Reduction electrochimique de molecules dimeres du paraquat en milieu aqueux

Deronzier, Alain; Galland, Bruno; Vieira, Mathias Miranda

doi:10.1016/0013-4686(83)85151-2

Cited by 21 publications

(24 citation statements)

References 15 publications

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“…As mentioned earlier, bis‐viologen derivatives can generate π‐dimers when linked though a suitable flexible spacer such as a simple propyl chain –. Our main objective was thus to synthesize and characterize a series of Zn II and Fe II metallopolymers made from the C3 4+ ligand and to study the possible formation of π‐dimers in the polymer chains following the reduction of the viologen centers (1 e − per viologen unit).…”

Section: Resultsmentioning

confidence: 99%

Redox‐Triggered Folding of Self‐Assembled Coordination Polymers incorporating Viologen Units

Abdul-Hassan

Roux

Bucher

et al. 2018

Chemistry A European J

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We report the study of stimuli-responsive Zn and Fe coordination polymers (MC3 or MC2 with M=Fe or Zn ). These soluble metallopolymers were formed spontaneously by reaction of an organic ligand (C3 or C2 ) with one molar equivalent of metal ions. The C3 and C2 ligands incorporate two chelating terpyridine groups bridged by a redox responsive hinge featuring two viologen units (viologen=N,N'-dialkyl-4,4'-bipyridinium) linked either with propyl (C3 ) or ethyl (C2 ) chains. The viologen units in the polymer chains were reduced (1 e per viologen group) either by bulk electrolysis or by visible-light irradiation carried out in the presence of a photosensitizer. The 1 e reduction of the viologen units in the MC2 polymers induced a slight decrease in the viscosity of the solutions due to a modification of the overall charge carried by the metallopolymers. In strong contrast, reduction of coordination polymers involving propyl linkers (MC3 ) led to a remarkable increase (≈+400 %) in observed viscosity. This reversible effect was attributed to a folding of the polymer chains triggered by π-dimerization of the photo-generated viologen cation radicals.

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Section: Resultsmentioning

confidence: 99%

Redox‐Triggered Folding of Self‐Assembled Coordination Polymers incorporating Viologen Units

Abdul-Hassan

Roux

Bucher

et al. 2018

Chemistry A European J

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“…The intramolecular interactions lead to wave splitting and greater than predicted separation between successive formal potentials. Even in the bisviologen derivatives (V 2+ -V 2+ ), the most simple polyviologens four reduction processes were considered [12].…”

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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“…Reversible redox systems of this type are of interest as components of electrochromic memory display devices [2][3][4][5], as bielectronic mediators [6,7] and as components of redox active membranes [8]. In a different area of application they have very recently been found to be of great interest as intercalators of D N A [9].…”

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confidence: 99%

“…Attempts to convert the monoquaternary salt (6 ) to the diquaternary salt (4; n = 2, X = Br) by heating it with more 1,2-dibromoethane resulted in the formation of polyviolo gen. However, by allowing a solution of l-(2-bromoethyl)-4,4'-bipyridinium bromide (6) in di methyl sulfoxide and 1,2-dibromoethane to stand at ambient temperature for seven days the diquaternary salt l,l'-bis-(2-bromoethyl)-4,4'-bipyridinium di bromide (4; n = 2, X = Br) was obtained in moder ate yield. The dibromide anion of (4; n -2, X = Br) was converted to the diperchlorate anion for the pur poses of characterisation and analyses of the salt.…”

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confidence: 99%

“…The dibromide anion of (4; n -2, X = Br) was converted to the diperchlorate anion for the pur poses of characterisation and analyses of the salt. It was subsequently ascertained that reaction of 4,4'-bipyridine with excess 1,2-dibromoethane in di methyl sulfoxide in the same conditions gave the di quaternary salt (4; n = 2, X = Br) without isolating the intermediate monoquaternary salt (6). This route was, therefore, adopted for the preparation of 1,1'-bis-(3-bromopropyl)-4,4'-bipyridinium dibromide yield by reaction with 4,4'-bipyridine in dimethyl sulfoxide for 7-10 days at ambient temperature.…”

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confidence: 99%

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