scholarly journals Synthesis, Characterization, and Electrochemistry of Diferrocenyl β-Diketones, -Diketonates, and Pyrazoles

Molecules ◽  
2020 ◽  
Vol 25 (19) ◽  
pp. 4476
Author(s):  
Steve W. Lehrich ◽  
Julia Mahrholdt ◽  
Marcus Korb ◽  
Alexander Hildebrandt ◽  
Jannie C. Swarts ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Square Wave Voltammetry ◽  
Charge Transfer Band ◽  
Redox Processes ◽  
Wave Voltammetry ◽  
Reversible Redox ◽  
Hydrogen Bond Pattern ◽  
Intervalence Charge Transfer ◽  
Form Compound ◽  
Solid State Structures

The synthesis of FcC(O)CH(R)C(O)Fc (Fc = Fe(η5-C5H4)(η5-C5H5); R = H, 5; nBu, 7; CH2CH2(OCH2CH2)2OMe, 9), [M(κ2O,O′-FcC(O)CHC(O)Fc)n] (M = Ti, n = 3, 10; M = Fe, n = 3, 11; M = BF2, n = 1, 12), and 1-R′-3,5-Fc2-cC3HN2 (R′ = H, 13; Me, 14; Ph, 15) is discussed. The solid-state structures of 5, 7, 9, 12, 13, 15, and 16 ([TiCl2(κ2O,O′-PhC(O)CHC(O)Ph)2]) show that 7 and 9 exist in their β-diketo form. Compound 13 crystallizes as a tetramer based on a hydrogen bond pattern, including one central water molecule. The electrochemical behavior of 5–7 and 9–16 was studied by cyclic and square-wave voltammetry, showing that the ferrocenyls can separately be oxidized reversibly between −50 and 750 mV (5–7, 9, 12–15: two Fc-related events; 10, 11: six events, being partially superimposed). For complex 10, Ti-centered reversible redox processes appear at −985 (TiII/TiIII) and −520 mV (TiIII/TiIV). Spectro-electrochemical UV-Vis/NIR measurements were carried out on 5, 6, and 12, whereby only 12 showed an IVCT (intervalence charge-transfer) band of considerable strength (νmax = 6250 cm−1, Δν½ = 4725 cm−1, εmax = 240 L·mol−1·cm−1), due to the rigid C3O2B cycle, enlarging the coupling strength between the Fc groups.

Synthesis, electrochemical and spectroelectrochemical studies of octaphenylthio-substituted phthalocyanines

2005 ◽  
Vol 09 (07) ◽  
pp. 484-490 ◽  
Author(s):  
Fungisai Matemadombo ◽  
M. David Maree ◽  
Kenneth I. Ozoemena ◽  
Philippe Westbroek ◽  
Tebello Nyokong
Keyword(s):  
Cyclic Voltammetry ◽  
Square Wave Voltammetry ◽  
Redox Processes ◽  
Tetrabutylammonium Perchlorate ◽  
Square Wave ◽  
Wave Voltammetry

Cobalt (4) and iron (5) phenylthio-substituted phthalocyanines ( MPc ( SR )8) have been synthesized and characterized. Cyclic square wave voltammetry in dimethylformamide containing tetrabutylammonium perchlorate revealed five and six redox processes, respectively, for complexes 4 and 5. The complexes are easier to reduce compared to the corresponding unsubstituted MPc and to butylthio substituted derivatives. The first oxidation and reduction occurs on the metal for both complexes. Spectroelectrochemistry (in dimethylformamide containing tetrabutylammonium perchlorate) was employed to assign the cyclic voltammetry peaks, and gave spectra characteristic of Fe I Pc for reduction of 5 and Co I Pc for the reduction of 4. The spectrum of the former is particularly of importance since such species have not received much attention in the literature.

