高活性氨基胍树脂负载Pd(0)配合物的催化性能研究

以氨基碳酸胍改性氯球为载体,与氯化钯溶液反应并还原制备氨基胍树脂负载钯(0)催化剂.对催化剂进行了FT-IR,XRD,BET,TG-DTA表征.研究了该催化剂对各种取代卤代苯与丙烯酸、苯乙烯的Heck芳基化反应催化性能.实验结果表明,该催化剂对活性(吸电子基)溴代苯和碘苯具有良好的催化活性,对含活性吸电子基的溴代苯(4-溴苯甲醛和4-溴硝基苯)于140℃时能在22min内完成Heck芳基化反应;催化剂具有较好的重复使用性能,在90℃下催化碘苯与丙烯酸的反应循环21次时仍能保持良好的催化活性.反应机理研究表明:催化反应的活性组分是可溶性钯物种;可溶性钯是由卤代苯与催化剂表面上的钯氧化加成所致.     

Theoretical Analysis of Rayleigh Backscattering Noise in Fiber Raman Amplifiers

In this paper, a new theoretical model for Rayleigh backscattering （RB） analysis of fiber Raman amplifiers is proposed. The model includes all the interactions among the pumps, signals, and all orders of RB. The results show that the higher order RB has a negligible influence on the performance of the amplifier. The co-propagating and counterpropagating RB power of the signal grow quadratically with the net-gain of the amplifier. The signal to double Rayleigh backscattering noise ratio （OSNRDRB ） of backward-pumped FRAs is better than that of the forward-pumped ones at high net-gain level （〉 13 dB）, while at low net-gain level the OSNRDRB of the forward-pumped FRAs is slightly better than that of the backward-pumped ones.     

聚芳酯树枝状分子接枝改性纳米二氧化硅

功能化改性二氧化硅广泛应用于色谱分离、异相催化、酶和蛋白质的固定及高分子复合材料等领域 [1] .通过改性 ,不仅可以使二氧化硅粉体的表面功能化 ,而且可以显著改善纳米二氧化硅在聚合物基体中的分散性和相容性 ,从而提高聚合物基纳米复合材料的综合性能 [2 ] .二氧化硅的表面改性主要涉及表面硅醇基的化学反应和接枝聚合反应 [1] ,所接枝的有机分子一般为线型结构 ,而具有规则枝化结构的树枝状分子近年来也受到了关注 [3～ 8] .Tsubokawa等 [3 ]用发散法将聚酰胺类树枝状高分子 (PAMAM)接枝到了纳米二氧化硅的表面 ,经改性后的产品在…     

Novel Inorganic–Organic Hybrid Coordination Polymer [(C10H16N)3(Ag6I9)] n : Synthesis, Structure and Optical Limiting Effect

A novel 1-D organic–inorganic silver(I)-iodide coordination architecture [(C₁₀H₁₆N)₃(Ag₆I₉)] _n (1) (C₁₀H₁₆N⁺=N-butyl-2-methyl-pyridinium) templated by appropriate cation has been constructed and structurally and optically characterized. The inorganic moiety of 1 presents one-dimensional hackle chain arrangement that results from the edges-sharing of AgI₄ tetrahedrons. Static attracting interactions between organic counter cations and inorganic chains are presented and contribute to the crystal packing. The optical limiting experiment shows that the present polymer exhibits a large optical limiting capacity.     

Si_n(n≤30)团簇光谱与电子性质的密度泛函理论研究

采用密度泛函理论对Sin(5≤n≤30)团簇的吸收光谱,能隙(HOMO-LUMO)及电子性质进行了模拟分析.硅团簇的吸收光谱计算采用含时密度泛函理论的ALDA内核.结果表明,随着Sin(5≤n≤30)团簇尺寸的增大,团簇的吸收光谱逐渐红移,表现出较强的量子尺寸效应.团簇Sin(5≤n≤30)的吸收峰主要集中在红外光区.团簇的吸收峰主要受团簇的原子个数和电子结构影响.     

A Self-Assembled Capsule for Propylene/Propane Separation

The development of energy-saving technology for the efficient separation of olefin and paraffin is highly important for the chemical industry. Herein, we report a self-assembled Fe₄L₆ capsule containing a hydrophobic cavity, which can be used to encapsulate and separate propylene/propane. The successful encapsulation of propylene and propane by the Fe₄L₆ cage in a water solution was documented by NMR spectroscopy. The binding constants K for the Fe₄L₆ cage toward propylene and propane were determined to be (5.0±0.1)×10³ M⁻¹ and (2.1±0.7)×10⁴ M⁻¹ in D₂O at 25 °C, respectively. Experiments and theoretical studies revealed that the cage exhibited multiple weak interactions with propylene and propane. The polymer-grade propylene (>99.5 %) can be obtained from a mixture of propylene and propane by using the Fe₄L₆ cage as a separation material in a U-shaped glass tube. This work provides a new strategy for the separation of olefin/paraffin.     

