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Electrochemical and Electron Transfer Behavior of o ‐Chloranil with the Presence of Mg 2+ in Acetonitrile
Author(s) -
Park Hyun,
Oyama Munetaka
Publication year - 2002
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/1521-4109(200210)14:18<1269::aid-elan1269>3.0.co;2-3
Subject(s) - chloranil , chemistry , acetonitrile , electrochemistry , electron transfer , redox , inorganic chemistry , adsorption , electrode , photochemistry , organic chemistry
The reduction process of o ‐chloranil ( o ‐CA) with the presence of Mg 2+ was observed in acetonitrile on a platinum electrode to compare that of p ‐chloranil ( p ‐CA) with Mg 2+ . Although the reduction potentials of o ‐CA and p ‐CA were not so different without Mg 2+ , apparent differences were recognized for both reduction processes in the presence of Mg 2+ . While the adsorption of a Mg 2+ salt of p ‐CA dianion, Mg 2+ p ‐CA 2− , was reported, no adsorption of the reduced forms of o ‐CA was observed. Alternatively, significant changes in the electrochemical responses were observed implying a rigid complexation between Mg 2+ and o ‐CA 2− in solution. In addition , using a stopped‐flow technique, the occurrence of the electron transfer between ferrocene, whose formal oxidation potential is +0.26 V (vs. $\rm{{I}_3^-}$ , I − ), and o ‐CA, whose formal reduction potential is 0.00 V, was observed in the presence of Mg 2+ , though the spontaneous electron transfer did not occur without Mg 2+ . This indicates the effect of Mg 2+ to make the redox potential of o ‐CA positive by complexing, while this is not the case of p ‐CA.