SYNTHESIS, ELECTROCHEMICAL AND HETEROGENEOUS ELECTROCATALYTIC BEHAVIORS OF A NOVEL NON SYMMETRICAL COPPER(II) COMPLEX

We describe in this paper the synthesis of new unsymmetrical tetradentate copper(II) Schiff base complex, prepared from tridentate Schiff base ligand (HL) and pyridine molecule. This new copper complex was identified by various physicochemical characteristics such as elemental analysis (EA), FT-IR, UV-Vis, XPS analysis and thermogravimetry (TG/DTG). The electrochemical behavior of the copper(II) complex was investigated by cyclic voltammetry in N,N-dimethylformamide (DMF). These experiments have been allowed to obtain new conducting polymeric films, prepared by successive cycling at the suitable potentials. These polymeric films containing metallic centers were studied to evaluate their electrocatalytical performances in which copper (II) ions were used as electrocatalysts in the heterogeneous conditions for the electroreduction of 1,4-dibromobutane

Dioxygen activation with a cytochrome P450 model. Characterization and electrochemical study of new unsymmetrical tetradentate Schiff-base complexes with iron(III) and cobalt(II)

Salicylaldehyde or 5-bromosalicylaldehyde react with 2,3-diaminophenol to give two unsymmetrical Schiff-bases H2L1, H2L2, respectively. With Fe(III) and Co(II), these ligands lead to four complexes: Fe(III)ClL1, Fe(III)ClL2, Co(II)L1, Co(II)L2. The structures of these complexes were determined by mass spectroscopy, infrared and electronic spectra. Cyclic voltammetry in dimethylformamide (DMF) showed irreversible waves for both ligands. In the same experimental conditions, Fe(III)ClL1 exhibited a reversible redox couple Fe(III)/Fe(II) while the three other complexes showed quasi-reversible systems. The behavior of some of these complexes in the presence of dioxygen and the comparison with cytochrome P450 are described

SURFACE MODIFICATION OF SILICA NANOPARTICLES BY MEANS OF SILANES: EFFECT OF VARIOUS PARAMETERS ON THE GRAFTING REACTIONS

The adsorption of four silanes, namely: N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane (AEAPTMS), 3-methacryloxypropyltrimethoxysilane (MPTMS), allyltrimethoxysilane (ATMS), N-2-[(N-vinylbenzylamino)ethyl]-3-aminopropyltrimethoxysilane hydrochloride (CVBS) onto the surface of silica nanoparticles has been studied using water/ethanol (5/95, v/v) mixture. Four experimental parameters were explored for the grafting of the silanes: pH, concentration, time, and temperature. Possible interactions between the silanes and the surface of silica were investigated by means of FT-IR Spectroscopy. The FT-IR analyses confirmed the effectiveness of the silanization of the silica surface. The amount of the adsorbed silane on the silica nanoparticles appeared to be influenced by the initial concentration of the silane, pH, time and temperature of modification

Is the electrocatalytic epoxidation of stilbene isomers using manganese (III) tetradentate Schiff bases complexes stereoselective?

Three manganese (III) complexes were obtained with H2Salen derivatives and used as catalysts in the epoxidation reactions of E- and Z-stilbene isomers. The preparative electrolyses were carried out at 25 °C in acetonitrile solution containing 0.1 M TBAP, 10−3 M complex, 10−2 M 2-methylimidazole and 0.1 M benzoic anhydride plus stilbene as substrate. Our results showed clearly that E-stilbene was totally converted to Z-stilbene oxide whereas Z-stilbene leads to a mixture in which the benzaldehyde was the major by-product. In our experimental conditions, the turnovers recorded for different experiments were located in the 3.7–6.6 range. Keywords: Electrocatalysis, Manganese complexes, Olefins epoxidation, Molecular oxygen, Biomimetic catalysi

Nearest-Neighbor-based Collision Avoidance for Quadrotors via Reinforcement Learning

Collision avoidance algorithms are of central interest to many drone applications. In particular, decentralized approaches may be the key to enabling robust drone swarm solutions in cases where centralized communication becomes computationally prohibitive. In this work, we draw biological inspiration from flocks of starlings (Sturnus vulgaris) and apply the insight to end-to-end learned decentralized collision avoidance. More specifically, we propose a new, scalable observation model following a biomimetic nearest-neighbor information constraint that leads to fast learning and good collision avoidance behavior. By proposing a general reinforcement learning approach, we obtain an end-to-end learning-based approach to integrating collision avoidance with arbitrary tasks such as package collection and formation change. To validate the generality of this approach, we successfully apply our methodology through motion models of medium complexity, modeling momentum and nonetheless allowing direct application to real world quadrotors in conjunction with a standard PID controller. In contrast to prior works, we find that in our sufficiently rich motion model, nearest-neighbor information is indeed enough to learn effective collision avoidance behavior. Our learned policies are tested in simulation and subsequently transferred to real-world drones to validate their real-world applicability.Comment: Accepted to the 39th IEEE Conference on Robotics and Automation (ICRA). Fixed some typo

Electrochemical oxidation of benzyl germatranes.

International audienc

Electrochemical Characterization of Carbon Solid[BOND]like Paste Electrode Assembled Using Different Carbon Nanoparticles

olid like carbon paste electrodes (SCPEs) are built using different carbon materials namely carbon black N110, N220, N375, N772 and acetylene black. The electrochemical behavior of these electrodes and the influence of carbon black/paraffin ratio were studied and the results were discussed and compared to other electrodes prepared with graphite, mesoporous carbon and nanopowder carbon. Cyclic voltammetry, amperometry and electrochemical impedance spectroscopy were employed for their electrochemical and analytical characterizations. Amperometric measurements using N110, N220, N375 SCPEs with solid paraffin, showed a linear response of benzoquinone concentration with a detection limit of 75, 32 and 171 nM respectively

Electrochemical reactivity and anodic cyanation of germatranes. Soualmi, S., Ignatovich, L., Lukevics, E., Ourari, A., Jouikov, V.

International audienc

Ni(II)-MACROMOLECULAR COMPOUND DERIVED FROM POLY(4-VINYLPYRIDINE-CO-DIVINYLBENZENE) AND SCHIFF BASE NICKEL COMPLEX: THERMO-DEGRADATION AND KINETICS BEHAVIOR

Various kinetic techniques have been developed to obtain the different kinetic parameters such as degree of conversion (α), activation energy (E), pre-exponential factor (A) and rate constant (r). Consequently, the aim of this paper is to study the decomposition kinetics of Divinylbenzene-4-vinylpyridine unmodified copolymer (Unm-Polym) with its modified structure with nickel Schiff base complex (Co-Polym-Ni-SB) by thermal analysis. The TG/DTG analysis was conducted between 25 and 800°C using four different heating rates and four methods were chosen to calculate the previous mentioned parameters. The obtained Ea values are between 162 and 441 kJ mol for Kissinger, Ozawa and Friedman methods. The resulting activation energies calculated by Coats-Redfern method were used to evaluate the thermodynamic parameters like ΔS, ΔH and ΔG. By using these methods, the higher obtained values of Ea were estimated for nickel complex that caused its lower thermostability compared to the structure of Co-Polym-Ni-SB.The authors thank the Algerian Ministry of Higher Education and Scientific Research (MESRS) and the Directorate General of Scientific Research and Technological Development (DGRSDT) for their financial support. We would like to thank (ICTP-CSIC) of Madrid, España for TG/DTG analysis and for discussion