Synthesis and properties of sulfur‐contained poly(silylene arylacetylene)s

Poly(silylene arylacetylene) (PSA) is a kind of poly(arylacetylene) silicon‐containing resins with excellent heat resistance and good mechanical performances. In this article, the sulfur atom is introduced into the main chain of the PSA molecule to obtain a sulfur‐containing poly(silylene arylacetylene), named S‐PSA. By Williamson and Sonogashira reactions, bis(4‐ethynylphenyl)sulfide and bis(4‐ethynylphenyl)sulfone were synthesized. Thereafter, through Grignard reagent way, the poly(silylene ethynylene phenylene sulfide phenylene ethynylene) (PSESE) and poly(silylene ethynylene phenylene sulfone phenylene ethynylene) (PSESO₂E) were synthesized from bis(4‐ethynylphenyl)sulfide, bis(4‐ethynylphenyl)sulfone, and methylphenyl dichlorosilane. Poly(silylene ethynylene phenylene sulfoxide phenylene ethynylene) (PSESOE) was synthesized by the oxidation of PSESE. The structures and properties of these resins were characterized and the mechanical properties of the T300 reinforced composites were tested. The results show that the novel S‐PSA resins have excellent heat resistance and good mechanical properties, and could be used as resin matrices for high‐performance composites in high‐tech fields. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2324–2332     

Crystal structures and properties of two hydrated conglomerate forms of the heart‐rate‐lowering agent ivabradine hydrochloride

Ivabradine hydrochloride (IVA‐HCl) (systematic name: {[3,4‐dimethoxybicyclo[4.2.0]octa‐1(6),2,4‐trien‐7‐yl]methyl}[3‐(7,8‐dimethoxy‐2‐oxo‐2,3,4,5‐tetrahydro‐1H‐3‐benzazepin‐3‐yl)propyl]methylazanium), is a novel medication used for the symptomatic management of stable angina pectoris. In many recent patents, it has been claimed to exist in a very large number of polymorphic, hydrated and solvated phases, although no detailed analysis of the structural features of these forms has been published to date. Here, we have successfully crystallized the tetrahydrate form of IVA‐HCl (form β), C₂₇H₃₇N₂O₅⁺·Cl^?·4H₂O, and elucidated its structure for the first time. Simultaneously, a new crystal form of IVA‐HCl, i.e. the hemihydrate (form II), C₂₇H₃₇N₂O₅⁺·Cl^?·0.5H₂O, was discovered. Its crystal structure was also accurately determined and compared to that of the tetrahydrate form. While the tetrahydrate form of IVA‐HCl crystallized in the orthorhombic space group P2₁2₁2₁, the new form (hemihydrate) was solved in the monoclinic space group P2₁. Detailed conformational and packing comparisons between the two forms have allowed us to understand the role of water in the crystal assembly of this hydrochloride salt. The stabilities of the two forms were compared theoretically by calculating the binding energy of the water in the crystal lattice using differential scanning calorimetry (DSC). The stability experiments show that the tetrahydrate is stable under high‐humidity conditions, while the hemihydrate is stable under high‐temperature conditions.     

[2]Pseudorotaxane-Based Supramolecular Optical Indicator for the Visual Detection of Cellular Cyanide Excretion

Cyanide is extremely hazardous to living organisms and the environment. Owing to its wide range of applications and high toxicity, the development of functional materials for cyanide detection and sensing is highly desirable. Host–guest complexation between bis(p-phenylene)-34-crown-10 H and N-methylacridinium salt G remarkably decreases the detection limit for cyanide anions compared with that of the guest itself. The [2]pseudorotaxane selectively recognizes the cyanide anion with high optical sensitivity as a result of the nucleophilic addition of the cyanide anion at the 9-position of G . The host–guest complexation is further incorporated into supramolecular materials for the visual detection of cyanide anions, especially the detection of cellular cyanide excretion with a detection limit of 0.6 μm . This supramolecular method provides an extremely distinct strategy for the visual detection of cyanide anions.     

Two lanthanum(III) complexes containing η2‐pyrazolate and η2‐1,2,4‐triazolate ligands: intramolecular C—H...N/O interactions and coordination geometries

The lanthanum(III) complexes tris(3,5‐diphenylpyrazolato‐κ²N,N′)tris(tetrahydrofuran‐κO)lanthanum(III) tetrahydrofuran monosolvate, [La(C₁₅H₁₁N₂)₃(C₄H₈O)₃]·C₄H₈O, (I), and tris(3,5‐diphenyl‐1,2,4‐triazolato‐κ²N¹,N²)tris(tetrahydrofuran‐κO)lanthanum(III), [La(C₁₄H₁₀N₃)₃(C₄H₈O)₃], (II), both contain La^III atoms coordinated by three heterocyclic ligands and three tetrahydrofuran ligands, but their coordination geometries differ. Complex (I) has a mer‐distorted octahedral geometry, while complex (II) has a fac‐distorted configuration. The difference in the coordination geometries and the existence of asymmetric La—N bonding in the two complexes is associated with intramolecular C—H...N/O interactions between the ligands.     

