Influence of organic bases on constructing 3D photoluminescent open metal-organic polymeric frameworks

Four three-dimensional non-interpenetrating open coordination frameworks constructed from the CTC ligand (CTC =cis,cis-1,3,5-cyclohexanetricarboxylate) coordinated to metal ions (Mn(II) and Cd(II)): Mn(3)(CTC)(2)(DMF)(2)(1); Cd(3)(CTC)(2)(H(2)O)(3).H(2)O (2); Cd(3)(CTC)(2)(4,4'-bpy)(2)(EG)(2)(3); Cd(3)(CTC)(2)(mu(2)-hmt)(DMF)(C(2)H(5)OH)(H(2)O).2H(2)O (4)(DMF = dimethylformamide and EG = ethylene glycol) have been synthesized by slow evaporation of DMF-C(2)H(5)OH-H(2)O solutions of M(II)(Mn(II) or Cd(II)) and CTC in the presence of the organic bases TEA (triethylamine), TEA, 4,4'-bpy (4,4'-bipyridine) and hmt (hexamethylenetetramine), respectively, and structurally characterized by X-ray crystallography. The polymer constructed by CTC and Mn(II) exhibits a 3-D architecture with 5 x 9 A channels; the polymer formed by CTC and Cd(II) exists a 3-D extended framework with 9 x 9 A channels; wave-like sheet subunits of the polymer are upheld by 4,4'-bpy ligands resulting in a 3-D framework with 4 x 10 A channels; two-fold alternate sheet subunits of the polymer are interlinked by mu(2)-hmt ligands to form a novel 3-D architecture with 7 x 8 A channels. Polymers exhibit their strongest excitation peaks at 391, 390 and 394 nm, respectively, and their main strong emission peaks are at 543, 460 (with a shoulder peak at about 570 nm) and 557 nm, respectively.     

Hydrothermal Synthesis and Optical Properties of ZnO Nanostructured Films Directly Grown from/on Zinc Substrates

Uniform ZnO nanorods arrays are grown directly from and on Zn foils in pure water under hydrothermal conditions at a relatively low temperature. The nanorods are 80–200 nm in diameter and ∼ 1 μm in length, which grow on the Zn foil along the [001] direction. By changing the pure water to a urea solution, a Zn compound ([Zn₅(OH)₆(CO₃)₂], a precursor of ZnO nanoflowers film, is created by self-assembly. The ZnO nanoflowers film can be easily obtained by heating the [Zn₅(OH)₆(CO₃)₂] compound in N₂ at 350∘C for 5–6 hours. Possible growth processes of the ZnO nanorods arrays and the [Zn₅(OH)₆(CO₃)₂] nanoflowers are discussed. Photoluminescence properties of the as-prepared ZnO nanostructures have been measured. The ZnO nanorods array synthesized using our method has minimal defects so that only band-gap emission is observed. However, the ZnO nanoflowers film, obtained by heating the [Zn₅(OH)₆(CO₃)₂] nanoflower precursor in N₂, is polycrystalline and displays strong defect-related emission.     

Gaseous nitryl azide N4O2: A joint theoretical and experimental study

Gaseous nitryl azide N₄O₂ is generated by the heterogeneous reaction of gaseous ClNO₂ with freshly prepared AgN₃ at −50 °C. The geometric and electronic structure of the molecule in the gas phase has been characterized by in situ photoelectron spectroscopy (PES) and quantum chemical calculations. The experimental first vertical ionization energy of N₄O₂ is 11.39 eV, corresponding to the ionization of an electron on the highest occupied molecular orbital (HOMO) {4a″(π_{nb(N4–N5–N6)})}⁻¹. An apparent vibrational spacing of 1600 ± 60 cm⁻¹ (ν_asO1N2O3) on the second band at 12.52 eV (π_{nb(O1–N2–O3)}) further confirms the preference of energetically stable chain structure in the gas phase. To complement the experimental results, the potential-energy surface of this structurally novel transient molecule is discussed. Both calculations and spectroscopic results suggest that the molecule adopts a trans-planar chain structure, and a five-membered ring decomposition pathway is more favorable.     

