超价化合物NLin+4和OLin+4电子结构和性质

以6-3lG·基组利用HF、MP2和DFT方法优化了超价化合物NLin+4和OLn+4的几何构型.研究结果表明,MP2和DFT法计算出的OLi4分子解离出Li和Li2的反应能与已有的实验值吻合.对于NLi4分子,得到其解离出Li和Li2的反应能分别为191.78和515.37 kJ/mol(MP2值).并预测了OLin+4和NLin+4分子的基振动频率.     

2-乙酰吡啶吖嗪及其与Co2+、Ni2+、Fe3+、Zn2+配合物的合成和生物活性

过渡金属;超氧离子;白血病;肺癌;2-乙酰吡啶吖嗪及其与Co2+、Ni2+、Fe3+、Zn2+配合物的合成和生物活性     

Ce3+-Yb3+共掺CaF2纳米粒子的近红外发光

采用简单的水热方法制备了一系列Ce3+ -Yb3+共掺的CaF2纳米粒子.XRD测试结果表明,Ce3+和Yb3+不同掺杂浓度下的CaF2纳米粒子结晶良好.SEM和TEM分析表明,纳米粒子的平均粒径为30 nm左右.系统地研究了各样品的发光性质包括激发谱、紫外-可见发射谱、近红外发射谱和荧光寿命.激发Ce3+的5d能级,在900 ～ 1050 nm波长范围得到很强的近红外发射.随着Yb3离子浓度的增加,Ce3的发射强度降低,Yb3+的发射强度先升高后降低,Ce3+的寿命减少,能量传递效率增加.作为一个下转换光转换器,这种材料应用于硅基太阳能电池前端,能够减少电池热损失,增加电池转换效率.     

过渡金属催化[2 + 2 + 2]环加成反应合成吡啶衍生物

环加成反应可以一步同时构建多个化学键,是目前国内外研究最为活跃的领域之一。相比于传统方法,过渡金属催化的[2+2+2]环加成反应是合成吡啶衍生物的有效手段。本文从反应机理、非手性吡啶化合物合成和手性吡啶化合物合成三个方面阐述了近年来吡啶衍生物的研究情况,涉及Co、Rh、Ru、Fe、Ni、Ti等金属催化体系。     

激光等离子体反应生成的AgP+n、AumP+n的结构分析

原子簇化合物的合成方法,由于条件限制,只有B、C、St等非金属元素与过渡金属袈基化合物等较为成熟．贵金属原子簇的合成则较困难．然而,应用激光等离子体反应,可使周期表内几乎所有元素都生成原子簇,为原子簇的生成与研究提供了一条新途径．该方法生成的原子簇在飞行时间质谱仪上可记录到一系列信号,某些信号呈现区域极大（或被称为‘匈数’吵］．郑兰芬等用纯化的红磷粉分别与金粉、银粉混合,在激光等离子作源飞行时间质谱仪上得到一系列谱图【2］：ig与P作用只得到单核xg与P形成的lgy：iE离子簇．谱图较简单,＊沪X最大可达叱叱…     

Li+共掺杂对Er3+-Yb3+∶TiO2紫外、可见和红外发光同步增强研究

采用溶胶-凝胶(Sol-gel)法制备了Li+共掺杂的Er3+-Yb3+∶TiO2粉末。976 nm激光激发下在波长350~1700 nm范围内观察到了紫外、蓝色、绿色和红色上转换发光和红外下转换发光。随着Li+共掺杂浓度由0增大到20mol%,Er3+-Yb3+∶TiO2的紫外、可见和红外发光强度同步增强。低Li+共掺杂浓度引起的Li+固溶以及高Li+共掺杂浓度引起的相变过程相继破坏了Er3+的晶体场对称性,导致紫外、可见和红外发光显著增强。结果表明共掺杂Li+是一种提高Er3+掺杂材料发光性能的有效方法。     

