-BINOL对N，-节基异毒黎碱拆分得到了旋光纯的N，-节基异毒黎碱和异毒黎碱，-N，-节基异毒黎碱的旋光度［a］D20：-61．50（c＝2．0，乙醇），卜异毒黎碱的旋光度fa］D20：-14．4"（c-1．0，乙醇）；将C关异毒黎碱用（RMTPA和（s）MT队衍生为Mosher酞胺，应用Mosllel方法确定了C）异毒黎碱手性中心的绝对构型为R型，即（R）-C）异毒黎碱，同时发现，由（R）一MTPA合成的Mosller酞胺中顺式旋转异构体占优。而通常在环胺的Mosller酞胺中，是反式旋转异构体占优。这一例外被MollteCarlo模型模拟计算结果解释：稀溶液中C卜异毒黎碱的Moshel－酞胺，顺式构型能量上比反式更有利。不对称合成天然生物碱更具有挑战性。对异毒黎碱还原合成中的呱l淀烯类中间体，用BINAP-灿催化体系进行了催化不对称还原的合成研究，氢化N'-节基-1，，4，，5，，6，-四氢一2，3，一联吡陡时得到了最高为21．5％的对映体选择性，而对N'-节基一1，，2'，5'，6，-四氢-2，3'一联吡陡的氢化则只得到了不超过10．0％的对映体选择性。

Defect production in silicon carbide irradiated with Ne and Xe ions with energy of 2.3 MeV/amu

In the present work specimens of mono-crystalline silicon carbide (4H polytype) were irradiated to three successively increasing ion fluences ranging from 7.2 x 10(14) to 6.0 x 10(16) ions/cm(2) (corresponding to the peak displacement damage of 1, 4 and 13 dpa) with Ne and Xe ions respectively with the energy of 2.3 MeV/amu. The irradiated specimens were subsequently annealed at temperatures of 1173 and 1273 K. Defect structure was investigated with transmission electron microscopy (TEM) using a cross-sectional specimen preparation technique. The typical microstructures of the annealed specimens irradiated with Ne or Xe ions to high fluences are characterized by small gas bubbles in high concentration in the peak damage region and black dots and dislocation loops (located in the basal plane) in a shallower and broader depth region. Larger dislocation loops were observed in the Xe-ion irradiated specimen than in the Ne-ion irradiated specimen at the same peak damage level. The enhanced formation of dislocation loops in the case of Xe-ion irradiation is understandable by assuming stronger inclination of heavier inert-gas atoms to occupy substitute site in the peak damage region.

维生素C发酵中2-酮-L-古龙酸还原酶的研究

由于２酮Ｌ古龙酸还原酶（简称ＫＧＲ）的存在，理论上造成了Ｖｃ合成前体２酮Ｌ古龙酸（简称２ＫＬＧ）部分被还原成Ｌ艾杜糖酸［１，２］，影响了Ｖｃ二步发酵的产率。而从Ｌ山梨糖到２酮Ｌ古龙酸的转化中，除被ＫＧＲ催化的还原负反应外，均属...

Hydrothermal Synthesis, Structures, and Luminescent Properties of Seven d(10) Metal-Organic Frameworks Based on 9,9-Dipropylfluorene-2,7-Dicarboxylic Acid (H(2)DFDA)

A series of Zn(II) and Cd(II) metal-organic frameworks, namely, [Zn(DFDA)] (1), [Cd(DFDA)(C2H5OH)] (2), [Zn-2(DFDA)(2)(L-1)(2)](2) center dot 3H(2)O (3), [Cd-2(DFDA)(2)(L-1)(2)] (4), [Zn(DFDA)(L-2)] (5), [Cd(DFDA)(L-2)(DMF)] (6), and [Zn(DFDA)(L-3)] (7) (where DFDA = 9,9-dipropylfluorene-2,7-dicarboxylate anion, L-1 = 1,4-bis(imidazol-1-ylmethyl)benzene, L-2 = 1,1'-(1,4-butanediyl) bis(imidazole), L-3 = 2,2'-bipyridine) have been synthesized under hydrothermal conditions and structurally characterized. Compound 1 exhibits a three-dimensional (3D framework containing one-dimensional (1D) Zn(II)-O clusters, with (4(8).6(7)) topology. Compound 2 contains hydrophobic channels built from infinite 1D Cd(II)-O clusters, with (4(8).5(4).6(3)) topology.

