A Study on Relationship Between Gas Chromatographic Retention Value and Atomic Hydrophobic Parameters

A study on relationship between molecular structure and chromatographic retention values for realizing the identification and prediction of chromatographic retention values has been the major task of chromatographic thermodynamics. In 1964, Prof. Lu Peizhang established the relationship between molecular structural parameters and chromatographic retention values in gas-liquid chromatography by using statistical thermodynamical methods. Based on his work, some Chinese researchers have performed the prediction of chromatographic retention values.     

QSRR Study on the Relationship between the Chromatographic Capacity Factor and Lipophilicity and Structure Parameters of Halogenated Thiophenols

The capacity factors (k') of fourteen types of halogenated thiophenols in different phases of methanol-water eluent were determined by reversed phased high-performance liquid chromatography (RP-HPLC) and the relationships between the logarithm of capacity factor lgK' and methanol ratio ψ were analyzed. A fair linear relationship is found between lgK' and ψ, and the correlation coefficients R2 of the constructed linear equations are all greater than 0.990. Relationship between the chromatographic data lgKw' when extrapolated to pure water and n-octanol/water partition coefficient lgKow obtained by the group contribution method has shown a good linear correlation with R2 = 0.956. The structure parameters of fourteen halogenated thiophenols were calculated by using DFT, and the correlation equation of lgKw' and structure parameters was obtained by using SPSS, lgKw' = -0.409 + 0.039α and R2 = 0.981, meaning that lgKw' is mainly determined by the polarizability α.     

Selective Oxidation of Methane to Methanol Using Molecular Oxygen on MoOx／（LaCoO3＋Co3O4） Catalysts

Comparatively high CH3OH selectivity (60.0%) and yield (6.7%) were obtained on MoOx/(LaCoO3 Co3O4) catalysts in selective oxidation of methane to methanol using molecular oxygen as oxidant. The interaction between MoOx and La-Co-oxide modified the molecular structure of molybdenum oxide and the ratio of O^-/O^2- on the catalyst surface, which controlled the catalytic performance of MoOx/(LaCoO3 Co3O4) catalysts.     

Theoretical Calculations of the pKa Values of 1-Aryl-4-0rooylpiperazine Drugs in Aqueous Solution

Theoretical calculations were carried out to predict the aqueous-phase acidities of a series of drug 1-phenyl-4-propylpiperazine and its derivatives. The performances of the density functional theory（DFT） methods B3LYP and B3P86, solvation models[the polarized continuum model（PCM） and the conductor-like polarized conti- nuum model（CPCM）], and the basis set effect were tested. A comparison between the theoretical and experimental pKa values for para-substituted 1-phenyl-4-propylpiperazines reveals that the accuracy of B3LYP is better than that of B3P86, and the basis set 6-31＋＋G（d,p） and the CPCM model are suitable for calculating pKa values of the substituted 1-phenyl-4-propylpiperazine. For the investigated compounds, a reasonable agreement between the experimental and calculated oKo values was also observed.     

3D－QSAR Study on Diindolylmethane and Its Analogues with Comparative Molecular Field Analysis(CoMFA)

Comparative molecular field analysis (CoMFA),a three dimensional quantitative structure-activity relationship (3D-QSAR) method was applied to a series of diindolylmethane(DIM) analogs to study the relationship between their structure and their induction of CYP 1A1-associated ethoxyresorufin-O-deethylase(EROD) activity.A DISCO model of pharmacophore was derved to guide the superposition of the compounds.The coefficient of cross-validation (q^2) and non cross-validation(r^2) for the model established by the study are 0.827 and 0.988 respectively,the value of variance ratio (F) is 103.53 and standard error estimate (SEE)is 0.044.These values indicate that the CoMFA model derived is significant and might have a good prediction for the catalytic activity of DIM compounds.As a consequence,the predicted activity values of new designed compounds were all higher than that of the reported value.     

