基于3,5-二硝基苯甲酸和2,2′-联吡啶的Cu(Ⅱ)、Zn(Ⅱ)配合物的合成及晶体结构

以3,5-二硝基苯甲酸(3,5-Hdnbc)和2,2′-联吡啶(2,2′-bipy)为配体,与Zn2+和Cu2+反应,得到了4个配合物[Zn(3,5-dnbc)2(2,2′-bipy)(H2O)]·(3,5-Hdnbc)(1),[Cu(3,5-dnbc)2(2,2′-bipy)(H2O)](2),[Cu(2,2′-bipy)2(3,5-dnbc)](NO3)·2(3,5-Hdnbc)(3),和[Cu(2,2′-bipy)2Cl](3,5-dnbc)·(3,5-Hdnbc)(4)。用元素分析、红外光谱对其进行了表征,并用单晶X-射线衍射测定了配合物的晶体结构;对配合物1和2进行了热重分析。4个配合物均为单核分子。配合物1中,Zn2+离子是五配位的三角双锥结构;配合物2中,Cu2+离子是五配位的变形四方锥结构;配合物3和4中,Cu2+离子均是五配位的三角双锥结构;配合物中存在氢键和π-π堆积等弱的分子间作用力。     

以三唑农药为配体的两个铜配合物的合成、晶体结构与抑菌活性(英文)

由三唑农药烯效唑和多效唑合成了2个铜配合物[CuL14Cl2](1)和[CuL24Cl2·4H2O](2)(L1=uniconazole,L2=paclobutrazol)。通过元素分析、红外光谱和X-ray单晶衍射对其结构进行了表征。结构分析表明,1属三斜晶系,P1空间群,晶胞参数为a=0.895 6(3)nm,b=1.326 7(4)nm,c=1.491 8(4)nm,α=94.828(3)°,β=97.774(3)°,γ=105.280(3)°,V=1.680 8(9)nm3。2属三斜晶系,P1空间群,晶胞参数为a=1.021 89(19)nm,b=1.329(3)nm,c=1.366 4(3)nm,α=81.564(2)°,β=79.508(2)°,γ=79.185(2)°,V=1.785 3(7)nm3。在2个配合物中,六配位的铜离子都采取扭曲的八面体配位构型,分别来自三唑配体的4个氮原子和2个氯原子配位。1和2都由分子间氢键连接成一维链结构。与相应的配体相比,1和2的抑菌活性明显增强。     

以混合阳离子-嵌段共聚物表面活性剂为模板合成介孔MCM-48

利用阳离子和嵌段共聚物混合表面活性剂为模板,在水热条件、碱性介质中成功地合成出MCM-48介孔分子筛。在1TEOS(正硅酸乙酯)∶0.125CTAB(十六烷基三甲基溴化铵)∶nP123(聚氧乙烯-聚氧丙烯-聚氧乙烯三嵌段共聚物)∶0.50NaOH(氢氧化钠)∶61H₂O(物质的量的比)体系中,n值在较大范围内(0.000 625～0.018 75)可调。通过粉末X射线衍射(XRD)、N₂物理吸附、扫描电镜(SEM)对合成样品进行表征。结果表明：聚氧乙烯-聚氧丙烯-聚氧乙烯三嵌段共聚物(P123)的加入可以更大程度地降低合成MCM-48所需阳离子表面活性剂的用量;合成的MCM-48具有高比表面积、高度有序的孔道结构、较集中的孔径分布和较高的热和水热稳定性。     

Iodobismuthates with N-alkyl- or N,N'-dialkyl-4,4'-bipyridinium: syntheses, structures and dielectric properties

