Skeletal Reorganization of Mercaptoacetaldehyde Dialkyl Acetal in Acid: Formation of Disulphide, 1,2-Bis(mercapto)ethylene and 1,1,2-Tris(mercapto)ethane Derivatives

The reaction of mercaptoacetaldehyde dialkyl acetals 1 a-c in the presence of sulfuric acid, polyphosphoric acid and zinc chloride is described. Other than the disulfide reported previously, new compounds 1,2-bis-(mercapto)ethylene, 1,2,3-tris-(mercapto)ethane and 1,2-bis-(mercapto)methane have been isolated for the first time.     

亚硝基R盐和乙基紫高灵敏度分光光度法测定铋

乙基紫在酸性体系中作为显色剂已有不少报道,而在碱性中未曾见过.本法表观摩尔吸光系数7.73×10~6 L·mol~(-1)·cm~(-1),操作简便,用于试样分析,结果满意.     

Asymmetric borane reduction of prochiral ketones catalyzed by phosphinamides prepared from L‐serine

Synthesis of several new chiral phosphinamide catalysts with a proximal hydroxyl group from L ‐serine was described. These compounds have been successfully used in the asymmetric catalytic borane reduction of prochiral ketones. The optically active secondary alcohols were obtained with an enantiomeric excess (ee) up to 81% and excellent yields. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:288–291, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10145     

Remarkable synergistic effect in cobalt-iron nitride/alloy nanosheets for robust electrochemical water splitting

Design and synthesis of noble-metal-free bifunctional catalysts for efficient and robust electrochemical water splitting are of significant importance in developing clean and renewable energy sources for sustainable energy consumption.Herein,a simple three-step strategy is reported to construct cobalt-iron nitride/alloy nanosheets on nickel foam(CoFe-NA/NF)as a bifunctional catalyst for both hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).The electrocatalyst with optimized composition(CoFe-NA2/NF)can achieve ultralow overpotentials of 73 mV and 250 mV for HER and OER,respectively,at a current density of 10 mA cm^-2 in 1 M KOH.Notably,the electrolyzer based on this electrocatalyst is able to boost the overall water splitting with a cell voltage of 1.564 V to deliver 10 mA cm^-2 for at least 50 h without obvious performance decay.Furthermore,our experiment and theoretical calculation demonstrate that the combination of cobalt-iron nitride and alloy can have low hydrogen adsorption energy and facilitate water dissociation during HER.In addition,the surface reconstruction introduces metal oxyhydroxides to optimize the OER process.Our work may pave a new pathway to design bifunctional catalysts for overall water splitting.     

Synthesis of chiral 2‐oxo‐ and 2‐thio‐1,3,2‐oxazaphospholidines via the asymmetric cyclization of l‐serinoates with (thio)phosphoryl dichlorides

In this article, we have described the asymmetric cyclization of L‐serinoates and N‐benzyl L‐serinoate with phosphoro(no‐)dichloridates or their thio‐analog, respectively, and we have investigated the asymmetric induction effect of the chiral carbon center on the forming of a chiral phosphorus center. The diastereomeric excess percentages (de%) of the desired products 2‐oxo‐ and 2‐thio‐1,3,2‐oxazaphospholidines, are obtained based on their ³¹P NMR data. In some cases, the cyclization products have been separated as pure diastereomers by column chromatography. Their configuration is preliminarily discussed. © 2000 John Wiley & Sons, Inc. Heteroatom Chem 11:187–191, 2000     

Metalloporphyrin Dendrimers with Folding Arms

Rigid and flexible linkers are combined in the new dendrimer shown schematically in the picture, which contains nine metalloporphyrin units (Porph). The construction is such that the four “arms” of the dendrimer can fold in a cooperative and predetermined manner in response to added 1,4-diazabicyclo[2.2.2]octane (DABCO).     

A μ-1,1,1,3,3,3 Azide Anion inside a Trigonal Prism of Silver Centers

Layers of face- and edge-sharing trigonal Ag ₆ prisms , of which half are filled with azide units, are contained in the novel compound AgN₃⋅2 AgNO₃ (see structure). Pendant η¹-nitrate groups are attached to both sides of each layer.