认识孔雀石绿

孔雀石绿具有高残留、高致癌和高致畸性而被禁用于水产养殖和工业染料业,本文综述有关孔雀石绿的分类、结构、性质以及对人体的毒性机理。     

锂离子电池高电压和耐燃电解液研究进展

电解液作为锂离子电池的重要组成部分,起着传输离子的作用,电解液的性质对电池的容量、循环性能及安全性能等影响巨大.近年来,随着高电压、高能量密度锂离子电池的开发应用,现有常规碳酸酯电解液存在正极稳定性差、闪点低、易燃烧等问题.因此,发展高电压耐燃电解液是应用高电压高容量正极材料、发展高电压高容量高安全性锂离子电池的迫切需要.主要综述了高电压电解液、耐燃性电解液及兼具抗氧化性和耐燃性的高浓度电解液的研究进展和现状.在此基础上,对锂离子电池新型电解液的发展方向进行了展望.     

高硒及高硒高维生素E合用对十二月龄大鼠血清MDA和ALT的影响

给动物喂食高Se、高vitaminE、高Se高vitaminE合用饲料 ,探讨单独及合用高Se、高vitaminE对十二月龄动物血清中MDA和ALT的影响。结果显示 ,与对照组比较 ,单独及合用高Se、高vitaminE均可显著降低血清中MDA的含量 (P <0 0 1 ) ,高vitaminE尚能使血清中ALT水平升高 (P <0 0 5 ) ,而高Se高vitaminE合用则可纠正高vitaminE引起的血清中ALT水平的升高     

影响高师生化学学习观形成的心理因素调查分析

高师生要形成积极向上的学习观,离不开心理因素的积极作用。结合调查结果,辩证地分析了影响高师生化学学习观形成的心理因素主要是高师生自身学习心理的因素如学习动机、学习兴趣、学习价值取向和自我专业发展意识等。探讨高师生心理因素对化学学习观的影响,有利于提高高师生化学学习的积极性,从而提高学习效率。     

NEWS

发展高灵敏、高选择性的检测技术用于区分具有生物活性的脂肪族硫醇和高毒性的苯硫酚,在化学、生物、环境领域具有非常重要的意义。台州学院化学系韩得满研究组与华东理工大学药学院邓卫平     

高硒情况下维生素E对幼龄大鼠抗氧化作用的研究

研究了高Se或高维生系E下,幼龄大鼠体内抗氧化活性的变化以及高Se下,维生素E对其体内抗氧化水平的影响。将三月龄Wistar大鼠32只随机分成4组：正常饲料组、高Se高维生素E饲料组、高Se饲料组和高维生素E饲料组。饲至十周末,处死大鼠,按试剂盒要求分别取其血液、心、肝、肾制成标本测SOD、CAT活性及MDA、GSH含量。结果表明,高Se或高维生素E下饲养下的大鼠与对照组比较,血液中SOD活性明显下降;维生素E能明显抑制高Se大鼠血液中SOD活性的下降。结论：单独高Se或高维生素E会降低幼龄大鼠的抗氧化活性,而维生素E能明显提高高Se下幼龄大鼠体内抗氧化活性。     

欧盟REACH法规中钴、砷、铬、锡、铅等高关注物质X射线荧光光谱法定量筛选用橡胶标准样品的研制

<正>欧洲化学品管理署(ECHA)于2008年10月至今已公布8批、共计138种高关注物质(SVHC),包括含钴、砷、铬、锡和铅的高关注物质共30多种物质,它们广泛应用于塑料、橡胶、染料、油漆、涂料等多个领域。因残留在橡胶和塑料制品中的高关注物质危害人类的健康,欧盟REACH法规[1]规定进入欧盟的化学品若高关注物质含量超过0.1%,必须向欧洲化学品管理署通报。X射线荧光光谱法(XRF)由于具有准确度高、     