Cu2+-壳聚糖螯合物及壳聚糖吸附Cu2+机理的XPS研究

吸附机理;XPS;Cu2+-壳聚糖螯合物及壳聚糖吸附Cu2+机理的XPS研究     

Li+共掺杂对Er3+-Yb3+:TiO2紫外、可见和红外发光同步增强研究

采用溶胶-凝胶(Sol-gel)法制备了Li+共掺杂的Er3+-Yb3+:TiO2粉末.976 nm激光激发下在波长350～1700nm范围内观察到了紫外、蓝色、绿色和红色上转换发光和红外下转换发光.随着Li+共掺杂浓度由0增大到20mol%,Er3+-Yb3+:TiO2的紫外、可见和红外发光强度同步增强.低Li+共掺杂浓度引起的Li+固溶以及高Li+共掺杂浓度引起的相变过程相继破坏了Er3+的晶体场对称性,导致紫外、可见和红外发光显著增强.结果表明共掺杂Li+是一种提高Er3+掺杂材料发光性能的有效方法.     

分子离子NO+激发态的势能函数

100公里以上的大气分子离子主要为NO~+。它的辐射特点及它与电子、原子或分子的相互作用,对于理解大气的化学过程具有特别重要的意义。为了研究这些过程,确定NO~+分子离子基态及其各个激发态的分子势能函数是非常重要的。精确的X~1Σ~+,A~1Ⅱ和a~3∑~+势能曲线已发表;基于光电子谱的研究发现了NO~+的其它激发态,但对于这些激发态的研究尤其是势能函数的研究不多。本文研究并导出NO~+的基态和10个激发态的势能函数。     

改性花生壳对Cu2+的吸附

以农林废弃物花生壳作为吸附剂对废水中的Cu2+进行吸附.结果表明,花生壳的最佳改性方法为KMnO4改性法.在50mLCu2+浓度为10mg/L的水样中,改性花生壳的最佳吸附条件为:298K下投加4mesh筛上改性花生壳0.8g,pH=5,吸附75min,此时改性花生壳对Cu2+吸附率高达96.80％.KMnO4改性花生壳对Cu2+的吸附以Langmuir方程拟合更佳.     

Isopiestic Study of Water + Mannitol(sat) + Sodium Chloride + Ammonium Chloride + Barium Chloride at <Emphasis Type="Italic">T</Emphasis> = 298.15 K and Comparison with the Ideal-Like Solution Model

Isopiestic measurements have been carried out at the temperature 298.15 K for the quinary system (water + mannitol(sat) + sodium chloride + ammonium chloride + barium chloride) saturated with mannitol and its ternary sub-systems (water + mannitol(sat) + sodium chloride), (water + mannitol(sat) + ammonium chloride) and (water + mannitol(sat) + barium chloride). Taking aqueous sodium chloride as reference solutions, osmotic coefficients of the other aqueous solutions were determined. The experimental results show that the isopiestic activities of the quinary system in relation to its ternary sub-systems are in excellent agreement with the ideal-like solution model.     

四元轻稀土硝酸盐水溶液体系{H2O+La(NO3)3+Pr(NO3)3+Nd(NO3)3}的热力学研究

在298.15 K条件下, 利用等压法研究了四元轻稀土硝酸盐水溶液{H2O La(NO3)3 Pr(NO3)3 Nd(NO3)3}及其3个二元亚系{H2O La(NO3)3}, {H2O Pr(NO3)3}和{H2O Nd(NO3)3}的热力学性质. 以NaCl或CaCl2水溶液为参考溶液, 测定了不同水活度条件下该四元溶液的渗透系数及各溶质组元的活度系数. 实验结果表明, 上述四元系与其3个二元亚系之间存在简单共性, 在实验误差允许范围之内(|Δ|≤0.0010), 该四元系符合偏理想溶液模型.     

Hexavalent chromium recovery by liquid-liquid extraction with tributylphosphate from acidic chloride media.

