Li2O-Na2O-B2O3-SiO2烧结助剂对BaAl2Si2O8陶瓷结构与介电性能的影响

采用传统固相反应工艺,按化学计量比合成BaO-Al_2O3-SiO_2(BAS)-x%(w/w) Li_2O-Na_2O-B_2O3-SiO_2(LNBS)(x=0,1,2,3,4)陶瓷。研究不同LNBS烧结助剂添加量对BAS系微波介质陶瓷的结构和介电性能的影响。通过Clausius-Mossotti公式计算讨论了BAS理论与实验介电常数(εr)的差异。研究结果表明:LNBS烧结助剂中Li+进入钡长石Al3+位或单四元环(S4R)间隙,并产生了O_2-空位或Ba2+空位,从而促进BAS六方相向单斜相的转变。添加适量的LNBS烧结助剂后,BAS陶瓷的烧结温度从1 400℃降低到1 325℃,同时BAS陶瓷样品密度、品质因数(Qf)值以及频率温度系数(τf)得到改善。当x=1,烧结温度为1 325℃时,可获得综合性能相对较好的BAS陶瓷,其介电性能:Qf=35 199 GHz,εr=6.37,τf=-1.613×10-5℃-1。     

Na2B4O7-Na2SO4-NaCl-H2O四元体系288K相平衡研究

采用等温溶解平衡法研究了四元体系Na2B4O7-Na2SO4-NaCl-H2O在288 K的相平衡关系,测定了平衡液相的溶解度及其密度。由研究结果知该四元体系为简单共饱和型,无复盐及固溶体形成。根据实验数据绘制了相应的相图。相图中有一个共饱点,三条单变曲线,三个结晶区平衡固相分别为:Na2B4O7·10H2O,Na2SO4·10H2O和NaCl。实验结果表明NaCl对Na2B4O7和Na2SO4有盐析作用,并简要讨论了实验结果。     

SO2F2/H2O2/碱和硫醚的氧化反应

考察了一种新型高效的氧化体系SO₂F₂/H₂O₂/碱应用于硫醚的氧化反应,结果以良好到优秀的收率生成了相应的产物砜.对该反应中碱和溶剂进行了优化,确定了最优的反应条件.对底物普适性进行了研究,实验结果表明该氧化体系显示了良好的官能团耐受性.该氧化体系的一个突出的优点是,所使用的试剂都为无机物,反应后副产物为易溶于水的无机盐和水,后处理时易于除去,从而大大简化了产物的分离和纯化.     

273 K下Na2CO3-Na2SO4-Na2B4O7-H2O四元体系介稳相平衡的实验研究

采用等温蒸发法研究了四元体系Na2CO3-Na2SO4-Na2B4O7-H2O在273 K时的介稳相平衡及平衡液相的密度. 利用溶解度数据绘制了该四元体系273 K下的相图. 研究结果表明, 该四元体系有异成分复盐2Na2SO4·Na2CO3形成. 相图中有2个共饱点、5条单变量曲线和4个结晶相区. 4个结晶相区分别为盐Na2CO3·10H2O, Na2SO4·10H2O, Na2B4O7·10H2O和2Na2SO4·Na2CO3的结晶区. 复盐2Na2SO4·Na2CO3同时存在于包含Na2CO3-Na2SO4-H2O三元体系的其它四元体系或高元体系中. 在273 K介稳平衡相图中, 碳酸钠以Na2CO3·10H2O形式析出; 硫酸钠以Na2SO4·10H2O的形式析出; 硼酸钠的完整分子式为Na2B4O5(OH)4·8H2O. Na2CO3对Na2B4O7有盐析作用.     

IrO2-SnO2上氧析出机理

本文研究IrO_2-SnO_2电极上氧析出过程的动力学和机理.实验得到,在所研究的电极上氧析出极化曲线的Tafel斜率约为75mV,H~+的反应级数为-0.75.此外,XPS结果证明研究电极表面Ir以+4价存在.根据实验结果提出IrO_2-SnO_2电极上氧析出过程的机理为:IrO_2+H_2O→IrO_2-OH+H~++cIrO_2-OH(?)IrO_2-O~-+(H~+)_sIrO_2-O~-(?)IrO_2-O+c2(IrO_2-O)(?)2IrO_2+O_2其中第一步为反应速度步骤(r.d.s.),(H~+)_s表示电极表面上的吸附质子。     