分子高振动激发态的光谱学和动力学

分子的高振动激发态的研究是深入、细致、准确地认识化学运动规律的重要环节,因此是当前物理化学前沿课题之一。本文介绍以下三方面问题:一、高振动激发态研究的历史及受激辐射泵浦(SEP)技术的基本原理。二、初步介绍规则运动与混沌运动的基本概念,着重讨论了高振动激发态光谱及量子混沌。三、高振动激发态在研究反应速率及反应机理上获得的信息。     

微量元素与食物

含钙高的食物:牛奶、黄豆、乳制品、海参、海带、蚕豆、豆制品、芝麻酱、虾皮、燕麦、小麦、酸奶、牛肉等。含镁高的食物:荷叶、香蕉、黄豆、蕃茄、绿豆、红小豆、蕃石榴、蜂蜜、燕麦等。含锌高的食物:牡蛎、猪肝、鱼类、高锌鸡蛋、板栗、核桃、红枣、黄鳝、海参等。含铁高的食     

用超临界CO_2制备环烯烃共聚物共混物微孔材料

微孔聚合物是80年代初发明的一种新型多孔材料，其特征为泡孔直径1～10μm，泡孔密度10^9～10^1^2cells/cm^3，相对密度0．05～0．95．具有缺口冲击强度高、韧性高、比强度高、疲劳寿命长、热稳定性高、介电常数低和导热系数低等优异性能．同时，制备微孔聚合物使用无公害、易回收的CO2     

Synthesis of propylene carbonate from urea and 1,2-propanediol

The production of propylene carbonate(PC)from urea and 1,2-propanediol(PG)was investigated in a batch process.The catalytic performances of zinc chloride and magnesium chloride were investigated for this reaction system.The influences of various operation conditions on the PC yield were explored.In this work,MgCl_2 and ZnCl_2 showed the excellent catalytic activity toward PC synthesis,and the yields of propylene carbonate reached 96.5%and 92.4%,respectively.The optimum reaction conditions were as follows...     

Mixed-metal sandwich complexes [M(II)2(H2O)2Fe(III)2(P2W15O56)2]14- (M(II) = Co, Mn): synthesis and stability. The molecular structure of [M(II)2(H2O)2Fe(III)2(P2W15O56)2]14-

Two new mixed-metal sandwich complexes [M(II)2(H2O)2Fe(III)2(P2W15O56)2]14- (abbreviated [M2Fe2P4W30], M(II) = Co(II), Mn(II)) were obtained at pH 3 by addition of M2+ to [Na2(H2O)2Fe(III)2(P2W15O56)2]16- (abbreviated [Na2Fe2P4W30]) without substitution in the alpha-[P2W15O56]12- (abbreviated [P2W15]) units. Their X-ray structures are reported. At lower pH, back conversion to [Na2Fe2P4W30] was followed by 31P NMR, electrochemistry and UV-visible spectroscopy. The preparation and the characterization in solution of the lacunary intermediate [NaCo(II)(H2O)2Fe(III)2(P2W15O56)2]15- (abbreviated [NaCoFe2P4W30]) is also described.     

Di- and tricobalt Dawson sandwich complexes: synthesis,spectroscopic characterization,and electrochemical behavior of Na(18)[(NaOH(2))(2)Co(2)(P(2)W(15)O(56))(2)] and Na(17)[(NaOH(2))Co(3)(H(2)O)(P(2)W(15)O(56))(2)

