活性炭表面固载十二硅钨酸的表征

活性炭表面固载十二硅钨酸的表征王新平，叶兴凯，吴越（中国科学院长春应用化学研究所，长春１３００２２）关键词硅钨酸，杂多酸，活性炭，负载型催化剂，表征由于杂多酸的优异催化性能，近年来其固载化的研究深受人们的关注［１］．活性炭是固载杂多酸较好的载体之一［...     

单臂冠醚液晶LB膜的相变研究

研究了两种单臂冠醚液晶及配合物(1, 2及1.Eu^3^+)的LB膜的成膜特性,实验发出它们均可在气-液界面形成单分子膜, 但不易转移, 化合物1在压膜过程中出现一维相变。用CPK模型对成膜分子构型和面积进行估算, 其结果与实验相一致, 并讨论了冠醚液晶结构对LB膜相变的影响。     

Studies on Liquid/liquid Extraction of Copper Ion with Room Temperature Ionic Liquid

Room temperature ionic liquids are regarded as “Green solvents” for their nonvolatile and thermally stable properties. They are employed to replace traditional volatile organic solvents in organic synthesis, solvent extraction, and electrochemistry. In this work, a water immiscible room temperature ionic liquid, 1‐butyl‐3‐methylimidazolium hexafluorophosphate [C₄mim][PF₆], was used as an alternative solvent for liquid/liquid extraction of copper ions. Metal chelators, including dithizone, 8‐hydroxyquinoline, and 1‐(2‐pyridylazo)‐2‐naphthol, were employed to form neutral metal‐chelate complexes with copper ions so that copper ions were extracted from aqueous solution into [C₄mim][PF₆]. The parameters that affect the extraction of copper ions with this biphasic system were investigated. The extraction behavior in this novel biphasic system is shown to be consistent with that of traditional solvents. For example, the extraction with this biphasic system is strongly pH dependent. So, the extraction efficiency of coppers ion from an aqueous phase can be manipulated by tailoring the pH value of the extraction system. Hence, the extraction, separation and preconcentraction of copper ions can be accomplished by controlling the pH value of the extraction system. It appears that the use of ionic liquid as an alternate solvent system in liquid/liquid extraction of copper ions is very promising.     

Syntheses and Crystal Structures of Cadmium Complexes with Thiophenedicarboxylate and Bipyridine‐like Ligands

Two new coordination polymers [Cd(tdc)(bpy)(H₂O)]_n ( 1 ) and [Cd(tdc)(phen)]_n ( 2 ) (H₂tdc = thiophene‐2,5‐dicarboxylic acid, bpy = 2,2′‐bipyridine and phen = 1,10‐phenanthroline) have been synthesized under hydrothermal condition. Their crystal structures have been established by X‐ray single‐crystal diffraction. Complex 1 crystallizes in the orthorhombic space group Fdd2 with a = 14.757(7), b = 45.38(2), c = 10.518(5) Å, V = 7044(6) ų, Z = 16; 2 in the monoclinic space group P2₁/c with a = 7.262(1), b = 21.970(2), c = 10.051(1) Å, β = 105.01(1)°, V = 1548.8(2) ų, Z = 4. Both of them are double‐stranded chains and further assembled into three‐dimensional networks by π‐π stacking interactions. 1 and 2 are stable in air, and show blue photoluminescence at 415 nm and 410 nm, respectively.     

An annulene-fused cyclopentadienide. A photochromic cyclopentadienodimethyldihydropyrene where the fused cyclopentadienide group resembles benzene in its effect on the dihydropyrene-metacyclophanediene valence isomerization

The synthesis of the green cyclopentadiene-fused dimethyldihydropyrene 12 was achieved in 36% yield in 7 steps from the parent dihydropyrene 3. Reaction of 12 with KH or LiCH(2)SiMe(3) gave the [14]annulene-fused cyclopentadienide anion quantitatively. In the (1)H NMR spectra, the internal methyl protons of 12 at delta -3.9, change dramatically on formation of anion 5, becoming deshielded to delta -1.82. This is caused by the reduction in diatropicity of the [14]annulene ring on fusion to the 6pi-cyclopentadienide ring. The anion is also a photochromic switch. Irradiation of the closed form 5 with visible light opens it to the open form 5', which reverts to the closed form 5 either with UV light or thermally. The switching behavior is between that of the parent 3/3' and the benzannelated system 4/4' and suggests that in its effect on the photoswitching, cyclopentadienide is behaving chemically similar to benzene.     

