Hybrid Materials Based on Conducting Polymers for Nitrite Sensing: A Mini Review

Well-known as a hazardous compound, nitrite constitute a real threat to the public health. So, there is a pressing need to detect and quantify them in different matrix. Even though conventional analytical methods can be used to address this issue, electrochemistry allows a fast, sensitive, and efficient analysis. Conducting polymers continue to raise great interest among scientific communities due to their properties. Moreover, their combination with carbon nanomaterials, or metallic nanoparticles improves their properties, and provides great results. In this paper, we will focus on some revealing works devoted to the electrochemical detection of nitrite using this kind of materials.     

Precursor Carboxy-silica for Functionalization With Interactive Ligands. II. Carbodiimide Assisted Preparation of Silica Bonded Stationary Phases with D-glucamine for Hydrophilic Interaction Liquid Chromatography

Chromatographia - A precursor carboxy-silica support was introduced for grafting a retentive polar ligand, namely D-glucamine, for use in hydrophilic interaction liquid chromatography. This support...     

A PDE based and interpolation-free framework for modeling the sifting process in a continuous domain

The empirical mode decomposition (EMD) is a powerful tool in signal processing. Despite its algorithmic origin making its theoretical analysis and formulation very difficult, a few recent works has contributed to its theoretical framework. Herein, the former local mean is formulated in a more convenient way by introducing operators to calculate local upper and lower envelopes. This enables the use of differential calculus and other classical calculations on the new local mean. Based on its more accurate formulation, a partial differential equation (PDE) consistency result is provided to approximate the sifting process iterations, without any envelope interpolation. In addition, a new stopping criterion based on the introduced local mean is proposed. This new criterion is a local measure and resolves the null integral conservative property of the previous derived PDE, which made any signal having a null integral be a PDE-based mode. Moreover, the δ inner model parameter is now linked to the signal intrinsic properties, providing to the latter a physical meaning and making the proposed model keep the auto-adaptive property of the EMD. New decomposition modes are now analytically and fully characterized, and also interpolation free. Finally, properties of the interpolation free PDE model are presented. Results obtained with our proposed approach by explicit computations thanks to the eigendecomposition of the Laplacian operator, and also by numerical resolution of the derived PDE, show noticeable improvements for both stationary and non stationary signals, in comparison to the former EMD algorithm.     

Etude Des Propriétés Physico-Chimiques De ZnRb 4 (P 3 O 9 ) 2 ·6H 2 O

The dehydration of ZnRb 4 (P 3 O 9 ) 2 ·;6H 2 O was investigated, between 25 and 600°;C, by TG-DTA, X-ray diffraction, IR. It leads, between 300 and 500°;C, to a mixture of long chain polyphosphates RbPO 3 and ZnRb 2 (PO 3 ) 4 which stays stable until its melting point. The IR (1400-30 cm m 1 ) and Raman spectra (1400-100 cm m 1 ) of ZnRb 4 (P 3 O 9 ) 2 ·;6H 2 O are reported and assignments of fundamental modes proposed and compared with theoretical results obtained via the MNDO method for P 3 O 9 ring with C s symmetry. (La déshydratation, sous pression atmosphérique, du cyclotriphosphate ZnRb 4 (P 3 O 9 ) 2 ·;6H 2 O, a ét´;e effectuée, entre 25 and 600°;C, par spectrométrie IR, diffraction des rayons X, ATG et ATD. Elle conduit, entre 300 and 500°;C, au mélange de polyphosphates RbPO 3 et ZnRb 2 (PO 3 ) 4 qui reste stable jusqu'à la fusion. Les spectres vibrationnels IR (1400-30 cm m 1 ) et Raman (1400-100 cm m 1 ) du sel étudié ont été interprétés dans le domaine des vibrations de valence et de déformation du cycle P 3 O 9 et comparés avec les résultats des calculs théoriques par la méthode MNDO pour un cycle isolé de symétrie C s .)     

The Carbenic Insertion into the P-P Bond

Abstract

The cycloaddition reactions on Phosphorus Chemistry¹ has allowed a new development of the three membered ring organophosphorus compounds. Starting from functionulized diphosphiranes obtained by action of carbenes on diphosphenes, we have studied their ring opening reactions leading to carbon insertion into P-P bond.     

Phosphorus ozonides adducts

Abstract

Ozone reacts quantitatively on tricoordinated and dicoordinated Phosphorus Compounds. The oxidative addition of ozone on phosphites leads to pentacoordinated or hexacoordinated phosphorus adducts. These adducts are unstable in solution. The decomposition gives the corresponding phosphoric ester with singlet oxygen evolution. In the same conditions, ozone reacts on diphosphene and gives after double bond rupture an adduct: the metaphosphonate. The relative stabilities and oxidative properties are discussed.     

A New Convenient Laboratory Synthesis of Trimethylsilyl Bromide

Trimethylsilyl bromide is prepared in a laboratory scale from trimethylsilyl 4-bromo 2-alkenoates in almost quantitative yield.