Original scientific paper

https://doi.org/10.5562/cca1999

Middle Phase Electrochemistry of Two Pentacyano(L)Ferrates(II)

Daniela Bala ; Physical Chemistry Department, Faculty of Chemistry, University of Bucharest, Regina Elisabeta 4-12, Bucharest RO-030018, Romania
Petronia Dasu ; Physical Chemistry Department, Faculty of Chemistry, University of Bucharest, Regina Elisabeta 4-12, Bucharest RO-030018, Romania
Constantin Mihailciuc ; Physical Chemistry Department, Faculty of Chemistry, University of Bucharest, Regina Elisabeta 4-12, Bucharest RO-030018, Romania

Abstract

The electrochemical behaviour of two water soluble redox species (pentacyano(L)ferrate(II)
complexes, where L is 4,4'-bipyridine and ammonia), belonging to cyanoferrate(II) series, was investigated
by using cyclic voltammetry (CV) technique in a "middle phase microemulsion" (MPME). The
microemulsion (ME) is formed between water and toluene, by using, besides the redox species, sodium
dodecyl sulphate as surfactant, 1-butanol as cosurfactant and sodium chloride as supporting electrolyte.
Three different three-electrode configuration arrangements were used. In each case reversible behaviour
for both species was obtained. Different behaviour was found in "middle phase" for the two investigated
electroactive species based on the presence of the sixth ligand (coligand). The coligand determines, on one
hand, different electronic influence on the electron transfer reaction at Pt working electrode and, on the
other hand, specific interaction with the "microscopic organic phase" from "middle phase". This paper
demonstrates, based on Randles-Sevcik equation, that [Fe(CN)5(4,4'–bpy)]3– is distributed between the
"water phase" and "microscopic aqueous phase" rather in latter phase. For [Fe(CN)5(NH3)]3–, its distribution
is similar with that of the common hexacyanoferrate(III) or hexacyanoferrate(II). The CV study of the
two different electroactive species illustrates an almost reversible behaviour both in "middle phase" and
"water phase". (doi: 10.5562/cca1999)

Keywords

middle phase microemulsion; cyclic voltammetry; active working electrode area

Hrčak ID:

105398

URI

https://hrcak.srce.hr/105398

Publication date:

1.7.2013.

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