The reaction of the trivacant Dawson anion alpha-[P(2)W(15)O(56)](12-) and the divalent cations Co(2+) is known to form the tetracobalt sandwich complex [Co(4)(H(2)O)(2)(P(2)W(15)O(56))(2)](16-) (Co(4)P(4)W(30)). Two new complexes, with different Co/P(2)W(15) stoichiometry, [(NaOH(2))(2)Co(2)(P(2)W(15)O(56))(2)](18-) (Na(2)Co(2)P(4)W(30)) and [(NaOH(2))Co(3)(H(2)O)(P(2)W(15)O(56))(2)](17-) (NaCo(3)P(4)W(30)), have been synthesized as aqueous-soluble sodium salts, by a slight modification of the reaction conditions. Both compounds were characterized by IR, elemental analysis, and (31)P solution NMR spectroscopy. These species are "lacunary" sandwich complexes, which add Co(2+) cations according to Na(2)Co(2)P(4)W(30) + Co(2+) --> NaCo(3)P(4)W(30) + Na(+) followed by NaCo(3)P(4)W(30) + Co(2+) --> Co(4)P(4)W(30) + Na(+). A Li(+)/Na(+) exchange in the cavity was evidenced by (31)P dynamic NMR spectroscopy. The electrochemical behaviors of the sandwich complexes [(NaOH(2))Co(3)(H(2)O)(P(2)W(15)O(56))(2)](17-) and [(NaOH(2))(2)Co(2)(P(2)W(15)O(56))(2)](18-) were investigated in aqueous solutions and compared with that of [Co(4)(H(2)O)(2)(P(2)W(15)O(56))(2)](16-). These complexes showed an electrocatalytic effect on nitrite reduction.     

Inorganic supramolecular host architectures: [(M@18c6)2][TlI4].2H2O, M=0.5 Tl, (NH4,NH3), (H3O,H2O)

The compounds [(M@18c6)2][TlI4].2H2O, M=Tl, (NH4,NH3), (H3O,H2O) (cubic, Fd; a=1481.00 pm, for M=0.5 Tl, a=1304.65 pm for M=(NH4,NH3), a=1313.67 pm for M=(H3O,H2O)) can be obtained from solution in the presence of traces of transition metal halides (like copper and mercury halides). Apparently the transition metal cations work as a template in the form of tetrahedral [MX4] units during the synthesis of the supramolecular host architecture. That the compounds are versatile host lattices for tetrahedrally coordinated transition metal units becomes obvious by the large group of known host-guest complex compounds, [(MIIX4)(MI@18c6)4][TlX4]2.nH2O (MII=Cu, Co, Zn, Mn; MI=NH4+, Rb, Tl; X=Cl, Br).     

Aqueous speciation studies of europium(III) phosphotungstate

The incorporation of lanthanide ions into polyoxometalates may be a unique approach to generate new luminescent, magnetic, and catalytic functional materials. To realize these new applications of lanthanide polyoxometalates, it is imperative to understand the solution speciation chemistry and its impact on solid-state materials. In this study we find that the aqueous speciation of europium(III) and the trivacant polyoxometalate, PW9O34 9-, is a function of pH, countercation, and stoichiometry. For example, at low pH, the lacunary (PW11O39)7- predominates and the 1:1 Eu(PW11O39)4-, 2, forms. As the pH is increased, the 1:2 complex, Eu(PW11O39)2 11- species, 3, and (NH4)22[(Eu2PW10O38)4(W3O8(H2O)2(OH)4].44H2O, a Eu8 hydroxo/oxo cluster, 1, form. Countercations modulate this effect; large countercations, such as K+ and Cs+, promote the formation of species 3 and 1. Addition of Al(III) as a counterion results in low pH and formation of [Eu(H2O)3(alpha-2-P2W17O61)]2, 4, with Al(III) counterions bound to terminal W-O bonds. The four species observed in these speciation studies have been isolated, crystallized, and characterized by X-ray crystallography, solution multinuclear NMR spectroscopy, and other appropriate tech-niques. These species are 1, (NH4)22[(Eu2PW10O38)4(W3O8(H2O)2(OH)4].44H2O (P; a=20.2000(0), b=22.6951(6), c=25.3200(7) A; alpha=65.6760(10), beta=88.5240(10), gamma=86.0369(10) degrees; V=10550.0(5) A3; Z=2), 2, Al(H3O)[Eu(H2O)2PW11O34].20H2O (P, a=11.4280(23), b=11.5930(23), c=19.754(4) A; alpha=103.66(3), beta=95.29(3), gamma=102.31(3) degrees; V =2456.4(9) A3; Z=2), 3, Cs11Eu(PW11O34)2.28H2O (P; a=12.8663(14), b=19.8235(22), c=21.7060(23) A; alpha=114.57(0), beta=91.86(0), gamma=102.91(0) degrees ; V=4858.3(9) A3; Z=2), 4, Al2(H3O)8[Eu(H2O)3(alpha-2-P2W17O61)]2.29H2O (P; a=12.649(6), b=16.230(8), c=21.518(9) A; alpha=111.223(16), beta=94.182(18), gamma=107.581(17) degrees ; V=3842(3) A3; Z=1).     

