Search results for "Volt"
showing 10 items of 2187 documents
ESR and electrochemical studies of 2-acylpyridines and 6,6'-diacyl-2,2'-bipyridines.
2005
Abstract The ESR spectra of radicals obtained by electrolytic reduction of 2-acylpyridines and 6,6′-diacyl-2,2′-bipyridines were measured in dimethylsulfoxide (DMSO) and analyzed by quantum chemical calculations. The electrochemistry of these compounds was characterized using cyclic voltammetry, in DMSO solvent. The results showed a two step reduction mechanism, first wave was assigned to the generation of the correspondent free radical species, and the second wave was assigned to the dianion derivatives. AM1 and DFT calculations were performed to obtain the optimized geometries, theoretical hyperfine constants, and spin distributions, respectively. The theoretical results are in complete a…
The Radical Trap in Atom Transfer Radical Polymerization Need Not Be Thermodynamically Stable. A Study of the MoX3(PMe3)3 Catalysts
2005
The molybdenum(III) coordination complexes MoX(3)(PMe(3))(3) (X = Cl, Br, and I) are capable of controlling styrene polymerization under typical atom transfer radical polymerization (ATRP) conditions, in conjunction with 2-bromoethylbenzene (BEB) as an initiator. The process is accelerated by the presence of Al(OPr(i))(3) as a cocatalyst. Electrochemical and synthetic studies aimed at identifying the nature of the spin trap have been carried out. The cyclic voltammogram of MoX(3)(PMe(3))(3) (X = Cl, Br, I) shows partial reversibility (increasing in the order ClBrI) for the one-electron oxidation wave. Addition of X(-) changes the voltammogram, indicating the formation of MoX(4)(PMe(3))(3) f…
Digestion-free determination of heavy metals (Pb, Cd, Cu) in honey using anodic stripping differential pulse voltammetry and potentiometric stripping…
1995
Experiments have been carried out to assess the potential of differential pulse voltammetry and potential stripping analysis for determining Pb, Cu and Cd directly in dissolved honey samples using a flow-through cell. With the hanging mercury drop electrode Pb alone can be determined only if the electrode is first modified in-situ with Triton X 100 to increase the separation between the Pb peak and a broad, interfering adsorption peak which overlaps the Cu peak. If the (more sensitive) thin film mercury electrode is used the interference encountered is less so also Cu and Cd can be determined. With potentiometric stripping analysis Cu and Pb can be determined using normal procedures. The de…
Anthracene-containing PPE-PPV copolymers: Effect of side-chain nature and length on photophysical and photovoltaic properties
2009
Rupali Jadhav1,2, Stefan Turk3, Florian Kuhnlenz1, Vera Cimrova4, Silke Rathgeber5, Daniel A. M. Egbe*,2,3, and Harald Hoppe**,1 1 Institute of Physics, Ilmenau University of Technology, Weimarer Str. 32, 98693 Ilmenau, Germany 2 Linz Institute for Organic Solar Cells (LIOS), Johannes Kepler University Linz, Altenbergerstr. 69, 4040 Linz, Austria 3 Institute for Print and Media Technology, Chemnitz University of Technology, Reichenhainer Str. 70, 09126 Chemnitz, Germany 4 Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovský Sq. 2, 162 06 Prague 6, Czech Republic 5 Johannes Gutenberg-University Mainz, Staudingerweg 7, 55128 Mainz, Germany
The different redox-activity of dianthrylbenzene and dianthrylbiphenyl
1989
Abstract The reduction of dianthrylbenzene and dianthrylbiphenyl to stable tetraanion salts is described by NMR spectroscopy and cyclic voltammetry. The significantly different Coulomb interactions between the anthracene units are compared with those in dianthrylalkanes.
Electronic Interactions in a New π-Extended Tetrathiafulvalene Dimer
2006
The first pi-extended tetrathiafulvalene (exTTF) dimer in which the two exTTF units are covalently connected by 1,3-dithiole rings has been obtained in a multistep synthetic procedure involving the Ullmann cross-coupling reaction by using copper(I) thiophene-2-carboxylate (CuTC). The electronic spectrum reveals a significant electronic interaction between the exTTF units. The electrochemical study carried out by cyclic voltammetry in solution and in thin-layer conditions, and the electrochemical simulation and spectroelectrochemical (SEC) measurements confirm the electronic communication and show that the oxidation of dimer 14 occurs as two consecutive 2 e(-) processes D(0)-D(0)-->D(2+)-D(0…
Effect of high levels of CO 2 on the electrochemical behavior and the enzymatic and non‐enzymatic antioxidant systems in black and white table grapes…
2019
[Bakghround]: In this study, we analyzed the effect of the application of high levels of CO2 (20 kPa CO2 + 20 kPa O2 + 60 kPa N2 ) for 3 days at low temperature on a white table-grape cultivar (Superior Seedless) in comparison with a black one (cv. Autumn Royal) in terms of quality parameters. We also used a solid-state voltammetry methodology to analyze the effect of the 3-day gaseous treatment in berry tissues from both cultivars in the first stage of storage. We determined the role of the non-enzymatic (total phenols, total anthocyanins, and antioxidant activity) and the enzymatic antioxidant (catalase (GCAT), ascorbate peroxidase (VcAPX) gene expression) systems in the behaviors of bo…
Synthesis and studies of calcium channel blocking and antioxidant activities of novel 4-pyridinium and/or N-propargyl substituted 1,4-dihydropyridine…
2014
The novel 1,4-dihydropyridine derivatives containing the cationic pyridine moiety at the position 4, and the N-propargyl group as a substituent at position 1 of the 1,4-DHP cycle were designed, synthesised, and assessed in biological tests. Among all the novel compounds, the 4-(N-dodecyl) pyridinium group-containing compounds 11 (without the N-propargyl group) and 12 (with the N-propargyl group) demonstrated the highest calcium antagonistic properties against neuroblastoma SH-SY5Y (IC50 about 5–14 mM) and the vascular smooth muscle A7r5 cell (IC50 – 0.6–0.7 mM) lines, indicating that they predominantly target the L-type calcium channels. These compounds showed a slight total antioxidant act…
Study on the sensitive and selective adsorption voltammetry of vanadium with antipyrylazo III (APA III)
1994
The sensitive and selective adsorption voltammetric determination of the vanadium(V)-antipyrylazoIII complex in HAc-NaAc solution is investigated. The V-complex is strongly adsorbed onto a stationary Hg-electrode and is reduced at a potential more negative than that corresponding to the reduction of its ligand. The conditions for determining vanadium are investigated and the mechanism of the reduction peak of the vanadium complex is discussed, as also the influence of foreign ions on the determination of vanadium. An at least 20-fold excess of foreign ions does not cause any interference. The detection limit is 4×10−10 mol/l V with 3 min enrichment time.
Antonio Belguardo. Un maestro nella Palermo tra XV e XVI secolo: il regesto documentario
2016
Le informazioni documentarie emerse in questi ultimi anni sulla figura di Antonio Belguardo permettono di tracciare con maggiore compiutezza il profilo biografico e la parabola professionale di uno dei più prolifici protagonisti della stagione tardogotica dell’architettura siciliana; la sua attività, per quanto sinora noto, si concentra prevalentemente a Palermo tra l’ultimo quarto del XV secolo e i primi decenni del XVI. New documents that have come to light on Antonio Belguardo allow us to draw a more complete biographic profile of one of the most prolific protagonists of Late Gothic Sicilian architecture; His activity, as far as we know, was mainly carried out in Palermo, between the las…