Total Synthesis of Several 8, 8",-Biflavones

8,8"-Biflavonoidsareantw0rtantclass0fbiflavonoids.Asasystematicresearchofthe8,8"-biflav0noids,wehavepreviouslyreportedthestudyonthereactionof2'-hydroxychaloneswithl2-H2SO4-DMSOsystem.'InthispaPer,thesynthesisof5,5",7,7',-tetTameth0xy-8,8"-biflavonela2,4,4",7,7"-tetramethoxy-8,8"-biflavone1b',4',4",,5,5,',7,7"-hexamethoxy-8,8"-biflav0ne1c4and4,4"-dibenZyl0xy-5,5",7,7"-tetramothoxy-8,8"-biflavoneldisreported.ThesyntheticmethodisshownintheSchemebelow.2-Hydroxyacet0phenonescondensedwithsubsti…     

具有三维交叉孔道的新型亚磷酸锌的合成与结构

本文报道了一种新型三维亚磷酸锌[HO(CH₂)₂NH₃]₂•[Zn₃(HPO₃)₄]的合成和晶体结构。在它的结构中，ZnO₄和HPO₃严格按照顶点连接的方式交替相连。骨架结构存在两个沿着不同方向无限延伸的由ZnO₄和HPO₃组成的四元环链，在[0 1 0]、[0 4 15]和[0 -4 15]三个方向形成了三个交叉8元环孔道，有机胺阳离子起着平衡电荷和稳定骨架的结构。它的晶体数据为：[HO(CH₂)₂NH₃]₂•[Zn₃(HPO₃)₄],M=640.21, 正交晶系, Fdd2空间群, a=2.8528, b=0.8426, c=1.6159nm, Z=8, V=3.884nm³, R₁=0.0219, wR₂=0.0544。     

Multifunctional peptide-assembled micelles for simultaneously reducing amyloid-β and reactive oxygen species

The excessive production and deposition of amyloid-β (Aβ) is one of the most important etiologies of Alzheimer''s disease (AD). The interaction between Aβ and metal ions produces aberrant reactive oxygen species (ROS), which induce oxidative stress and accelerate the progression of AD. To reduce Aβ plaques and ROS to maintain their homeostasis is an emerging and ingenious strategy for effective treatment of AD. Herein, we report the rational design of multifunctional micelles (MPGLT) based on a polymer-grafted peptide to simultaneously clear Aβ and ROS for AD therapy. The MPGLT integrating three functional peptides as a ROS scavenger (tk-GSH), β-sheet breaker (LP) and an autophagy activator (TK) respectively, could capture and degrade Aβ. Meanwhile, the tk-GSH on the surface of MPGLT effectively scavenges the intracellular ROS. Consequently, MPGLT reduced the cytotoxicity of Aβ and ROS. In vivo animal studies using an AD mouse model further showed that MPGLT could transport across the blood–brain barrier for decreasing the Aβ plaque and eliminating ROS in vivo. This peptide micelle-based synergistic strategy may provide novel insight for AD therapy.

Multifunctional micelles based on a peptide–polymer for simultaneously targeting Aβ degradation and ROS scavenging for AD therapy.     

新型手性Salen双核锌配合物的分子识别研究

合成了新型手性Salen配体（H3L）及新型手性Salen双核锌配合物（主体）.通过研究主体对咪唑类客体及氨基酸酯类客体的分子识别行为,测定了这些配位反应的缔合常数.主体对咪唑类客体分子识别的缔合常数顺序为:K(Im) >K(2-MeIm) >K(2-Et-4-MeIm).主体对氨基酸酯类客体分子识别的缔合常数顺序为:K(LeuOCH3) >K(ValOCH3) >K(AlaOCH3) >K(SerOCH3),配位数均为2.主体与D、 L型氨基酸酯分子识别反应在不同温度下的缔合常数结果表明,随着温度的升高,对映选择性下降.实验发现反应体系中存在焓熵补偿关系. CD光谱的研究结果也反映了主体对不同客体识别能力的差异.     

Electron paramagnetic resonance study of amphiphiles partitioning behavior in desiccation-tolerant moss during dehydration

Desiccation tolerance is a crucial characteristic for desert moss surviving in arid regions. Desiccation procedure always induces amphiphiles transferring from the polar cytoplasm into lipid bodies. The behavior of amphiphiles transferring can contribute to the enhancement of desiccation tolerance and the reduction of plasma membrane integrity simultaneously. The effects of amphiphiles partitioning into the lipid phase during water loss has been studied for pollen and seeds using electron paramagnetic resonance (EPR) spectroscopy. However, desiccation-tolerant high plants occur among mosses, several angiosperms and higher plants seeds or pollens. They have different strategies for survival in dehydration and rehydration. A desiccation-tolerant moss Tortula desertorum was used to investigate the behaviors of amphiphilic molecules during drying by spin label technology. There are small amount of amphiphilic probes partitioning into membrane during moss leaves dehydration, comparing with that in higher plants. Cytoplasm viscosity changed from 1.14 into glass state only dehydration less than 60 min. Moss leaves lost plasma membrane integrity slightly, from 0.115 to 0.237, occurred simultaneously with amphiphiles partition. The results showed the more advantages of mosses than higher plants in adapting fast dehydration. We propose that EPR spin label is feasible for studying the amphiphiles partitioning mechanisms in membrane protection and damage for desiccation-tolerant mosses.     

