Electrochemical oxidation of 6-propionyl-2-(N,N-dimethylamino)naphthalene (prodan) in acetonitrile on Pt electrodes: Reversible dimerization of prodan radical cations

2002 ◽  
Vol 80 (9) ◽  
pp. 1232-1241 ◽  
Author(s):  
Marcela Beatriz Moressi ◽  
María Alicia Zón ◽  
Héctor Fernández
Keyword(s):  
Electron Transfer ◽  
Cyclic Voltammetry ◽  
Diffusion Coefficient ◽  
Electrochemical Oxidation ◽  
Digital Simulation ◽  
Formation Rate ◽  
Radical Cations ◽  
Cyclic Voltammograms ◽  
Controlled Potential ◽  
Reversible Dimerization

The electrooxidation of 6-propionyl-2-(N,N-dimethylamino)naphthalene (prodan) has been investigated for the first time. It has been performed on both conventional size platinum electrodes and platinum ultramicroelectrodes in acetonitrile by cyclic voltammetry with convolution analysis and controlled-potential electrolysis. The voltammetric responses at room temperature are similar to those corresponding to a kinetically controlled anodic electron-transfer process. Cyclic voltammetry measurements were also carried out at different concentrations of prodan and at different temperatures. Chemical transformation of the radical monocation formed after the electrochemical oxidation of prodan, as deduced from reverse controlled potential bulk electrolysis and cyclic voltammetry measurements, gives evidence for the reversible dimerization of prodan radical cations. Both diagnostic criteria and digital simulation confirm that radical–radical coupling is the reversible chemical reaction coupled to the initial electron transfer step, to give the corresponding dimeric dication. The kinetic and thermodynamic parameters for the first electron transfer reaction and the dimerization process were estimated from digital simulation at 293 K. Values of 8.0 × 106 M–1 and 3.2 × 105 M–1 s–1 were determined for the dimerization reaction equilibrium constant and the dimer formation rate constant, respectively. The diffusion coefficient of prodan was determined from both limiting currents from convoluted cyclic voltammograms as well as limiting currents on ultramicroelectrodes. For such cases where the electron number exchanged in the electrode process is unknown, a method derived from the combination of data previously indicated is also proposed to obtain the diffusion coefficient of the electroactive species.Key words: prodan, cyclic voltammetry, reaction mechanism, reversible dimerization, electron transfer reactions, radical cation.

scholarly journals Integrated Study of the Dinitrobenzene Electroreduction Mechanism by Electroanalytical and Computational Methods

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Andrey S. Mendkovich ◽  
Mikhail A. Syroeshkin ◽  
Ludmila V. Mikhalchenko ◽  
Mikhail N. Mikhailov ◽  
Alexander I. Rusakov ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Quantum Chemical ◽  
Bond Cleavage ◽  
Digital Simulation ◽  
Radical Anions ◽  
Theoretical Methods ◽  
Controlled Potential Electrolysis ◽  
Proton Donors ◽  
Controlled Potential ◽  
Integrated Study

Electroreduction of 1,2-, 1,3-, and 1,4-dinitrobenzenes in DMF has been investigated by a set of experimental (cyclic voltammetry, chronoamperometry, and controlled potential electrolysis) and theoretical methods (digital simulation and quantum chemical calculations). The transformation of only one nitro group is observed in the presence of proton donors. The process selectivity is provided by reactions of radical anions' intermediate products. The key reactions here are protonation of radical anions of nitrosonitrobenzenes and N-O bond cleavage in radical anions of N-(nitrophenyl)-hydroxylamines.

Electrochemical Studies on Novel LiMnPO4 Coated with Magnesium Oxide-Gold Composite Thin Film in Aqueous Electrolytes

2016 ◽  
Vol 44 ◽  
pp. 90-99 ◽  
Author(s):  
Ntuthuko Wonderboy Hlongwa ◽  
Chinwe O. Ikpo ◽  
Natasha Ross ◽  
Myra Nzaba ◽  
Miranda M. Ndipingwi ◽  
...  
Keyword(s):  
Thin Film ◽  
Electron Transfer ◽  
Cyclic Voltammetry ◽  
Diffusion Coefficient ◽  
Electrochemical Impedance ◽  
Composite Cathode ◽  
Aqueous Electrolytes ◽  
Electrochemical Studies ◽  
Discharge Capacities ◽  
Microscopic Techniques

Abstract. Pristine LiMnPO4 and LiMnPO4/Mg-Au composite cathode materials were synthesized and their electrochemical properties interrogated using voltammetric, spectroscopic and microscopic techniques. The composite cathode exhibited better reversibility and kinetics than the pristine LiMnPO4. This was demonstrated in the values of the diffusion coefficient (D) and the charge and discharge capacities determined through cyclic voltammetry. For the composite cathode, D = 2.0 x 10-9 cm2/s while the pristine has a D value of 4.81 x 10-10 cm2/s. The charge and discharge capacities of LiMnPO4/Mg-Au at 10 mV/s were 259.9 mAh/g and 157.6 mAh/g, respectively. The corresponding values for pristine LiMnPO4 were 115 mAh/g and 44.75 mAh/g, respectively.. A similar trend was observed in the results obtained from electrochemical impedance spectroscopy measurements. These results indicate that LiMnPO4/Mg-Au composite has better conductivity and will facilitate faster electron transfer and better electrochemical performance than pristine LiMnPO4.

