配合物[Li(DME)~3] [(t-BuCp)~2Nd(NPh~2)~2]·1/2 DME的合成及晶体结构

本文合成了配合物[ Li(DME)~3] [(t-BuCp)~2Nd(NP-h~2)~2]·1/2 DME 并测定了其晶体结构. 晶体结构利用Patterson 和Fourier 技术得到, 并经最小二乘法修正.转入各向异性温度因子后, 按理论模型投入所有氢原子坐标, 最后一致性因子R=0.042, Rw=0.040.     

A novel TGS-like inorganic-organic hybrid and a preliminary investigation of its possible ferroelectric behavior

The homochiral inorganic-organic hybrid compound (H(3)NHPA)(SnCl(3))(2)(H(2)O)(3) [1, (S)-4-(4'-aminophenyl)-2-aminobutanoic acid diammonium trichloride stannite triaqua] has a TGS (triglycine sulfate)-like structure. Preliminary investigation suggests a possible ferroelectric behavior with a saturation spontaneous polarization (P(s)) of ca. 3.5 microC.cm(-)(2), which is slightly greater than that of TGS (P(s) = 3.0 microC.cm(-)(2)).     

氦-3熔化压力方程

在广泛收集实验数据和理论关联式的基础上,提出了低温流体3He的宽温区、高精度熔化压力方程。该方程采用国际标准单位制,首次以统一而非分段的形式描述了3He在0．001 K-30 K宽温区熔化压力与温度的关系,方程计算值相对于406个实验数据点的最大和平均偏差分别为3．02％和0．106％。计算表明,该方程在0．31586 K时存在最小压力 2．93113 MPa,这一结论与以往的实验和理论研究非常吻合。     

夹心杂多化合物的合成及晶体结构

PW~9O~3~4^9^-(简写PW~9)阴离子可以与Sn^4^+反应生成[Sn~3^I^V(PW~9O~3~4)~2]^6^-杂多化合物。标题化合物经元素分析、红外、极谱、^3^1P和^1^8^3W核磁共振谱、X射线光电子能谱及X射线单晶测定了结构。K~5O~4Na~4H~5[Sn~3(PW~9O~3~4)~2].16H~2O的单晶是单斜晶系,空间群P2~1/n,晶胞参数a=1.3625(3)nm,b=2.3625(5)nm,c=2.9306(6)nm,α=90ⅲ,β=99.67(3)ⅲ,γ=90ⅲ,V=9.299nm^3,Z=4。它是一种三个Sn^4^+在两个PW~9单元间的夹心结构。     

甘草次酸衍生物的合成

豆科植物甘草中含有大量甘草次酸(Glycyrrhetinic Acid)。近代药理实验表明,甘草的抗炎症、抗溃疡以及抗变态反应等功效,主要归因于甘草中所含的甘草甜素,甘草次酸及其衍生物。多年来,国内外学者对甘草次酸     

三(3-羟基黄酮)合铝(Ⅲ)的合成及晶体结构

合成了三(3-羟基黄酮)合铝(Ⅲ),制得[Al(C₁₅H₉O₃)₃]₂·2CHCl₃·8H₂O晶体,X射线衍射结果表明:其结构属于三方晶系,空间群为R3.晶胞参数:a=b=1.6558(3)nm,c=3.6465(20)nm,α=β=90°,γ=120°,V=8.65608(0.00586)nm₃,D_c=1.45g/cm³,μ(MoKα)=3.20cm^-1,F(000)=3924.分子中每个3-羟基黄酮以其独特的酮基和羟基同时与Al³⁺配位,3个配体中的6个配位氧原子形成扭曲的配位八面体.     

GaAs-Based Metamorphic Long-Wavelength InAs Quantum Dots Grown by Molecular Beam Epitaxy

A bilayer stacked InAs/GaAs quantum dot structure grown by molecular beam epitaxy on an In0.05Ga0.95As metamorphic buffer is investigated. By introducing a InGaAs：Sb cover layer on the upper InAs quantum dots （QDs） layers, the emission wavelength of the QDs is extended successfully to 1.533 μm at room temperature, and the density of the QDs is in the range of 4× 10^9-8 ×10^9cm^-2. Strong photoluminescence （PL） intensity with a full width at half maximum of 28.6meV of the PL spectrum shows good optical quality of the bilayer QDs. The growth of bilayer QDs on metamorphic buffers offers a useful way to extend the wavelengths of GaAs-based materials for potential applications in optoeleetronic and quantum functional devices.     

General Sobolev type inequalities for symmetric forms

A general Sobolev type inequality is introduced and studied for general symmetric forms by defining a new type of Cheeger's isoperimetric constant. Finally, concentration of measure for the Lp type logarithmic Sobolev inequality is presented.     

非结合非分配的环(Ⅰ)

本文抛弃通常用元素满足一些特定等式来定义环的观念,而用特定点集满足一些特定点集所包含的关系式来引进环的概念,从而定义了非结合非分配的环,它包含通常的各种环类,此外,本文还对非结合非分配环建立了理想理论。     

Noncentrosymmetric organic solids with very strong harmonic generation response

The molten reaction of 2-naphthol, 4-(aminomethyl)pyridine, and 4-pyridinecarboxaldehyde at about 180 degrees C yields trans-2,3-dihydro-2,3-di(4'-pyridyl)benzo[e]indole (1) which possesses two chiral centers, rather than an expected Betti-type reaction product with only one chiral carbon center. The same reactions, using 3-pyridinecarboxaldehyde, 4-cyanobenzaldehyde, or 3- cyanobenzaldehyde instead of 4-pyridinecarboxaldehyde produce the related compounds trans-2,3-dihydro-2-(4'-pyridyl)-3-(3"-pyridyl)benzo[e]indole (2), trans-2,3-dihydro-2-(4'-pyridyl)-3-(4"-cyanophenyl)benzo[e]indole (3), and trans-2,3-dihydro-2-(4'-pyridyl)-3-(3"-cyanophenyl)benzo[e]indole (4), respectively. This reaction proceeds with a high degree of stereoselectivity with a trans/cis ratio of about 98:2 at elevated temperature. Compounds 1, 2, and 4 crystallize in a noncentrosymmetric space group (Pca2(1), Pca2(1), and Cc), while compound 3 has a chiral space group (P2(1)). These successfully acentric packing arrangements are probably due to the molecule bearing both two chiral centers and potential hydrogen-bonding groups. Furthermore, the reaction of racemic 6-hydroxy-2'-methyl-2-naphthaleneacetic acid with ethyl-2-cyano-1-(4'-pyridyl)acrylic acetate in the presence of piperidine gives 1-pyridyl-2-ethoxycarbonyl-3-amino-1H-naphtho[2,1-b]pyran-2'-methylacetic acid (5), which likewise crystallizes in a chiral space group. All of compounds are second harmonic generation (SHG) active, and have a very strong SHG response approximately about 8.0, 5.0, 12.0, 6.0, and 1.4 (for 1-5 compounds) times that of urea. Ferroelectric property measurements indicate that compounds 1, 2, 4, and 5 may display ferroelectric behavior.