CRYSTAL AND MOLECULAR STRUCTURE OF 4-CHLORO-5- ETHYL-5-METHYL-3-PHENYL-1, 3, 4-DIAZAPHOSPHOLIDIN-2-THIONE-4-SULFIDE

<正> Crystal of the title compound Mr=304. 80 belongs to the triclinic, space group P1, with a = 7. 282)2), b=9. 064(2), c=11. 737(5) A , α=75. 79 (3), β=78. 70(3), γ=88. 49(2)°, V-736. 21 A3, Z=2, Dx = l. 375 g/cm3. The final refinement is converged with R=0. 062 and Rw= 0. 069.The five-membered heterocycle is in envelope conformation. The P - N bond length (1. 68(1)) indicates that the dπ-Pπ bond between P and N of the title compound is stronger than that of the corresponding 4-phenyl compound.     

Evidence for hydrophobic attraction between latex particles in aqueous systems as investigated by turbidimetry

We report the evidence for attractive interaction of latex particles which are covered by poly(ethylene oxide) chains. These particles are suspended in aqueous solutions of ammonium sulfate. The interaction is probed by measurements of the turbidity of the suspensions up to 70 g/l. Turbidity is insensitive to multiple scattering and allows the static structure factor, S(q) [q=(4πn ₀/λ₀)sin(θ/2), where θ is the scattering angle, n₀ is the refractive index of the medium and λ₀ is the wavelength in vacuo], to be determined at small q values. The analysis of S(q) at small q values yields information about possible attraction of the particles. The analysis of the turbidity data furthermore shows that no aggregation took place in these systems. A weak but long-range attractive interaction was found at ammonium sulfate concentrations of 0.01 and 0.1 M. The relation of this attractive force to hydrophobic forces is discussed. Received: 9 March 2000/Accepted: 28 June 2000     

呋喃基聚酯的结构与性能关系研究进展

呋喃基聚酯是指以2,5-呋喃二甲酸(FDCA)为主要单体合成的生物基或部分生物基高分子,其主链含有刚性的呋喃环,因而在结构、性能上与大规模使用的传统石油基芳香族聚酯(如PET、PBT)相似,有望在瓶、片、薄膜、化纤等领域部分替代后者。本文综述了呋喃基聚酯的分子结构、聚集态结构以及力学、气体阻隔、降解等性能方面的最新研究进展,讨论了结构与性能之间的关系。重点关注呋喃基聚酯突出的阻隔性能及其对应的影响因素,主要从分子结构(呋喃环的非对称性和极性)和聚集态结构(结晶等)两方面加以阐明。简介了呋喃基聚酯的发展现状及其在包装、纺织等领域的潜在应用,并展望其主要研究趋势。     

水凝胶流变学研究概况

水凝胶具有良好的生物相容性和生物可降解性,其结构呈三维网状结构,与细胞外基质相似,在药物释放和组织工程等领域具有广阔的应用前景,被广泛地用于生物制药、生物材料和医学等领域。流变学可以描述材料的流动特性和力学性能,水凝胶的粘弹响应对材料内部结构的变化也非常敏感,因此流变行为被视为研究水凝胶的一种重要方法。本文综述了流变学方法在水凝胶研究中的应用,介绍了水凝胶流变学的研究方法,讨论了影响水凝胶流变学特征的因素,并展望了水凝胶流变学的发展前景。     

The Reaction of Cs2[Tc(NO)F5] with BF3 in Acetonitrile: Formation and Structure of [{Tc(NO)(CH3CN)4}2(μ‐F)](BF4)3

The deep blue, paramagnetic Cs₂[Tc^II(NO)F₅] is formed during reactions of pertechnetate, acetohydroxamic acid, and CsF in aqueous HF. A reaction of Cs₂[Tc(NO)F₅] with BF₃ · MeOH in acetonitrile gives yellow blocks of the fluorido‐bridged dimer [{Tc^I(NO)(CH₃CN)₄}₂F](BF₄)₃. The compound is stable as solid and in acetonitrile solutions. The complex cation contains a bent μ‐F^– ligand and two linear nitrosyl groups.     

N-苯基苯二甲酰亚胺和2-苯基喹噁啉晶态分子动力学行为研究

本文在晶体结构分析的基础上, 对二个芳香杂环高聚物模型化合物N-苯基苯二甲酰亚胺和2-苯基喹噁啉分子的原子热振动参数进行分析, 结果表明N-苯基苯二甲酰亚胺晶态分子基本上为刚性分子, 而2-苯基喹噁啉分子的热振动应包含分子内取代苯基的内旋转运动, 其平均平方振幅为53(25) deg~2。     

测定晶体结构的系统试差法的研究(II)系统位相超解方程得改进

本文证明了|E(k)E(h-k)|的大小是由结构决定的。与原点无关, 在这种认识的基础上, 提出了用归一化结构振幅|E|估量它的三种模式。特别是通过四位相结构不变量的二级Noighborhood~[1,2]原理解决三位相不变量间的匹配问题而算出的|E(k)E(h-k)|_(QE), 这是在没有位相数据的情况下对它的理想的估量。予期它能改进系统试差法中位相超解方程的功能, 提高测得位相的准确性。     