Study of Redox Processes in Zeolite Y-Associated 2,4,6-Triphenylthiopyrylium Ion by Square Wave Voltammetry

2003 ◽  
Vol 107 (13) ◽  
pp. 3040-3050 ◽  
Author(s):  
Antonio Doménech ◽  
Hermenegildo García ◽  
Mercedes Alvaro ◽  
Esther Carbonell
Keyword(s):  
Square Wave Voltammetry ◽  
Zeolite Y ◽  
Redox Processes ◽  
Square Wave ◽  
Wave Voltammetry

Square wave voltammetry at disc microelectrodes for characterization of two electron redox processes

2012 ◽  
Vol 14 (23) ◽  
pp. 8319 ◽  
Author(s):  
E. Laborda ◽  
A. Molina ◽  
Q. Li ◽  
C. Batchelor-McAuley ◽  
R. G. Compton
Keyword(s):  
Square Wave Voltammetry ◽  
Redox Processes ◽  
Square Wave ◽  
Wave Voltammetry

scholarly journals Voltammetric Generation and Kinetic Stability of Nitro Anion Radical from Nitrofurazone in Ionic Liquids

2021 ◽  
Author(s):  
Luisa Chiavassa ◽  
Fernanda Camilo ◽  
Mauro La Scalea
Keyword(s):  
Ionic Liquids ◽  
Anion Radical ◽  
Square Wave Voltammetry ◽  
Cathodic Peak ◽  
Carbon Fiber Microelectrode ◽  
Wave Voltammetry ◽  
Reversible Redox ◽  
Order Chemical Reaction ◽  
Ec Mechanism ◽  
Anion Radical Formation

The nitrofurazone (NF) electrochemical reduction has been studied by cyclic voltammetry (CV) and square wave voltammetry (SWV) in non-aqueous medium using three different ionic liquids (IL): BMImTf2N, BMImBF4 and BMMImTf2N, having a carbon fiber microelectrode as working electrode. In all of them, two reversible cathodic peaks were recorded for NF. Under higher frequency values, only one reversible cathodic peak was registered. The systems reversibility could also be observed by CV, since a reversible redox couple was registered for this reduction. The systems reversibility with product and reagent adsorptions on the electrode surface was confirmed and the electrons number involved in this reduction indicated the nitro-anion radical formation followed by its respective dianion. For the first reduction, the EC mechanism (an electrochemical step followed by a chemical one) was considered for the systems in aprotic medium, in which there was a probable second-order chemical reaction after the charge transfer process, being the kinetic constants calculated following the Olmstead and Nicholson model.

Facile and Fast Detection of Genistein in Derris scandens by Square Wave Voltammetry using a Cobalt(II) Phthalocyanine-Modified Screen-Printed Electrochemical Sensor

2020 ◽  
Vol 16 (3) ◽  
pp. 341-348
Author(s):  
Surinya Traipop ◽  
Suchada Chuanuwatanakul ◽  
Orawon Chailapakul ◽  
Eakkasit Punrat
Keyword(s):  
Electrochemical Sensor ◽  
Square Wave Voltammetry ◽  
Silver Chloride ◽  
Reference Electrode ◽  
High Sensitivity ◽  
Plastic Substrate ◽  
Fast Analysis ◽  
Square Wave ◽  
Wave Voltammetry ◽  
Screen Printed

Background: Recently, Derris scandens, a Thai herbal medicine with anti-inflammatory activity, is widely used as beverage and supplementary food. When the traditional medicine is a choice for health therapy, the simple and reliable equipment is required to control the suitable consuming amount of the active component. Objective: To develop the electrochemical sensor for genistein determination in Derris scandens with high sensitivity and rapid operation. Methods: An in-house screen-printed electrochemical sensor consisting of a three-electrode system was developed for genistein determination. A silver/silver chloride (Ag/AgCl) reference electrode, a carbon counter electrode and a carbon working electrode were prepared on a 0.3-mm-thick plastic substrate by the screen-printing technique using conductive ink. The dimensions of each sensor were 2.5×1.0 cm. Only 50 µL of sample solution was required on this device for the determination of genistein concentration by rapid response square wave voltammetry. Results: The oxidation peak of genistein appeared with good response in acidic media at a peak potential of 0.6 V. Moreover, the signal was enhanced by modifying the conductive carbon ink with cobalt( II) phthalocyanine. Under the optimized conditions, the linear range was found to be 2.5-150 µM and the detection limit was 1.5 µM. Moreover, the small volume extraction was successfully developed without any further pre-concentration. This proposed method was applied to determine genistein in Derris scandens with satisfying results. Conclusion: The proposed method is promising as an alternative method for genistein determination with facile and fast analysis.

