Investigation of the nature of electrodeposited neutral viologens formed by reduction of the dications

Engelman, E.Eric; Evans, Dennis H.

doi:10.1016/0022-0728(93)80169-i

Cited by 29 publications

(24 citation statements)

References 47 publications

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“…[43][44][45] Electrode fouling due to electrodeposition of the neutral form of the molecule has also been observed in aqueous solvents. [46] We show that in acetonitrile, repeatable measurements of the standard rate constant may be obtained, free from such complications, by using fast scan voltammetry and convolution analysis. [47] First we present the results of slow-scan cyclic voltammetry experiments and demonstrate that the one-electron reduction of the viologen derivatives is a well-behaved, simple electron transfer, then we discuss the measurements of standard electrochemical rate constants by using fast-scan cyclic voltammetry (FSV), impedance spectros-copy (EIS) and steady-state microelectrode voltammetry.…”

Section: Introductionmentioning

confidence: 91%

Heterogeneous Electron‐Transfer Rates for the Reduction of Viologen Derivatives at Platinum and Bismuth Electrodes in Acetonitrile

Cook

Horrocks

2016

ChemElectroChem

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The standard heterogeneous rate constants for the reduction of a series of viologen derivatives with a range of inter‐ring torsion angles were measured at Bi and Pt electrodes. The electrode potentials for the first one‐electron reduction of the viologens vary from −684 mV to −1070 mV vs. Ag/0.01 m Ag+; this enabled a comparison of the behaviour of metallic (Pt) and semi‐metallic (Bi) electrodes over a wide range of applied potentials. The differential capacitance (6.5 μF cm−2) of Bi/MeCN,TBAPF6 interfaces at the potential of zero charge (pzc=−0.60 V) is at least an order of magnitude greater than that calculated on the basis of the bulk Bi carrier density (3×1017 cm−3) and the differential capacitance (9.5 μF cm−2) of Pt/MeCN interfaces at their pzc (−0.43 V) is of the same order. The series of viologen derivatives exhibited simple one‐electron redox behaviour and showed similar rate constants at Pt (1.8×10−4–1.6×10−3 cm s−1) and Bi electrodes (1.1×10−4–1.9×10−3 cm s−1) after application of the Frumkin correction. These results demonstrate that the density of states at the Bi surface is much higher than in bulk. Finally, the Frumkin‐corrected standard rate constants were observed to be inversely correlated with the inter‐ring torsion angle of the viologens.

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Section: Introductionmentioning

confidence: 91%

Heterogeneous Electron‐Transfer Rates for the Reduction of Viologen Derivatives at Platinum and Bismuth Electrodes in Acetonitrile

Cook

Horrocks

2016

ChemElectroChem

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“…Finally, the peak pair P 5 /P 5 ' should be due to the second one-electron transfer step (DHVC + /DHV 0 ). Because a DHVC + Cl À precipitate can form due to a conproportionation reaction between the uncharged DHV 0 formed below À425 mV and the dicationic DHV 2 + solution species, [42] the oxidation peak of the radical cation from the DHVC + Cl À precipitate in the reverse anodic sweep shows up and leads to an enhancement of the anodic DHV 0 /DHVC + peak. The more negative the cathodic potential limit is, the more DHVC + Cl À precipitate is produced.…”

Section: Electrochemical Behaviour Of Heptyl Viologen On a Cu(100) Elmentioning

confidence: 97%

Redox Activity and Structural Transition of Heptyl Viologen Adlayers on Cu(100)

Jiang¹,

Sak²,

Gentz³

et al. 2010

ChemPhysChem

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The redox behaviour and potential-dependent adsorption structure of heptyl viologen (1,1'-diheptyl-4,4'-bipyridinium dichloride, DHV(2+)) on a Cu(100) electrode was investigated in a chloride-containing electrolyte solution by cyclic voltammetry (CV) and in situ electrochemical scanning tunneling microscopy (EC-STM). The dicationic DHV molecules generate a few pairs of current waves in CV measurements which are ascribed to two typical one-electron transfer steps. STM images obtained in a KCl-containing electrolyte solution disclose a well-ordered c(2x2) chloride adlayer on a Cu(100) electrode surface. After injecting DHV(2+) molecules into the KCl electrolyte solution, a highly ordered 2D "dot-array" structure in STM images emerges on the c(2x2)-Cl modified Cu(100) electrode surface. DHV(2+) molecules spontaneously arrange themselves with their molecular planes facing the electrode surface and their long molecular axis parallel to the step edge. Such adsorption structure can be described by mirror domains and rotational domains which stably exist between 200 mV and -100 mV. One-electron reduction of the dications DHV(2+) around -150 mV causes a phase transition from a 'dot-array' assembly to a stripe pattern formed by DHV(*+) radical monocations in STM images which has a bilayer structure. With a further decrease of the applied electrode potential, the structure of the DHV(*+) adlayer undergoes a change from a loose stripe phase to a more compact stripe phase, a subsequent decay of the compact structure, and finally the formation of a new dimer phase. A further electron transfer reaction at -400 mV causes the formation of an amorphous phase on the chloride free electrode surface. In a reverse anodic sweep, the reproduction of the ordered DHV(*+) stacking phase occurs again on top of the chloride lattice.

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“…This is a function of the solvent, the substituents, the anions and the electrode material [3,13]. The voltammogram characteristics become usually more complex if deposits are formed.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, chemically and electrochemically polymerized viologens have been widely studied concerning the kinetics and mechanism of their redox reactions [2][3][4]. The viologens are usually prepared by the Menschutkin reaction of 4,4 0 -dipyridyls and dibromoalkanes in aprotic solvents, e.g., acetonitrile, dimethyl-formamide, and dimethylsulfoxide.…”

Section: Introductionmentioning

confidence: 99%

The Electrochemical Properties of Some Alkylviologens

1998

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Ethyl-, and butylviologens were prepared by the Menschutkin reaction of 4,4 0 -dipyridyl and 1,2-dibromoethane and 1,4-dibromobutane. Elemental analysis and 1 H-NMR spectra showed that products consisted of symmetrical and asymmetrical substituted dipyridyls. Electrochemical reduction of these compounds in KBr and HCl solutions has been studied by the voltammetry method. The reduction process proceeds through several electrochemical and protonation steps, depending on the viologen structure and pH of the solution. The process results in a film formation on the electrode surface. The film is partly electroactive in the KBr solution, but completely passive in HCl. Reaction schemes have been proposed to explain this phenomenon.

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Investigation of the nature of electrodeposited neutral viologens formed by reduction of the dications

Cited by 29 publications

References 47 publications

Heterogeneous Electron‐Transfer Rates for the Reduction of Viologen Derivatives at Platinum and Bismuth Electrodes in Acetonitrile

Heterogeneous Electron‐Transfer Rates for the Reduction of Viologen Derivatives at Platinum and Bismuth Electrodes in Acetonitrile

Redox Activity and Structural Transition of Heptyl Viologen Adlayers on Cu(100)

The Electrochemical Properties of Some Alkylviologens

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