RECTIFYING EFFECT OF POLYANILINE(PANI)/N-TYPE POROUS SILICONE HETEROJUNCTION*

Heterojunctions between polyaniline (PANI) and n-type porous silicon (PS), Al/PS-PANI/Au cell,were fabricated, and the rectifying parameters of this heterojunction diode were measured as a function of thepreparation conditions of PANI and PS, the electronic structure of PANI as well as cell structure. Therectifying parameters of Al/PS-PANI/Au cell were determined to be γ= 1 .8×10~1～ 1 .0×10~5 for the rectifyingratio at 3V, n = 3 ～12 for the ideal factor,j_0 = 8.0×10~(-5)～5.6×10~(-2) mA/cm~2 for the reversed saturated currentdensity, and φ_b = 0.67～ 0.83 V for the barrier height, respectively. The best rectifying heterojunction diodemade between PANI and n-type PS with higher rectifying factor (γ= 1 .0×10~5 at 3V ), output current (>1500mA/cm~2 at 3V) and lower ideal factor (n = 3.3) was obtained by preventing the oxidation of PS beforeevaporating Al electrode.     

PHASE SEPARATION IN BIMODAL MOLECULAR WEIGHT HIGH DENSITY POLYETHYLENE WITH DIFFERING BRANCH CONTENTS BY MOLECULAR DYNAMICS AND MESODYN SIMULATION

The phase behavior of bimodal molecular weight high density polyethylene(BHDPE) in solid state was investigated.Hildebrand solubility parameters(δ) were calculated for the models of blends of higher molecular weight branch polyethylene(HBPE) with different branch contents and lower molecular weight linear polyethylene(LLPE),by using molecular dynamics(MD) simulations.These 3 values were then used to calculate the corresponding Flory-Huggins interaction parameter(x) between HBPE and LLPE models.In order t...     

Syntheses and Crystal Structures of Two Copper~Ⅱ Complexes with Tetracyanonickelate~Ⅱ

Two copper-nickel complexes, {[Cu(i-Pr3TACN)][Ni(CN)4]}2·2H2O (1) and {[Cu(DACH)][Ni(CN)4]}n (2), have been synthesized by the self-assembly reactions of K2[Ni(CN)4] with CuCl2 and the corresponding chelating ligand 1,4,7-triisopropyl-1,4,7- triazacyclononane (i-Pr3TACN) or 1,4-diazacycloheptane (DACH), respectively. The complexes were structurally characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra and magnetic properties. Complex 1 presents a [2+2] type of molecular square structure and 2 features a 2D β-pucker structure. The magnetic susceptibility measurements reveal a weak antiferromagnetic interaction between the Cu(Ⅱ) ions, with the J values of-22.11 and -32.50 cm-1 for 1 and 2. Moreover, by changing the size of macrocyclic ligands we have successfully constructed two different strictures, which may provide useful information for the construction of the structure.     

Crystal and Molecular Structure of BiCl3(15-Crown-5)

Single crystals of complex BiCl3(15-crown-5) were synthesized by gel method, and the structure was solved from X-ray diffraction data by direct and Fourier methods. The crystal is orthorhombic, space group is P212121 with unit cell parameters:a = 7. 677(4), 6=13. 254(6) and c= 15. 911(6) A , and 2=4. The final structural refinement converged with unweighted and weighted factors of 0. 053 and 0. 063 respectively for 1290 observed reflections. The structure consists of discrete BiCl3(15-crown-5) molecules in which bismuth atom is sandwiched between two essentially parallel planes, one of which contains five oxygen atoms and the other contains three chlorine atoms.     

Pu3M和PuM3 (M=Ga,In, Sn,Ge)化合物的电子结构和形成热

采用全势线性缀加平面波(FPLAPW)方法, 在广义梯度近似(GGA)+自旋轨道耦合(SOC)+自旋极化(SP)下计算了具有AuCu3构型的Pu3M和PuM3 (M=Ga, In, Sn, Ge)化合物的平衡结构、电子结构和形成热. 计算的晶格常数与实验值符合得很好; 态密度分析表明Pu 和M 原子轨道间的杂化作用决定于Pu 6d-Pu 5f、Mp-Pu 6d和Msp-M sp轨道杂化之间的竞争, 而这种竞争又依赖于M的含量; 电负性差和电子杂化效应是影响Pu3M和PuM3化合物形成热和稳定性的两个重要因素, 电负性差越大, M的s、p带中心距费米能级越远, Pu3M(PuM3)化合物的形成热越负, 稳定性越高.     

