1-D zigzag double-chain coordination polymers of transition metals derived from pyridine-2,3,5,6-tetracarboxylic acid

Three new 1-D zigzag coordination polymers {[M₂(pdtc)(bpy)₂(H₂O)₃]?·?4H₂O} _n [M?=?Zn (1), Ni (2), Co (3)] (H₄pdtc?=?pyridine-2,3,5,6-tetracarboxylic acid, bpy?=?2,2′-bipyridine) have been synthesized by the reactions of H₄pdtc and corresponding metal salts in the presence of bpy at room temperature and characterized by elemental analyses, IR, TGA, fluorescence, and X-ray diffraction. The main structural feature of 1–3 is the presence of octahedrally coordinated M1(II) and M2(II) centers sequentially bridged by pdtc ligands; bpy acts as a blocking ligand to avoid further polymerization. These coordination modes lead to 1-D double-chain structures. The 2-D or 3-D supramolecular structures of 1–3 are built up by π?···?π and hydrogen-bond interactions. Two (H₂O)₃ clusters are observed in 1–3. The zinc complex shows strong fluorescent emission at 325?nm.     

(1,2-(1H-1,2,4-三唑))乙烷的一维双链Cu(Ⅱ)配合物合成与表征(英文)

利用高度柔性的双三唑配体(1,2-(1H-1,2,4-三唑))乙烷(L)和铜盐反应合成了1个新的具有一维双链结构的铜(Ⅱ)配合物{[Cu(cis-L)2Br]Br.2H2O}n(1)。单晶结构表明:配合物1的晶体属于三斜晶系,P1空间群。在配合物1中双三唑配体采用反式构型,桥联相邻的中心铜离子形成一维双链结构,晶格中游离的Br原子同配位水分子形成了四元环状的Br…O超分子环。测定了配合物1在2～300 K的变温磁化率,结果表明相邻铜离子间存在弱的反铁磁相互作用。     

Adhesive ability of a heat-resistant double-chain polymer and the strength of CFRP based on it

The adhesive ability of a heat-resistant polyiminoquinazolindione (PIQD) binder, based on a double-chain polymer, and the physicomechanical characteristics of unidirectional CFRPs made with it are investigated. It is shown that, at room temperature, the strength of model adhesive joints (PIQD-steel wire) and of the CFRPs in shear and bending is rather low — about half of that of similar specimens based on an epoxy binder. At the same time, all their mechanical characteristics, to a large measure (50%), are retained at temperatures up to 450°C, which considerably exceeds the heat resistance of all polymer matrices used at the present time. The elastic modulus of the CFRPs in bending practically remains the same up to 450°C. __________ Translated from Mekhanika Kompozitnykh Materialov, Vol. 44, No. 4, pp. 535–546, July–August, 2008.     

新型一维[Co(phen)(μ3-md)]n的水热合成与结构

采用有机分子建筑块与金属离子制备具有微孔结构材料在催化、化学吸附、磁性和导电性等方面具有潜在的应用前景, 因而成为研究的热点[1～4]. 近来的研究表明, 多齿的有机配体是很好的建筑块, 其中多羧酸化合物和含多氮化合物均是很好的多齿配体. 多羧酸化合物如均苯四甲酸、间苯三甲酸、对苯二甲酸等, 多氮化合物如1,10-邻菲咯啉、 4,4′-联吡啶、 2,2′-联吡啶等[5～11]. 但对同样具有多齿特征的间苯二甲酸作为配体的化合物研究得很少. 本文采用水热合成法合成了[Co(phen)(μ3-md)]n(phen=1,10-phenanthroline, md=Benzene-1,3-dicarboxylate). 该聚合物呈一维双链结构, 通过间苯二甲酸连接3个Co(Ⅱ)形成双分子链, 间苯二甲酸和它连接的3个Co(Ⅱ)离子在同一平面上, 通过垂直于该平面的phen之间的π-π共轭作用形成二维结构.     

