scholarly journals Synthesis, UV/vis spectra and electrochemical characterisation of arylthio and styryl substituted ferrocenes

2011 ◽  
Vol 9 (4) ◽  
pp. 610-618 ◽  
Author(s):  
Thomas Sørensen ◽  
Merete Nielsen
Keyword(s):  
Cyclic Voltammetry ◽  
Absorption Spectroscopy ◽  
Substituent Effect ◽  
Electronic Communication ◽  
Substituent Effects ◽  
Para Position ◽  
Electronic Transitions ◽  
Ferrocene Derivatives ◽  
Order Of Magnitude ◽  
Electrochemical Characterisation

AbstractTwo series of substituted ferrocenes were synthesised using either the Horner-Wadsworth-Emmons reaction or monolithiation of ferrocene. The series consist of arylthio- and styryl-ferrocenes with different substituents in the para position of the aryl rings of the systems. The electronic communication was investigated by comparing the substituent effects in absorption spectroscopy and in cyclic voltammetry. A small substituent effect was found in the electronic transitions of the styryl substituted ferrocenes. The oxidation of the ferrocene derivatives showed clear substituent effects as illustrated by the linear Hammett plots. The effect was shown to be an order of magnitude larger in the arylthio-systems than in the styryl systems. It is suggested that the reason behind the large effect is a direct sulfur-iron orbital overlap.

Substituent effect on wave numbers of C=O valence vibrations in ferrocene derivatives

1983 ◽  
Vol 48 (6) ◽  
pp. 1635-1646 ◽  
Author(s):  
Alexander Perjéssy ◽  
Štefan Toma
Keyword(s):  
Linear Correlation ◽  
Substituent Effect ◽  
Empirical Relation ◽  
Ferrocene Derivatives ◽  
Wave Numbers ◽  
Complex Structural ◽  
Transmission Factors

Wave numbers of C=O valence vibrations of 83 ferrocene derivatives have been measured in tetrachloromethane. For a series of 154 compounds containing ferrocene skeleton linear correlation has been found between wave numbers of C=O vibration and X+(R) constants of structural fragments in the sense of modified and extended Seth-Paul-Van Duyse equation. Validity has been verified of the recently derived empirical relation for calculation of the X+(R) constants of complex structural fragments from values of constants of substituents and transmission factors for simple structural groupings. The transmission factors γ and π' for 1,3- and 1,1'-ferrocene system have been found to be well applicable to calculation of constants of structural fragments containing ferrocene skeleton.

Hydrophobic Ferrocene Derivatives as Potential Standards in Electrochemistry

1997 ◽  
Vol 62 (2) ◽  
pp. 185-198 ◽  
Author(s):  
Jaroslav Podlaha ◽  
Petr Štěpnička ◽  
Róbert Gyepes ◽  
Vladimír Mareček ◽  
Alexander Lhotský ◽  
...  
Keyword(s):  
Surface Tension ◽  
Cyclic Voltammetry ◽  
Redox Potential ◽  
Diffusion Coefficients ◽  
Carbon Electrodes ◽  
X Ray Diffraction ◽  
Ferrocene Derivatives ◽  
X Ray ◽  
Special Cases ◽  
As Solubility

Ferrocene (FcH) derivatives monosubstituted by palmitoyl (1), hexadecyl (2), 1-adamantoyl (3) or 1-adamantylmethyl (4) groups were sythesized and characterized by NMR, mass and 57Fe Mossbauer spectroscopy. The structure of 1-adamantoylferrocene was determined by single-crystal X-ray diffraction. Cyclic voltammetry on gold and glass-like carbon electrodes demonstrated that the compounds can serve as electrochemical standards for special cases since their ferrocene/ferricinium redox potential remains stable and reversible, while the properties such as solubility, diffusion coefficients and surface tension are strongly solvent-dependent.

Kinetic Study of Hydrolysis of Benzoates. Part XXVI. Variation of the Substituent Effect with Solvent in Alkaline Hydrolysis of Substituted Alkyl Benzoates

2006 ◽  
Vol 71 (11-12) ◽  
pp. 1557-1570 ◽  
Author(s):  
Vilve Nummert ◽  
Mare Piirsalu ◽  
Ilmar A. Koppel
Keyword(s):  
Kinetic Study ◽  
Alkaline Hydrolysis ◽  
Rate Constants ◽  
Substituent Effect ◽  
Substituent Effects ◽  
Alkyl Substituent ◽  
Solvent Parameters ◽  
Substituent Constants ◽  
Hydrolysis Of ◽  
Main Factor