分步沉淀对CeO2-ZrO2-Y2O3-La2O3材料热稳定性的影响

研究了传统沉淀法和分步沉淀对CeO₂-ZrO₂-Y₂O₃-La₂O₃(CZ)材料结构和性能的影响. N₂-吸/脱附、 OSC、 H2-TPR和催化剂三效活性等测试结果表明:分步沉淀所制备的CZ材料表现出更优的氧化还原性能和织构性能.基于此,继续优化分步沉淀中晶种的含量(10%、 50%、 90%),结果表明:较少的晶种诱导可以极大程度提高材料热稳定性能和织构性能,但进一步增加晶种含量对材料热稳定性能提升作用不明显.其中,当晶种量为10%时,所得CZ材料在高温焙烧后仍保持最大比表面积及稳定的立方相结构,表现出最好的织构性能和热稳定性能,其负载的单Pd三效催化剂也因此表现出最优的三效催化活性.     

25℃时三元体系SrCl2-CaCl2-H2O相平衡研究

采用等温溶解平衡法,研究了三元体系SrCl2-CaCl2-H2O 25℃相平衡,同时测定了平衡溶液的物化性质(密度和折光率)。平衡液相所对应的平衡固相由湿渣法、偏光显微镜观测法和XRD法确定。根据实验研究数据,绘制了该三元体系相图。相图由3个无变量点、4条单变量曲线和4个盐类结晶区构成,4个结晶区分别对应CaCl2.6H2O、钙盐为基固溶体、锶盐为基固溶体和SrCl2.6H2O结晶区。     

富勒烯配合物C60Pd(Ph2PCH2CH2CH2CH2PPh2)的合成和光电性能

本文在惰性气氛中通过取代反应合成出富勒烯金属配合物C₆₀Pd(Ph₂PCH₂CH₂CH₂CH₂PPh₂)，采用元素分析、红外光谱、紫外可见光谱、光电子能谱以及X射线粉末衍射等手段对产物进行表征,同时研究了产物的氧化还原性能及热稳定性能。此外，在光电化学电池中测定了C₆₀Pd(Ph₂PCH₂CH₂CH₂CH₂PPh₂)在GaAs电极上形成n+n型异质结的光伏效应，结果表明：产物具有优良的光电转化性能，尤其是在BQ/H2Q介质电对中，光生电压最大达到212 mV；当C₆₀Pd(Ph₂PCH₂CH₂CH₂CH₂PPh₂)薄膜厚度为1 μm时，光伏效应值最大。     

新型层状磷酸铝[Al6P8O32][(C2H5)2NHCH2CH2NH3]2·[C2H5NH2CH2CH2NH2C2H5] 的合成、表征及其共模板作用

在溶剂热体系中,以N,N-二乙基乙二胺为结构导向剂,合成了Al/P为3/4的层状磷酸铝[Al6P8O32][(C2H5)2NHCH2CH2NH3]2·[C2H5NH2CH2CH2NH2C2H5]单晶,并通过X射线单晶衍射结构分析.XRD,ICP,元素分析,差热-热重分析等手段进行了表征.该化合物属单斜晶系,P2(1)/c空间群,晶胞参数:a=0.90945(2)nm,b=1.46424(4)nm,c=1.87572(5)nm,β=102.672(2)°,Z=4.其阴离子层由AlO4四面体和PO3(=O)四面体单元交替连接构成,形成四、六、八元环拓扑结构,无机层以ABAB方式堆积,两种质子化的有机胺分子N,N-二乙基乙二胺及其重排产物N,N′-二乙基乙二胺填充在层间.用分子动力学模拟方法,考察了标题化合物中有机胺与无机层间的相互作用,讨论了这两种有机胺的共模板作用.     

2MgO·2B2O3·MgCl2·14H2O-7.8%H3BO3-H2O体系多温相关系研究

研究了2MgO·2B2O3·MgCl2·14H20在不同温度下的7.8%H3BO3水溶液中的相转化产物及其溶解度.IR,XRD,TG及化学分析表明,相转化产物在0～22℃范围内为MgO·2B2O3·9H20;22～68℃为MgO·2B2O3·7.5H20;68～95℃为MgO·2B2O3·7H20;95～98.8℃为MgO·2B2O3·5H20;100～110℃为MgO·B2O3·3H20;110～120℃为2MgO·B2O3·2H20;120～170℃为2MgO·B2O3·1.5H20;170～200℃为2MgO·B2O3·H20.提出了相转化反应原理.     