The solvothermal reactions of BiI(3), KI, I(2), 4,4'-bipyridine (4,4'-bipy), and a small amount of water in alcohol and acetonitrile produced four bipyridinium iodobismuthates {[MQ](3)[Bi(2)I(6)(μ-I)(3)][Bi(2)I(6)(μ-I)(2)(MQ)(2)](3)} (1, MQ(+) = N-methyl-4,4'-bipyridinium), {[EQ](3)[Bi(2)I(6)(μ-I)(3)][Bi(2)I(6)(μ-I)(2)(EQ)(2)](3)} (2, EQ(+) = N-ethyl-4,4'-bipyridinium), [MV][BiI(5)] (Eur. J. Inorg. Chem., 2010, 5326) (3, MV(2+) = N,N'-dimethyl-4,4'-bipyridinium), and [EV](2)[Bi(4)I(10)(μ-I)(4)(μ(3)-I)(2)] (4, EV(2+) = N,N'-diethyl-4,4'-bipyridinium). In these reactions, 4,4'-bipy was partly or completely alkylated by alkyl groups generated from the cleavage of C-O bond of alcohols, forming the N-alkyl-4,4'-bipyridinium cation (Q(+)) and the N,N'-dialkyl-4,4'-bipyridinium dication (V(2+)), respectively. Compounds 1-4 were characterized by elemental analysis, IR, (1)H NMR and single-crystal X-ray diffraction analysis. The optical, electrical conductive and dielectric properties of these compounds were investigated. The dielectric constants of the Q(+)-based compounds were larger than the values of the V(2+)-based ones, which showed that the weak electrostatic interactions in the structures may benefit the polarizability of molecules, thereby resulting in a larger dielectric response of the structures under an external electric field, while the strong electrostatic interactions between the positive and negative charge units would lead to a low dielectric constant (low-k) behavior of these compounds.     

大孔炭载Pd催化剂对甲酸氧化的电催化性能

用X射线能量色散谱(EDS)、X射线衍射(XRD)谱、拉曼光谱和电化学技术研究和比较了直接甲酸燃料电池(DFAFC)中Vulcan XC-72炭黑载Pd (Pd/XC)和大孔炭载Pd (Pd/MC)催化剂对甲酸氧化的电催化性能. 循环伏安曲线测量表明甲酸在Pd/XC和Pd/MC催化剂电极上主要氧化峰的峰电位基本相同, 在0.15 V左右, 但在Pd/MC催化剂电极上的峰电流密度比在Pd/XC催化剂上的大30%左右. 计时电流曲线测量表明, 在6000 s时, 在Pd/MC催化剂电极上的峰电流密度比在Pd/XC催化剂上的大38%左右, 这些结果说明Pd/MC催化剂对甲酸氧化的电催化活性和稳定性要好于Pd/XC催化剂. 由于Pd/MC和Pd/XC催化剂的Pd粒子平均粒径和相对结晶度相似, 因此, Pd/MC催化剂电催化性能好的原因只能归结于MC大的孔径和高的石墨化程度引起的高电导率.     

A green strategy for lithium isotopes separation by using mesoporous silica materials doped with ionic liquids and benzo-15-crown-5

Three new mesoporous silica materials IL15SGs (HF15SG, TF15SG and DF15SG) doped with benzo-15-crown-5 and imidazolium based ionic liquids (C₈mim⁺PF₆ ^?, C₈mim⁺BF₄ ^? or C₈mim⁺NTf ₂ ^? ) have been prepared by a simple approach to separating lithium isotopes. The formed mesoporous structures of silica gels have been confirmed by transmission electron microscopy image and N₂ gas adsorption–desorption isotherm. Imidazolium ionic liquids acted as templates to prepare mesoporous materials, additives to stabilize extractant within silica gel, and synergetic agents to separate the lithium isotopes. Factors such as lithium salt concentration, initial pH, counter anion of lithium salt, extraction time, and temperature on the lithium isotopes separation were examined. Under optimized conditions, the extraction efficiency of HF15SG, TF15SG and DF15SG were found to be 11.43, 10.59 and 13.07 %, respectively. The heavier isotope ⁷Li was concentrated in the solution phase while the lighter isotope ⁶Li was enriched in the gel phase. The solid–liquid extraction maximum single-stage isotopes separation factor of ⁶Li–⁷Li in the solid–liquid extraction was up to 1.046 ± 0.002. X-ray crystal structure analysis indicated that the lithium salt was extracted into the solid phase with crown ether forming [(Li_0.5)₂(B15)₂(H₂O)]⁺ complexes. IL15SGs were also easily regenerated by stripping with 20 mmol L^?1 HCl and reused in the consecutive removal of lithium ion in five cycles.     

