A series of lanthanide-organic frameworks constructed by 2-methyl imidazole dicarboxylate and oxalate: synthesis,structures, and properties

Five lanthanide(III) coordination polymers with 2-methyl-1H-imidazole-4,5-dicarboxylic acid (H₃MIDC) and ammonium oxalate, {[(Ln1)₂(HMIDC)₂(C₂O₄)(H₂O)₃]?·?3H₂O} _n (Ln1?=?Nd (1), Sm (2)), {[Eu₂(HMIDC)₂(C₂O₄)(H₂O)₃]?·?0.5EtOH?·?3H₂O} _n (3), {[Ce₂(HMIDC)₂(C₂O₄)(H₂O)₃]?·?EtOH?·?3H₂O} _n (4), and {[Gd₂(HMIDC)₂(C₂O₄)(H₂O)₃]?·?MeOH?·?3H₂O} _n (5), have been prepared and structurally characterized. Single-crystal X-ray diffraction analyses reveal that 1 and 2 are isostructural, as are 3, 4, and 5. Each exhibits a 3-D open framework, which is built by a regular 2-D grid connected by HMIDC^2? and Ln(III). The luminescence and thermal properties of these complexes have been investigated as well.     

Preparation,Structure and Thermal Decomposition of Cu(II) Complexes with 2-Chloro- and 2,3-Dichlorobenzoic Acids and Imidazole

The reaction products of Cu(II) 2-chlorobenzoate and imidazole (1), and of Cu(II) 2,3-dichlorobenzoate and imidazole (2) formulated as CuL'₂·3imd and CuL"·3imd (L' = C₇H₄ClO₂, L" = C₇H₄Cl₂O₂ ^?, imd = imidazole), were prepared and characterized by means of structural and spectroscopic measurements and thermochemical properties. The blue (1) and green (2) compounds crystallize in the monoclinic system with space group C2/c, cell parameters a = 20.753(4), b = 8.414(2), c = 14.429(3) Å, β = 90.15(3)°, V = 2519.5(9) &Aringsup3;, Z = 4 for (1) and a = 21.335(4), b = 8.417(2), c = 15.030(3) Å, β = 94.11(3)°, V = 2692.1(10) &Aringsup3;, Z = 4 for (2). The complexes decompose at 483 K.     

Syntheses,Crystal Structures,Superoxide Dismutase-Like Behaviors and Physical Properties of Four Manganese(III) Complexes with Di-Schiff Bases Derived from Salicylaldehyde and Polyamines

Four manganese(III) complexes, [Mn(salMeDPT)(O 2 CMe)] 1 , [Mn(salMeDPT)Cl]·MeCN 2 , [Mn(salEDPA)] Cl 3 and [Mn(salEDPA)](MeCO 2 ) 4 have been prepared, where the di-Schiff-base salMeDPT and salEDPA were from the (2 + 1) condensation of salicylaldehyde with 4-methyl-4-azaheptane-1,7-diamine and with 4,7-diazadecane-1,10-diamine, respectively. The four complexes have been characterized by elemental analyses and cyclic voltammetry, while complexes 1 - 3 have also been characterized by single-crystal x-ray diffraction, which reveals all the Mn(III) atoms in these complexes adopt slightly compressed octahedra with the Mn-O and Mn-N bond lengths in ranges 1.882(3)-1.890(3) and 2.021(4)-0.546(4) Å, respectively. The results of activity assay indicate that complexes 1 - 4 have moderate superoxide dismutase activities.     

Syntheses,crystal structures,thermal behaviors,and sensitivities of new initiator compositions: rubidium salts of trinitrophenol and trinitroresorcinol

Three new polymeric Rb(I) salts of trinitrophenol and trinitroresorcinol, rubidium trinitrophenol ([RbTNP]_n), bi-substituted rubidium salt of trinitroresorcinol ([Rb₂TNR·H₂O]_n), and mono-substituted rubidium salt of trinitroresorcinol ([RbHTNR]_n) were synthesized and characterized by X-ray single-crystal diffraction, elemental analysis, and IR spectroscopy. The central Rb(I) cations are 10 or 11-coordinated by oxygens from nitro group, phenolic hydroxyl and coordinated water, and the multidentate ligands bridged different Rb(I) centers. Coordination bonds, electrostatic interaction, and intermolecular hydrogen bonds assemble the ions into 3-D polymeric network structures. Thermal decomposition behaviors of the compounds were studied by applying differential scanning calorimetry under various linear heating rates. Sensitivities measurements revealed that these compounds are sensitive to flame, insensitive to impact and friction stimulates. All properties show that the compounds are promising to be an eco-friendly initiating composition, especially [RbTNP]_n.     