Synthesis of [Ru(phen)(2)dppz](2+)-tethered oligo-DNA and studies on the metallointercalation mode into the DNA duplex

To explore the binding properties of [Ru(phen)(2)dppz](2+) complex (phen = 1,10-phenanthroline, dppz = dipyrido[3,2-a:2',3'-c]phenazine) in a sequence-specific manner in DNA duplex, it was tethered through the dppz ligand to a central position as well as both at the 3'- and 5'-ends of oligodeoxyribonucleotide (ODN). The middle [Ru(phen)(2)dppz](2+)-ODN tethered was resolved and isolated as four pure diastereomers, while the 3'- or 5'-[Ru(phen)(2)dppz](2+)-ODNs were inseparable on RP-HPLC. Thermal stability of the (Ru(2+)-ODN).DNA duplexes is found to increase considerably (DeltaT(m) = 12.8-23.4 degrees C), depending upon the site of the covalent attachment of the tethered [Ru(phen)(2)dppz](2+) complex, or the chirality of the [Ru(phen)(2)dppz](2+)-linker tethered at the middle of the ODN, compared to the unlabeled counterpart. Gross differences in CD between the [Ru(phen)(2)dppz](2+)-tethered and the native DNA duplexes showed that the global duplex conformation of the former has considerably altered from the B-type, but is still recognized by DNase I. The thermal melting studies, CD measurements, as well as DNase I digestion data, are interpreted as a result of intercalation of the dppz moiety, which is realized by threading of the Ru(phen)(2) complex part through the DNA duplex core. DNase I footprinting with four diastereomerically pure middle ([Ru(phen)(2)dppz](2+)-ODN).DNA duplexes furthermore showed that the tethered [Ru(phen)(2)dppz](2+)-linker chirality dictates the stereochemical accessibility of various phosphodiester moieties (around the intercalation site) toward the cleavage reaction by the enzyme. The diastereomerically pure ruthenium-modified duplexes, with the well-defined pi-stack, will be useful to explore stereochemistry-dependent energy- and electron-transfer chemistry to understand oxidative damage to the DNA double helix as well as the long-range energy- and electron-transfer processes with DNA as a reactant.     

一个嫁接有羧酸羟基乙基酯的二吡啶吩嗪Ru(II)配合物的合成、与DNA的相互作用以及溶剂变色性质的研究

合成并表征了一个新的Ru(II)配合物[Ru(bpy)₂(hedppc)](ClO₄)₂ {bpy＝2,2'-联吡啶, hedppc＝二联吡啶[3,2-a: 2',3'-c]吩嗪-11-羧酸(2-羟乙基)酯}. 通过紫外-可见吸收光谱、与溴化乙锭竞争实验、粘度测量和DNA裂解实验研究了配合物与小牛胸腺DNA的相互作用性质. 结果表明配合物以插入模式与DNA键合,键合常数K_b＝(6.99±1.34)×10⁶ mol^－1•L (s＝2.03±0.04)与母体配合物[Ru(bpy)₂ (dppz)]^2＋相近,但光致发光和溶剂变色等光学性质与[Ru(bpy)₂ (dppz)]^2＋有明显的差别.     

Enantioselective luminescence quenching of DNA light-switch [Ru(phen)2dppz]2+ by electron transfer to structural homologue [Ru(phendione)2dppz]2+

The quenching of the luminescence of [Ru(phen)(2)dppz](2+) by structural homologue [Ru(phendione)(2)dppz](2+), when both complexes are bound to DNA, has been studied for all four combinations of Delta and Lambda enantiomers. Flow linear dichroism spectroscopy (LD) indicates similar binding geometries for all the four compounds, with the dppz ligand fully intercalated between the DNA base pairs. A difference in the LD spectrum observed for the lowest-energy MLCT transition suggests that a transition, potentially related to the final localization of the excited electron to the dppz ligand in [Ru(phen)(2)dppz](2+), is overlaid by an orthogonally polarized transition in [Ru(phendione)(2)dppz](2+). This would be consistent with a low-lying LUMO of the phendione moiety of [Ru(phendione)(2)dppz](2+) that can accept the excited electron from [Ru(phen)(2)dppz](2+), thereby quenching the emission of the latter. The lifetime of excited Delta-[Ru(phen)(2)dppz](2+) is decreased moderately, from 664 to 427 ns, when bound simultaneously with the phendione complex to DNA. The 108 ns lifetime of opposite enantiomer, Lambda-[Ru(phen)(2)dppz](2+), is only shortened to 94 ns. These results are consistent with an average rate constant for electron transfer of approximately 1.10(6) s(-1) between the phenanthroline- and phendione-ruthenium complexes. At binding ratios close to saturation of DNA, the total emission of the two enantiomers is lowered equally much, but for the Lambda enantiomer, this is not paralleled by a decrease in luminescence lifetime. A binding isotherm simulation based on a generalized McGhee-von Hippel approach shows that the Delta enantiomer binds approximately 3 times stronger to DNA both for [Ru(phendione)(2)dppz](2+) and [Ru(phen)(2)dppz](2+). This explains the similar decrease in total emission, without the parallel decrease in lifetime for the Lambda enantiomer. The simulation also does not indicate any significant binding cooperativity, in contrast to the case when Delta-[Rh(phi)(2)bipy](3+) is used as quencher. The very slow electron transfer from [Ru(phen)(2)dppz](2+) to [Ru(phendione)(2)dppz](2+), compared to the case when [Rh(phi)(2)phen](3+) is the acceptor, can be explained by a much smaller driving free-energy difference.     

