Effect of film thickness on the electro-reduction of molecular oxygen on electropolymerized cobalt tetra-aminophthalocyanine films

We studied the electrocatalytic activity of cobalt tetra-aminophthalocyanine (CoTAPc) for the reduction of molecular oxygen (O₂) on adsorbed monomeric and on electropolymerized films of different thicknesses on glassy carbon (GC) electrode. The polymeric films, denoted poly-CoTAPc, were first characterized by electrochemical impedance spectroscopy and it appears that the types of phenomena revealed to be occurring depend less on the film thickness in basic than in acid media. For O₂ reduction, the results showed that poly-CoTAPc is more active than the monomeric CoTAPc adsorbed on GC. Indeed, rotating ring-disk electrode data showed that polymeric CoTAPc promotes the four-electron reduction of O₂ to water in parallel to a two-electron reduction to give peroxide. On monomeric and thin films of poly-CoTAPc, a two-electron reduction mechanism predominates. In basic media the activity increases very slightly with thickness, whereas in acid media this increase is more pronounced. This parallels the observed behavior revealed by electrochemical impedance spectroscopy.     

Heterocyclisation of Unsaturated Phenylsulfides. Synthesis of a Novel Series of 2 Substituted-2,3-dihydrobenzothiazoles

Aminoarylhydroxy thioalkenes react with tosyl derivatives to provide mainly N substituted -2 vinyl -2,3 dihydrobenzothiazoles. A different regiochemistry of cyclization depending on whether a methyl or a phenyl susbtituent was used, was observed Formation of -2H-3,4-dihydrobenzothiazines and dienes was observed.     

Asymptotic normality of the extreme quantile estimator based on the POT method

The POT (Peaks-Over-Threshold) approach consists in using the generalized Pareto distribution (GPD) to approximate the distribution of excesses over thresholds. In this Note, we propose extreme quantile estimators based on this method. We establish their asymptotic normality under suitable general assumptions. To cite this article: J. Diebolt et al., C. R. Acad. Sci. Paris, Ser. I 341 (2005).     

Phosphorus dendrimers as viewed by 31P NMR spectroscopy; synthesis and characterization

This review emphasizes the role of phosphorus for the elaboration of dendrimers and of various highly sophisticated dendritic structures, and the invaluable role played by ³¹P NMR for their characterization and to ascertain their purity. A few properties, highlighting the importance of phosphorus are reported at the end of this review.     

A potential fortuitous binding of inhibitors of an inverting family GH9 β-glycosidase derived from isofagomine

Using structural insight, the binding mode of isofagomine-derived inhibitors with family GH9 glycosidases is achieved via the study of Alicyclobacillus acidocaldarius (AaCel9A) endoglucanase. In contrast to what was observed in the first report using these compounds with inverting glycosidases from family GH6, these inhibitors do not adopt a distorted conformation in the active site.     

Conditional marginal expected shortfall

Extremes - In the context of bivariate random variables $\left (Y^{(1)},Y^{(2)}\right )$ , the marginal expected shortfall, defined as $\mathbb {E}\left (Y^{(1)}|Y^{(2)} \ge Q_{2}(1-p)\right )$ for...