含硒杂环化合物的合成和对超氧阴离子作用的ESR研究

引言硒作为人体必需的微量元素,其主要生化作用与谷胱甘肽过氧化物酶密切相关.在体内,该酶可以催化许多过氧化物的分解,并且与谷胱甘肽一起组成一个强有力的细胞防御体系,发挥其抗氧化作用.近几年来,人们发现了一种小分子有机硒化物2-苯基-1,2-苯并异硒唑酮-3(简称Ebselen)具有类似谷胱甘肽过氧化物酶的活性.它能有效地抑制活性氧自由基的产生而引起的细胞损伤,具有良好的抗炎活性,且毒性极低(大鼠LD_(50)>6180mg/os).因而,普遍认为Ebselen及其类似物是一类具有广谱抗炎活性的潜在药物,在医药领域具有广阔的应用前景.     

胆汁酸盐对胆红素钙沉淀过程的影响

研究了六种人胆汁主要胆汁酸盐对胆红素钙沉淀形成过程的影响。用曲线拟合法处理数据取得热力学及动力学参数。结果表明,六种胆汁酸盐都表现动力学和热力学抑制,而且抑制作用有浓度依赖关系。在一定条件下出现诱导期。虽然不同胆汁酸盐的作用结果相似,但在相同条件下,二羟基胆汁酸和三羟基胆汁酸影响程度不同。     

Assembly of a supramolecular cube, [(Cp*WS3Cu3)8 Cl8(CN)12Li4] from a preformed incomplete cubane-like compound [PPh4][Cp*WS3(CuCN)3

A supramolecular cube has been formed by linking WS3Cu3 clusters with bidentate ligands. Eight WS3Cu3 clusters, which have an incomplete cubane-like structure, serve as the three connecting nodes of the cube, while 12 bridging cyanide anions coordinated to copper centers lie along the edges of the cube. Eight chloride anions and four lithium cations are located inside the cube.     

Spectroscopic Interrogation of Layer-by-layer Assembled Films of Conjugated Polyelectrolytes

Layer-by-layer fluorescent conjugated polyelectrolyte films have been studied. The photoluminescence of conjugate polyelectrolytes was observed to be highly tunable during this film assembly process. Efficient photoinduced electron transfer from thus prepared highly luminescent film to a natural electron-transfer protein cytochrome c has also been observed.     

Poly[[aqua­tetra­imidazole­di‐μ‐phthalato‐dicopper(II)] monohydrate]

The title complex, {[Cu₂(C₈H₄O₄)₂(C₃H₄N₂)₄(H₂O)]·H₂O}_n, is a three‐dimensional polymer formed through bridging by phthalate dianions of two different Cu^II cations and a network of O(N)—H⋯O hydrogen bonds. The Cu—O and Cu—N inter­action distances are in the ranges 2.0020 (16)–2.4835 (17) and 1.968 (2)–1.9855 (19) Å, respectively. The structure is composed of alternating polymer chains parallel to the c axis, with a shortest Cu⋯Cu distance of 6.3000 (5) Å.     

Selective bonding of pyrazine to silicon(100)-2x1 surfaces: the role of nitrogen atoms

The covalent binding of pyrazine on Si(100) have been investigated using high-resolution electron energy loss spectroscopy (HREELS) and x-ray photoelectron spectroscopy. Experimental results clearly suggest that the attachment occurs exclusively through the bonding of the two para-nitrogen atoms with the surface without the involvement of the carbon atoms, as evidenced from the retention of the (sp2) C-H stretching mode in HREELS and a significant down shift of 1.6 eV in the binding energy of N 1s. The binding mechanism for pyrazine on Si(100) demonstrates that reaction channels for heteroatomic aromatic molecules are strongly dependent on the electronic properties of the constituent atoms.     

Ar n HF van der Waals clusters revisited. I. New low-energy isomeric structures for n=6-13

New low-lying isomeric structures of Ar(n)HF clusters are reported for n=6-13. They were determined using simulated annealing and evolutionary programming, for pairwise additive intermolecular potential energy surfaces. New global minima were found for the clusters with n=7, 10, 11. The new lowest-energy structure of Ar(7)HF and several new local minima for n=6, 7 clusters have the HF bound on a threefold surface site, consistent with the recent spectroscopic data for Ar(n)HF clusters in helium nanodroplets. A new type of low-energy local minima were determined for n=9-13 clusters.     

Novel hydrogen-bonded three-dimensional network complexes containing cobalt-pyridine-2,6-dicarboxylic acid

The novel complex, Co(H₂O)₅[Co(2,6-pydc)₂] (1) has been prepared in aqueous solution and characterized by single-crystal X-ray diffraction, elemental analyses and i.r. spectra. X-ray structural analysis revealed that three novel compounds each possess both – stacking and hydrogen-bonding interaction three-dimensional (3-D) networks.     

Self-assembled multivalent vancomycin on cell surfaces against vancomycin-resistant enterococci (VRE)

A vancomycin (Van) derivative self-assembles in a phosphate buffer as a divalent Van and on cell surfaces as a multivalent Van, which offers potent activity against VRE.