含嘧啶环的双冠醚(Ⅳ)

前文已报道由啶环桥联两个苯并冠醚的双冠醚的合成与性质。由于嘧啶环的刚性较大,能把两个冠醚单元固定在有效地协同作用位置,因此以它们作中性载体的离子选择性电极具有较好的选择性。为了进一步研究这类双冠醚的性质,我们合成了四种嘧啶环桥联两个脂肪族冠醚的双冠醚,并经元素分析、IR、′HNMR鉴定。     

Influence of shell strength on shape transformation of micron-sized,monodisperse, hollow polymer particles

Micron-sized, monodisperse, non-spherical polymer particles with "rugby ball" and "red blood corpuscle"-like shapes were produced by seeded polymerization of the dispersion of (divinylbenzene/vinylbiphenyl/xylene)-swollen polystyrene particles prepared by utilizing the dynamic swelling method which the authors proposed in 1991. Their non-spherical shapes were based on buckling of the shell of the resultant hollow particles. In this article, the reversible shape transformation of the hollow composite polymer particle between spherical and such non-spherical shapes was studied in detail by controlling the shell strength. A part of the shell was buckled by external pressure which was caused by evaporation of xylene from the hollow when the shell had the tensile modulus below the critical value calculated from the pressure-buckling relationship of a spherical shell proposed by Uemura. The plasticization of the shell by a good solvent was one of key factors for the shape transformation.     

Synthesis and photoinduced memory effect of poly[2-N-carbazolylethyl acrylate-co-2-(3,5-dinitrobenzoyloxy) ethyl methacrylate]

Copolymers containing an intramolecular electron donor-acceptor (EDA) complex were synthesized by free radical copolymerization of 2-N-carbazolylethyl acrylate and 2-(3,5-dinitrobenzoyloxy)ethyl methacrylate. Glass transition temperatures show a positive deviation from the weight-average values of copolymers, indicating the presence of the specific EDA interaction in copolymers in the solid state. Photoinduced “memory effect,” which is defined as the percentage of the difference of the surface potential given by corona charging before and after irradiation of light on polymer films, was 30% for the copolymer with 5 mol% of acceptor content. Memory effect increased to 70% for a 8 μm film by doping with 2 wt% of trichloroacetic acid (TCAA), and leveled off at 5 wt% of TCAA content. Memory effect was also enhanced by increasing the thickness of polymer films and irradiation time. The largest value of memory effect (85%) was obtained from the film of the copolymer with 5 mol% acceptor content doped with 1 wt% TCAA and with thickness larger than 14 μm.     

X-ray investigation of the role of the mixed emulsifier in the structure formation in o/w creams

The aim of this research work was to clarify the role of the mixed emulsifier in the structure formation and water binding mode in the case of o/w creams prepared with different surfactants. The swelling behavior of mixed emulsifiers was examined by means of direct investigation methods such as transmission electron microscopy (TEM) and X-ray diffraction. The detailed structure image of the creams was created with the help of the latter. The influence of the structure of the hydrophilic gel phase, and the structural changes during storage were studied with rheological methods. On the basis of the results, it can be stated that the investigated creams had different structures from those mentioned in the literature: surfactant did not create a mixed bilayer with the structure to furnish fatty amphiphile; instead, micelles were formed. These results correlated well with the results of the rheological tests.     

薄层液/液界面电子转移动力学的研究进展

薄层循环伏安法是研究液/液界面电荷转移的一种新方法,具有简单、快速、易操作的优点。文章回顾了液/液界面电化学的发展历史,介绍了薄层法的实验原理,对其在电化学中的应用和研究进展进行了评述,总结了界面驱动力与电子转移速率的关系。     

Ab initio study of the complexes of halogen-containing molecules RX (X=Cl, Br, and I) and NH3: towards understanding the nature of halogen bonding and the electron-accepting propensities of covalently bonded halogen atoms

Ab initio calculations have been performed on a series of complexes formed between halogen-containing molecules and ammonia to gain a deeper insight into the nature of halogen bonding. It appears that the dihalogen molecules form the strongest halogen-bonded complexes with ammonia, followed by HOX; the charge-transfer-type contribution has been demonstrated to dominate the halogen bonding in these complexes. For the complexes involving carbon-bound halogen molecules, our calculations clearly indicate that electrostatic interactions are mainly responsible for their binding energies. Whereas the halogen-bond strength is significantly enhanced by progressive fluorine substitution, the substitution of a hydrogen atom by a methyl group in the CH(3)X...NH(3) complex weakened the halogen bonding. Moreover, remote substituent effects have also been noted in the complexes of halobenzenes with different para substituents. The influence of the hybridization state of the carbon atom bonded to the halogen atom has also been examined and the results reveal that halogen-bond strengths decrease in the order HC triple bond CX > H(2)C=CHX approximately O=CHX approximately C(6)H(5)X > CH(3)X. In addition, several excellent linear correlations have been established between the interaction energies and both the amount of charge transfer and the electrostatic potentials corresponding to an electron density of 0.002 au along the R-X axis; these correlations provide good models with which to evaluate the electron-accepting abilities of the covalently bonded halogen atoms. Finally, some positively charged halogen-bonded systems have been investigated and the effect of the charge has been discussed.     