A method is introduced for recuperation of chromium(VI) in water samples by liquid-liquid extraction with tributylphosphate PO(C4H9O)3 (TBP) from acidic chloride media. The optimum conditions for quantitative extraction of Cr(VI) were evaluated by varying the experimental parameters, such as the shaking period, the pH of the aqueous phase, the hydrochloric acid concentration, the hydrogen and chloride ion concentrations, the extractant concentration and the ratio of aqueous-to-organic phase. The probable extracted species of hexavalent chromium in organic phase, deduced from log-log plots, were H2CrO4 in acid media in absence of chloride and HCrO3Cl in acidic chloride media. Chromium(VI) was found to be extracted with tributylphosphate from acidic chloride media according to the following reaction: HCrO4-(aq), + 2H+(aq) + Cl-(aq) + 2TBP(org) <==> [HCrO3Cl, 2TBP](org) + H2O(aq). Since the tributylphosphate (TBP) exhibited a high selectivity for chromium(VI), this method can be applicable to the extraction and the determination of chromium in both oxidation states [Cr(VI) and Cr(III)] in water samples.     

五元交互体系Li+,Na+,K+//CO32-,Cl--H2O在298.15K的相平衡研究

针对西藏扎布耶盐湖卤水组成,采用等温溶解平衡法研究了五元交互体系Li+,Na+,K+//CO32-,Cl--H2O于298.15K时的相平衡,并绘制了相图(空间立体图和Li2CO3饱和的投影图).结果表明,该五元体系相图含有7个结晶区、13条单变量线和4个无变量点.7个结晶区由6个单盐结晶区和1个复盐结晶区组成,分别为LiCl·H2O,NaCl,KCl,Li2CO3,K2CO3·3/2H2O,Na2CO3·10H2O和NaKCO3·6H2O,没有形成固溶体和天然碱(Na2CO3·NaHCO3·2H2O).4个无变量点标记成K1,K2,K3和K4,所对应的平衡固相盐分别是:Li2CO3+NaKCO3·6H2O+Na2CO3·10H2O+KCl,Li2CO3+NaKCO3·6H2O+K2CO3·3/2H2O+KCl,Li2CO3+NaCl+KCl+LiCl·H2O和Li2CO3+NaCl+Na2CO3·10H2O+KCl.     

Density functional theory-based prediction of the formation constants of complexes of ammonia in aqueous solution: indications of the role of relativistic effects in the solution chemistry of gold(I)

A prediction of the formation constants (log K1) for complexes of metal ions with a single NH3 ligand in aqueous solution, using quantum mechanical calculations, is reported. DeltaG values at 298 K in the gas phase for eq 1 (DeltaG(DFT)) were calculated for 34 metal ions using density functional theory (DFT), with the expectation that these would correlate with the free energy of complex formation in aqueous solution (DeltaG(aq)). [M(H2O)6]n+(g) + NH(3)(g) = [M(H2O)5NH3]n+(g) + H2O(g) (eq 1). The DeltaG(aq) values include the effects of complex changes in solvation on complex formation, which are not included in eq 1. It was anticipated that such changes in solvation would be constant or vary systematically with changes in the log K(1) value for different metal ions; therefore, simple correlations between DeltaG(DFT) and DeltaG(aq) were sought. The bulk of the log K1(NH3) values used to calculate DeltaG(aq) were not experimental, but estimated previously (Hancock 1978, 1980) from a variety of empirical correlations. Separate linear correlations between DeltaG(DFT) and DeltaG(aq) for metal ions of different charges (M2+, M3+, and M4+) were found. In plots of DeltaG(DFT) versus DeltaG(aq), the slopes ranged from 2.201 for M2+ ions down to 1.076 for M4+ ions, with intercepts increasing from M2+ to M4+ ions. Two separate correlations occurred for the M3+ ions, which appeared to correspond to small metal ions with a coordination number (CN) of 6 and to large metal ions with a higher CN in the vicinity of 7-9. The good correlation coefficients (R) in the range of 0.97-0.99 for all these separate correlations suggest that the approach used here may be the basis for future predictions of aqueous phase chemistry that would otherwise be experimentally inaccessible. Thus, the log K1(NH3) value for the transuranic Lr3+, which has a half-life of 3.6 h in its most stable isotope, is predicted to be 1.46. These calculations should also lead to a greater insight into the factors governing complex formation in aqueous solution. All of the above DFT calculations involved corrections for scalar relativistic effects (RE). Au has been described (Koltsoyannis 1997) as a "relativistic element". The chief effect of RE for group 11 ions is to favor linear coordination geometry and greatly increase covalence in the M-L bond. The correlation for M+ ions (H+, Cu+, Ag+, Au+) involved the preferred linear coordination of the [M(H2O)2]+ complexes, so that the DFT calculations of DeltaG for the gas-phase reaction in eq 2 were carried out for M = H+, Cu+, Ag+, and Au+. [M(H2O)2]+(g) + NH3(g) = [M(H2O)NH3]+(g) + H2O(g) (eq 2). Additional DFT calculations for eq 2 were carried out omitting corrections for RE. These indicated, in the absence of RE, virtually no change in the log K1(NH3) value for H+, a small decrease for Cu+, and a larger decrease for Ag+. There would, however, be a very large decrease in the log K1(NH3) value for Au(I) from 9.8 (RE included) to 1.6 (RE omitted). These results suggest that much of "soft" acid behavior in aqueous solution in the hard and soft acid-base classification of Pearson may be the result of RE in the elements close to Au in the periodic table.     

