新型吸附剂——球形碳化树脂的研究Ⅲ.

聚偏二氯乙烯球体经185℃预裂解后,进行960℃高温裂解,得到0.6—0.8mm粒径的球形碳化吸附树脂,碳收率为74％以上。碳化吸附树脂机械强度好,比表面为1,000M~2/g以上,对肌酸酐吸附率可达99％。     

Azobenzene-containing polyamic acid with excellent Langmuir-Blodgett-Kuhn film formation behavior suitable for all-optical switching

To generate command surfaces for all-optical switching, highly ordered polymeric Langmuir-Blodgett-Kuhn (LBK) multilayers were fabricated onto silicon substrates and gold-coated optical glass slides from novel azobenzene-bearing polyamic acid systems. Pronounced Bragg peaks and well-defined Kiessig fringes observed in the X-ray reflectivity measurement for samples on silicon substrates indicate that these films possess a regularly repeated Y-type LBK multilayer structure and ultrasmooth surfaces. Fourier transform infrared (FT-IR) spectra taken by grazing incidence reflection suggest specific orientations of the functional groups in the layers. The excellent film-forming properties of the polyamic acid allow for a smooth buildup of several hundreds of layers of the LBK films onto gold-coated glass slides, which in turn allows for determining the geometrical thickness and the anisotropic refractive indices of the films by using optical waveguide spectroscopy. Interestingly, the probe laser beam induced a distinct fluorescence signal from the films, which remained even after the film underwent a thermal imidization process at 160 degrees C for 8 h in vacuo. LBK films fabricated from these compounds can be successfully applied for all-optically switching the alignment of liquid crystals by irradiation with light of different wavelengths.     

(±)-金锦香酸二甲酯甲醚的合成

本文以呋喃甲酸甲酯为原料, 经羟烷基化反应, 醇解反应和O-甲基化反应合成(±)-金锦香酸二甲酯甲醚。同时, 还发现了制备2-乙烯基呋喃衍生物的新方法。     

两个双核铁（Ⅲ）和三足配体的配合物的合成和晶体结构

运用三足四齿配体三（2－甲基吡啶）胺（TPA）或三（2－甲基苯丙咪唑）胺（TBA）,得到两个双核铁(III)配合物，[Fe₂L₂(μ₂-O)(μ₂-p-NH₂-C₆H₄COO)]³⁺ (L = TPA, 1 和 L = TBA, 2)。两个配合物均为单斜晶系，空间群为P2(1)/c.晶胞参数 1: a = 1.4529(4), b = 1.6622(5), c = 2.0625(6) nm, β= 100.327(5)º, V = 4.900(3) nm³, z = 4, F(000) = 2344, 分子量M_r = 1142.91, Dc = 1.549 g/cm³, R₁ = 0.0544, R₂ = 0.0962. 2: a = 1.3378(4), b = 2.1174(7), c = 2.4351(7) nm, β= 97.315(6)º, V = 6.842(4) nm³, z = 4, F (000) = 3116, 分子量M_r = 1505.08, Dc = 1.444 g/cm³, R₁ = 0.0793, R₂ = 0.1623. 在两个双核铁(III)配合物中，中心的三价铁和配体TPA或TBA上的四个氮原子和两个氧原子通过不同的桥形成一个畸变的八面体构型。     

醇系溶剂中冠醚与碱金属离子的配位反应

The enthalpy changes, entropy changes and equilibrium constants of coordination reactions of 18-crown-6 with the alkali ions Na+ and K+ at 298.15K were measured by using RD-496 microcalorimeter with methanol, ethanol, n-propanol and n-butanol as solvents respectively. The results indicated that the enthalpy changes △rHm, entropy changes △rSm, and the stability of the complexes are closely related with the polarity of the solvents, and the order of the stability is ethanol>methanol>n-propanol>n-butanol>H2O for the same complex in the solvents investigated. The stability order was reasonably explained by relating the stability constants of the complexes with the dielectric constants of these solvents, and by using the model of solvated-desolvated ions and ion pair in the coordination reactions.     

L-脯氨酸催化下甲基酮和1-芳基-2,2,2-三氟乙酮的不对称Aldol反应

Direct asymmetric aldol addition of methyl ketones to 2,2,2-trifluoro-1-phenylethanone and its ring-substituted derivatives was achieved using L-proline as a chiral promoter. Various optically active β-trifluoromethyl-β-hydroxy ketones were obtained in almost quantitative yields with moderate enantioselectivities up to 64 % ee.     