含双dppz配体的钌(Ⅱ)配合物与G-四联体的相互作用研究

应用紫外-可见吸收光谱、荧光光谱、热变性、圆二色谱等方法在K+溶液中研究了富含鸟嘌呤的G-四联体(AG3(T2AG3)3)与钌髤配合物[Ru(L)(dppz)2](PF6)4(L=5,5′-二(三正丁胺基甲基)-2,2′-联吡啶离子,dppz=二吡啶并[3,2-a∶2′,3′-c]吩嗪)的相互作用。紫外和荧光滴定实验表明,配合物与G-四联体之间存在较强的亲和力,拟合得到的结合常数可达107;从热变性实验可以看出,该配合物能够有效地稳定DNA的四螺旋结构。     

吲哚咪唑基钌(Ⅱ)联吡啶配合物与酵母RNA的相互作用

通过紫外-可见光谱和荧光光谱滴定、稳态荧光猝灭和溴化乙啶竞争键合实验研究了Ru(Ⅱ)配合物[Ru(bpy)(H₂iip)₂](ClO₄)₂{bpy=2,2′-联吡啶, H₂iip=2-(吲哚-3-基)-咪唑[4,5-f][1,10]-邻菲罗啉}的酵母RNA键合性质. 结果表明, 二者键合模式为嵌入键合, 其键合常数为7.09×10⁶ L/mol, 比小牛胸腺DNA的键合常数大, 且比同类配合物[Ru(bpy)₂(H₂iip)](ClO₄)₂的酵母RNA键合常数大.     

Base-specific and enantioselective studies for the DNA binding of iron(II) mixed-ligand complexes containing 1,10-phenanthroline and dipyrido[3,2-a:2',3'-c]phenazine

Base specificity and enantioselectivity for the DNA binding of [Fe(phen)2(dppz)]2+ (phen=1,10-phenanthroline and dppz=dipyrido[3,2-a:2',3'-c]phenazine) have been studied by determining the equilibrium binding constant (Kb) of the iron(II) complex to calf thymus DNA (ct-DNA), poly[(dA-dT)2], poly[(dG-dC)2] and poly[(dI-dC)2] using spectrophotometric titration and by monitoring the CD spectral profile of the iron(II) complex in the presence and absence of different types of DNA using circular dichroism (CD) spectroscopy, respectively. It has been shown that [Fe(phen)2(dppz)]2+ prefers to intercalate into the A-T and I-C sequences of poly[(dA-dT)2] and poly[(dI-dC)2] rather than into the G-C sequences of poly[(dG-dC)2] or into the base pairs of ct-DNA. In contrast to previous reports, it is a surprising observation that the enantioselectivity of the DNA binding for [Fe(phen)2(dppz)]2+ is base-dependent in nature. The Delta-enantiomer of [Fe(phen)2(dppz)]2+ is preferentially intercalated into the base pairs of poly[(dG-dC)2] or ct-DNA as indicated by its CD spectral profiles. On the other hand, the Lambda-enantiomer of [Fe(phen)2(dppz)]2+ is favorably intercalated into poly[(dA-dT)2] or poly[(dI-dC)2] as suggested by the opposite CD spectral profile. This preferential binding of Lambda-[Fe(phen)2(dppz)]2+)for the A-T sequence may be attributed to the fact that the binding site for the A-T sequence is relatively facile and thus the steric effect caused by the ancillary (non-intercalated) phen ligands is alleviated. The degree of enantioselectivity represented by inversion constants (Kinv) decreases as the salt concentration in the solution increases, indicating that electrostatic interaction is also operating in the ct-DNA-binding events of the iron (II) complex.     

