A new electrochemical sensor based on carbon paste electrode/Ru(III) complex for determination of nitrite: Electrochemical impedance and cyclic voltammetry measurements

International audienceThe modified carbon paste electrode with Ru(III) complex was studied as a novel sensor for the determination of nitrite. The behavior of NO2− at the electrode surface was investigated using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). EIS provided useful information on the charge transfer resistance (R) at the electrode/solution. The EIS measurements showed that R is low at oxidation potentials, and decreases with increasing temperature. The increase of the constant phase element with temperature is due to the accumulation of nitrite on the electrode, thus, facilitating the electron transfer between electrode and NO2−. CV was used to study the effect of pH on the electro-catalytic oxidation of NO2− and to determine the limit of detection (LOD). CV measurements showed a good linear relationship between the oxidation current and the concentration of NO2− over a wide concentration range 0–1.38 × 10−2 mol L−1. Low detection limit of 1.39 × 10−6 mol L−1 toward NO2− was obtained. LOD decreased by 23.2% compared to that determined using cavity microelectrode. © 2016 Elsevier Lt

Synthesis, characterization and molecular modeling of binuclear Pd(II) and Ir(IV) complexes with bis [4-hydroxy-6-methyl-3-{(1E)-N-[2-(ethylamino)ethyl]ethanimidoyl}-2H-pyran-2-one] Application to detection of glucose

International audienceTwo binuclear Pd (II) and Ir(IV) complexes with new bis [4-hydroxy-6-methyl-3-{(1E)-N-[2-(ethylamino) ethyl] ethanimidoyl}-2H-pyran-2-one] ligand (Schiff base L) have been prepared and characterized by elemental analysis, ESI-MS, conductivity, NMR (1H NMR, 13C NMR, COSY-NMR, HMBC-NMR and HSQC-NMR), EPR, FT-IR, ATR, UV–Visible spectra and cyclic voltammetry. Both antioxidant and antimicrobial activities were studied; the stability constants of the metal complexes and their interactions with glucose were estimated using spectrophotometric method. In addition, the detection of glucose using Pd(II) and Ir(IV) complexes was investigated using cavity microelectrode (CME) by chronoamperometric method. The characterization results and the molecular parameters were determined using DFT technique; a square planar geometry around Pd (II) and an octahedral geometry around Ir(IV) was found. The antioxidant measurements showed that the ligand and its complexes exhibited remarkable activity, and the antimicrobial studies revealed that all compounds are biologically active for some bacteria and fungi. Electrochemical measurements showed the presence of sensitive responses towards glucose using both Pd(II) and Ir(IV) complexes; these results were found to be higher than other materials around glucose concentration range of 0–4 mM. © 201

Fishing anti-inflammatories from known drugs: In silico repurposing, design, synthesis and biological evaluation of bisacodyl analogues

Herein is described in silico repositioning, design, synthesis, biological evaluation and structure-activity relationship (SAR) of an original class of anti-inflammatory agents based on a polyaromatic pharmacophore structurally related to bisacodyl (BSL) drug used in therapeutic as laxative. We describe the potential of TOMOCOMD-CARDD methods to find out new anti-inflammatory drug-like agents from a diverse series of compounds using the total and local atom based bilinear indices as molecular descriptors. The models obtained were validated by biological studies, identifying BSL as the first anti-inflammatory lead-like using in silico repurposing from commercially available drugs. Several biological in vitro and in vivo assays were performed in order to understand its mechanism of action. A set of analogues of BSL was prepared using low-cost synthetic procedures and further biologically investigated in zebrafish models. Compound 5c and 7e exhibited the best antiinflammatory activities and represent new promising anti-inflammatory agents for further preclinical development.Dany Siverio-Mota acknowledges the Laboratory for Molecular Biodiscovery, Department of Pharmaceutical and Pharmacological Sciences, University of Leuven (Belgium) for kind hospitality and VLIR (Vlaamse InterUniversitaire Raad, Flemish Interuniversity Council, Belgium) under the IUC Program VLIR-UCLV for in part financial support of this work. Yovani Marrero Ponce thanks the program ‘Estades Temporals per a Investigadors Convidats’ for a fellowship to work at Universitat de València, Spain. The spanish Ministry of Science and Innovation (project SAF2009- 10399) and LabEx LERMIT (ANR-10-LABX-33) are also acknowlwdged for the financial supportPeer Reviewe

Fishing Anti-Inflammatories from Known Drugs: In Silico Repurposing, Design, Synthesis and Biological Evaluation of Bisacodyl Analogues

International audienc

Effect of organoclay modifier structure on the viscoelastic and thermal properties of poly(methyl methacrylate)/organoclay nanocomposites

Poly(methyl methacrylate) (PMMA)/clay nanocomposites (NCs) were prepared by suspension polymerization of methyl methacrylate in the presence of two different organoclays (Cloisite 30B, Cloisite 15A) with clay loading ranged from 0.5 to 5 wt%. Increase in molecular weight of the PMMA matrix with addition of the clay was revealed by gel permeation chromatography (GPC) and intrinsic viscosity measurements. As confirmed by X-ray diffraction (XRD), the NCs had an intercalated structure. The organoclays-MMA/PMMA compatibility was investigated by swelling tests and solubility parameter approach. Rheological behavior of PMMA NCs in molten state was analyzed through construction of master curves of complex viscosity, storage, and loss modulus by applying the time-temperature superposition procedure. Melt rheology, scanning electron microscopy (SEM), and UV/Vis spectroscopy results confirmed higher extent of clay dispersion in the NCs with Cloisite 30B. Compared to pure PMMA, all these NCs show increase of glass transition temperature as measured by DSC and improved thermal stability determined by thermogravimetric analysis (TGA). The results obtained by dynamic mechanical analysis showed that the storage modulus of the NCs was higher by incorporation of clay into the PMMA matrix, increasing as the amount of clay increased and that their mechanical performance was significantly enhanced