Evaluation of manganese and oxygen content in La0.7Sr0.3MnO3−δ and correlation with the thermodynamic data

In order to understand how the thermodynamic properties are related to the oxygen and manganese content in the Sr-doped lanthanum manganites, nonstoichiometric perovskite phases La_0.7Sr_0.3MnO_3−δ have been investigated by using solid state electrochemical techniques, as well as wet chemical methods. The influence of the oxygen stoichiometry change on the thermodynamic properties was examined using the data obtained by a coulometric titration technique coupled with solid state electromotive force measurements (EMF). The results were correlated with the average Mn valence values as determined by a chemical method based on two independent iodometric titrations, with amperometric dead-stop end point detection. New features related to the relationship between the average Mn valence, the oxygen nonstoichiometry variation, and the thermodynamic behavior were evidenced.     

Local interpolants for Numerov‐type methods and their implementation in variable step schemes

The classical explicit fourth‐order Numerov‐type method is considered. The equations of condition for deriving the corresponding interpolants are given. Then using a local error estimation, we may construct a stable variable step scheme. Applying this new implementation in a set of problems, we get very pleasant results.     

(Z,Z)-Selanediylbis(2-propenamides): Novel Class of Organoselenium Compounds with High Glutathione Peroxidase-Like Activity. Regio- and Stereoselective Reaction of Sodium Selenide with 3-Trimethylsilyl-2-propynamides

The efficient regio- and stereoselective synthesis of (Z,Z)-3,3′-selanediylbis(2-propenamides) in 76–93% yields was developed based on the reaction of sodium selenide with 3-trimethylsilyl-2-propynamides. (Z,Z)-3,3′-Selanediylbis(2-propenamides) are a novel class of organoselenium compounds. To date, not a single representative of 3,3′-selanediylbis(2-propenamides) has been described in the literature. Studying glutathione peroxidase-like properties by a model reaction showed that the activity of the obtained products significantly varies depending on the organic moieties in the amide group. Divinyl selenide, which contains two lipophilic cyclohexyl substituents in the amide group, exhibits very high glutathione peroxidase-like activity and this compound is considerably superior to other products in this respect.     

A highly-enriched 244Pu reference material for nuclear safeguards and nuclear forensics measurements

Journal of Radioanalytical and Nuclear Chemistry - A highly-enriched 244Pu isotope dilution reference material has been prepared and characterized for metrologically traceable measurements of very...     

Quantum-chemical study of the mechanism of aminomethylation of tetrazoles according to the elimination–addition scheme without preliminary formation of N-protonated azolium salts

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Novel positive allosteric modulator of AMPA-receptors based on tricyclic scaffold

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One-pot two-step stannylation/Stille homocoupling of aryl bromides and iodides under solvent-free conditions

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