PH dependence of the electrochemical behavior of surfaces modified with a polymer derived from a monomer consisting of two viologen subunits linked by a quinone: evidence for rectification by synthetic molecular materials

1986 ◽  
Vol 108 (12) ◽  
pp. 3522-3525 ◽  
Author(s):  
Diane K. Smith ◽  
Gregg A. Lane ◽  
Mark S. Wrighton
Keyword(s):  
Electrochemical Behavior ◽  
Ph Dependence ◽  
Molecular Materials

Elektrochemisches Verhalten der Nitrophenole und ihrer Reduktionsprodukte an Graphitelektroden/ Electrochemical Behavior of the Nitrophenols and Their Reduction Products at Graphite Electrodes

1981 ◽  
Vol 36 (7) ◽  
pp. 840-845 ◽  
Author(s):  
Elli Theodoridou ◽  
Dimitrios Jannakoudakis
Keyword(s):  
Aqueous Solutions ◽  
Electrochemical Behavior ◽  
Ph Dependence ◽  
Chemical Oxidation ◽  
Potential Range ◽  
Cyclic Voltammograms ◽  
Hanging Mercury Drop Electrode ◽  
Oxidation Peak ◽  
Graphite Electrodes ◽  
Reduction Potentials

Abstract The electrochemical reduction of the isomeric nitrophenols at graphite electrodes is investigated in aqueous solutions with pH = 1-13 and is compared with the electro-chemical oxidation of their reduction products. o-Nitrophenol and p-nitrophenol are reduced to the corresponding amines, as the observed oxidation peaks in their cyclic voltammograms can be simulated by those of o-and p-aminophenol. m-Nitrophenol is reduced to m-hydroxylaminophenol, as its oxidation peak appears at much more negative » potential than that of m-aminophenol, within the potential range of the oxidation of phenylhydroxylamine. The pH-dependence of the reduction potentials of the nitrophenols at the graphite electrodes is discussed in comparison with that at a hanging mercury drop electrode.

Electrochemical and spectroscopic behavior of trifluoromethylacetophenone in aqueous and micellar medium

1995 ◽  
Vol 73 (9) ◽  
pp. 1488-1496 ◽  
Author(s):  
Elodie Liotier ◽  
Guy Mousset ◽  
Christine Mousty
Keyword(s):  
Electrochemical Behavior ◽  
Ph Dependence ◽  
Asymmetric Induction ◽  
Micellar Medium ◽  
Medium Ph ◽  
Ketone Reduction ◽  
Aromatic Ketones ◽  
Uv Visible ◽  
Chiral Surfactants ◽  
Spectroscopic Behavior

The electrochemical behavior of 4-trifluoromethylacetophenone (TFMA) has been studied in aqueous (2 ≤ pH ≤ 10), micellar, and ethanolic solutions using polarographic techniques. A slow hydration process of the carbonyl group has been observed by means of polarography and UV–visible spectrophotometry. Besides the well-known pH dependence of the electroreduction of aromatic ketones, C—F bond cleavages concomitant to the ketone reduction occur under electrolysis conditions in alkaline medium (pH = 10) at a very negative potential (−1.7 V), leading to the formation of 4-methylacetophenone, which is reduced at this potential with formation of the carbinol and of symmetrical and dissymmetrical pinacols. Finally, the reduction of TFMA has been performed in the presence of chiral surfactants in order to test their ability to induce an asymmetric induction. Keywords: 4-trifluoromethylacetophenone, 4-methylacetophenone, electroreduction, micellar medium, chiral surfactants, hydration, C—F bond fission.

Electrochemical behavior of self-assembled monolayers based on functionalized oligothiophenes

1998 ◽  
Vol 95 (6) ◽  
pp. 1339-1342 ◽  
Author(s):  
R. Michalitsch ◽  
A. El Kassmi ◽  
P. Lang ◽  
A. Yassar ◽  
F. Garnier
Keyword(s):  
Electrochemical Behavior ◽  
Self Assembled Monolayers ◽  
Assembled Monolayers ◽  
Self Assembled

Molecular materials based upon organic π-donors and magnetic anions

2000 ◽  
Vol 10 (PR3) ◽  
pp. Pr3-35-Pr3-40 ◽  
Author(s):  
S. Triki ◽  
F. Bérézovsky ◽  
J. Sala Pala ◽  
C. J. Gómez-García ◽  
E. Coronado
Keyword(s):  
Molecular Materials

Self-association of insulin. Its pH dependence and effect of plasma

Diabetes ◽  
1987 ◽  
Vol 36 (3) ◽  
pp. 261-264 ◽  
Author(s):  
E. Helmerhorst ◽  
G. B. Stokes
Keyword(s):  
Ph Dependence ◽  
Self Association

Rationalizing the pH-Activity Response for Escherichia Coli’s Glycinamide Ribonucleotidetransformylase Through Computational Methods

2019 ◽  
Author(s):  
Adrian Roitberg ◽  
Pancham Lal Gupta
Keyword(s):  
Transfer Reaction ◽  
Catalytic Mechanism ◽  
Ph Dependence ◽  
Ph Effects ◽  
Dependent Manner ◽  
E Coli ◽  
Gar Tfase ◽  
Activity Curve ◽  
Ph Dependent ◽  
Formyl Transfer

<div>Human Glycinamide ribonucleotide transformylase (GAR Tfase), a regulatory enzyme in the de novo purine biosynthesis pathway, has been established as an anti-cancer target. GAR Tfase catalyzes the formyl transfer reaction from the folate cofactor to the GAR ligand. In the present work, we study E. coli GAR Tfase, which has high sequence similarity with the human GAR Tfase with most functional residues conserved. E. coli GAR Tfase exhibits structural changes and the binding of ligands that varies with pH which leads to change the rate of the formyl transfer reaction in a pH-dependent manner. Thus, the inclusion of pH becomes essential for the study of its catalytic mechanism. Experimentally, the pH-dependence of the kinetic parameter kcat is measured to evaluate the pH-range of enzymatic activity. However, insufficient information about residues governing the pH-effects on the catalytic activity leads to ambiguous assignments of the general acid and base catalysts and consequently its catalytic mechanism. In the present work, we use pH-replica exchange molecular dynamics (pH-REMD) simulations to study the effects of pH on E. coli GAR Tfase enzyme. We identify the titratable residues governing the pH-dependent conformational changes in the system. Furthermore, we filter out the protonation states which are essential in maintaining the structural integrity, keeping the ligands bound and assisting the catalysis. We reproduce the experimental pH-activity curve by computing the population of key protonation states. Moreover, we provide a detailed description of residues governing the acidic and basic limbs of the pH-activity curve.</div>

Corrosion-electrochemical behavior of β-W based CVD coatings in NaCl solution

2019 ◽  
pp. 29-32
Author(s):  
V.V. Dushik ◽  
◽  
G.V. Redkina ◽  
N.V. Rozhanskii ◽  
T.V. Rybkina ◽  
...  
Keyword(s):  
Electrochemical Behavior ◽  
Nacl Solution ◽  
Corrosion Electrochemical Behavior
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