基于{Er_2}和{Cu_2}单元构建的超分子网络(英文)

利用水热法成功合成了一个新颖的稀土-过渡金属有机骨架Er(pyba)3(H2O)2CuI(Hpyba=4-吡啶-3-苯甲酸),并通过元素分析、红外光谱、X-射线粉末衍射、单晶X-射线衍射及热分析等对其进行了表征。结构分析表明:2种不同的{Er2}和{Cu2}单元经配体连接形成一维链,这些一维链通过氢键和π-π堆积作用进一步连接形成三维超分子网络。     

一个处理共轭分子光谱的近似公式

运用一维势箱模型结合Hückel简单分子轨道理论,提出了一个预测共轭多烯烃吸收光谱的简便公式。将该公式用于处理并苯和石墨烯,解释了石墨烯和石墨导电以及π∞∞键具有金属键的特性。     

Surface and interfacial properties of 1,3-dialkyl glyceryl ether hydroxypropyl sulfonates as surfactants for enhanced oil recovery

A series of double-chain anionic surfactants, 1,3-dialkyl glyceryl ether hydroxylpropyl sulfonates (diC_mGE-HS, m?=?8, 10, 12), were synthesized from renewable materials. These surfactants possess very low γ_cmc (～25?mN/m) at 25°C, and their mixtures with conventional surfactants can reduce Daqing crude oil/connate water IFT to ultralow at 45°C in wide total concentration range (0.625-10?mM) in the presence of 0.5?wt.% Na₂CO₃. It seems that diC₁₂GE-HS behaves as a hydrophobic component, whereas diC₁₀GE-HS and diC₈GE-HS behave as hydrophilic components in these mixtures. The mixtures also exhibit high resistance against adsorption by sandstone and good ability of keeping sandstone surface water-wet.     

一维椭圆方程边值问题的高精度差分方法

本文研究一维椭圆方程边值问题的差分方法,利用Lagrange插值理论与积分因子技巧,发展了一套有效的高精度算法,对非等距节点和等距节点,其精度分别可达O(h~4)和O(h~5).数值结果显示了该方法的优越性     

Double-Chain Cationic Surfactants: Swelling,Structure, Phase Transitions and Additive Effects

Double-chain amphiphilic compounds, including surfactants and lipids, have broad significance in applications like personal care and biology. A study on the phase structures and their transitions focusing on dioctadecyldimethylammonium chloride (DODAC), used inter alia in hair conditioners, is presented. The phase behaviour is dominated by two bilayer lamellar phases, L_β and L_α, with “solid” and “melted” alkyl chains, respectively. In particular, the study is focused on the effect of additives of different polarity on the phase transitions and structures. The main techniques used for investigation were differential scanning calorimetry (DSC) and small- and wide-angle X-ray scattering (SAXS and WAXS). From the WAXS reflections, the distance between the alkyl chains in the bilayers was obtained, and from SAXS, the thicknesses of the surfactant and water layers. The L_α phase was found to have a bilayer structure, generally found for most surfactants; a L_β phase made up of bilayers with considerable chain tilting and interdigitation was also identified. Depending mainly on the polarity of the additives, their effects on the phase stabilities and structure vary. Compounds like urea have no significant effect, while fatty acids and fatty alcohols have significant effects, but which are quite different depending on the nonpolar part. In most cases, L_β and L_α phases exist over wide composition ranges; certain additives induce transitions to other phases, which include cubic, reversed hexagonal liquid crystals and bicontinuous liquid phases. For a system containing additives, which induce a significant lowering of the L_β–L_α transition, we identified the possibility of a triggered phase transition via dilution with water.     

(1，2-(1H-1，2，4-三唑))乙烷的一维双链Cu(Ⅱ)配合物合成与表征

利用高度柔性的双三唑配体(1,2-(1H-1,2,4-三唑))乙烷(L)和铜盐反应合成了1个新的具有一维双链结构的铜(Ⅱ)配合物{[Cu(cis-L)₂Br]Br·2H₂O}_n(1)。单晶结构表明：配合物1的晶体属于三斜晶系,P1 空间群。在配合物1中双三唑配体采用反式构型,桥联相邻的中心铜离子形成一维双链结构,晶格中游离的Br原子同配位水分子形成了四元环状的Br…O超分子环。测定了配合物1在2~300 K的变温磁化率,结果表明相邻铜离子间存在弱的反铁磁相互作用。