Alpha-gamma decay studies of 255Rf, 251No and 247Fm

The decay of the isotopes ²⁵⁵Rf, ²⁵¹No and ²⁴⁷Fm produced in the reactions , and was investigated by means of α-γ spectroscopy. Previously observed γ transitions in coincidence with α decays of ²⁵⁵Rf were confirmed, their energies and line intensities were measured more precisely, and their multipolarities were determined as E1. In ²⁵¹No a new isomeric state at E ^* > 1700keV with a half-life of ≈ 2μs was identified. The decay of ²⁴⁷Fm was measured more precisely. A partial level scheme of the daughter nucleus ²⁴³Cf could be established.     

脂肪酸糖酯类表面活性剂的合成及应用

脂肪酸糖酯是一类绿色、安全、可生物降解的非离子型表面活性剂,因其具有良好的乳化能力和杀菌性能以及对皮肤刺激性低等诸多优点而被广泛应用于食品、医药、化妆品和农业领域。本文对脂肪酸糖酯的合成及应用进行了综述,从而为深入研究并开发脂肪酸糖酯类表面活性剂提供参考。     

PCDL型超支化水性聚氨酯的合成与性能

以甲苯-2,4-二异氰酸酯（TDI）、聚碳酸酯二醇（PCDL）、二羟甲基丙酸（DMPA）和二乙醇胺（DEOA）为原料,采用A₂＋bB₂共聚合路线合成了具有超支化结构的水性聚氨酯（HBAPU）乳液。采用红外光谱（FT-IR）、核磁共振（13C NMR）对产物结构进行了表征,证实了超支化聚氨酯的支化度随 n(NCO)/n(OH)比值的增大而增大。用PCS、TG、电子拉力机对产物的性能进行了测试,同时也对胶膜的耐水性进行了测试,发现在DMPA含量为0.4 mmol/g时,HBAPU的粒径仅有20.57 nm,而线性水性聚氨酯粒径有130.91 nm,并且HBAPU具有良好的耐水性、热稳定性和较高的拉伸强度。     

Cohesive zone finite element analysis of crack initiation from a butt joint’s interface corner

Cohesive zone (CZ) fracture analysis techniques are used to predict the initiation of crack growth from the interface corner of an adhesively bonded butt joint. In this plane strain analysis, a thin linear elastic adhesive layer is sandwiched between rigid adherends. There is no preexisting crack in the problem analyzed, and the focus is on how the shape of the traction–separation (T–U) relationship affects the predicted joint strength. Unlike the case of a preexisting interfacial crack, the calculated results clearly indicate that the predicted joint strength depends on the shape of the T–U relationship. Most of the calculations used a rectangular T–U relationship whose shape (aspect ratio) is defined by two parameters: the interfacial strength σ¹ and the work of separation/unit area Γ. The principal finding of this study is that for a specified adhesive layer thickness, there is any number of σ¹, Γ combinations that generate the same predicted joint strength. Each combination corresponds to a different CZ length. An approximate CZ-like elasticity solution was developed to show how such combinations arise and their connection with the CZ length.     

X@Mg_8B_(14)(X=H,Li)团簇核壳结构与性质的密度泛函理论研究

运用杂化密度泛函B3LYP方法,在6-31G*水平上对X@Mg_8B_(14)(X=H,Li)两种团簇进行了几何结构优化,并计算了其电子结构、振动特性和成键特性.计算结果表明:优化后的X@Mg_8B_(14)(X=H,Li)团簇均为橄榄球状核壳结构,对称性点群均为D2h.用自然键轨道方法分析了成键性质,发现X@Mg8B14(X=H,Li)团簇中B原子主要是sp杂化轨道参与成键,Mg原子主要是s轨道参与成键.Mg原子和B原子之间发生了大量的电子转移,在B原子层堆积了大量的电子;尤其是封装Li原子后,B原子层得电子数量明显增加.