Anion and Additive Effects on the Structure of Mercury(II) Halides Complexes with Tripodal Ligand

The metal complexes [Hg₂(tbim)₂Br₄]·2DMF ( 1 ) and [Hg₂(tbim)I₄]·1.5DMF ( 2 ) were prepared by reactions of 1,3,5‐tris(benzimidazol‐1‐ylmethyl)‐2,4,6‐trimethylbenzene (tbim) with HgBr₂, HgI₂, respectively, and [Hg₂(tbim)I₄]·0.5(FeCp₂)·H₂O ( 3 ) was obtained by the same method with addition of ferrocene (FeCp₂) as additive. Their structures were determined by X‐ray crystallographic analyses. Complex 1 has a macrocyclic binuclear structure with one benzimidazole arm of the ligand free of coordination and the binuclear units are further connected by C‐H···N hydrogen bonds to give an infinite zigzag chain. Complexes 2 and 3 have a 2D network structure in which tbim serves as a tridentate ligand. The results showed that the halides of bromide and iodide have remarkable impact on the structure of the complexes. The FeCp₂ molecules are trapped in the voids of framework 3 .     

Hydrogenation of nitrobenzenes catalyzed by platinum nanoparticle core-polyaryl ether trisacetic acid ammonium chloride dendrimer shell nanocomposite

Platinum nanoparticle core-polyaryl ether trisacetic acid ammonium chloride dendrimer shell nanocomposites (Pt@G_n-NACl) were prepared and used as catalysts for hydrogenation of nitrobenzenes to anilines with molecular hydrogen under mild conditions. The as-prepared nanoparticles have mean particle size from 2.0 to 5.5 nm, depending on the molar ratio of the metal and the dendrimer. The Pt nanoparticles demonstrate near-monodisperse when the molar ratio of Pt and G₃-NACl is below 30. The interaction among three carboxyl groups terminated at the dendron and the metallic core keeps the Pt nanoparticles from agglomerating. The colloidal solution of Pt nanoparticles stabilized by the dendrimer, in which the molar ratio of Pt/G₃-NACl was less than 60, is stable without precipitation for several weeks. The dendrons attach to the metal core radially, and a substantial fraction of the surface of the metal nanoparticle is unpassivated and available for catalytic reactions. Turnover frequencies for the hydrogenation of nitrobenzenes to anilines change from 353 to 49 h⁻¹ depending on the dendrimer generation and substrates. The dendrimer catalysts are stable during the catalytic hydrogenation process and can be recovered by centrifugation and reused. The results suggest the effectiveness of polyaryl ether trisacetic acid ammonium chloride dendrimer as a stabilizer for the preparation of Pt nanoparticle catalysts.     

Spectrothermal studies of 1,10-phenanthroline complexes of Co(II), NI(II), Cu(II) and Cd(II) orotates

The 1,10-phenanthroline (phen) complexes of Co(II), Ni(II), Cu(II) and Cd(II) orotates were synthesized and characterized by elemental analysis, magnetic susceptibility, spectral methods (UV-vis and FTIR) and thermal analysis techniques (TG, DTG and DTA). The Co(II), Ni(II), Cu(II) and Cd(II) ions in diaquabis(1,10-phenanthroline)metal(II) diorotate octahedral complexes [M(H₂O)₂(phen)₂](H₂Or)₂·nH₂O (M=Co(II), n=2.25; Ni(II), n=3; Cu(II) and Cd(II), n=2) are coordinated by two aqua ligands and two moles of phen molecules as chelating ligands through their two nitrogen atoms. The monoanionic orotate behaves as a counter ion in the complexes. On the basis of the first DTG_max, the thermal stability of the hydrated complexes follows the order: Cd(II), 68°C 68°C     

在线质谱仪在车内VOCs现场快速监测中的应用

挥发性有机物(VOCs)影响车内空气质量和驾乘者的身心健康。自主研发的在线挥发性有机物质谱仪(SPI-MS 2000),实现了有机物分子的单光子电离,产生无碎片的分子离子,可实现秒级响应,仪器的质量分辨率优于800 FWHM,质量精度优于0.02 amu,对甲苯的测定限优于3μg/m^3,且在3~8000μg/m^3范围内有良好的线性关系。将该仪器应用于某客车车内空气的在线检测:在5 s内检测到20多种微克~毫克每立方米量级的有机物。该仪器在车内VOCs现场快速监测方面有广泛的应用前景。