Catalytic performance of metal oxides for the synthesis of propylene carbonate from urea and 1,2-propanediol

The influences of acid–base properties of metal oxides on the catalytic performance for synthesis of propylene carbonate from urea and 1,2-propanediol was investigated, and the reaction was stepwise. The amphoteric ZnO showed the best activity, and the yield of propylene carbonate reached 98.9%. The urea decomposition over oxides was characterized by using FTIR. ZnO, CaO, MgO and La₂O₃ were favorable to promote urea decomposition to form the isocyanate species, and the formation of isocyanate species was the key to urea alcoholysis. The catalytic activity of urea decomposition was consistency to the catalytic performance for synthesis of propylene carbonate. Based on these, the probable reaction mechanism was proposed.     

MCF固载离子液体催化CO2合成碳酸丙烯酯的研究

通过原位合成法将[(EtO)3SiPMIm]Cl固载在MCF材料上,制得MCF固载化离子液体催化剂[(EtO)3Si PMIm]Cl/MCF。用N2吸附-脱附、TEM和FT-IR等手段表征催化剂,并考察其在CO2与环氧丙烷(PO)环加成合成碳酸丙烯酯(PC)反应中的催化性能。结果表明,嫁接等量离子液体后,MCF固载化离子液体催化剂体系对CO2环加成合成PC反应的催化活性高于SBA-15催化剂体系。在2.5MPa、140℃反应条件下,PO的转化率高达85.4%,且催化剂具有良好的循环使用性。     

氰根桥联三核异金属配合物的合成、晶体结构及磁性研究

采用[(Tp)Fe(CN)₃]-(Tp=hydrotris(pyrazolyl)borate)与Mn(Ac)₂·4H₂O反应，合成了氰根桥联的异金属三核配合物[Mn(phen)₂][(Tp)Fe(CN)₃]₂·5H₂O (1)(phen=1，10-phenanthroline)，并对其结构和磁性进行了研究。晶体结构分析结果表明该化合物晶体属于三斜晶系，P1空间群。在该配合物中，Mn(Ⅱ)与2个phen分子及2个[(Tp)Fe(CN)₃]^-配位，形成一种弯曲的三核结构。磁性测量结果表明，Mn(Ⅱ)和Fe(Ⅲ)之间通过氰根桥联产生弱的反铁磁相互作用。     

Computational modeling of di-transition-metal-substituted gamma-keggin polyoxometalate anions. Structural refinement of the protonated divacant lacunary silicodecatungstate

The B3LYP density functional method has been validated for the di-Mn-substituted gamma-Keggin polyoxometalate (POM) anion, [(SiO4)MnIII2(OH)2W10O32]4-, and for the divacant lacunary silicodecatungastate, gamma-[(SiO4)W10O32]8-. This approach was shown to adequately describe the geometries of [(SiO4)MnIII2(OH)2W10O32]4- and gamma-[(SiO4)W10O32]8. Three different geometrical models, "full", "medium", and "small", for Mn2-gamma-Keggin have also been validated. It was shown that the medium [(SiO4)MnIII2(OH)2W6O24H8]4- model, as well as small [(SiO4)MnIII2(OH)2W4O18H10]2- model, preserves structural features of the full system, [(SiO4)MnIII2(OH)2W10O32]4-. However, the small model distorts the charge distribution at the "active site" of the system and should be used with caution. The same computational approach was employed to elucidate the structure of the di-Fe-substituted gamma-Keggin POM. The structure of the acidic (tetra-protonated form) of lacunary POM, gamma-[(SiO4)W10O32H4]4-, was shown to be gamma-[(SiO4)W10O28(OH)4]4- with four terminal hydroxo ligands, rather than gamma-[(SiO4)W10O30(H2O)2]4- with two aqua and two oxo(terminal) ligands as reported by Mizuno and co-workers (Science 2003, 300, 964). The observed and calculated asymmetry in the W-O(terminal) bond distances of gamma-[(SiO4)W10O32H4]4- is explained in terms of the existence of O1H1...O2H2 and O4H4...O3H3 hydrogen-bonding patterns in the gamma-[(SiO4)W10O28(OH)4]4- structure.     