Density functional theory-based prediction of some aqueous-phase chemistry of superheavy element 111. Roentgenium(I) is the "softest" metal ion

A previous approach (Hancock, R. D.; Bartolotti, L. J. Inorg. Chem. 2005, 44, 7175) using DFT calculations to predict log K1 (formation constant) values for complexes of NH3 in aqueous solution was used to examine the solution chemistry of Rg(I) (element 111), which is a congener of Cu(I), Ag(I), and Au(I) in Group 1B. Rg(I) has as its most stable presently known isotope a t(1/2) of 3.6 s, so that its solution chemistry is not easily accessible. LFER (Linear free energy relationships) were established between DeltaE(g) calculated by DFT for the formation of monoamine complexes from the aquo ions in the gas phase, and DeltaG(aq) for the formation of the corresponding complexes in aqueous solution. For M2+, M3+, and M4+ ions, the gas-phase reaction was [M(H2O)6]n+(g) + NH3(g) = [M(H2O)5NH3]n+(g) + H2O(g) (1), while for M+ ions, the reaction was [M(H2O)2]+(g) + NH3(g) = [M(H2O)NH3]+(g) + H2O(g) (2). A value for DeltaG(aq) and for DeltaE for the formation of M = Cu2+ in reaction 1, not obtained previously, was calculated by DFT and shown to correlate well with the LFER obtained previously for other M2+ ions, supporting the LFER approach used here. The simpler use of DeltaE values instead of DeltaG(aq) values calculated by DFT for formation of monoamine complexes in the gas phase leads to LFER as good as the DeltaG-based correlations. Values of DeltaE were calculated by DFT to construct LFER with M+ = H+, and the Group 1B metal ions Cu+, Ag+, Au+, and Rg+, and with L = NH3, H2S, and PH3 in reaction 3: [M(H2O)2]+(g) + L(g) = [M(H2O)L]+g) + H2O(g) (3). Correlations involving DeltaE calculated by DMol3 for H+, Cu+, Ag+, and Au+ could reliably be used to construct LFER and estimate unknown log K1 values for Rg(I) complexes of NH3, PH3, and H2S calculated using the ADF (Amsterdam Density Functional) code. Log K1 values for Rg(I) complexes are predicted that suggest the Rg(I) ion to be a very strong Lewis acid that is extremely "soft" in the Pearson hard and soft acids and bases sense.     

The effect of salt on protein chemical potential determined by ternary diffusion in aqueous solutions

We use accurate thermodynamic derivatives extracted from high-precision measurements of the four volume-fixed diffusion coefficients in ternary solutions of lysozyme chloride in aqueous NaCl, NH4Cl, and KCl at pH 4.5 and 25 degrees C to (a) assess the relative contributions of the common-ion and nonideality effects to the protein chemical potential as a function of salt concentration, (b) compare the behavior of the protein chemical potential for the three salts, which we found to be consistent with the Hofmeister series, and (c) discuss our thermodynamic data in relation to the dependence of the protein solubility on salt concentration. The four diffusion coefficients are reported at 0.6 mM lysozyme chloride and 0.25, 0.5, 0.9, 1.2, and 1.5 M KCl and extend into the protein-supersaturated region. The chemical potential cross-derivatives are extracted from diffusion data using the Onsager reciprocal relation and the equality of molal cross-derivatives of solute chemical potentials. They are compared to those calculated previously from diffusion data for lysozyme in aqueous NaCl and NH4Cl. We estimate the effective charge on the diffusing lysozyme cation at the experimental concentrations. Our diffusion measurements on the three salts allowed us to analyze and interpret the four diffusion coefficients for charged proteins in the presence of 1:1 electrolytes. Our results may provide guidance to the understanding of protein crystallization.     