Spectra analysis of Nd(DBM)3(TPPO)2 in MMA solution and PMMA matrix

The absorption spectra of Nd(DBM)3(TPPO)2 (DBM = dibenzoylmethane; TPPO = triphenylphosphine oxide) in methyl methacrylate (MMA) and polymethyl methacrylate (PMMA) were measured. Slater-Condon parameters (F2, F4, F6), Lander parameter (zeta4f), nephelauxetic effect parameters (beta, delta) and Judd-Ofelt parameters (Omega2, Omega4, Omega6) were calculated on the basis of the absorption spectra. Analysis of the relationship between the structure of rare-earth complexes and the nephelauxetic effect, Judd-Ofelt parameter Omega2 was carried out. The radiative properties of Nd(DBM)3(TPPO)2 in PMMA were also predicted according to the Judd-Ofelt theory. The values of the radiative lifetime and the emission cross-section of 4F3/2 --> 4I11/2 fluorescence transition are comparable with those shown by glasses used in the solid-state laser applications.     

Optical-transition Probability of Tm^3＋ Ions in Tm^3＋／Er^3＋：YVO4 Crystal

1INTRODUCTIONThelasersoperatedataround2mmwavelengthhavegainedmuchinterestbecauseofvariousappli-cations,e.g.(1)groundorspaceremotesensingforLIDARandmetrology,(2)medicalapplicationssinceliquidwaterhasastrongabsorptionbandnear2mm,and(3)eyesafelaser[1,2].The2…     

4-苄基哌啶类拮抗剂选择性识别hCCR3的分子模拟

以牛视网膜紫质X射线衍射晶体结构为模板, 参考定位突变实验数据, 采用配体支持同源模建(Ligand-supported homology modeling)方法构建了拮抗剂键合(Antagonist-bound)的人类趋化因子受体hCCR3和hCCR1的三维结构模型. 将一系列1,4-二取代哌啶类拮抗剂分别对接进优化后的hCCR3和hCCR1模型中, 以配体在hCCR3中的结合自由能理论值对-lgIC₅₀值进行线性回归, 确定性系数r²为0.94. 分析对接结果发现, 配体主要通过疏水芳香作用与hCCR3结合, 而4-苄基哌啶类拮抗剂对hCCR3产生选择性的主要原因在于配体的哌啶环与hCCR3中Tyr255(TM7)的苯酚侧链产生面对面的范德华作用, 而且hCCR3中处于结合口袋的EL2区的疏水性也为拮抗剂对hCCR3的选择性做出了贡献.     

Investigations of the spin-Hamiltonian parameters for Er3+ at the Th4+ site in ThGeO4

The spin-Hamiltonian (SH) parameters g factors g(parallel), g(perpendicular) and the hyperfine structure parameters A(parallel) and A(perpendicular) for Er3+ at the tetragonally distorted dodecahedral Th4+ site in ThGeO4 are theoretically investigated by using the perturbation formulas of the SH parameters for a 4f11 ion in tetragonal symmetry. In these formulas, the contributions to the SH parameters from the second-order perturbation terms and the admixture of various energy levels are taken into account. The related crystal-field parameters are calculated from the geometrical relationship of the impurity center and the superposition model. Based on the studies, the lowest Kramers doublet is found to be Gamma7, rather than Gamma6 suggested in the previous work. The calculated SH parameters for Gamma7 doublet in this work are smaller than those obtained for Gamma6 doublet in the previous work and in good agreement with the observed values. The various contributions to the SH parameters are discussed.     

马来酰胺类糖原合成酶激酶-3β抑制剂的分子对接和三维定量构效关系

通过分子对接和三维定量构效关系(3D-QSAR)两种方法来确定两类马来酰胺类的糖原合成酶激酶-3β(GSK-3β)抑制剂的结合方式. 首先, 用分子对接确定抑制剂与GSK-3β结合模式及其相互作用; 然后用比较分子力场分析法(CoMFA)与比较分子相似性指数分析法(CoMSIA)对48个化合物做三维定量构效关系的分析. 两种方法得出的交互验证回归系数分别为0.669(CoMFA)和0.683(CoMSIA), 证明该模型具有很好的统计相关性, 同时也说明该模型具有较高的预测能力.根据该模型提供的信息, 设计出9个预测活性较好的分子.     