Zur Reaktion eines Bis(amino)germylens mit Germaniumaziden: Abfangreaktionen von instabilen Germa-Iminen

Reaction of a Cyclic Bis(amino)germylene with Germaniumazides: Trapping-Reactions of Unstable Germa-Imines . The cyclic bis(amino)germylene 1 reacts with different germaniumazides of the type Me₂Si(NtBu)₂Ge(R)N₃ (R = Me ( 2 ), tBu ( 3 ), N(SiMe₃)₂ ( 4 ), R = N₃ ( 5 )). With the exception of 4 all azides lose dinitrogen when treated with 1 and the Ge^II center coordinates the α-nitrogen of the azide group. It seems to be reasonable to assume a transient germaimine (nitride) which is trapped by further reaction with the azide molecules 2 and 5 or by reaction with the solvent pyridine ( 3 ). In the case of 2 the germatetrazole [Me₂Si(NtBu)₂]GeN₄[Ge(NtBu)₂SiMe₂]₂ ( 6 ) is formed, the tetrazole nitrogens being exclusively substituted by germanium atoms (point symmetry of the molecule C_s(m)). When 1 is treated with 5 a tris(germa)amine [Me₂Si(NtBu)₂Ge(N₃)]₃N ( 8 ) is formed, which has an azide group attached to each Ge-atom. X-ray analysis reveals that the nine nitrogen atoms of the azide groups are coplanar with the trigonal planar Ge₃N moiety (crystallographic symmetry: 3/m). The reaction of 1 with 3 is very surprising: the pyridine in the product Me₂Si(NtBu)₂Ge(C₅H₄N)? N(H)Ge(tBu)(NtBu)₂SiMe₂ ( 7 ) is bonded via an α-carbon atom while the remaining hydrogen has added to the nitride-nitrogen. 6 crystallizes in the monoclinic system space group C2/m, a = 24.306(9), b = 10.933(6), c = 19.420(9) Å, β = 91.81(2)° and Z = 4. 7 crystallizes in the hexagonal system space group P6₃/m with a = b = 16.73(1), c = 11.006(8) Å, γ = 120° and Z = 2, and 8 crystallizes in the monoclinic system space group P2₁/n, a = 11.341(6), b = 26.086(9), c = 13.244(7) Å, β = 98. I2(2)° mit Z = 4.     

Komplexe von Vanadium und Titan mit Salicylaldehyd-benzoylhydrazon und 2-(2′-Hydroxyphenyl)-chinolin-8-ol. Kristallstruktur von μ-Oxo-bis[oxo{2-(2′-Hydroxyphenyl)-chinolin-8-olato(2-)}-vanadium(V)]

Complexes of Vanadium and Titanium with Salicylaldehyde benzoylhydrazone and 2-(2′-Hydroxyphenyl)-8-quinolinol. Crystal Structure of μ-Oxo-bis[oxo{2-(2′-hydroxyphenyl)-8-quinolinato(2-)}-vanadium(V)] . By reaction of titanium(IV)-isopropoxide and bis(acetylacetonato)-oxovanadium(IV) with salicylaldehyde benzoylhydrazone and 2-(2′hydroxyphenyl)-8-quinolinol, respectively, the metal complexes of the tridentate diacidic ligands were synthesized and characterized mass spectrometrically. The mass spectra of the titanium compounds correspond to the expected bisligand complexes whereas several species are demonstrable in the case of vanadium. Crystals of μ-oxo-bis[oxo{2-(2′-hydroxyphenyl)-8-quinolinolato(2-)}-vanadium(V)] were isolated and characterized by X-ray structural analysis. The complex exhibits C₂ symmetry, accordingly the μ₂-oxygen atom is situated on the 4 axis. The VOV bridge is angular with the unusually small bond angle of 107.3°. The coordination polyhedron is distorted octahedral. The compound additionally contains one molecule of chloroform per formula unit which is disordered in two positions. Crystallographic data see “Inhaltsübersicht”.     

Darstellung und Kristallstruktur von TICu[CuO2]

Investigations on Electronically Conducting Oxide Systems. XVI. Solid Solutions and Conductivity in the System MgTi₂O₅? Ti₃O₅ Solid solution formation is reported for the system Mg_1–xTi_2–x^IVTi_2x^IIIO₅. With increasing x there is at room temperature a transition from the orthorhombic pseudobrookite structure to the monoclinic low-temperature modification of Ti₃O₅. The X-ray diffraction pattern results are supported by DSC measurements, electrical and magnetic investigations. The tendency of Ti? Ti pair formation in the low-temperature Ti₃O₅ structure is accompanied by a drop of the activation energy for electrical conductivity and a decreasing susceptibility at high Ti^III concentrations.