Soluble neodymium chloride 2-ethylhexanol complex as a highly active catalyst for controlled isoprene polymerization

Soluble NdCl3 center dot 3EHOH (2-ethyl hexanol) in hexane combined with AlEt3 is highly active for isoprene polymerization in hexane. The NdCl3 center dot 3EHOH/AlEt3 has higher activity than the typical binary catalyst NdCl3 center dot 3(i)PrOH (isopropanol)/AlEt3 and ternary catalyst NdV3 (neodymium versatate)/AlEt2Cl/Al(i-Bu)(2)H. The molecular weight of polyisoprenes can be controlled by variation of [Nd], [Al]/[Nd] ratio and polymerization temperature and time. The NdCl3 center dot 3EHOH/AlEt3 catalyst polymerized isoprene to afford products featuring high cis-1,4 stereospecificity (ca. 96%), high molecular weight (ca. 10(5)) and relatively narr ow molecular weight distributions (M-w/M-n = 2.0-2.8) simultaneously. More importantly, some living polymerization characteristics were demonstrated: (a) absence of chain termination; (b) linear correlation between M-n and polymer yield; (c) increment of molecular weight in the 'seeding' polymerization. Though some deviation from the typical living polymerization such as molecular weight distribution is not narrow enough and the line of M-n and polymer yield does not extrapolate to zero, controlled polymerization with the current catalyst can still be concluded.

Self-immobilized metallocene catalysts bearing an allyl group for ethylene polymerization, X-ray crystal structure of [(CH2=CHCH2)CH3Si(C13H8)(2)]ZrCl2

A series of ansa-metallocene complexes with an allyl substituted silane bridge [(CH =CHCH2)CH3Si(C5H4)(2)]TiCl2 (1), [(CH2=CHCH2)CH3Si(C9H6)(2)]MCl2 [M = Ti (2), Zr (3), Hf (4)] and [(CH2=CHCH2)CH3Si(C13H8)(2)]ZrCl2 (6) have been synthesized and characterized. The molecular structure of 6 has been determined by X-ray crystallographic analysis. Complexes 1-4, 6 bearing allyl groups have been investigated as self-immobilized catalysts for ethylene polymerization in the presence of MMAO. The results showed that the self-immobilized catalysts 1-4, 6 kept high ethylene polymerization activities of ca. 10(6) g PE mol(-1) M h(-1) and high molecular weight (M-w approximate to 10(5)) of polyethylene.

Morphology and structure of nylon-2,14 single crystals from dilute solution

A perfect single crystal of nylon-2,14 was prepared from 0.02% (w/v) 1,4-butanediol solution by a "self-seeding" technique and isothermal crystallization at 120 and 145 degreesC. The morphology and structure features were examined by transmission electron microscopy with both image and diffraction modes, atomic force microscopy, and wide-angle X-ray diffraction (WAXD). The nylon-2,14 single crystal grown from 1,4-butanediol at 145 degreesC inhabited a lathlike shape with a lamellar thickness of about 9 nm. Electron diffraction and WAXD data indicated that nylon-2,14 crystallized in a triclinic system with lattice dimensions a = 0.49 nm, b = 0.51 nm, c = 2.23 nm, alpha = 60.4degrees, beta = 77degrees, and gamma = 59degrees. The crystal structure is different from that of nylon-6,6 but similar to that of other members of nylon-2Y.

Use of lanthanide metal complexes for the hydrolysis of 3 ',5 '- and 2 ',3 ' cyclic nucleotides

Lutetium(III) and lanthanum(III) complexes of 2-carboxyethylgermanium sesquioxide (Ge-132) can hydrolyze the phosphodiester linkage of 3',5'-cyclic adenosine monophosphate (cAMP), 3',5'-cyclic deoxyadenosine monophosphate (dcAMP) and 2',3'-cyclic adenosine monophosphate (2',3'-cAMP). Both cAMP and dcAMP are hydrolyzed with high selectivity, yielding predominantly 3'-monophosphates. 2',3'-cAMP is converted to 3'-AMP and 2'-AMP, the ratio of 3'-AMP to 2'-AMP produced being 1.4.

Synthesis and characterization of diblock copolymer of butadiene and 2-ethyl-2-oxazoline

By mechanism-transformation (anionic --> cationic) polymerization, diblock copolymer of butadiene and 2-ethyl-2-oxazoline (PBd-b-PEOx) was synthesized in two steps. The first step is the polymerization of butadiene block capped with ethylene oxide and its tosylation; the second step is the cationic ring-opening polymerization of 2-ethyl-2-oxazoline. The products were characterized by various methods, such as IR, (HNMR)-H-1, DMA, TEM and SAXS. The results show that the obtained copolymers possess high molecular weight and narrow molecular weighs distribution, and that the content of 1,4-structure was controllable.

