Highly flexible polyelectrolyte nanotubes

A pressure-filter-template approach was employed to prepare polyelectrolyte nanotubes through layer-by-layer deposition in the alumina template. With the thicker wall, the ordered polymer nanotubes possess a high flexibility. The results demonstrate that the electrostatic interactions of polyelectrolytes play a key role in fabricating water-soluble charged polymer nanotubes. The structure of the polyelectrolyte nanotube was confirmed by SEM, TEM, and UV, respectively.     

色谱法在三氯半乳蔗糖合成中的应用

采用薄层色谱和柱色谱法，选择优化展开体系，有效地分析了三氯半乳蔗糖中间体2，3，6，3′，4′-五氧乙酰蔗糖混合物，并证实该混合物中杂质为三苯甲醇，为三氯半乳蔗糖的合成研究取得了重要发现。     

Preparation and Characterization of Three-dimensionally Ordered Crystalline Macroporous CeO2

Three-dimensional ordered macroporous (3DOM) materials are of great potential importance in catalysis, selective separation, sensor arrays and communications with optical band gaps1. Many results in the synthesis of 3DOM materials have been reported, such as closed-packed silica spheres or polystyrenes (PS) templating routes for silica2, metal oxides1-6 and metals7. Recently, poly(methyl methacrylate) (PMMA) colloidal crystal templates have been used to prepare 3DOM materials of metals8,…     

Syntheses and structures of mono-, di- and tetranuclear rhodium or iridium complexes of thiacalix[4]arene derivatives

The reactions of [Cp*MCl2]2(Cp*=eta5-C5Me5, M = Rh, Ir) with thiacalix[4]arene (TC4A(OH)4) and tetramercaptothiacalix[4]arene (TC4A(SH)4) gave the mononuclear complexes [(Cp*M){eta3-TC4A(OH)2(O)2}] and the dinuclear complexes [(Cp*M)2{eta3eta3-TC4A(S)4}] respectively, while the analogous reactions with dimercaptothiacalix[4]arene (TC4A(OH)2(SH)2) produced the tetranuclear complexes [(Cp*M)2(Cp*MCl2)2-{eta3eta3eta1eta1-TC4A(O)2(S)2}].     

A new-type photoreaction of a carbonyl compound: Part 2. Photoinduced ω-bond dissociation in p-halomethylbenzophenone studied by time-resolved EPR technique and laser flash photolysis

Photodissociation of the carbon-X (X = Br and Cl) bonds in p-bromo- and p-chloromethylbenzophenone (BMBP and CMBP) in solution were investigated by time-resolved EPR and laser flash photolysis techniques. BMBP and CMBP were found to undergo ω-bond cleavage to yield the p-benzoylbenzyl radical (BBR) at 295 K, and the quantum yields (Φ_BBR) were determined. The CIDEP signal originated from BBR formed upon decomposition of CMBP was obtained while that for BMBP was absent. By using triplet sensitization of acetone, the efficiencies (_BBR) of the CX bond fission in the triplet states of BMBP and CMBP were determined. The agreement between the Φ_BBR and _BBR values for CMBP indicates that the CCl bond dissociation occurs only in the triplet state. In contrast to CMBP, the cleavage of the CBr bond in BMBP upon direct excitation was concluded to be the event only in the excited singlet state without triplet formation, whereas the triplet state was also reactive for ω-bond dissociation. The rate of CBr bond dissociation seemed to be greater than that of intersystem crossing from the S₁ to the T₁ state. Schematic energy diagrams of the excited states of BMBP and CMBP were shown, and the reaction profiles were discussed from the viewpoint of the CX bond enthalpies.     

Magnetic circular dichroism and anomalous fluorescence spectra of [2,2] (2,6)azulenophanes

The electronic absorption spectra of syn-[2,2] (2,6) azulenophane (1) and anti-[2,2] (2,6)azulenophane (2) were investigated via magnetic circular dichroism spectra. The anomalous fluorescence spectra were also observed. From the assignment of the absorption spectra, it was concluded that molecules 1 and 2 emitted the fluorescence from the third excited singlet state.     

Metal-ion-assisted hydrolysis of dipeptides involving a serine residue in a neutral aqueous solution

Dipeptides having a serine residue at the C-terminus, X-Ser, where X is an appropriate amino acid residue, were efficiently hydrolyzed in the presence of ZnCl2 at pH 7.0. The rapid hydrolysis of X-Ser is due to an autocatalysis of the hydroxy group in the serine residue, and is found to be accelerated by a metal ion, in particular by ZnCl2. Roles of the metal ion in the hydrolysis of peptides involving a serine residue, in relation to the recently reported protein cleavages, are discussed.