Molecular structure of 3-methylthiophene studied by gas electron diffraction combined with microwave spectroscopic data

The molecular structure of 3-methylthiophene has been determined by gas electron diffraction (GED) combined with microwave (MW) spectroscopic data. Ab initio calculations at the HF/3–21G* level were carried out and used as structural constraints in the data analysis. The torsional vibration of the methyl group was treated as a large-amplitude motion. The structural parameters were determined to be: r_{g(S---C2) = 1.719(2) Å}, r_{g(C2=C3) = 1.370(3) Å}, r_{g(C3---C6) = 1.497(6) Å}, r_{g(C2---H) = 1.101(5) Å}, CSC = 91.6(2)°, SC₂C₃ = 113.3(5)°, SC₅C₄ = 111.3(3)°, C₂C₃C₆ = 123.2(11)° and C₃C₆H = 112(2)°. The values of r(S---C₂) - r(S=C₅) and r(C₂=C₃)-r(C₄ =C₅) were fixed at the 3–21G* value of 0.002 Å. Parenthesized values are the estimated limits of error (3σ) referring to the last significant digit.     

Molecular structure of 3-methylthiophene studied by gas electron diffraction combined with microwave spectroscopic data

The molecular structure of 3-methylthiophene

has been determined by gas electron diffraction (GED) combined with microwave (MW) spectroscopic data. Ab initio calculations at the HF/3–21G* level were carried out and used as structural constraints in the data analysis. The torsional vibration of the methyl group was treated as a large-amplitude motion. The structural parameters were determined to be: r_g(S---C₂) = 1.719(2) Å, r_g(C₂=C₃) = 1.370(3) Å, r_g(C₃---C₆) = 1.497(6) Å, r_g(C₂---H) = 1.101(5) Å, CSC = 91.6(2)°, SC₂C₃ = 113.3(5)°, SC₅C₄ = 111.3(3)°, C₂C₃C₆ = 123.2(11)° and C₃C₆H = 112(2)°. The values of r(S---C₂) − r(S---C₅) and r(C₂=C₃) − r(C₄=C₅) were fixed at the 3–21G* value of 0.002Å. Parenthesized values are the estimated limits of error (3σ) referring to the last significant digit.     

Préparation Chimique,Caracterisation Cristallographique,Etudes Thermique et Vibrationnelle du Cyclotriphosphate Hexahydraté de Manganèse et de Tetra-Argent,MnAg 4 (P 3 O 9 ) 2 .6H 2 O

The cyclotriphosphate hexahydrate of manganese and silver, MnAg 4 (P 3 O 9 ) 2 .6H 2 O, was prepared by Boullé's process. MnAg 4 (P 3 O 9 ) 2 .6H 2 O crystallizes in the triclinic system, P-1, Z = 1 and its structure was determined by Rietveld's method. The refinement of 54 parameters by this method, using 1752 independent reflections leads to Rw p = 0.098, R p = 0.065 and R B = 0.033 on the basis of its isotype NiAg 4 (P 3 O 9 ) 2 .6H 2 O. The unit cell parameters of this salt are the following a = 8.824(1)Å, b = 8.485(1)Å, c = 6.609(1)Å, f = 90.30(1)°;, g = 92.89(1)°; and n = 107.28(1)°;. The thermal behavior of this new compound was studied, between 25 and 600°;C, under atmospheric pressure by infrared spectrometry, X-ray diffraction, thermal analyses TGA and DTA coupled. This study allows us the identification and the crystallographic characterization of a new phase, MnAg 2 (PO 3 ) 4 isotype of ZnRb 2 (PO 3 ) 4 , obtained between 350 and 450°;C, mixed with the long-chain polyphosphate of silver AgPO 3 . The kinetic characteristics of the dehydration of MnAg 4 (P 3 O 9 ) 2 .6H 2 O and the thermal phenomena accompanying this dehydration were determined and discussed on the basis of the proposed crystalline structure. The vibrational spectrum of the, MnAg 4 (P 3 O 9 ) 2 .6H 2 O, was examined and interpreted in the domain of the stretching vibrations of the P 3 O 9 rings, on the basis of the proposed crystalline structure and in the light of the calculation of the thirty fundamental IR frequencies for the idealized D 3h symmetry.