丁二烯-2-乙基-2-噁唑啉嵌段共聚物的合成及表征

采用阴离子转阳离子的机理转移聚合方法 ,两步合成了丁二烯 2 乙基 2 唑啉二嵌段共聚物 (PBd b PEOx) ;第一步阴离子聚合丁二烯 ,然后使其带上端功能基团 ;第二步是 2 乙基 2 唑啉的阳离子开环聚合 .对产物用IR ,1HNMR ,GPC ,DMA ,TEM和SAXS等手段进行了广泛的结构表征 .结果表明 ,所得嵌段共聚物具有较高分子量和窄的分子量分布 ,而且其中的聚丁二烯段中的 1 ,4 结构含量可通过反应条件的控制来调节.

STRUCTURE AND SITE-SYMMETRY INVESTIGATION ON THE HEXAGONAL KCAY(PO4)(2)

A new double phosphate, KCaY(PO4)(2), isostructural with hexagonal LaPO4, is reported. It crystallizes in the hexagonal system with a = 0.6903 nm and c = 0.6331 nm. Its vibrational spectra, IR and Raman spectra showed that the site symmetry of the PO4 anion slightly deviated from D-2 toward C-2.

ELECTROCHEMICAL STUDY OF ISOPOLY AND HETEROPOLY ANION TRANSFER ACROSS THE WATER NITROBENZENE INTERFACE .2. VANADIUM-CONTAINING HETEROPOLYTUNGSTATE ANIONS

The electrochemical transfer behaviour of vanadium-containing heteropolytungstate anions [PW12-xVxO40]((3+r)-) (x = 1-4) across the water \nitrobenzene interface has been investigated by cyclic voltammetry and chronopotentiometry with cyclic linear current scanning. The transfer of PW11V1O404-, HPW10V2O404-, H2PW10V2O403-, H3PW9V3O403- and H4PW8V4O(40)(3-) across the water \nitrobenzene interface can be observed within the potential window. The effects were observed of pH in the water phase on the transfer behaviour and the formation of vanadium-containing heteropolytungstate anions in solution. Heteropolytungstate anions become more stable due to their involving the vanadium atom. The degree of protonation and the dissociation constant of the trivalent vanadium-containing heteropolytungstate anion of protonation increase with increasing vanadium content. The transfer processes are diffusion-controlled The standard transfer potential, the standard Gibbs energy and the dissociation constant for vanadium-containing heteropolytungstate anions have been obtained and the transfer mechanisms are discussed.

ISOPRENE POLYMERIZATION WITH (ETA(3)-C3H5)(2)CECL5MG2(TMED)(2)/ALKYLALUMINUM

(eta(3)-C3H5)(2)CeCl5Mg2(tmed)(2) combined with HAl(i-Bu)(2) or Al(i-Bu)(3) can initiate the polymerization of isoprene with about 50% of the cis-1, 4 microstructure contained in the polymer. The insertion reaction of isoprene occurring between Ce3+ and e

海藻酸钙固定混合SRB菌群生物吸附Ni^2＋的动力学

利用海藻酸钙为载体包埋固定化硫酸盐还原菌（SRB）混合菌群，研究了固定化微生物吸附重金属镍离子的动力学特性．结果表明：固定化混合SRB菌群对Ni^2＋具有良好的吸附性能，最大吸附容量qm高达931．9mg（Ni^2＋）／g（SRB）颗粒，是一种颇具应用前景的生物吸附剂．固定化SRB吸附Ni^2＋的动力学过程可以用准二次动力学方程描述，整个吸附过程可以明显地分为两个阶段，即物理化学吸附阶段和生物沉淀阶段．扩散动力学研究表明，固定化颗粒的内扩散并非是唯一控制吸附速率的机制，整个吸附过程涉及到多种吸附机制．

Analysis of phenols by high-performance liquid chromatography with pre-column derivatization by 2-(9-carbazole)-ethyl-chloroformate

2-(9-Carbazole)-ethyl-chloroformate (CEOC), a novel pre-column fluorescence labeling reagent, has been synthesized and applied for the derivatization of phenols. Taken phenol, p-chlorophenol, 2,5-dimethylphenol, 2,4-dichlorophenol and 1,4-dihydroxybenzene as testing standards, the effects of derivatization conditions, such as pH of borate buffer, reaction time and fluorescent tagging reagent concentration, have been systematically studied. Under the optimized conditions, CEOC reacts readily with the phenols to form stable derivatives with excitation and emission wavelengths, respectively, at 293 and 360 nm. The single step derivatization reaction could be finished within 20 min even at room temperature. Such a method has been successfully applied to the analysis of phenols in printing ink by high-performance liquid chromatography. (c) 2005 Elsevier B.V. All rights reserved.