Convolution voltammetry of metal complexes

Toman, Jeffrey J.; Corn, Robert M.; Brown, Steven D.

doi:10.1016/s0003-2670(01)83171-8

Cited by 18 publications

(14 citation statements)

References 30 publications

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“…This was followed by the development of analog circuitry that performed semiintegration or semidifferentiation to directly generated M ( t ) . However, this hardware approach requires a specific resistor‐capacitor ladder network suited to a particular time domain and numerical generation is preferred if a wide range of scan rates is investigated . Evans and co‐workers developed a computerized digital data acquisition system for collecting experimental data and then transferred the data to a larger computer to transform and analyze .…”

Section: Determining M(t)mentioning

confidence: 99%

“…[25][26][27][28] However, this hardware approach requires a specific resistorcapacitor ladder network suited to a particular time domain and numerical generation is preferred if a wide range of scan rates is investigated. [29] Evans and co-workers developed a computerized digital data acquisition system for collecting experimental data and then transferred the data to a larger computer to transform and analyze. [30] A generalized differintegration algorithm based on the Grü nwald definition for any value of the differintegration order v was developed.…”

Section: Determining M(t)mentioning

confidence: 99%

“…The value of E8' is readily obtained by combining the slope and the intercept. If the electrode area is known then the common diffusion coefficient can be calculated based on Equation (29), from the definition of M lim…”

Section: Electrode Kineticsmentioning

confidence: 99%

“…The basis of semiintegration and convolutive analysis is diffusion characterized by the diffusivities of the members of the redox couple. It is M lim , the limiting value of M(t), that is used to determine D R based on equation (29). In addition to the numerous determinations undertaken in conventional solvents, the use of semiintegration has enabled diffusion coefficients to be electrochemically determined in ionic liquids, [20,55] molten salts [56] and deep eutectic solvents [57] where slow diffusion ensures effectively semiinfinite planar diffusion conditions.…”

Section: Transportmentioning

confidence: 99%

“…Under reversible conditions with D R = D P , the potential at M lim /2 corresponds to

E^{\circ}^{'}

and is a reliable method that is used as the reference potential when comparing the slopes of log‐plots observed from differing kinetic zones when evaluating the mechanism of a following chemical reaction . This approach has also been employed to determine the stability constants of metal complexes, and was found to be superior to alternative polarographic analysis . If the electron transfer is quasireversible then

E^{\circ}^{'}

can be calculated as already described based on Equations (32) and (35).…”

Section: Applications Involving M(t)mentioning

confidence: 99%

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Semioperations and Convolutions in Voltammetry

Mahon

Oldham

2018

ChemElectroChem

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It is often useful to transform a measured signal into a form that is more easily interpreted. Thus, in voltammetry, where the measurement is of a current responding to a perturbation of the electrode potential, the complications arising from diffusional transport may be readily alleviated through the use of semioperators or convolutions. The use of semiintegration enables the voltammetric current to be transformed into an alternative signal that, in the case of a planar electrode, is linearly related to the concentrations of reactant and product at the electrode surface. Numerous advantages of semiintegration have been widely demonstrated. However, semiintegration is but a special case of the more general procedure of convolution. Convolving the voltammetric current with specifically designed functions of time allows the benefits of semiintegration to be applied to other electrode geometries and other experimental circumstances. The prime motive for semiintegration or convolution is to gain access to information about concentrations at the electrode surface. This information opens the door to the measurement of such quantities as bulk concentrations, rate constants, standard potentials, and diffusivities, as well as suggesting mechanisms and enabling the calibration of electrodes.

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Section: Determining M(t)mentioning

confidence: 99%

Section: Determining M(t)mentioning

confidence: 99%

Section: Electrode Kineticsmentioning

confidence: 99%

Section: Transportmentioning

confidence: 99%

“…Under reversible conditions with D R = D P , the potential at M lim /2 corresponds to

E^{\circ}^{'}

E^{\circ}^{'}

can be calculated as already described based on Equations (32) and (35).…”

Section: Applications Involving M(t)mentioning

confidence: 99%

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Semioperations and Convolutions in Voltammetry

Mahon

Oldham

2018

ChemElectroChem

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Photocatalytic Hydrogen Evolution by a Synthetic [FeFe] Hydrogenase Mimic Encapsulated in a Porphyrin Cage

Nurttila

Becker

Hessels

et al. 2018

Chemistry A European J

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The design of a biomimetic and fully base metal photocatalytic system for photocatalytic proton reduction in a homogeneous medium is described. A synthetic pyridylphosphole‐appended [FeFe] hydrogenase mimic was encapsulated inside a supramolecular zinc porphyrin‐based metal–organic cage structure Fe4(Zn‐L)6. The binding is driven by the selective pyridine–zinc porphyrin interaction and results in the catalyst being bound strongly inside the hydrophobic cavity of the cage. Excitation of the capsule‐forming porphyrin ligands with visible light while probing the IR spectrum confirmed that electron transfer takes place from the excited porphyrin cage to the catalyst residing inside the capsule. Light‐driven proton reduction was achieved by irradiation of an acidic solution of the caged catalyst with visible light.

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Center of Gravity (COG) Method as a Tool in Processing of Voltammetric Signals

et al. 2015

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The center of gravity method (COG) was applied (for the first time) in voltammetry (polarography) as a tool for very precise determination of peak potentials, and signal shifts. Basically, the adjustment of the method consists of finding the optimal fraction of the peak that contains information about peak position, either of original signal or of its 1st or 2nd derivatives, along with optimal selection of parameters for SavitzkyGolay smoothing of original curves and elimination of baseline influence. The principle of the method and its validation were demonstrated and checked on simulated differential pulse polarograms (DPP) representing a series of curves for the determination of stability constants of labile metal complexes (DeFord‐Hume method). It was shown that COG outperforms the classical “one‐point” method (OPM) in precision and accuracy, providing excellent results even if a very large step potential (e.g. 10 mV) was used. The problems of reduced accuracy and precision in case of curved (non‐ideal) baseline and asymmetric peaks were successfully overcome by applying COG on curves transformed by 1st and/or 2nd derivatives. The method was additionally examined in details on a simple experimental dataset of cadmium chloride complexes in 4 mol dm−3 ionic strength solution and on a more complex dataset of uranyl selenate complexes in 3 mol dm−3 ionic strength solution. Stability constants obtained by COG agree well with those in the literature with much better precision than the classical one‐point method (checked by standard error of the fit).

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Convolution voltammetry of metal complexes

Cited by 18 publications

References 30 publications

Semioperations and Convolutions in Voltammetry

Semioperations and Convolutions in Voltammetry

Photocatalytic Hydrogen Evolution by a Synthetic [FeFe] Hydrogenase Mimic Encapsulated in a Porphyrin Cage

Center of Gravity (COG) Method as a Tool in Processing of Voltammetric Signals

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