Synthesis and Crystal Structures of N′-3,5-Dibromo-2-Hydroxybenzylidene)-2-Hydroxy-3-Methylbenzohydrazide and its Oxovanadium(V) Complex [N′-(3,5-Dibromo-2-Oxidobenzylidene-κO)-2-Hydroxy-3-Methylbenzohydrazidato-κ2N′,O](Methanol-κO)(Methanolato-κO)Oxidovanadium(V)

Abstract  

A new hydrazine ligand N′-3,5-dibromo-2-hydroxybenzylidene)-2-hydroxy-3-methylbenzohydrazide (1) and its oxovanadium(V) complex [N′-(3,5-dibromo-2-oxidobenzylidene-κO)-2-hydroxy-3-methylbenzohydrazidato-κ ² N′,O](methanol-κO)(methanolato-κO)oxidovanadium(V) (2), were prepared and were structurally characterized by elemental analysis, IR spectra and single-crystal X-ray diffraction. Compound 1 crystallizes in the triclinic space group P−1, with unit cell dimensions a = 7.813(2) ?, b = 8.748(2), c = 26.071(6) ?, α = 85.763(2)°, β = 81.521(2)°, γ = 89.358(3)°, V = 1757.6(7) ?³, Z = 4, R ₁ = 0.0587, and wR ₂ = 0.1054. Compound 2 crystallizes in the triclinic space group P-1, with unit cell dimensions a = 7.777(3) ?, b = 11.594(3), c = 12.363(3) ?, α = 107.965(3)°, β = 103.190(2)°, γ = 96.656(2)°, V = 1011.3(5) ?³, Z = 2, R ₁ = 0.0634, and wR ₂ = 0.1480. The hydrazine ligand coordinates to the V atom through the phenolic O, imino N, and ethanolic O atoms. The V atom in the complex is in an octahedral coordination, with the three donor atoms of the hydrazine ligand and one methanolato O atom defining the equatorial plane, and with one methanol O and one oxo O atoms occupying the axial positions. The displacement of the V atom from the equatorial plane towards the axial oxo O atom is 0.305(2) ?.     

Fabricating a reactive surface on the fibroin film by a room-temperature plasma jet array for biomolecule immobilization

A simple dielectric barrier discharge(DBD) jet array was designed with a liquid electrode and helium gas.The characteristics of the jet array discharge and the preliminary polymerization with acrylic acid(AA) monomer were presented.The plasma reactor can produce a cold jet array with a gas temperature lower than 315 K,using an applied discharge power between 6 W and 30 W(V dis × I dis).A silk fibroin film(SFF) was modified using the jet array and AA monomer,and the treated SFF samples were characterized by atomic force microscopy(AFM),scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),and contact angle(CA).The deposition rate of the poly acrylic acid(PAA) was able to reach 300 nm/min,and the surface roughness and energy increased with the AA flow rate.The FTIR results indicate that the modified SFF had more carboxyl groups(-COOH) than the original SFF.This latter characteristic allowed the modified SFF to immobilize more quantities of antimicrobial peptide(AP,LL-37) which inhibited the Escherichia coli(E.Coli) effectively.     

滑石粉及混炼顺序对PA6/PP/MAPP合金相形态及力学性能的影响

通过挤出和注射成型制备了滑石粉(Talc)填充的尼龙6/聚丙烯/马来酸酐接枝聚丙烯(PA6/PP/MAPP)合金, 研究了Talc和混炼顺序(一步法和PA6母料法)对合金相形态和力学性能的影响. 场发射扫描电镜(FESEM)分析结果表明, 添加Talc后注射样条中心部分的PP相由球状转变为沿流动方向取向的有分支的条状结构, 且用PA6母料法制样比用一步法制样的相形态更为精细. 溶解PA6相后对PP相进行热重分析(TGA), 确定了Talc在PA6相和PP相中的分布比例, Talc选择性分布于PA6相中. PA6母料法中Talc的分散好于一步法. 研究了材料的拉伸、 弯曲、 冲击、 热变形温度和动态力学性能, Talc的添加能够明显提高材料的刚性, 且母料法样品的性能优于一步法样品.     

“四化”教学在无机化学理论课中的应用实践

在无机化学教学中采用通俗化、系统化、形象化和娱乐化的教学方式,使深奥的理论、抽象的概念变得容易理解和接受,使零散、枯燥的知识变得更易掌握。