Synthesis,crystal structures and DNA/human serum albumin binding of ternary Cu(II) complexes containing amino acids and 6‐(pyrazin‐2‐yl)‐1,3,5‐triazine‐2,4‐diamino

Two water‐soluble 6‐(pyrazin‐2‐yl)‐1,3,5‐triazine‐2,4‐diamino (pzta)‐based Cu(II) complexes, namely [Cu(l ‐Val)(pzta)(H₂O)]ClO₄ ( 1 ) and [Cu(l ‐Thr)(pzta)(H₂O)]ClO₄ ( 2 ) (l ‐Val: l ‐valinate; l ‐Thr: l ‐threoninate), were synthesized and characterized using elemental analyses, molar conductance measurements, spectroscopic methods and single‐crystal X‐ray diffraction. The results indicated that the molecular structures of the complexes are five‐coordinated and show a distorted square‐pyramidal geometry, in which the central copper ions are coordinated to N,N atoms of pzta and N,O atoms of amino acids. The interactions of the complexes with DNA were investigated using electronic absorption, competitive fluorescence titration, circular dichroism and viscosity measurements. These studies confirmed that the complexes bind to DNA through a groove binding mode with certain affinities (K_b = 4.71 × 10³ and 1.98 × 10³ M^?1 for 1 and 2 , respectively). The human serum albumin (HSA) binding properties of the complexes were also evaluated using fluorescence and synchronous fluorescence spectroscopies, indicating that the complexes could quench the intrinsic fluorescence of HSA in a static quenching process. The relevant thermodynamic parameters revealed the involvement of van der Waals forces and hydrogen bonds in the formation of complex–HSA systems. Finally, molecular docking technology was also used to further verify the interactions of the complexes with DNA/HSA.     

Enantioselective Sulfoxidation Catalyzed by a Bisguanidinium Diphosphatobisperoxotungstate Ion Pair

The first enantioselective tungstate‐catalyzed oxidation reaction is presented. High enantioselectivities were achieved for a variety of drug‐like phenyl and heterocyclic sulfides under mild conditions with H₂O₂, a cheap and environmentally friendly oxidant. Synthetic utility was demonstrated through the preparation of (S)‐Lansoprazole, a commercial proton‐pump inhibitor. The active ion‐pair catalyst was identified to be bisguanidinium diphosphatobisperoxotungstate using Raman spectroscopy and computational studies.     

Fe (III)‐grafted Bi2MoO6 nanoplates for enhanced photocatalytic activities on tetracycline degradation and HMF oxidation

Fe (III)‐grafted Bi₂MoO₆ nanoplates (Fe (III)/BMO) with varying small quantity of Fe (III) clusters modification were fabricated through a simple hydrothermal and impregnation process. The characterization results indicate that the modification of Fe (III) clusters on the surface of Bi₂MoO₆ nanoplates with intimate interfacial contact is beneficial to the expansion of visible light absorption range and the separation of photoinduced carriers during the interface charge transfer process. The photocatalytic properties of the samples were studied by degradation of tetracycline (TC) and selective aerobic oxidation of biomass‐derived chemical 5‐hydroxymethylfuraldehyde (HMF) under visible light. The 1.5 wt% Fe (III) clusters‐grafted Bi₂MoO₆ nanoplates exhibited optimum photocatalytic activity, which is the TC degradation kinetic rate constant is 5.3 times higher than that of bare BMO, and the highest HMF conversion of 32.62% can be obtained with a selectivity of 95.30%. Furthermore, a possible visible light photocatalysis mechanism over Fe (III)/BMO sample has been proposed. This study may supply some insight for the development of visible‐light‐driven Bi₂MoO₆‐based photocatalysts applicable to both environmental remediation and biomass‐derived chemical transformation.     

A mass‐fraction‐based interface‐capturing method for multi‐component flow

An interface‐capturing method based on mass fraction is developed to solve the Riemann problem in multi‐component compressible flow. Equations of mass fraction with modified form, which is derived from conservative equations of mass, are employed here to capture the interface. By introducing mass fraction into Euler equations system, as well as other conservative coefficients, a quasi‐conservative numerical model is created. Numerical examples show that the mass fraction model performs well not only in multi‐component fluids modeled by simple stiffened gas equation of state (EOS) but also in that modeled by complex Mie–Grüneisen EOS. Moreover, the mass fraction model is applied to Riemann problem with piecewise EOS; the expression of which depends on density. It is found that the mass fraction model can well adapt to the analytic change in piecewise EOS and produce accuracy solutions with fewer unknown quantities, and the model can be easily extended to m‐component fluid mixture by using only m + 4 equations with no additional conditions. Copyright © 2013 John Wiley & Sons, Ltd.