Electrochemical performance of LaNi0.6Co0.4O3-δ–Ce0.9Gd0.1O1.95 composite electrode and evaluation of its effective reaction length

Journal of Solid State Electrochemistry - The electrochemical properties of LaNi0.6Co0.4O3-δ–Ce0.9Gd0.1O1.95 composite electrodes as a function of temperature and p(O2) were investigated...     

Iron-catalyzed δ-selective conjugate addition of methyl and cyclopropyl Grignard reagents to α,β,γ,δ-unsaturated esters and amides

Iron-catalyzed δ-selective conjugate addition of methyl and cyclopropyl Grignard reagents to α,β,γ,δ-unsaturated esters and amides took place in good yields to give products exclusively with cis-β,γ-olefinic bond.     

Fluorine-containing amino acids and their derivatives. 6. An efficient synthesis of β-fluorinated alanines via fluorohalomethylation of aminomalonates

Aminomalonates, e.g., $\text{1}$ and $\text{2}$, smoothly reacted with difluoro- and chlorofluorocarbene to produce the adducts ($\text{3}$, $\text{4}$, and $\text{5}$) in good yields. These products were successfully converted to various versatile β-fluorinated alanine derivatives, i.e., β,β-difluoroalanine ($\text{6}$), N-acyl-β-fluorodehydroalaninate ($\text{7}$), and fluoropyruvic acid ($\text{8}$).     

2-Oxabutane as a substitute for internal monomer units of oligosaccharides to create lectin ligands

The synthesis of bioactive oligosaccharides is too tedious to scale up for commercialization. However, structurally simplified glycomimetics are commercializable, if they can be synthesized much more easily than the oligosaccharides while having a comparable bioactivity. In this study, we propose a 2-oxabutane (OB) structure as an imitation of the internal monosaccharide units in oligosaccharides. Two trimannoside and three pentamannoside OB-glycomimics were synthesized in remarkably short steps. Among them, Manα1-OB-2Man 10, a trimannoside mimic, showed eight-fold affinity toward concanavalin A (ConA) relative to methyl mannoside in latex agglutination lectin assay and equilibrium dialysis assay (EDA), while the other mimics showed three- to four-fold affinities. EDA indicated that the bindings between each mimic molecule and a ConA subsite were all in one-to-one stoichiometry and thus these mimics were monovalent ligands, excluding multivalence effect for the high affinities. The strong affinity of 10 could be explained by the occupation of two mannose binding sites of a ConA subsite by its two mannose units. Mimic 10 proved to be even a better ligand for ConA than the natural disaccharide Manα1,2Man, while been much more easy to synthesize, thereby illustrating the potential of the approach here presented.     

Rare earth metal trifluoromethanesulfonates catalyzed benzyl-etherification

Rare earth metal trifluoromethanesulfonates [rare earth metal triflate, RE(OTf)3] were found to be efficient catalyst for benzyl-etherification. In the presence of a catalytic amount of RE(OTf)3, condensation of benzyl alcohols and aliphatic alcohols proceeded smoothly to afford the benzyl ethers. The condensation between benzyl alcohols and thiols also proceeded, and thio ethers were obtained in good yield. In these reactions, RE(OTf)3 could be recovered easily after the reactions were completed and could be reused without loss of activity.     

A kinetic method for the determination of copper(II) by its catalytic effect on the oxidation of 3-methyl-2-benzothiazolinone hydrazone with hydrogen peroxide: a mechanistic study.

A catalytic spectrophotometric method for the determination of traces of copper(II) is proposed. 3-Methyl-2-benzothiazolinone hydrazone (MBTH) is oxidized by hydrogen peroxide to form a yellowish-brown compound. The reaction is accelerated by trace amounts of copper(II), and can be followed by measuring the increase in the absorbance at 390 nm. Since the absorbance at 40 min from the reaction start increases with an increase in the copper(II) concentration, the absorbance value is used as a parameter for copper(II) determination. Under the optimum experimental conditions (8.4 x 10(-3) mol dm(-3) MBTH, 0.7 mol dm(-3) hydrogen peroxide, pH 5.2, 35 degrees C), copper(II) can be determined in the range 0-50 microg dm(-3). The relative standard deviations are 6.9, 3.5, 2.7% for 2, 20 and 40 microg dm(-3), respectively. The detection limit of this method (3sigma) is 0.27 microg dm(-3). It was successfully applied to a determination of copper(II) in river water, tap water and ground-water samples. According to the results of a kinetic study, a mechanism is proposed which leads to the following rate equation: R0(cat) = kK1K2[MBTH][H2O2][Cu(II)]0/{(1 + K2[H2O2])[H+]}.     

Cobalt Ion-Doped TiO(2) Photocatalyst Response to Visible Light

Photocatalytic activity under visible light irradiation was generated by doping a small amount of Co(2+) ions into TiO(2) particles. Nanometer-sized particles with the composition xCoO-(100-x) TiO(2) (xCo/TiO(2); 0300 nm) light irradiation but also induced the visible light (lambda>400 nm) response. The highest photocatalytic activities were obtained at x=0.03 for both irradiations. Copyright 2000 Academic Press.     

Synthesis and properties of TSF-based spin-polarized donor

A novel organic donor radical, TSBN, which is a benzotetraselenafulvalene derivative carrying a nitronyl nitroxide group in a cross-conjugated manner was prepared. X-ray crystallographic analysis revealed that TSBN forms a sheet-like network within the ac plane through intermolecular chalcogen contacts. Its spin-polarized structure was confirmed by cyclic voltammogram, ESR spectra of singly oxidized species and DFT calculation. The neutral crystal of TSBN showed nonlinear I–V characteristics at 2 K and exhibited negative magnetoresistance (?5% at 2 K under 5 T).