Hybrid Materials from Carbon Nanotubes,Nickel Tetrasulfonated Phthalocyanine and Thin Polymer Layers for the Selective Electrochemical Activation of Nitric Oxide in Solution

The elaboration of hybrid materials from single‐wall carbon nanotubes (SWCNT) and tetrasulfonated nickel phthalocyanine (NiTSPc) was electrochemically performed to obtain chemically modified electrodes with improved electrocatalytic activity towards the electrooxidation of nitric oxide (NO). The characterization of these hybrid electrodes was achieved by cyclic voltammetry and AFM. The electrochemical performances of the electrodes towards the oxidation of NO were then analyzed by chronoamperometry and the obtained results show that the presence of SWCNT greatly enhances the electrocatalytic performances in terms of current intensity. Additional coatings were then electrodeposited over the hybrid electrodes to act as selective membranes against four major interfering analytes: nitrite, ascorbate, hydrogen peroxide and L ‐arginine. Several polymer coatings were tested to achieve the best balance between sensitivity to NO and selectivity against interferents.     

Synthesis of 4H-benzo[e]-1,2-selanazin-4-one derivatives: a new heterocyclic ring system

The synthesis of novel 1,2-benzoselenazin-4-ones which are six-membered homologues of ebselen, is described in order to evaluate their glutathione peroxidase-like activity.     

Measurement of thermal radiative and conductive properties of semitransparent materials using a photothermal crenel method

This paper deals with a theoretical and an experimental study allowing the measurement of the radiative and the conductive properties of semitransparent materials. The method consists of applying a crenel heat flux on the front face of a semitransparent sample and recording the temperature at the rear face using an open thermocouple junction.Parameter identification is performed by the minimization of the ordinary least-squares function comparing the measured and the calculated temperatures. This later is obtained from the thermal model describing the heat transfer by conduction and radiation in the medium. This model is built by the thermal quadrupole formalism.Measurements are reported on commercial glasses and plexiglass samples, and the used iterative algorithm is based on the Gauss-Newton method.     

OPTIMIZATION APPROACH FOR THE MONGE-AMPèRE EQUATION

In this paper, we introduce and study a method for the numerical solution of the elliptic Monge-Ampère equation with Dirichlet boundary conditions. We formulate the Monge-Ampère equation as an optimization problem. The latter involves a Poisson Problem which is solved by the finite element Galerkin method and the minimum is computed by the conjugate gradient algorithm. We also present some numerical experiments.     

L-Fourier multipliers for the Dunkl operator on the real line

We consider Fourier multipliers for L^p associated with the Dunkl operator on and establish a version of Hörmander's multiplier theorem. In applying this version, we come up with some results regarding the oscillating multipliers, partial sum operators and generalized Bessel potentials.     

PEDOT/Superoxide Dismutase Electrode Surface Modification for Superoxide Bioelectrochemical Sensing

An amperometric biosensor for the sensitive detection of superoxide was designed utilizing a drop‐coating approach for immobilizing the superoxide dismutase enzyme on Pt electrode modified with a thin layer of poly (3,4‐ethylenedioxythiophene) (PEDOT). The layer electrodeposited on Pt was characterized by cyclic voltammetry and atomic force microscopy (AFM). Then, drop‐coating procedure was chosen for the immobilization of superoxide dismutase (SOD), which was incorporated at the electrode surface using a solution containing SOD, glutaraldehyde and bovine serum albumin (optimized composition: SOD 0.1 % – BSA 2 % – GA 2.5 %.) This simple procedure allows forming a reproducible enzymatic biocomposite layer that allows optimal sensitivity and limit of detection for superoxide sensing. The synergistic effect integrates an effective conductivity and permselectivity attributed to the PEDOT layer, as well as the specificity and selectivity of SOD for the detection of superoxide. A high sensitivity (0.82±0.01 μA/μM) and a low detection limit of 11 nM were obtained, as well as good selectivity against main interfering biological compounds such as uric acid and ascorbic acid. Our results suggest that the biosensor could be used for the detection and quantification of in vitro and in vivo.     

