聚糖联乙炔类脂仿生膜与大肠杆菌的识别作用研究

生物膜是生物进化的产物.生物膜中的脂类(糖脂、磷脂、胆固醇)的组成极为复杂,种类敏多,分子结构也各不相同,但全部属于极性分子,即在分子中都含有一个亲水头部基团和一个疏水尾部基团.     

基于罗丹明荧光信号报告基团的细胞通透性铜离子荧光探针

分别以罗丹明B和罗丹明6G为荧光信号报告基团,以增强水溶性为目的的羟乙基肼为修饰基团,合成了反应型的Cu_(2+)离子选择性荧光探针分子L1和L2.紫外光谱和荧光光谱等分析结果表明,探针分子L1和L2对Cu_(2+)离子具有高灵敏度、高选择性的光谱识别行为.探针分子对Cu_(2+)离子的识别过程是通过Cu_(2+)离子催化水解控制氧杂蒽荧光信号的螺环酰肼基团实现荧光信号的开启,从而达到识别检测Cu_(2+)离子的目的,对Cu_(2+)离子的检出限均可达到10-8mol/L量级.同时,探针分子对常见金属离子和铵离子均具有较强的抗干扰能力.由于羟乙基肼的引入增强了探针的水溶性,使得探针L1和L2具有良好的细胞通透性和低毒性,实现了其对β-胰岛细胞(INS-1细胞)中Cu_(2+)离子的荧光成像检测.     

新型一维麻花状超分子配合物的合成与结构

具有特殊结构及性能的超分子化合物由于其结构上的新颖性及潜在的应用价值而成为人们关注的热点 .以一个苯环为间隔基两端含两个吡啶基团的配体 L1与 Pd( ) ,Pt( )形成 2 -索烃 [1 ] ,与Cd( NO3) 2 则形成具有一维平面结构的聚合物 [2 ] .以联苯为间隔基的配体 L2在 4 ,4′-二联吡啶共同作用下与 Pd( )形成 2 -索烃 [3] .同样以一个苯环为间隔基两端含两个咪唑基团的配体 L3与 Zn( NO3) 2 ,Ag NO3反应得到新型多聚轮烷配合物 [4,5 ] .研究结果表明 ,配体或配位金属离子等的微小差别即导致形成结构不同的超分子化合物 .但这些超分子…     

寡糖快原子轰击质谱中碱金属加合离子应用技术的研究

生命科学的研究成果^[1～3]表明,糖蛋白和糖脂中的糖基可作为细胞的识别信号,能控制细胞的分裂和分化.快原子轰击(FAB)质谱是测定寡糖的重要手段^[4,5],但目前还存在不少问题.我们在对麦芽各糖的研究中.     

β-环糊精聚合物膜拆分氨基酸对映体

环糊精（CD）具有亲水的外围及憎水的内腔,在溶液中可与许多有机物形成包合物,并对其形状、体积与极性呈现选择性^[1]。通过化学修饰引入新的识别基团,可使CD具有更高的结合选择性,即多重分子识别^[2]。CD及其衍生物可用作气相色谱固定相、液相色谱固定相和流动相手性添加剂、毛细管电泳溶剂介质分离各种光学异构体,但作为膜分离材料来拆分手性化合物的有关报道却很少^[3]。本文将氨基取代的环糊精子分子共价键合于聚乙烯醇上,制得带有环糊精基团的聚合物膜,并用此膜拆分了某些消旋氨基酸。     

STN型液晶显示用聚酰亚胺表面取向材料的性能

与传统的扭曲向列 (TN)型液晶显示 (L CD)相比 ,超扭曲向列 (STN)型 L CD的信息容量和清晰度都有了很大的提高 ,已成为 L CD产品的重要组成部分 .为防止反倾斜 (reverse tilt)现象产生 ,液晶分子相对于取向膜表面必须具有一定的预倾角 .一般来说 ,TN型要求预倾角为 1～ 2°,STN型为 3～ 2 0°.稳定的大预倾角控制是 STN制造的关键技术之一 ,它直接影响到显示器件的对比度、阈值电压、响应时间、视角大小等特性 [1～ 4 ] .通过在聚酰亚胺分子长链中引入强极性基团或长烷基侧链可以获得大预倾角 [5～ 8] .本文合成了含有三氟甲基基团…     

甘油糖脂的UPLC-Q-TOF-MS研究

糖脂是植物光合膜脂的主要成分[1],在影响光合作用的效率[2-3]、帮助植物体适应生态条件的改变[4]等方面起着非常重要的作用,糖脂及其降解产物在抗肿瘤活性[5-6]及影响细胞凋亡、分化、衰老等方面的研究[7-9]现在也越来越深入,所以研究植物膜糖脂具有十分重要的意义.     