Construction of a novel ZnCo2O4/Bi2O3 heterojunction photocatalyst with enhanced visible light photocatalytic activity

A novel ZnCo₂O₄/Bi₂O₃ heterojunction photocatalyst was prepared via balling method. The enhanced photocatalytic activity is mainly attributed to the broad photoabsorption and low recombination rate of photogenerated electron-hole pairs, which is driven by the photogenerated potential difference formed at the ZnCo₂O₄/Bi₂O₃ heterojunction interface.     

CO加氢制备低碳烯烃Fe基、Co基催化剂研究进展

CO加氢制备低碳烯烃是非石油路线获得烯烃的重要反应,其反应路线有直接法和间接法。直接法制备低碳烯烃具有反应路线短、能源利用率高、经济高效等优势。综述了近年来Fe基催化剂、Co基催化剂在CO直接制备低碳烯烃中的研究进展。分析认为：费托合成过程产物选择性遵循Anderson-Schulz-Flory（ASF）分布规律,助剂和载体的使用一定程度提高Fe基、Co基催化剂的低碳烯烃选择性。     

基于核酸探针的光学传感方法和细胞成像研究

许多疾病的特征在于各种生物分子表现出的异常活性,这些物质通常在细胞内外显示过表达现象,因此对其灵敏靶向识别可以提供诊断和治疗效用。由于基因诊疗和化学传感技术的发展,用于灵敏检测细胞内外生物化学物质的核酸探针突显优势。核酸探针可以在稳定进入细胞的同时,特异性地结合目标物质,通过光学方法检测或通过成像技术标识出来。本文综述了采用光学传感方法和成像技术,基于核酸探针检测生物分子的新进展。根据检测对象进行分类,概括分析了几个代表性体系:核酸序列、蛋白质和酶、化学物质和物理化学条件,并详细阐述其关键设计原理、灵敏度及样品检测等结果,同时指出了各类核酸探针的优缺点。     

氢在钯单晶表面的解离与在体相的扩散

氢分子在金属表面的解离吸附与氢原子在金属体相的扩散是个典型的表面过程.前者在甲烷化及合成氨等基础化工反应中起着关键作用;后者常常导致金属材料的脆化与断裂,但过渡金属及其合金是安全和优良的储氢材料.因此,研究氢分子在金属表面的解离吸附与氢原子在金属体相的扩散,是多相催化与金属物理广泛感兴趣的课题,具有重要的理论和应用价值.本文采用分子动力学方法初步探讨了二者之间的关联.分子催化动力学为从微观层次上研究上述课题提供了一种理论方法.本文采用经过我们改进的半经验LEPS方法,计算了氢分子在Pd(100)和(110)晶面的解离和氢原子在钯表面与体相扩散的相互作用位能面,并根据计算结果探讨了其微观机理.     

制备方法对MoO_3／ZrO_2结构的影响及MoO_3／ZrO_2固体超强酸的结构特征 Ⅰ．ZrO_2的形态与样品比表面的研究

ＸＲＤ，ＤＴＡ，比表面测定等结果表明，制备方法对ＭｏＯ３／ＺｒＯ２结构有决定性影响．仲钼酸铵浸渍仅经干燥的Ｚｒ（ＯＨ）４再经高温焙烧所得团体超强酸ＭｏＯ３／ＺｒＯ２（Ⅰ）与浸渍晶态ＺｒＯ２所得部分氧化催化剂ＭｏＯ３／ＺｒＯ２（Ⅱ）的载体形态有明显不同．（１）ＭｏＯ３／ＺｒＯ２（Ⅰ）的比表面数倍于ＭｏＯ３／ＺｒＯ２（Ⅱ）；（２）ＭｏＯ３含量增加时，ＭｏＯ３／ＺｒＯ２（Ⅰ）的比表面逐步增大至一极大值再缓缓下降，而ＭｏＯ３／ＺｒＯ２（Ⅱ）的比表面随ＭｏＯ３含量增加而单调下降；（３）在ＭｏＯ３／ＺｒＯ２（Ⅰ）中，ＺｒＯ２以介稳四方相存在，而在ＭｏＯ３／ＺｒＯ２（Ⅱ）中则是稳定的单斜相．在此基础上研究了事先引入的活性组分在载体织构形成过程中的作用，包括延迟ＺｒＯ２晶化，阻碍晶粒长大及与之相关的相变等，并讨论了ＭｏＯ３／ＺｒＯ２（Ⅰ）中ＭｏＯ３最佳含量的科学含义．     

苯酚、马尿酸和甲基马尿酸的反相高效液相色谱分析

本文提出了人体内苯、甲苯和二甲苯的代谢产物苯酚、马尿酸和甲基马尿酸的反相高效液相色谱分析法,讨论了其保留机制和样品预处理技术.以ODS为固定相,甲醇-水-醋酸为流动相时可实现良好分离.方法回收率为97.3%,相对标准偏差为1.02%.提出的方法可用于尿样分析,适用于临床与职业病防治的监测分析.