Another example of carborane based trianionic ligand: Syntheses and catalytic activities of cyclohexylamino tailed ortho-carboranyl zirconium and titanium dicarbollides

In situ reaction of Li[closo-1-Ph-1,2-C₂B₁₀H₁₀] with 7-azabicyclo [4.1.0] heptane results in the formation of the disubstituted carborane, closo-1-Ph-2-(2′-aminocyclohexyl)-1,2-C₂B₁₀H₁₀ (1), in 63% yield. Decapitation of (1) with potassium hydroxide in refluxing ethanol produces the cage-opened nido-carborane, K[nido-7-Ph-8-(2′-aminocyclohexyl)-7,8-C₂B₉H₁₀]⁻ (2), in 80% yield. Deprotonation of the above monoanion with two equivalents of n-butyllithium followed by reaction with anhydrous MCl₄ · 2THF (M = Zr, Ti) provides d⁰-half-sandwich metallocarboranes, closo-1-M(Cl)-2-Ph-3-(2′-σ-(H)N-cyclohexyl)-2,3-η⁵-C₂B₉H₉ (3 M = Zr; 4 M = Ti) in 53% and 42% yields, respectively. The reaction of Li[closo-1,2-C₂B₁₀H₁₁] with 7-azabicyclo [4.1.0] heptane in THF affords closo-1-(2′-aminocyclohexyl)-1,2-C₂B₁₀H₁₀ (5) in 59% yield. Immobilization of the carboranyl amino ligand (1) to an organic support, Merrifield’s peptide resin (1%), has been achieved by the reaction of the sodium salt of (5) with polystyryl chloride in THF to produce closo-1-(2′-aminocyclohexyl)-2-polystyryl-1,2-C₂B₁₀H₁₀ (6) in 87% yield. Further reaction of the dianion derived from (6) with anhydrous ZrCl₄ · 2THF led to the formation of the organic polystyryl supported d⁰-half-sandwich metallocarborane, closo-1-Zr(Cl)-2-(2′-σ-(H)N-cyclohexyl)-3-polystyryl-2,3-η⁵-C₂B₉H₉ (7), in 38% yield. These new compounds have been characterized by elemental analyses, NMR, and IR spectra. Polymerizations of both ethylene and vinyl chloride with (3) and (7) have been performed in toluene using MMAO-7 (13% ISOPAR-E) as the co-catalyst. Molecular weights up to 32.8 × 10³ (M_w/M_n = 1.8) and 9.5 × 10³ (M_w/M_n = 2.1) were obtained for PE and PVC, respectively.     

Effect of the acid activation levels of montmorillonite clay on the cetyltrimethylammonium cations adsorption

For the first time, the intercalation properties of acid-activated montmorillonites treated at different acid/clay (w/w) ratios with a cationic surfactant cetyltrimethylammonium (C16TMA) hydroxide are reported. The acid activation causes a reduction in the number of cation exchange sides and, hence improves the exfoliation of the silicate sheets at higher pH values. The basal spacing increases significantly from 1.54 to 3.80 nm, and is related to the acid activation extent. The acid activated clays with acid/clay ratios above 0.2 intercalated significant amounts of C16TMA cations with a basal spacing of 3.8 nm compared to the non acid activated montmorillonite with a basal spacing of 2.10 nm. The 13C CP/MAS NMR indicates that the intercalated surfactants exhibit a significant degree of gauche conformation in the acid-activated clays. According to in-situ powder XRD, an increase of the basal spacing to 4.08 nm is observed at intermediate temperatures of 50-150 degrees C for organoclay with basal spacing of 3.80 nm, at higher temperatures above 300 degrees C, the decomposition of the surfactant occurs and the basal spacing decreases to a value of about 1.4 nm, with the persistence of a reflection at 3.8 nm for clay at a higher acid/clay ratio of 0.5.     

