1,721,048 research outputs found
EPR Study of Ternary Complexes of Copper(II), 1,10-Phenantroline and Oxidised Glutathione
No full text
Erratum to "Electrochemical, spectroscopic and microscopic characterisation of novel poly(3,4-ethylenedioxythiopene)/gold nanoparticles composite materials" [Journal of Electroanalytical Chemistry 619-620 (2008) 75-82] (DOI:10.1016/j.jelechem.2008.03.009)
No full textElectrochemical reduction of 1,1-diaryl-substituted ethenes in dimethylformamide
No full textThe cathodic behaviour of 1,1-diaryl-substituted ethenes (Ar)PhC=CH 2 (where Ar = phenyl-2-naphthyl-, 2-pyridyl-, 2-thienyl-, 2-furyl-) at a Hg cathode in N,N-dimethylformamide (DMF) and 0.1 mol dm-3 tetraethylammonium tetrafluoroborate (TEAF), was investigated by cyclic voltammetry and controlled potential electrolysis experiments. In cyclic voltammetry, at a potential scan rate of 0.2 V s-1 all substrates showed an irreversible reduction peak [(Ep.c) between -2.27 and -2.54 V vs. saturated calomel electrode (SCE)]. Controlled potential coulometries indicated that the apparent charge number of the process involved ranges from 1 to 2. The reduction products were characterised as (Ar)PhCH-Me (1-aryl-1-phenylethanes) and (Ar)PhCH-[CH2]2-CHPh(Ar) (1,4-diaryl-1,4-diphenylbutanes). The charge number of the process and the ratio between the two different reduction products depended strongly on the structure and concentration of the substrate. Exhaustive electrolyses performed in the presence of variable amounts of D2O or in [2H 7]DMF allowed us to suggest that two distinct pathways are involved in the reduction process, leading to the monomeric and dimeric product, respectively. Hypotheses on the nature of the two reduction mechanisms are discusse
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Anionic clay modified electrode for detection of alcohols. An electrocatalytic amperometric sensor
No full textThe mechanism of the electrocatalytic oxidation towards a wide series of alcohols, by an electrode covered with the [Ni/Al-Cl] hydrotalcyte-like clay, has been analyzed in the different steps it consists of. Such a clay has been reported to be electrically conductive via a mechanism that shows similarities with that of the redox polymers. The overall process occurs in quite a complicated physical system that is completely different both from a classical electrode-solution one and from an electrode covered with a film of heterogeneous catalyst. By varying the characteristics of the substrate, in terms of steric hindrance and dipole moment of the molecule, the factors affecting the redox mediator-substrate reaction have been studied. The concentration ranges where the amperometric response varies linearly have been determined for the different substrates considered
Electrochemical study of Au(III) compounds with substituted pyridine and 2,2’-bipyridine ligands
No full textElectrochemical characterization of polythiophene derivatives modified electrodes using differential pulse techniques
No full textThe electrochemical behavior of poly[4,4′-bis(butylsulfanyl)-2,2′-bithiophene] (PBSBT) modified conventional-size and microelectrodes in acetonitrile and aqueous solutions has been investigated using differential pulse voltammetry and cyclic voltammetry. The differential pulse voltammograms of both conventional-size and microelectrodes modified with PBSBT in acetonitrile containing 0.1 M TBAPF6 show the appearance of two peaks, when the electrode potential is scanned from 0.0 to +1.0 V, which correspond to the polaron formation (peak at ca. +0.50 V), and to bipolaron formation (peak at ca. +0.90 V), respectively. This behavior of the polymer when submitted to differential pulse measurements is similar to that exhibited in cyclic voltammetric tests. The modified electrodes present good stability under repetitive scanning of the electrode potential
- …
