Oxocentered Units in Three Novel Rb‐Containing Copper Compounds Prepared by CVT Reaction Method

Three novel copper compounds, Rb₄Cu₄OCl₁₀ ( I ), Rb[Cu₃O](SeO₃)₂Cl ( II ), and RbCu₃(OH)(SeO₃)Cl₄(H₂O)₃ ( III ) were prepared by chemical vapor transport (CVT) reactions method from mixtures of CuO, SeO₂, RbCl, and CuCl₂. The crystal structures of the three compounds were determined by direct methods. Compound I is a Rb analogue of ponomarevite, K₄Cu₄OCl₁₀. Its crystal structure contains {[OCu₄]Cl₁₀}^4– clusters with oxocentered [OCu₄]⁶⁺ tetrahedra as cores. The clusters are linked by the Rb⁺ cations. The crystal structure of II contains complex {[O₂Cu₆](SeO₃)₄Cl₂}^2– layers formed by dimers of edge‐sharing [OCu₄]⁶⁺ tetrahedra interlinked via selenite groups and Cl^– anions. The crystal structure of III is based upon {[(OH)Cu₃](SeO₃)}³⁺ layers formed by the [(OH)Cu₃]⁵⁺ tetrahedra attached to (SeO₃)^2– groups. The layers are linked via Cl^– anions and via hydrogen bonds to H₂O molecules.     

Direct Electron Transfer Reaction of Ascorbate Oxidase Immobilized by a Self‐Assembled Monolayer and Polymer Membrane Combined System

This paper reports a novel enzyme‐immobilization method for the direct electron transfer (DET) reaction of ascorbate oxidase from Acremonium sp. HI‐25 (ASOM). ASOM was adsorbed onto a gold electrode modified with a self‐assembled monolayer (SAM) of alkanethiol derivatives and immobilized by a cationic polymer membrane and anionic ω‐carboxyalkanethiol combined system. The redox responses of the immobilized ASOM were investigated by cyclic voltammetry. We found that the DET reaction of ASOM was facilitated by this novel immobilization. On the other hand, the redox responses of poly(ethylene oxide) (PEO)‐modified ASOMs were also investigated. ASOM was modified with two types of PEO which possess straight chain‐shaped (PEO₂₀₀₀) or comb‐shaped conformation (PM₆₇). As a result, the DET reactions of PEO‐modified ASOMs were also facilitated by this immobilization method. We concluded that this immobilization method is effective for promoting the DET reaction of ASOMs.     

Continuous Reversible Addition‐Fragmentation Chain Transfer Polymerization in Miniemulsion Utilizing a Multi‐Tube Reaction System

Summary: A unique, multi‐tube, continuous reactor has been successfully designed and implemented for the study of reversible addition‐fragmentation chain transfer (RAFT) in miniemulsions. Data collection is greatly enhanced by the ability to simultaneously collect samples at five different residence times. The results of a styrene homopolymerization show that kinetically, the reactor exhibits similar behavior to a batch reaction. Number‐average molecular weights increased linearly with conversion, typical of living polymerizations.

The number‐average molecular weight of the polymers produced in the tubular reactor increased linearly with conversion, indicative of a controlled polymerization.     

酪氨酸-溴酸钾-硫酸-丙酮在三邻菲啰啉合铁(Ⅱ)催化下的B-Z振荡反应

研究了酪氨酸-溴酸钾-硫酸-丙酮在三邻菲啰啉合铁(Ⅱ)催化下的化学振荡反应,对振荡的影响因素进行了研究和讨论.运用正交实验法确立了振荡反应进行的浓度范围,得到一个40多次振荡寿命为60 min的振荡波.获得振荡的诱导期和周期与反应物浓度之间的变化趋势曲线,以及振荡反应在诱导期和振荡期的表观活化能分别为Ein=49.0 kJ/mol和E=57.0 kJ/mol.根据反应过程中的现象和实验数据,建立了振荡反应的模型和反应机理,确定[Br-]是振荡反应自发进行的关键因素.     

Catalytic Activity of Alkali Metal Cations for the Chemical Oxygen Reduction Reaction in a Biphasic Liquid System Probed by Scanning Electrochemical Microscopy

Chemical reduction of dioxygen in organic solvents for the production of reactive oxygen species or the concomitant oxidation of organic substrates can be enhanced by the separation of products and educts in biphasic liquid systems. Here, the coupled electron and ion transfer processes is studied as well as reagent fluxes across the liquid|liquid interface for the chemical reduction of dioxygen by decamethylferrocene (DMFc) in a dichloroethane-based organic electrolyte forming an interface with an aqueous electrolyte containing alkali metal ions. This interface is stabilized at the orifice of a pipette, across which a Galvani potential difference is externally applied and precisely adjusted to enforce the transfer of different alkali metal ions from the aqueous to the organic electrolyte. The oxygen reduction is followed by H₂O₂ detection in the aqueous phase close to the interface by a microelectrode of a scanning electrochemical microscope (SECM). The results prove a strong catalytic effect of hydrated alkali metal ions on the formation rate of H₂O₂, which varies systematically with the acidity of the transferred alkali metal ions in the organic phase.