scholarly journals Carbon Nanotube Yarn Microelectrodes Promote High Temporal Measurements of Serotonin Using Fast Scan Cyclic Voltammetry

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1173 ◽  
Author(s):  
Alexander Mendoza ◽  
Thomas Asrat ◽  
Favian Liu ◽  
Pauline Wonnenberg ◽  
Alexander G. Zestos
Keyword(s):  
Electron Transfer ◽  
Cyclic Voltammetry ◽  
Carbon Nanotube ◽  
Electrode Materials ◽  
Cyclic Voltammograms ◽  
Electron Transfer Kinetics ◽  
Fast Scan Cyclic Voltammetry ◽  
Peak Separation ◽  
Aspect Ratios ◽  
Carbon Fiber Microelectrodes

Carbon fiber-microelectrodes (CFMEs) have been the standard for neurotransmitter detection for over forty years. However, in recent years, there have been many advances of utilizing alternative nanomaterials for neurotransmitter detection with fast scan cyclic voltammetry (FSCV). Recently, carbon nanotube (CNT) yarns have been developed as the working electrode materials for neurotransmitter sensing capabilities with fast scan cyclic voltammetry. Carbon nanotubes are ideal for neurotransmitter detection because they have higher aspect ratios enabling monoamine adsorption and lower limits of detection, faster electron transfer kinetics, and a resistance to surface fouling. Several methods to modify CFMEs with CNTs have resulted in increases in sensitivity, but have also increased noise and led to irreproducible results. In this study, we utilize commercially available CNT-yarns to make microelectrodes as enhanced neurotransmitter sensors for neurotransmitters such as serotonin. CNT-yarn microelectrodes have significantly higher sensitivities (peak oxidative currents of the cyclic voltammograms) than CFMEs and faster electron transfer kinetics as measured by peak separation (ΔEP) values. Moreover, both serotonin and dopamine are adsorption controlled to the surface of the electrode as measured by scan rate and concentration experiments. CNT yarn microelectrodes also resisted surface fouling of serotonin onto the surface of the electrode over thirty minutes and had a wave application frequency independent response to sensitivity at the surface of the electrode.

Der elektronisch stabilisierende Beitrag des Ph3P=N-Liganden. Darstellung von CH3WCl4N =PPh3 und das elektrochemische Verhalten von Ph3PN-substituierten Wolfram(VI)-Halogeniden

1987 ◽  
Vol 42 (7) ◽  
pp. 877-880 ◽  
Author(s):  
Herbert W. Roesky ◽  
Tetsuro Tojo ◽  
Michaela Ilemann ◽  
Dieter Westhoff
Keyword(s):  
Cyclic Voltammetry ◽  
Nmr Spectroscopy ◽  
Cyclic Voltammograms ◽  
Cyclic Voltammogram ◽  
Electron Charge ◽  
Potential Reduction ◽  
Reduced Products ◽  
Controlled Potential

Abstract The reaction of CH3WCl5 and Me3SiN = PPh3 yields CH-3WCl4N = PPh3 (1). The electrochem ical reduction of 1, F5WN = PPh3 (2) and F4W (N = PPh3)2 (3) has been investigated using cyclic voltammetry and potentiostatic methods. The cyclic voltammogram of 1 shows two reduction waves at Ef + 1.72 and 0.420 V. The controlled potential reduction of 1 indicates two steps of reversible one-electron charge transfers. The cyclic voltammograms of 2 and 3 in CH2Cl2 show reversible one-electron waves at Ef -0.45 and -1.45 V, respectively. The reduced products were analyzed by 19F and 31P NMR spectroscopy.

Synthesis, spectroscopy and electrochemistry of octaphenoxyphthalocyaninato silicon complexes

2001 ◽  
Vol 05 (07) ◽  
pp. 555-563 ◽  
Author(s):  
M. DAVID MAREE ◽  
TEBELLO NYOKONG
Keyword(s):  
Electron Transfer ◽  
Cyclic Voltammetry ◽  
Organic Solvents ◽  
High Yield ◽  
Cyclic Voltammograms ◽  
H Nmr ◽  
Axial Ligands ◽  
Convenient Route ◽  
Cyclic Voltammetry Data

A number of octaphenoxyphthalocyaninato silicon complexes containing a variety of axial ligands, represented by ( OPh )8 PcSi ( X )2 (where X = chloro 3, hydroxy 4, (4-carboxybenzene) acetato 5, isonicatinato 6, propionato 7, nitrophenoxy 8 and dimethylaminoxy 9) have been synthesized using a convenient route starting with the 4,5-diphenoxy-1,2-dicyanobenzene. 1 H NMR and UV/vis spectra, and the cyclic voltammetry of the complexes are reported. The complexes are obtained in high yield and are soluble in many organic solvents. Cyclic voltammetry revealed two reduction couples and one oxidation couple for these complexes. Analysis of the cyclic voltammograms showed that compounds 6 and 8 were easier to oxidize and more difficult to reduce than the rest. Also cyclic voltammetry data suggested that electron transfer was not governed only by diffusion.

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