Triarylpyridinium-functionalized terpyridyl ligand for photosensitized supramolecular architectures: intercomponent coupling and photoinduced processes

The electronic (absorption spectra) and electrochemical properties of a novel series of triphenylpyridinium (H(3)TP(+)=A) electron-acceptor-based polyad species have been correlated with their steady-state (emission spectra) and time-resolved (ns and ps laser flash photolysis) photophysical behavior (at both 293 and 77 K). These d(6) transition metal complexes (M=Ru(II), Os(II)) of 2,2':6',2"-terpyridines (tpy) are denoted as P0 and P1, depending on whether they incorporate H(3)TP(+)-tpy or H(3)TP(+)-ptpy ligands (ptpy=4'-phenyl-substituted tpy), respectively. For the P0/Ru-based compounds, the luminescence quantum yield and excited-state lifetime of the "[Ru(tpy)(2)](2+)" chromophore have been found to be considerably enhanced at 293 K (e.g., tau=0.56 ns for isolated P0/Ru in acetonitrile vs tau=55 and 27 ns for P0/Ru within P0 A/Ru and P0 A(2)/Ru (A=electron acceptor), respectively). In spite of the lack of conjugation between P0 and A, this behavior has been ascribed to a through-bond mediated electronic substituent effect originating from the directly connected H(3)TP(+) electron-withdrawing group. For the P1-based compounds, the possibility of photoinduced electron-transfer (PET) processes with the formation of charge-separated (CS) states is discussed, and the main results may be summarized as follows: 1) when involved, the electron-donor D (D=Me(2)N of Me(2)N-ptpy) is strongly electronically coupled to P1 but cannot facilitate a reductive quenching of *P1 to give the *[D(+)-P1(-)]-type of CS state for thermodynamic reasons, irrespective of whether M is Ru(II) or Os(II); 2) the P1 and A components have been shown to be very weakly electronically coupled; 3) at 293 K, P1/Ru- and P1/Os-based polyad systems display distinct photophysical behavior with respect to A, with only the latter exhibiting a noticeable quenching of luminescence (up to 50 % for P1 A/Os with respect to P1/Os); 4) for assemblies made up of P1/Os and A components only, comparison between their room-temperature (RT) and low-temperature (LT; 77 K, frozen matrix) photophysical properties, together with information gleaned from combined transient absorption experiments and spectroelectrochemical studies of P1/Os and P1 A/Os, further supported by thermodynamic considerations, allowed us to conclude that a PET process does take place within the P1 A/Os dyad leading to the *[P1(+)-A(-)] CS state. For the DP1 A/Os triad, the formation of such a CS state followed by an enhanced electron-releasing inductive effect from D is postulated.     

Highly Efficient Methylene Blue Dye Removal by Nickel Molybdate Nanosorbent

Removing methylene blue (MB) dye from aqueous solutions was examined by the use of nickel molybdate (α-NiMoO₄) as an adsorbent produced by an uncomplicated, rapid, and cost-effective method. Different results were produced by varying different parameters such as the pH, the adsorbent dose, the temperature, the contact time, and the initial dye concentration. Adsorbent dose and pH had a major removal effect on MB. Interestingly, a lower amount of adsorbent dose caused greater MB removal. The amount of removal gained was efficient and reached a 99% level with an initial methylene blue solution concentration of ≤160 ppm at pH 11. The kinetic studies indicated that the pseudo-second-order kinetic model relates very well with that of the obtained experimental results. The thermodynamic studies showed that removing the MB dye was favorable, spontaneous, and endothermic. Impressively, the highest quantity of removal amount of MB dye was 16,863 mg/g, as shown by the Langmuir model. The thermal regeneration tests revealed that the efficiency of removing MB (11,608 mg/g) was retained following three continuous rounds of recycled adsorbents. Adsorption of MB onto α-NiMoO₄ nanoparticles and its regeneration were confirmed by Fourier transform infrared spectroscopy (FTIR) analysis and scanning electron microscopy (SEM) analysis. The results indicated that α-NiMoO₄ nanosorbent is an outstanding and strong candidate that can be used for removing the maximum capacity of MB dye in wastewater.