聚电解质膜PDAC/PSS诱导CaCO3结晶的研究

以模拟软体动物珍珠层的周期性基质控制形成过程制备仿生层状复合材料. 将聚苯乙烯磺酸钠(PSS)与聚二烯二甲基氯化铵(PDAC)用逐层浸渍的方法使其组装成多层膜, 用于诱导过饱和溶液中CaCO₃的结晶, 详细研究了膜紫外吸收随组装层数增加的线性变化. 扫描电镜和X射线衍射表征了晶体的形貌和结构. (PDAC/PSS)₁₅PDAC膜诱导获得的CaCO₃晶体为六面体结构, 晶体尺寸为30～40 μm; (PDAC/PSS)₁₅膜诱导CaCO₃结晶, 可以在膜表面获得形貌与珍珠层非常相似的CaCO₃晶体, 结晶10 h获得的晶片结构呈规则的六边形, 片尺寸约为10～20 μm. X射线衍射结果表明两种晶体的晶格结构与天然珍珠层差异明显, 说明静电作用为晶体形貌的主控因素之一, 但不是晶格结构的决定因素. 复合材料断面电镜照片表明其为层状结构.     

乙醇/水混合溶剂体系中碳酸钙晶体晶型和取向的控制

采用(NH4)2CO3分解法,制备得到了晶型和形貌可控的CaCO3晶体。研究结果表明,乙醇/水混合溶剂、陈化时间和L-半胱氨酸自组装单层模板对CaCO3晶体的晶型、取向和形貌都具有重要影响。无单层模板情况下,溶液中主要得到了球霰石,球霰石的形貌随陈化时间从花朵外形变为树叶形。同样的醇/水体系中,在自组装单层上却得到了取向为(104)晶面的方解石。这与水溶液中同一自组装单层上主要获得(001)结晶面的方解石有明显不同。方解石的形貌也随陈化时间变化而改变。陈化时间为3h时,得到具有孔洞结构的方解石;陈化时间为12 h时,得到表面光滑的菱面体方解石。     

L-半胱氨酸自组装膜诱导草酸钙结晶研究

在CaCl2.H2O和Na2C2O4配制的过饱和溶液中,利用L-半胱氨酸(L-Cys)在金片上形成的自组装膜为模板,研究了草酸钙(CaOxa)在自组装膜上的结晶行为,并探讨了溶液pH对CaOxa晶体组成、晶型及其形貌的影响。采用X射线衍射(XRD)和扫描电子显微镜(SEM)等技术对CaOxa晶体的结构和形貌进行了表征。实验结果表明:当溶液pH=3.0时,溶液中可以形成一水草酸钙(CaC2O4.H2O,COM)和二水草酸钙(CaC2O4.2H2O,COD)晶体,而在同样pH条件下,在L-Cys自组装膜上只形成COD晶体,表明自组装单层对CaOxa晶体的成核和生长有重要影响。通过改变溶液的pH,在自组装单层上可以得到不同晶型和不同形状的CaOxa晶体。当pH=3.0时得到四方块状的COD晶体,而pH=5.0和pH=7.0时分别得到六边形和拉长六边形的COM晶体。     

扩镓硅基GaN晶体膜质量的电镜分析

采用射频磁控溅射工艺在扩镓硅基上溅射Ga2O3薄膜,氮化反应组装GaN晶体膜,并对其生长条件进行研究．用扫描电镜(SEM)和X射线衍射(XRD)对样品进行结构、形貌分析．观测结果表明：采用此方法得到的在预沉积扩镓硅基上生长的GaN晶体膜,随着扩镓时间的增加,薄膜的晶化程度得到明显提高,而氮化时间对构成GaN薄膜的颗粒形态影响不大．     

珍珠质基底上CaCO3晶体的仿生生长研究

珍珠质是一种典型的有机，无机层状复合材料．其中95％以上是文石（CaCO3的一种晶型1小板片，填充在板片之间的薄层有机基质仅占1％-5％。这种精细的组织结构不仅使珍珠质具有绚丽的光泽。还赋予珍珠质超乎寻常的强度和韧性（为合成CaCO3晶体的3000多倍）。虽然在珍珠质中有机质的含量不足5％．然而正是这些有机质对珍珠质的结构、性能、晶体取向等起着至关重要的调控作用。     