活泼配盐[(μ-RE)(μ-E′)Fe_2(CO)_6][Et_3NH][E,E′=S,Se]的亲电反应研究——蝶状Fe_2SSe及Fe_2Se_2簇合物的合成及表征

本文由［（μｔＢｕＳ）（μＣＯ）Ｆｅ２（ＣＯ）６］［Ｅｔ３ＮＨ］和硒粉形成的［（μｔＢｕＳ）（μＳｅ）Ｆｅ２（ＣＯ）６］［Ｅｔ３ＮＨ］，分别与溴化苄，二碘甲烷及邻一、间一、对一双（溴甲基）苯反应，合成了蝶状Ｆｅ２ＳＳｅ单簇物（μｔＢｕＳ）（μＰｈＣＨ２Ｓｅ）Ｆｅ２（ＣＯ）６（３ａ）和双簇物［（μｔＢｕＳ）Ｆｅ２（ＣＯ）６］２（μＳｅＺＳｅμ）［Ｚ＝ＣＨ２，ｏ．ｍ．ｐ双（亚甲基）苯］（４ａｄ）。类似地，由［（μＰｈＳｅ）（μＣＯ）Ｆｅ２（ＣＯ）６］［Ｅｔ３ＮＨ］和硫粉或硒粉所形成的［（μＰｈＳｅ）（μＳ）Ｆｅ２（ＣＯ）６］［Ｅｔ３ＮＨ］或［（μＰｈＳｅ）（μＳｅ）Ｆｅ２（ＣＯ）６］［Ｅｔ３ＮＨ］分别与对一双（溴甲基）苯反应合成了蝶状Ｆｅ２ＳＳｅ和Ｆｅ２Ｓｅ２双簇物［（μＰｈＳｅ）Ｆｅ２（ＣＯ）６］２［μＳ（ｐＣＨ２Ｃ６Ｈ４ＣＨ２）Ｓμ］（５ａ）及［（μＰｈＳｅ）Ｆｅ２（ＣＯ）６］２［μＳｅ（ＰＣＨ２Ｃ６Ｈ４ＣＨ２）Ｓｅμ］（５ｂ）。所有产物均经元素分析、ＩＲ和１ＨＮＭＲ表征。     

喷雾热解法合成球形(Y,Gd)BO3:Eu荧光粉的研究

采用喷雾热解法合成了无团聚的球形(Y,Gd)BO3∶Eu荧光粉。研究了各因素对(Y,Gd)BO3∶Eu荧光粉体的结晶性能、外观形貌及发光强度的影响。结果表明,按120%硼酸的化学计量比于900℃喷雾热解,再经过1200℃后处理2 h,可以合成结晶良好的(Y,Gd)BO3∶Eu荧光粉体;喷雾热解溶液的浓度和载气流量对荧光粉的外观形貌影响较大;铕含量为10%时可以获得最佳的发光强度。在优化喷雾热解实验条件下成功合成出良好发光强度的PDP用(Y0.6Gd0.3)BO3∶Eu0.1荧光粉。     

FT-IR and Raman spectroscopic study of hydrated rubidium (cesium) borates and alkali double borates

FT-IR and Raman spectra of five hydrated alkali borates and five hydrated alkali double borates have been recorded at room temperature in the range 400 to 4000 cm⁻¹, and analyzed. Fundamental vibrational modes have been identified and assignments tentatively made in comparison with the work of Janda and Heller, and Li Jun. The text was submitted by the authors in English.     

氯化钠在球形纳米氧化铈形成过程中的作用

以水合碳酸铈为原料, 以氯化钠作为助磨剂和阻聚剂, 采用机械活化法制备了球形纳米氧化铈, 用XRD法研究了水合碳酸铈与氯化钠质量比、球磨时间、煅烧温度对CeO2粉体晶粒度的影响, 用TEM对最终产物粒子进行形貌观察. 结果表明: 在碳酸铈的球磨过程及其随后的煅烧过程中, 氯化钠的存在起到了很好的助磨和阻聚作用, 所得CeO2为类球形粒子, 分散性较好, 晶粒度约为30～50 nm.