A test of the transition-metal nanocluster formation and stabilization ability of the most common polymeric stabilizer, poly(vinylpyrrolidone), as well as four other polymeric protectants

Following an introduction to the nanocluster stabilization literature and DLVO (Derjaugin-Landau-Verwey-Overbeek) theory of colloidal stability, the most common steric stabilizer of transition-metal nanoclusters, poly(vinylpyrrolidone) (PVP), has been examined for its efficacy in the formation, stabilization, and subsequent catalytic activity of prototype, test case Ir(0)n nanoclusters. First, the five criteria established previously for ranking nanocluster protectants for their nanocluster formation and stabilization ability were evaluated for 1 monomer equiv of 10000 average molecular weight (MWav) PVP in the absence, and then presence, of the traditionally weakly coordinating anion BF4- as well as the absence and presence of the strongly coordinating, superior anionic stabilizer P2W15Nb3O62(9-), all in propylene carbonate solvent. It is found that neither 1 equiv of BF4- in propylene carbonate nor 1 monomer equiv of (undried) PVP alone allows for isolable and redissolvable nanoclusters without bulk Ir(0)n metal formation. Careful predrying of the PVP, and by implication other polymers, is shown to be necessary for the formation and stabilization of the nanoclusters. Next, 40 monomer equiv of 10000 MWav PVP and 1 equiv of BF4- in propylene carbonate are shown to allow isolable, redissolvable nanoclusters. Control experiments reveal little difference on nanocluster stabilization by 3500 or 55000 (i.e., vs 10,000) MWav PVP, but yield interesting effects on nanocluster nucleation by the 3500 MWav PVP, as well as by the polymer poly(bis(ethoxy)phosphazene) (PBEP). Four other key polymers reported in the literature to be nanocluster stabilizers are tested by the five criteria method for their efficacy in the formation and stabilization of Ir0n nanoclusters (now in acetone due to the polymers' solubility) and in comparison to each other, specifically, poly(methyl methacrylate) (PMMA), poly(styrene) (PS), poly(methylhydrosilane) (PMHS), and PBEP. Only 40 monomer equiv dried PMMA allows isolable and redissolvable nanoclusters in acetone. Control/reference point experiments show that the electrostatic stabilizer P2W15Nb3O62(9-) is superior to each of the five polymeric stabilizers studied herein in both acetone and propylene carbonate, at least for the test case of Ir(0)n nanoclusters. Further controls show that 40 monomer equiv of PVP added to P2W15Nb3O(62)9--stabilized nanoclusters has no discernible effect on the five criteria other than to reduce by approximately 50% the nanocluster catalytic activity and total catalytic lifetime for cyclohexene hydrogenation. The main finding of this work is that DLVO theory as applied to nanocluster stabilization is fully supported; that is, surface-bound anions in high dielectric constant solvents provide superior stabilization. The importance of even traditionally weakly coordinating anions such as BF4- in nanocluster stabilization is a second, important finding of this work. The fact that HPO4(2-) has been shown to be a simple, cheap, commercially available, thermally robust, and 31P-NMR-handle-containing analogue of the more esoteric P2W15Nb3O62(9-) stabilizer is also discussed in the 14 total Conclusions from this first study ranking polymeric stabilizers of modern transition-metal nanoclusters.