DNA Sequence and Ancillary Ligand Modulate the Biexponential Emission Decay of Intercalated [Ru(L)2dppz]2+ Enantiomers

The bi‐exponential emission decay of [Ru(L)₂dppz]²⁺ (L=N,N′‐diimine ligand) bound to DNA has been studied as a function of polynucleotide sequence, enantiomer, and nature of L (phenanthroline vs. bipyridine). The lifetimes (τ_i) and pre‐exponential factors (α_i) depend on all three parameters. With [poly(dA‐dT)]₂, the variation of α_i with [Nu]/[Ru] has little dependence on L for Λ‐[Ru(L)₂dppz]²⁺ but a substantial dependence for Δ‐[Ru(L)₂dppz]²⁺. With [poly(dG‐dC)]₂, by contrast, the Λ‐enantiomer α_i values depend strongly on the nature of L, whereas those of the Δ‐enantiomer are relatively unaffected. DNA‐bound linked dimers show similar photophysical behaviour. The lifetimes are identified with two geometries of minor‐groove intercalated [Ru(L)₂dppz]²⁺, resulting in differential water access to the phenazine nitrogen atoms. Interplay of cooperative and anti‐cooperative binding resulting from complex–complex and complex–DNA interactions is responsible for the observed variations of α_i with binding ratio. [Ru(phen)₂dppz]²⁺ emission is quenched by guanosine in DMF, which may further rationalise the shorter lifetimes observed with guanine‐rich DNA.     

Dual molecular light switches for pH and DNA based on a novel Ru(II) complex. A non-intercalating Ru(II) complex for DNA molecular light switch

A new Ru(II) complex of [Ru(phen)(2)(Hcdpq)](ClO(4))(2) {phen = 1,10-phenanthroline, Hcdpq = 2-carboxyldipyrido[3,2-f:2',3'-h]quinoxaline} was synthesized and characterized. The spectrophotometric pH and calf thymus DNA (ct-DNA) titrations showed that the complex acted as a dual molecular light switch for pH and ct-DNA with emission enhancement factors of 17 and 26, respectively. It was shown to be capable of distinguishing ct-DNA from yeast RNA with this binding selectivity being superior to two well-known DNA molecular light switches of [Ru(bpy)(2)(dppz)](2+) {bpy =2,2'-bipyridine, and dppz = dipyrido-[3,2-a:2',3'-c]phenazine}and ethidium bromide. The complex bond to ct-DNA probably in groove mode with a binding constant of (4.67 ± 0.06) × 10(3) M(-1) in 5 mM Tris-HCl, 50 mM NaCl (pH = 7.10) buffer solution, as evidenced by UV-visible absorption and luminescence titrations, the dependence of DNA binding constants on NaCl concentrations, DNA competitive binding with ethidium bromide, and emission lifetime and viscosity measurements. To get insight into the light-switch mechanism, theoretical calculations were also performed by applying density functional theory (DFT) and time-dependent DFT.     

季铵盐联吡啶-钌(Ⅱ)配合物的合成及其与小牛胸腺DNA的相互作用

利用紫外-可见吸收光谱、荧光光谱、圆二色谱等光谱手段,以及黏度测定等流体力学方法在三羟甲基氨基甲烷(tris)缓冲溶液和磷酸缓冲溶液中研究了含季铵盐联吡啶配体的钌(Ⅱ)配合物[Ru(L)(phen)2](PF6)4(L=5,5′-二(三甲铵基甲基)-2,2′-联吡啶离子,phen=邻菲咯啉)与小牛胸腺DNA(CT-DNA)的相互作用.结果表明,合成的配合物与CT-DNA之间存在一定的亲和作用,拟合得到的结合常数可达105;与此同时,该配合物能够稳定CT-DNA的结构,并对CT-DNA有较好的立体选择性(右旋异构体优先与DNA结合).     

A Novel Optical Properties of Molecular “Light Switch” and its Analytical Application

Because of the high affinity (Ka≥ 10^6 L mol^-1) between Ru(phen)2(dppz)^2 and DNA, the adding of DNA in the solution of Ru(phen)E(dppz)^2 -SDS makes the dissociation of Ru(phen)E(dppz)^2 -SDS, and results in decrease of the resonance light scattering (RLS) signals andincrease of the absorbance. Based on this, a novel method is proposed for DNA assay.