Isopotential points in square-wave voltammetry of reversible electrode reactions

2009 ◽  
Vol 74 (10) ◽  
pp. 1489-1501 ◽  
Author(s):  
Marina Zelić ◽  
Milivoj Lovrić
Keyword(s):  
Square Wave Voltammetry ◽  
Electrode Reaction ◽  
Time Model ◽  
Model Calculations ◽  
Square Wave ◽  
Electrode Reactions ◽  
Wave Voltammetry ◽  
Electron Transfer Processes ◽  
Diagnostic Criterion ◽  
First Time

Isopotential points in square-wave voltammetry are described for the first time. Model calculations and real measurements (performed with UO22+ and Eu3+ in perchlorate and bromide solutions, respectively) indicate that such an intersection could be observed when backward components of the net response, resulting from an increase in frequency or reactant concentration, are presented together. The electrode reaction should be fully reversible because quasireversible or slower electron transfer processes give the isopoints only at increasing reactant concentrations but not at increasing square-wave frequencies. The effect could be used as an additional diagnostic criterion for recognition of reversible electrode reactions where products remain dissolved in the electrolyte solution.

scholarly journals Simultaneous Hydrolysis and Detection of Organophosphate by Benzimidazole Containing Ligand-Based Zinc(II) Complexes

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 714
Author(s):  
Gaber A. M. Mersal ◽  
Hamdy S. El-Sheshtawy ◽  
Mohammed A. Amin ◽  
Nasser Y. Mostafa ◽  
Amine Mezni ◽  
...  
Keyword(s):  
Square Wave Voltammetry ◽  
Limit Of Detection ◽  
Organophosphorus Compounds ◽  
Organophosphorus Pesticides ◽  
Carbon Paste ◽  
Square Wave ◽  
Wave Voltammetry ◽  
Carbon Past Electrode ◽  
Hydrolysis Of ◽  
Biomimetic Sensor

The agricultural use of organophosphorus pesticides is a widespread practice with significant advantages in crop health and product yield. An undesirable consequence is the contamination of soil and groundwater by these neurotoxins resulting from over application and run-off. Here, we design and synthesize the mononuclear zinc(II) complexes, namely, [Zn(AMB)2Cl](ClO4) 1 and [Zn(AMB)2(OH)](ClO4) 2 (AMB = 2-aminomethylbenzimidazole), as artificial catalysts inspired by phosphotriesterase (PTE) for the hydrolysis of organophosphorus compounds (OPs) and simultaneously detect the organophosphate pesticides such as fenitrothion and parathion. Spectral and DFT (B3LYP/Lanl2DZ) calculations revealed that complexes 1 and 2 have a square-pyramidal environment around zinc(II) centers with coordination chromophores of ZnN4Cl and ZnN4O, respectively. Both 1 and 2 were used as a modifier in the construction of a biomimetic sensor for the determination of toxic OPs, fenitrothion and parathion, in phosphate buffer by square wave voltammetry. The hydrolysis of OPs using 1 or 2 generates p-nitrophenol, which is subsequently oxidized at the surface of the modified carbon past electrode. The catalytic activity of 2 was higher than 1, which is attributed to the higher electronegativity of the former. The oxidation peak potentials of p-nitrophenol were obtained at +0.97 V (vs. Ag/AgCl) using cyclic voltammetry (CV) and +0.88 V (vs. Ag/AgCl) using square wave voltammetry. Several parameters were investigated to evaluate the performance of the biomimetic sensor obtained after the incorporation of zinc(II) complex 1 and 2 on a carbon paste electrode (CPE). The calibration curve showed a linear response ranging between 1.0 μM (0.29 ppm) and 5.5 μM (1.6 ppm) for fenitrothion and 1.0 μM (0.28 ppm) and 0.1 μM (0.028 ppm) for parathion with a limit of detection (LOD) of 0.08 μM (0.022 ppm) and 0.51 μM (0.149 ppm) for fenitrothion and parathion, respectively. The obtained results clearly demonstrated that the CPE modified by 1 and 2 has a remarkable electrocatalytic activity towards the hydrolysis of OPs under optimal conditions.

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