以3-硝基邻苯二甲酸根构建的环状双核Zn(Ⅱ),Cd(Ⅱ)配合物的合成及晶体结构(英文)

以3-硝基邻苯二甲酸和咪唑及2,2′-联吡啶为配体构筑了2种配合物[Zn2(npa)2(Im)4](1)和[Cd2(npa)2(2,2′-bipy)2(H2O)2]·2H2O(2)(npa2-=3-硝基邻苯二甲酸根,Im=咪唑,2,2′-bipy=2,2′-联吡啶)。用元素分析、红外光谱对其进行了表征,并用单晶X-射线衍射测定了配合物的晶体结构;测定了配合物1和2的热稳定性。2个配合物均为双核分子,具有M2C8O4十四元大环结构。配合物1的双核单元通过分子间氢键形成3D网络结构,配合物2的双核单元通过分子间氢键和π-π堆积形成2D层状结构。     

A porphyrin derivative containing 2-(oxymethyl)pyridine units showing unexpected ratiometric fluorescent recognition of Zn2+ with high selectivity

A porphyrin derivative (1), containing two 2-(oxymethyl)pyridine units has been designed and synthesized as chemosensor for recognition of metal ions. Unlike many common porphyrin derivatives that show response to different heavy metal ions, compound 1 exhibits unexpected ratiometric fluorescence response to Zn²⁺ with high selectivity. The response of the novel chemosensor to zinc was based on the porphyrin metallation with cooperating effect of 2-(oxymethyl)pyridine units. The change of fluorescence of 1 was attributed to the formation of an inclusion complex between porphyrin ring and Zn²⁺ by 1:1 complex ratio (K = 1.04 × 10⁵), which has been utilized as the basis of the fabrication of the Zn²⁺-sensitive fluorescent chemosensor. The analytical performance characteristics of the proposed Zn²⁺-sensitive chemosensor were investigated. The sensor can be applied to the quantification of Zn²⁺ with a linear range covering from 3.2 × 10⁻⁷ to 1.8 × 10⁻⁴ M and a detection limit of 5.5 × 10⁻⁸ M. The experiment results show that the response behavior of 1 to Zn²⁺ is pH-independent in medium condition (pH 4.0-8.0) and show excellent selectivity for Zn²⁺ over transition metal cations.     

聚甲醛在强磁场下结晶的形貌分析

采用电子显微分析、X射线衍射法、傅里叶红外光谱法及差示扫描量热法分析强磁场对聚甲醛的结晶形态与片晶分布的影响, 探讨了微观组织特征与晶体学取向之间的关系. 研究结果表明, 聚甲醛(POM)在强磁场(12 T)作用下, 片晶厚度以及片晶间距都发生了明显的增大, 熔点升高, 分子链受到磁场的诱导而趋于定向结晶, 产生了沿磁场方向排列的类似漩涡状的结晶形貌.     

Massive Scalar Field Evolution in the Dyadosphere Spacetime of Charged Black Hole

Scalar field quasinormal modes in the dyadosphere spacetime of charged black hole are studied by using the third-order WKB approximation. From numerical results obtained, we find that the scalar field mass u plays an important role in studying the quasinormal frequencies. With the scalar field mass increases, the real parts increase and the magnitudes of the imaginary parts decrease. Particulary, these change are almost linearly.