Using three major criteria to evaluate aromaticity of five-member C-containing rings and their Si-, N-, and P-substituted aromatic heterocyclics

In this paper, we used bond-length equalization, aromatic stabilization energies (ASE) and nucleus-independent chemical shifts (NICS), calculated with (density functional theory) B3LYP levels at the 6-311+G^** basis set, to evaluate the aromaticity of a set of 38 five-member planar π-electron aromatic systems: sila-, aza- and phospha- derivatives and their parent systems. The result revealed statistically significant correlations among the above three criteria, and the order of aromaticity of the whole set was: Aza- derivatives rings > Phospha- derivatives rings > Sila- derivatives rings > Carbon-containing rings; NICS(0.6) and NICS(0.8) had the same results in evaluating the order of aromaticity in our case.     

三唑类硫醚及二硫醚化合物的合成

以2-苯基-1，2，3-三唑-4-甲酰肼为原料，合成了6个新的含连三唑和均三唑的硫醚类化合物，并经IR、^1HNMR、MS和元素分析进行了结构表征。     

用EXAFS研究NiO在γ-Al2O3表面上的分散

本文使用EXAFS方法研究NiO在γ-Al_2O_3的表面上的分散情况。文章讨论了Ni含量为7%、13%、18%、26%、35%的NiO/γ-Al_2O_3体系的径向结构函数图以及Ni含量为13%、26%的NiO/α-Al_2O_3样品的径向结构函数图,认为NiO能在γ-Al_2O_3表面上成单层分散。分散后的Ni-O距离接近NiO晶体的Ni-O距离,表明Ni离子和γ-Al_2O_3表面上的氧有很强的相互作用。     

活性位高度暴露的钴/氮/碳电催化剂的构建及氧还原性能研究

金属/氮/碳催化剂（M/N/C，M=Fe、Co等）是最有发展前景的非贵金属电催化剂之一，其性能依赖于催化剂表面的活性物种密度.通过常规的热解含氮前驱物与金属盐的方法制得的催化剂往往存在金属活性物种被包埋而不能有效利用的缺点.考虑到石墨相氮化碳（g-C₃N₄）富含类吡啶氮和亚纳米孔腔结构，将g-C₃N₄包覆在高导电性碳纳米笼（hCNC）表面，进而利用表层g-C₃N₄的配位和限域作用锚定大量Co²⁺离子，获得的Co/g-C₃N₄/hCNC复合物经热解后形成了活性位高度暴露、导电性好、孔结构丰富的Co/N/C催化剂.800℃热解得到的最优化催化剂在碱性介质中展现出优异氧还原活性，其起始电位（0.97 V）与商业Pt/C催化剂相当，且抗甲醇干扰性能和稳定性优异.此项研究提供了一种构建具有高度暴露活性位的M/N/C催化剂的有效策略.     

具有双螺旋链的新型二维无机-有机骨架晶体材料Ni(PDC)(H2O)2的合成与结构

本文报道由H2PDC合成的新型维层状无机-有机骨架晶体Ni(PDC)(H2O)2(H2PDC=吡啶-2,5-二羧酸), 该化合物的一层是由右手螺旋Ni—O—C链与左手螺旋Ni-pdc链组成, 而邻近的一层则是由左手螺旋Ni—O—C链与右手螺旋Ni-pdc链组成, 层与层之间通过氢键作用形成了三维超分子结构. 用ICP、TG、IR和X射线单晶衍射分析等手段对其结构进行表征.     

草酰胺桥联大环二羰四胺铜(Ⅱ)-钴(Ⅱ)异双核配合物的合成、结构、表征和电化学性质

合成了一种具有草酰胺桥联大环二羰四胺结构的 Cu( ) -Co( )异双核配合物 ,用红外光谱、电子光谱、摩尔电导、热重分析、室温磁矩、循环伏安等对其进行了表征 .初步推定 Cu( ) -Co( )异双核配合物具有草酰胺桥联大环二羰四胺结构 .室温磁矩测定表明 ,通过草酰胺桥联配体金属离子间有一定的反铁磁性自旋偶合作用 .循环伏安法测定了配合物的半波电位 ,实验表明 ,此类配合物能够稳定高价态 Cu( ) ,外延桥基配位对大环内腔 Cu( )离子的氧化还原过程无影响 .单核配合物 X射线晶体衍射研究表明 ,其为单斜晶系 ,空间群 P2 1 /c,a=0 .73 861 (1 5 ) nm,b=2 .1 2 1 1 (4 ) nm,c=0 .95 2 5 0 (1 9) nm,β=94.70 (3 )°,R1 =0 .0 5 1 3 ,w R2 =0 .1 1 77,Z=4.Cu( )处于大环四胺平面正方中心上方 0 .0 3 nm,并具有外延草酰胺桥