9,10-二(苯亚甲基-硫亚甲基)蒽的合成及其对Cu2+的识别

荧光分子开关和分子识别是超分子化学的重要组成部分。蒽环作为一个优良的荧光基团被广泛应用于分子开关的设计及分子识别中。Resorci-narenes母体衍生物的合成研究中采用蒽环作为荧光基团已被报道多次[1-4],Luigi Fabbrizzi合成的多氨基蒽衍生物[5]对Zn2 具有良好的PET效应。蒽系荧光分子在分子逻辑门系统中日益受到了研究者的重视,de Silva等在研究中发现一蒽环化合物[6]在Mg2 作用存在OR逻辑行为。在后续研究中发现两类蒽环化合物在一定条件下分别存在AND[7]和NOR[8]逻辑行为。在分子识别的研究中,Shin-ichi Sasaki合成的含穴状…     

磷脂酰胆碱LB单分子膜诱导下KDP晶体取向生长的研究

有机超薄膜诱导晶体生长是在化学、物理与生物多门学科相互交融的基础上发展起来的新兴学科 ,并逐渐成为仿生合成的重要分支 [1] .目前的研究重点主要集中于以有机化合物 LB膜作为模板剂诱导生物矿化材料上 [2～ 5] .磷脂 LB膜是生物膜的简化模型体系 [6 ] ,用它作模板剂将使该领域的研究进一步接近生物体系 .对晶体而言 ,修饰晶体材料的特征对于改善和测定材料的光学性能至关重要 [2 ] ,但目前有关上述领域的研究几乎均是空白 .KH2 PO4 ( KDP)晶体是性能优良的非线性光学材料 [7] ,本文首次以磷脂分子 LB膜作为模板剂诱导 KDP的晶化…     

葫芦[7]脲与紫精和香豆素修饰树枝形分子的分步结合及对体系发光性质的调控

合成了外围修饰香豆素PAMAM树枝形分子Gm-2(m+1)C, 外围和核心分别共价连接香豆素和紫精的树枝形分子EV-Gm-2(m+1)C (m=0, 1), 以及香豆素和紫精的模型化合物C-Model和EV, 化合物均通过了¹H NMR, IR和MALDI-TOF MS的鉴定. ¹H NMR和光物理研究结果表明, 在pH=4.5的醋酸-醋酸钠缓冲溶液中, CB[7]与紫精和树枝形分子外围的香豆素基团均可形成1:1的包结复合物, 结合常数分别为3.3×10⁶ mol^-1·L和1.4～1.6×10⁵ mol^-1·L. 香豆素基团中7位二乙氨基及取代侧部分香豆素环包裹在CB[7]刚性的疏水空腔内, 包结复合物的形成限制了香豆素7位N,N'-二乙氨基的扭转, 抑制了香豆素基团从发光的分子内电荷转移(ICT)态向不发光的扭曲的分子内电荷转移(TICT)态的转变, 而且CB[7]内腔的疏水环境有利于香豆素ICT态辐射跃迁, 使体系发光大大增强. EV-Gm-2(m+1)C与CB[7]的主客体作用为分步结合机制, 加入的CB[7]先与紫精基团作用形成包结复合物, 待体系中紫精基团与CB[7]结合后, 体系中香豆素基团再与CB[7]作用形成包结复合物. 无论是Gm-2(m+1)C还是EV-Gm-2(m+1)C体系, 均可以通过加入CB[7]的量调节体系中香豆素基团与CB[7]形成包结复合物的多少, 从而实现对Gm-2(m+1)C和EV-Gm-2(m+1)C体系发光的调控. 本工作为可调控发光树枝形聚合物的发展提供了一种新的策略.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.