水合偏硼酸钾的热化学研究

Hydrated potassium monoborate(KBO₂·4/3H₂O) was obtained from an aqueous solution in a mole ratio of K₂O∶B₂O₃=2∶1 and characterized by powder X-ray diffraction(XRD)， infrared spectroscopy(FT-IR) and Raman spectroscopy. The enthalpy of solution of hydrated potassium monoborate， KBO₂·4/3H₂O， in approximately 1mol·dm^-3 aqueous hydrochloric acid was determined. Together with the previously determined enthalpies of so-lution of H₃BO₃ in approximately 1mol·dm^-3 HCl(aq) ，and of KCl in aqueous(hydrochloric acid+boric acid)， the standard molar enthalpy of formation of -(1411.11±0.84)kJ·mol^-1 for KBO₂·4/3H₂O was obtained from the standard molar enthalpies of formation of KCl(s)， H₃BO₃(s)， and H₂O(l). The standard molar entropy of formation of -422.94J·K^-1·mol^-1 and standard molar entropy of 163.47J·K^-1·mol^-1 for KBO₂·4/3H₂O were calculated from the thermodynamic relations. A group contribution method is applicable to KBO₂·4/3H₂O.     

Acid-catalyzed oxidation of iodide ions by superoxo complexes of rhodium and chromium

Superoxometal complexes L(H(2)O)MOO(2+) (L = (H(2)O)(4), (NH(3))(4), or N(4)-macrocycle; M = Cr(III), Rh(III)) react with iodide ions according to the stoichiometry L(H(2)O)MOO(2+) + 3I(-) + 3H(+) --> L(H(2)O)MOH(2+) + 1.5I(2) + H(2)O. The rate law is -d[L(H(2)O)MOO(2+)]/dt = k [L(H(2)O)MOO(2+)][I(-)][H(+)], where k = 93.7 M(-2) s(-1) for Cr(aq)OO(2+), 402 for ([14]aneN(4))(H(2)O)CrOO(2+), and 888 for (NH(3))(4)(H(2)O)RhOO(2+) in acidic aqueous solutions at 25 degrees C and 0.50 M ionic strength. The Cr(aq)OO(2+)/I(-) reaction exhibits an inverse solvent kinetic isotope effect, k(H)()2(O)/k(D)2(O) = 0.5. In the proposed mechanism, the protonation of the superoxo complex precedes the reaction with iodide. The related Cr(aq)OOH(2+)/I(-) reaction has k(H)2(O)/k(D)2(O) = 0.6. The oxidation of (NH(3))(5)Rupy(2+) by Cr(aq)OO(2+) exhibits an [H(+)]-dependent pathway, rate = (7.0 x 10(4) + 1.78 x 10(5)[H(+)])[Ru(NH(3))(5)py(2+)][Cr(aq)OO(2+)]. Diiodine radical anions, I(2)(*)(-), reduce Cr(aq)OO(2+) with a rate constant k = 1.7 x 10(9) M(-1) s(-1).     

普钙-脲-水复合肥料体系的等温溶度研究

从发展复合肥料出发,研究了ＣａＳＯ－Ｃａ（Ｈ２ＰＯ４）２Ｈ２Ｏ体系及其三元边界体系Ｃａ（Ｈ２ＰＯ４）２－ＣＯ（ＮＨ２）２－Ｈ２Ｏｄ ２５℃时的等温溶度,三元体系中形成一个新化合物Ｃａ（Ｈ２ＰＯ４）２。ＣＯ（ＮＨ２）２。四元体系溶 度图可以指导商品普钙磷肥转化为含各合复肥。