Electrochemical behavior of the selenocyanate/triselenocyanate redox couple in acetonitrile on platinum electrodes

Martins, M.E.; Castellano, C.E.; Calandra, A.J.; Arvía, Alejandro Jorge

doi:10.1021/ac50024a016

Cited by 8 publications

(13 citation statements)

References 19 publications

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“…The cyclic voltammetric responses in the ILs closely parallel those reported by Martins et al 24 and Cauquis and Pierre 34 in their studies of the electrochemical oxidation of selenocyanate in acetonitrile at platinum electrodes. The two processes are defined overall by eqs 8 and 9, which are analogous to eqs 2 and 3 for iodide:…”

Section: Resultssupporting

confidence: 83%

“…Overall, these results are very similar to those reported for (SeCN) 3h /SeCN h cyclic voltammetry in acetonitrile. 24 The linearity of the relationship between peak height and concentration indicates that over the modest SeCN h concentration range examined (5 to 50 or 100 mM) there is no evidence for the presence of exchange-based enhancement of diffusion, such as transport diffusion. In our subsequent analyses we focus on the sum of both oxidation processes under steady-state conditions so as to avoid the obvious enhanced complexity of the second process.…”

Section: Resultsmentioning

confidence: 93%

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Comparison of Diffusivity Data Derived from Electrochemical and NMR Investigations of the SeCN¯/(SeCN)₂/(SeCN)₃¯ System in Ionic Liquids

et al. 2011

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Electrochemical studies in room temperature ionic liquids are often hampered by their relatively high viscosity. However, in some circumstances, fast exchange between participating electroactive species has provided beneficial enhancement of charge transport. The iodide (I¯)/iodine (I(2))/triiodide (I(3)¯) redox system that introduces exchange via the I¯ + I(2) ⇌ I(3)¯ process is a well documented example because it is used as a redox mediator in dye-sensitized solar cells. To provide enhanced understanding of ion movement in RTIL media, a combined electrochemical and NMR study of diffusion in the {SeCN¯-(SeCN)(2)-(SeCN)(3)¯} system has been undertaken in a selection of commonly used RTILs. In this system, each of the Se, C and N nuclei is NMR active. The electrochemical behavior of the pure ionic liquid, [C(4)mim][SeCN], which is synthesized and characterized here for the first time, also has been investigated. Voltammetric studies, which yield readily interpreted diffusion-limited responses under steady-state conditions by means of a Random Assembly of Microdisks (RAM) microelectrode array, have been used to measure electrochemically based diffusion coefficients, while self-diffusion coefficients were measured by pulsed field gradient NMR methods. The diffusivity data, derived from concentration and field gradients respectively, are in good agreement. The NMR data reveal that exchange processes occur between selenocyanate species, but the voltammetric data show the rates of exchange are too slow to enhance charge transfer. Thus, a comparison of the iodide and selenocyanate systems is somewhat paradoxical in that while the latter give RTILs of low viscosity, sluggish exchange kinetics prevent any significant enhancement of charge transfer through direct electron exchange. In contrast, faster exchange between iodide and its oxidation products leads to substantial electron exchange but this effect does not compensate sufficiently for mass transport limitations imposed by the higher viscosity of iodide RTILs.

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Section: Resultssupporting

confidence: 83%

Section: Resultsmentioning

confidence: 93%

Comparison of Diffusivity Data Derived from Electrochemical and NMR Investigations of the SeCN¯/(SeCN)₂/(SeCN)₃¯ System in Ionic Liquids

et al. 2011

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“…Meinke et al [26] used the reaction of silver selenocyanate with iodine in tetrahydrofuran at 0 °C to produce (SeCN) 2 . (SeCN) 3 − was produced during electrolysis (anodic oxidation) of KSeCN using platinum electrodes [27]. Kaufmann and Kogler [28] reported that the reaction between lead tetraacetate and KSeCN could produce the unstable (SeCN) 2 .…”

Section: Discussionmentioning

confidence: 99%

“…We can trace no papers at all discussing the biological properties of (SeCN) 2 . It is known that (SeCN) 2 adds to SeCN− anion to form a “tri-selenocyanate” (SeCN) 3 − anion (eq4) in the same way that iodide adds to iodine to form a triodide anion [23]. Since it is also known that tri-iodide anion is highly bactericidal [24], it would appear reasonable to hypothesize that (SeCN) 3 − could also be bactericidal.…”

Section: Discussionmentioning

confidence: 99%

Antimicrobial photodynamic inactivation is potentiated by the addition of selenocyanate: Possible involvement of selenocyanogen?