Photoelectrochemistry on Ru(II)-2,2'-bipyridine-phosphonate-derivatized TiO2 with the I3-/I- and quinone/hydroquinone relays. Design of photoelectrochemical synthesis cells

Photocurrent measurements have been made on nanocrystalline TiO2 surfaces derivatized by adsorption of a catalyst precursor, [Ru(tpy)(bpy(PO3H2)2)(OH2)]2+, or chromophore, [Ru(bpy)2 (bpy(PO3H2)2)]2+ (tpy is 2,2':6',2' '-terpyridine, bpy is 2,2'-bipyridine, and bpy(PO3H2)2 is 2,2'-bipyridyl-4,4'-diphosphonic acid), and on surfaces containing both complexes. This is an extension of earlier work on an adsorbed assembly containing both catalyst and chromophore. The experiments were carried out with the I3-/I- or quinone/hydroquinone (Q/H2Q) relays in propylene carbonate, propylene carbonate-water mixtures, and acetonitrile-water mixtures. Electrochemical measurements show that oxidation of surface-bound Ru(III)-OH2(3+) to Ru(IV)=O(2+) is catalyzed by the bpy complex. Addition of aqueous 0.1 M HClO4 greatly decreases photocurrent efficiencies for adsorbed [Ru(tpy)(bpy(PO3H2)2)(OH2)]2+ with the I3-/I- relay, but efficiencies are enhanced for the Q/H2Q relay in both propylene carbonate-HClO4 and acetonitrile-HClO4 mixtures. The dependence of the incident photon-to-current efficiency (IPCE) on added H2Q in 95% propylene carbonate and 5% 0.1 M HClO4 is complex and can be interpreted as changing from rate-limiting diffusion to the film at low H2Q to rate-limiting diffusion within the film at high H2Q. There is no evidence for photoelectrochemical cooperativity on mixed surfaces containing both complexes with the IPCE response reflecting the relative surface compositions of the two complexes. These results provide insight into the possible design of photoelectrochemical synthesis cells for the oxidation of organic substrates.     

Design and Theoretical Study of Nickel Catalysts for Syndiotactic Polyolefins

A nickel catalyst was nodeled with ligand L^2,[NH=CH-CH=CH-0]^-,which should have potential use as a syndiotactic plyolefin catalyst,and the reaction mechanism was studied by theoretical calculations using the density functinal method at the B3LYP/LANL2MB level.The mechanism involves the formation of the intermediate [NiL^2Me]^ ,in which the metal occupies a T-shaped geometry.This intermediate has two possible structures with the methyl group trans either to the oxygen or to the nitrogen atom of L^2.The results show that both structures can lead to the desired product via similar reaction paths,A and B.Thus,the polymerization could be considered as taking place either with the alkyl group occupying the position trans to the Ni-0 or trans to the Ni-N bond in the catalyst.The polymerization process thus favors the catalysis of syndiotactic polyolefins.The syndiotactic synthesis effects could also be enhanced by varations in the ligand substituents.From energy considerations,we can conclude that it is more favorable for the methyl ttrans-O position to form a complex than to occupy the trans-N position.From bond length considerations,it is also more favoured for ethene to occupy the trans-O position than to occupy the trans-N position.     

一种新的环糊精衍生物手性固定相的合成及其在对映异构体过量值测定中的应用

 以 β 环糊精为原料 ,合成了一种新的环糊精衍生物 2 ,6 二 O 苄基 3 O 戊酰基 β 环糊精 ,用核磁氢谱和红外光谱对产物进行了表征 ,并将所得环糊精衍生物用作毛细管气相手性固定相制备成柱 ,用于 2 ,4 二氯苯乙酮的不对称催化氢化产物 2 ,4 二氯苯乙醇和反式 2 己烯醇的Sharpless环氧化产物 反式 3 正丙基环氧乙烷甲醇的对映异构体过量值 (e.e .值 )测定和催化反应评价 ,取得了很好的结果。     

新型高吸水聚合物凝胶型屏蔽暂堵剂MTC-1的合成及性能

以丙烯酸（AA）、丙烯酰胺（AM）、2-丙烯酰胺基-2-甲基丙磺酸（AMPS）为原料，蒙脱土（MMT）为改性剂，过硫酸钾和无水亚硫酸氢钠为氧化还原引发体系，六亚甲基四胺（C₆H₁₂N₄）为交联剂，采用水溶液聚合法合成了一种新型高吸水聚合物凝胶型屏蔽暂堵剂（MTC 1），其结构经IR表征。在最优合成条件（AM/AMPS/AA=11/7/1, m/m/m，引发剂加量0.6 wt%，于45 ℃反应2.5 h）下，MTC-1的最大吸水倍率为1006倍。岩心流动实验结果表明：MTC-1的堵水性能较高，封堵效率达到83.72%。     

液相色谱手性拆分机理的热力学方法研究

手性识别是分子识别的一个重要组成部分。液相色谱手性拆分机理研究有助于色谱条件的优化和新型手性固定相的设计，也有助于理解手性识别机制。本文就线性色谱与非线性色谱条件下手性拆分过程对应热力学参数的推求方法进行了评述，阐述了相关热力学参数的涵义及其在色谱保留及手性拆分机理探讨中的应用，并展望了该领域的研究前景。