The second-order rate constants k2 (dm3 mol-1 s-1) for the alkaline hydrolysis of substituted alkyl benzoates C6H5CO2R have been measured spectrophotometrically in aqueous 0.5 M Bu4NBr at 50 and 25 °C (R = CH3, CH2Cl, CH2CN, CH2C≡CH, CH2C6H5, CH2CH2Cl, CH2CH2OCH3, CH2CH3) and in aqueous 5.3 M NaClO4 at 25 °C (R = CH3, CH2Cl, CH2CN, CH2C≡CH). The dependence of the alkyl substituent effects on different solvent parameters was studied using the following equations:      ∆ log k = c0 + c1σI + c2EsB + c3∆E + c4∆Y + c5∆P + c6∆EσI + c7∆YσI + c8∆PσI     ∆ log k = c0 + c1σ* + c2EsB + c3∆E + c4∆Y + c5∆P + c6∆Eσ* + c7∆Yσ* + c8∆Pσ* .  ∆ log k = log kR - log kCH3. σI and σ* are the Taft inductive and polar substituent constants. E, Y and P are the solvent electrophilicity, polarity and polarizability parameters, respectively. In the data treatment ∆E = ES - EH2O , ∆Y = YS - YH2O , ∆P = PS - PH2O were used. The solvent electrophilicity, E, was found to be the main factor responsible for changes in alkyl substituent effects with medium. When σI constants were used, variation of the polar term of alkyl substituents with the solvent electrophilicity E was found to be similar to that observed earlier for meta and para substituents, but twice less when σ* constants were used. The steric term for alkyl substituents was approximately independent of the solvent parameters.

scholarly journals Electrochemical synthesis of poly(2-methyl aniline): electrochemical and spectroscopic characterization

2001 ◽  
Vol 66 (1) ◽  
pp. 27-37 ◽  
Author(s):  
Aleksandra Buzarovska ◽  
Irena Arsova ◽  
Ljubomir Arsov
Keyword(s):  
Raman Spectroscopy ◽  
Cyclic Voltammetry ◽  
Redox Reactions ◽  
Electrochemical Polymerization ◽  
Spectroscopic Characterization ◽  
Potential Range ◽  
Cyclic Voltammograms ◽  
Impedance Measurements ◽  
Order Of Magnitude ◽  
Poly Aniline

Poly(2-methyl aniline) or poly(ortho-toluidine), as ring substituted derivative of aniline, has been synthesized electrochemically in various concentrations of H2SO4 and HCl, and then characterized by cyclic voltammetry, as well as by impedance and Raman spectroscopy. The cyclic voltammograms of poly(o-toluidine) and poly(aniline) show that the electrochemical polymerization of these two polymers proceeds by almost identical mechanisms. The Raman spectroscopical measurements suggest that the redox reactions of poly(aniline) and poly(o-toluidine) are similar in the potential range between -0.2 and 0.7V vs. SCE. The impedance measurements showed that the conductivity of poly(o-toluidine) is an order of magnitude lower than that of the corresponding poly(aniline) form.

scholarly journals Effects of State of Charge on the Physical Characteristics of V(IV)/V(V) Electrolytes and Membrane for the All Vanadium Flow Battery

Batteries ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 49
Author(s):  
Wyndom S. Chace ◽  
Sophia M. Tiano ◽  
Thomas M. Arruda ◽  
Jamie S. Lawton
Keyword(s):  
Cyclic Voltammetry ◽  
Rotational Diffusion ◽  
Supporting Electrolyte ◽  
State Of Charge ◽  
Vanadium Redox Flow Battery ◽  
Bulk Solution ◽  
Flow Battery ◽  
Vanadium Concentration ◽  
H2so4 Concentration ◽  
Order Of Magnitude

The VO2+/VO2+ redox couple commonly employed on the positive terminal of the all-vanadium redox flow battery was investigated at various states of charge (SOC) and H2SO4 supporting electrolyte concentrations. Electron paramagnetic resonance was used to investigate the VO2+ concentration and translational and rotational diffusion coefficient (DT, DR) in both bulk solution and Nafion membranes. Values of DT and DR were relatively unaffected by SOC and on the order of 10−10 m2s−1. Cyclic voltammetry measurements revealed that no significant changes to the redox mechanism were observed as the state of charge increased; however, the mechanism does appear to be affected by H2SO4 concentration. Electron transfer rate (k0) increased by an order of magnitude (10−6 ms−1 to 10−8 ms−1) for each H2SO4 concentrations investigated (1, 3 and 5 M). Analysis of cyclic voltammetry switching currents suggests that the technique might be suitable for fast determination of state of charge if the system is well calibrated. Membrane uptake and permeability measurements show that vanadium absorption and crossover is more dependent on both acid and vanadium concentration than state of charge. Vanadium diffusion in the membrane is about an order of magnitude slower (~10−11 m2s−1) than in solution (~10−10 m2s−1).

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