LB技术组装聚合物／有机染料多层膜的光致发光和电致发光

半导体超晶格材料由于其特殊的光电性质引起人们的关注,So和Tokito等人用分子束沉积的方式制备了有机及有机无机复合的超晶格材料器件,但分子沉积中有机小分子染料的结晶影响薄膜的质量及器件的寿命。最近,我们用两亲性聚合物分子成功地将有机染料分子组装在聚合物LB膜中,有效地限制有机小分子染料结晶,实验证明此多层LB膜具有超晶格结构和较好的稳定性及发光特性。为制备多量子阱结构器件提供了一种新方法。 两亲性聚合物(ES)是由环氧氯丙烷、乙二胺和硬脂酸共聚而成。将染料分子四苯基丁二烯(TPB)与ES相混合的氯仿溶液(TPB与ES质量比为2:10)分散在去离子水亚相表面,在20mN/m的膜压下将其转移到单晶硅片上。用小角X射线衍射实验观察其多层结构,在小角衍射区存在一个Bragg衍射峰(图1),根据Bragg衍射方程得到其层状周期结构为5.8nm。考虑到ES的分子尺寸,我们认为每一周期结构是由两层聚合物的LB膜组成。由于TPB分子是疏水的,通过分子间的相互作用,TPB分子可能镶嵌或吸附在ES的疏水脂肪链中,与无机半导体超晶格结构对照,聚合物ES的亲水网络由于是绝缘材料,带隙很宽相当于能垒,而镶嵌有TPB的疏水层则相当于势阱,这就很可能形成聚合物/有机染料的超晶格结构。考察其发光特性(图2)时,发现聚合物/有机染     

光致变色的PW12/1,10DAD自组装超晶格多层膜

本文报道了在固体基底表面上用PE方法连续自组装沉积PW₁₂和1,10-DAD分子,构建了PW₁₂/1,10-DAD自组装多层膜.紫外-可见吸收、X射线衍射等分析结果表明此多层膜有好的超晶格结构,层间距为3.19nm.与真空蒸镀WO₃薄膜相比,PW₁₂/1,10-DAD自组装多层膜表现出更好的光致变色特性.     

氨基酸-表面活性剂体系合成CaCO_3晶体

以L-组氨酸和十二烷基苯磺酸钠(SDBS)作为CaCO3生长调节剂,用粉末X射线衍射、红外光谱测试技术对生成的CaCO3晶体进行了表征,扫描电子显微镜对生成的CaCO3晶体形貌进行了分析,研究了表面活性剂浓度、温度和溶剂的组成对CaCO3晶型和形状的影响。结果表明,在实验条件下表面活性剂的浓度对CaCO3晶型没有影响,但影响晶体的形状,温度和溶剂的组成对CaCO3晶型和晶体形状有很大的影响。     

基于层层组装镍铝水滑石/聚电解质的无酶葡萄糖传感器

采用共沉淀法合成了镍铝水滑石(NiAl-LDH),将NiAl-LDH与聚苯乙烯磺酸钠(PSS)通过层层自组装法构筑了PSS/NiAl-LDH多层膜电极,并将其用于葡萄糖分析。X射线衍射光谱、红外光谱和SEM结果表明：共沉淀法合成的NiAl-LDH具有典型的水滑石特征峰及形貌。紫外-可见光谱表明：NiAl-LDH可与PSS均匀有效地组装构筑多层膜。电化学研究表明：NiAl-LDH修饰电极能有效地催化氧化葡萄糖。该传感器对葡萄糖在5.0×10-7~6.6×10-4 mol/L范围内呈良好的线性响应,灵敏度为8.9×10-4 A?L?mol-1,检出限(S/N=3)为2.8×10-7 mol/L。     

热处理对聚己二酸丁二醋多晶结构和降解行为的影响

通过熔融结晶并结合退火处理方法得到多晶结构的聚己二酸丁二酯(PBA)及具有不同热历史的热力学稳定的a晶型,采用广角X射线衍射仪(WAXD)、原子力显微镜(AFM)和差示扫描量热仪(DSC)研究了PBA的多晶结构、晶体尺寸和结晶形貌,跟踪了退火处理PBA的生物降解行为.结果表明,分子链在相同晶格排列中围绕c轴空间取向的不...     

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.     

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.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.