Huang

Xuan

Kozińska

et al. 2018

Journal of Biophotonics

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We previously showed that antimicrobial photodynamic inactivation (aPDI) of Gram-positive and Gram-negative bacteria mediated by the phenothiazinium dye, methylene blue (MB), was potentiated by the addition of potassium thiocyanate (10 mM). The mechanism was suggested to involve a singlet oxygen-mediated reaction with SCN to form sulfite and cyanide and then to produce sulfur trioxide radical anion. We now report that potassium selenocyanate (concentrations up to 100 mM) can also potentiate (up to 6 logs of killing) aPDI mediated by a number of different photosensitizers (PS): MB, rose bengal and 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin dihydrochloride (as low as 200 nM). When a mixture of selenocyanate with these PS in solution was illuminated and then bacteria were added after the light, there was up to 6 logs of killing (Gram-negative > Gram-positive) but the antibacterial species decayed rapidly (by 20 minutes). Our hypothesis to explain this antibacterial activity is the formation of selenocyanogen (SeCN) by reaction with singlet oxygen ( O ) as shown by quenching of O by SeCN and increased photoconsumption of oxygen. The fact that lead tetraacetate reacted with SeCN (literature preparation of (SeCN) ) also produced a short-lived antibacterial species supports this hypothesis.

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“…Previous reports on the electrochemistry of different Au/electrolyte solution interfaces, such as Au/C1-(aq) [4], Au/SCN-(aq) [5] and Au/KSCN (ACN) [6], indicate that the overall faradaic processes involve the electrodissolution of the metal yielding complex-ion species. This reaction depends on the solvent and on the halide or pseudo-halide ion present.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical kinetics of gold electrodes in SCN−/dimethylsulfoxide solutions

Martins

1978

Journal of Electroanalytical Chemistry

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The electrochemical behaviour of the Au/SCN--(DMSO) interface is studied at 25°C ~< T ~< 65°C, by means of the triangular potential sweep technique and the RDE. Within a relatively limited potential range the main electrode process is:The kinetics of this reaction involves a mixed control. At higher potentials the electrodissolution of the base metal takes place. Side reactions occurring there make the overall process rather complex. The electrochemical behaviours of the Au/SCN-(DMSO) and Au/SCN--(ACN) are compared.

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Electrochemical behavior of the selenocyanate/triselenocyanate redox couple in acetonitrile on platinum electrodes

Cited by 8 publications

References 19 publications

Comparison of Diffusivity Data Derived from Electrochemical and NMR Investigations of the SeCN¯/(SeCN)₂/(SeCN)₃¯ System in Ionic Liquids

Comparison of Diffusivity Data Derived from Electrochemical and NMR Investigations of the SeCN¯/(SeCN)₂/(SeCN)₃¯ System in Ionic Liquids

Antimicrobial photodynamic inactivation is potentiated by the addition of selenocyanate: Possible involvement of selenocyanogen?

Electrochemical kinetics of gold electrodes in SCN−/dimethylsulfoxide solutions

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Electrochemical behavior of the selenocyanate/triselenocyanate redox couple in acetonitrile on platinum electrodes

Cited by 8 publications

References 19 publications

Comparison of Diffusivity Data Derived from Electrochemical and NMR Investigations of the SeCN¯/(SeCN)2/(SeCN)3¯ System in Ionic Liquids

Comparison of Diffusivity Data Derived from Electrochemical and NMR Investigations of the SeCN¯/(SeCN)2/(SeCN)3¯ System in Ionic Liquids

Antimicrobial photodynamic inactivation is potentiated by the addition of selenocyanate: Possible involvement of selenocyanogen?

Electrochemical kinetics of gold electrodes in SCN−/dimethylsulfoxide solutions

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Comparison of Diffusivity Data Derived from Electrochemical and NMR Investigations of the SeCN¯/(SeCN)₂/(SeCN)₃¯ System in Ionic Liquids

Comparison of Diffusivity Data Derived from Electrochemical and NMR Investigations of the SeCN¯/(SeCN)₂/(SeCN)₃¯ System in Ionic Liquids