二氯合铜(Ⅰ)酸四(三苯基氧膦)二氯合希土(Ⅲ)配合物的合成和红外光谱研究

合成了通式为[(Ph₃P=O)₄LnCl₂][CuCl₂](Ln=La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、He、Er、Y)的新配合物共12个,测定了它们的红外光谱(100～4600m^-1)和部分配合物的³¹P NMR.比较了[(Ph₃P=O)₄LnCl₃]、[(Ph₃P=O)₄LnCl₂]⁺和[(Ph₃P=O)₅LnCl]²⁺的P=O伸缩振动频率.结果表明希土配合物的正电荷越高,P=O基对希土离子配合能力越强,P=O伸缩振动频率更多地移向低波数,ν_P=O的顺序为:[(Ph₃P=O)₄LnCl₃]>[(Ph₃P=O)₄LnCl₂]⁺≥[(Ph₃P=O)₅LnCl]²⁺.讨论了希土配位键的共价性。     

希土8-羟基喹啉醋酸盐的合成与性质

希土元素能通过氮、氧等杂原子的配位与许多有机化合物形成配合物。R.G.Charles合成了β-二酮醋酸铕。在这一化合物中,醋酸根是很好的离去基团,它能被许多有机金属负离子(如-Fe(CO)_2C_5H_5,-Sn(C_6H_5)_3)和碳负离子L<二] ,—CH(CH_3)_2)取代生成RE-M键和RE-C键,因而具有相当的研究价值。我们合成了希土8-羟基喹啉醋酸盐,测试了它们的热稳定性、磁性和红外光谱。     

锂离子电池正极材料LiMPO4的研究进展

述了近年来有关LiMPO₄(M=Fe、Mn、Co、V)系列材料的合成与性能研究的进展，重点讨论了LiFePO₄材料改性的最新研究成果，分析了该类材料今后可能的发展趋势。     

Construction of 2D-2D TiO2 nanosheet/layered WS2 heterojunctions with enhanced visible-light-responsive photocatalytic activity

Constructing nanocomposites that combine the advantages of composite materials, nanomaterials, and interfaces has been regarded as an important strategy to improve the photocatalytic activity of TiO₂. In this study, 2D-2D TiO₂ nanosheet/layered WS₂ (TNS/WS₂) heterojunctions were prepared via a hydrothermal method. The structure and morphology of the photocatalysts were systematically characterized. Layered WS₂ (～4 layers) was wrapped on the surface of TiO₂ nanosheets with a plate-to-plate stacked structure and connected with each other by W=O bonds. The as-prepared TNS/WS₂ heterojunctions showed higher photocatalytic activity for the degradation of RhB under visible-light irradiation, than pristine TiO₂ nanosheets and layered WS₂. The improvement of photocatalytic activity was primarily attributed to enhanced charge separation efficiency, which originated from the perfect 2D-2D nanointerfaces and intimate interfacial contacts between TiO₂ nanosheets and layered WS₂. Based on experimental results, a double-transfer photocatalytic mechanism for the TNS/WS₂ heterojunctions was proposed and discussed. This work provides new insights for synthesizing highly efficient and environmentally stable photocatalysts by engineering the surface heterojunctions.     

Hydrophobic solvent induced phase transition extraction to extract drugs from plasma for high performance liquid chromatography–mass spectrometric analysis

Novel sample preparation approaches for HPLC bioanalysis based on the phenomenon that acetonitrile can be separated from water by adding salts or cooling at subzero temperatures have been reported. These two methods are superior to conventional liquid–liquid extraction since the separated acetonitrile phase can be directly injected to the RP–LC system. However, the salting-out method suffers from a potential problem that the remained salt in the acetonitrile phase may harm the MS detector, while the subzero-temperature method is troublesome to operate. Here, we have reported a similar phase separation phenomenon that the acetonitrile aqueous mixture can be separated by adding a hydrophobic solvent; and capitalising on this phase transition phenomenon, we have proposed an alternative approach, named solvent induced phase transition extraction (SIPTE), to extract drug from plasma for HPLC–MS analysis. The proposed SIPTE method is much simpler and avoids contaminating the MS detector. Three structurally diverse drugs were selected as test compounds to design the SIPTE method and to validate the efficiency of this method. The four goals of plasma sample pretreatment for HPLC–MS analysis, i.e. removal of proteins, removal of other low-molecular interferences, preconcentration of the analytes of interest, and matching the sample solvent with the HPLC–MS system, can be rapidly performed in a very simple step by using the SIPTE method.     

Stability criteria for impulsive systems on time scales

In this paper we study stability of impulsive system on time scales. By using comparison method, Lyapunov function and analysis method, the asymptotic stability criteria for system with impulses at fixed times and impulses at variable times on time scales are obtained, respectively. An example is presented to illustrate the efficiency of proposed result.     

A tree-like complex network model

We propose a new tree-like network model. Our results indicate that the tree-like model has a small-world effect with a small average path length and large clustering coefficient. Strikingly, our tree-like model is scale-free. We also add weight to the links following the network structure. With this adding-weight method, the weight of the nodes shows exponential growth, which is ubiquitous in social networks.     

1-酰氧基-2,8,9-三氧杂-5-氮杂-1-锗杂三环[3,3,3,O~(1,5)]十-碳烷的合成和结构研究

1-氯代杂氮锗三环与羧酸钾盐反应生成1-酰氧基杂氮锗三环化合物。通过IR，1HNMR和质谱确定了它们的结构。测定了化合物SCH＝CHCHC－COOGe（OCH2CH2）3N的晶体结构，化合物为五配位，N→Ge键长为0．212nm。     

Sandwich-type (phthalocyaninato)(porphyrinato) europium triple-decker nanotubes. Effects of the phthalocyanine peripheral substituents on the molecular packing

Three sandwich-type (phthalocyaninato)(porphyrinato) europium triple-decker complexes, namely Eu(2)(Pc)(2)(TClPP) (1), Eu(2)[Pc(β-OC(4)H(9))(8)](2)(TClPP) (2), and Eu(2)[Pc(β-OC(8)H(17))(8)](2)(TClPP) (3), have been designed, synthesized, and fabricated into nanotubes using nanoporous anodized aluminium oxide (AAO) membrane as the template. In particular, the effects of peripheral-substituents at the two phthalocyanine ligands in the triple-decker molecule on the molecular stacking relative to the alumina surface and the molecular packing mode in the nanotubes were clarified on the basis of the scanning electron microscopy (SEM), spectroscopic, and X-ray diffraction results. High-resolution TEM (HRTEM) images, in combination with the electronic absorption and XRD results, indicate that the discotic molecules of 1 without peripheral substituent on the phthalocyanine ligands form columnar structures on the alumina surface with homeotropic molecular stacking depending on the intermolecular π-π interactions in a head-to-tail manner. In good contrast, introduction of eight long octyloxy substituents at the peripheral-positions of the phthalocyanine ligands of 3 induces an increase in the interaction of the triple-decker molecules with the alumina surface, resulting in the formation of nanotubes with discotic molecules of 3 parallel stacking relative to the alumina surface depending on the intermolecular π-π interactions in a face-to-face manner. Most interestingly, introduction of eight shorter length butyloxy substituents at the peripheral-positions of the phthalocyanine ligands of 2 leads to the formation of nanotubes with discotic molecules of 2 parallel stacking relative to the alumina surface but depending on the intermolecular π-π interactions in a head-to-tail manner. X-Ray diffraction (XRD) data confirm the above-mentioned results.     

具有脉冲的Dirichlet边值问题的Lyapunov不等式及其应用

该文首先研究具有脉冲的线性Dirichlet边值问题 $\left\{ \begin{array}{ll} x'(t)+a(t)x(t)=0, t\neq \tau_{k}, \ \Delta x(\tau_{k})=c_{k}x(\tau_{k}),\ \Delta x'(\tau_{k})=d_{k}x(\tau_{k}), \ x(0)=x(T)=0, \end{array} \right. (k=1,2\cdots,m) $ 给出该Dirichlet边值问题仅有零解的两个充分条件, 其中$a:[0,T]\rightarrow R$, $c_{k}, d_{k}, k=1,2,$ $\cdots,m$是常数, 该文首先研究具有脉冲的线性Dirichlet边值问题 $$\left\{ \begin{array}{ll} x'(t)+a(t)x(t)=0, t\neq \tau_{k}, \ \Delta x(\tau_{k})=c_{k}x(\tau_{k}),\ \Delta x'(\tau_{k})=d_{k}x(\tau_{k}), \ x(0)=x(T)=0, \end{array} \right. (k=1,2\cdots,m) $$ 给出该Dirichlet边值问题仅有零解的两个充分条件, 其中$a:[0,T]\rightarrow R$, $c_{k}, d_{k}, k=1,2,$ $\cdots,m$是常数, $0<\tau_{1}<\tau_{2}\cdots<\tau_{m}<T$为脉冲时刻. 其次利用上面的线性边值问题仅有零解这个性质和Leray-Schauder度理论, 研究具有脉冲的非线性Dirichlet边值问题 $$\left\{ \begin{array}{ll} x'(t)+f(t,x(t))=0, t\neq \tau_{k}, \ \Delta x(\tau_{k})=I_{k}(x(\tau_{k})), \ \Delta x'(\tau_{k})=M_{k}(x(\tau_{k})), \ x(0)=x(T)=0 \end{array} \right. (k=1,2\cdots,m) $$ 解的存在性和唯一性, 其中 $f\in C([0,T]\times R,R)$, $I_{k},M_{k}\in C(R, R),k=1,2,\cdots,m$. 该文主要定理的一个推论将经典的Lyaponov不等式比较完美地推广到脉冲系统.