Solvent and structural effects on the electro- and photo-reduction of cis - β -Co(trien)(RC6H4NH2)Cl]Cl2 type complexes in water/1,4-dioxane media |
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Abstract: | The electro- and photo-reduction of a series of cobalt(III) complexes of the type cis-β-Co(trien)(RC6H4NH2)Cl]Cl2 where R=H, p-OMe, p-OEt, p-Me, p-Et, p-F and m-Me has been studied in 1,4-dioxane/water. The redox potential (E 1/2) and photo-reduction quantum yield (φCo(II)) data were correlated with solvent and structural parameters to shed light on the mechanism of these reactions. Correlation of E 1/2 and φCo(II) with macroscopic solvent parameters viz. relative permittivity indicates that the reactivity is influenced by both specific and non-specific solute-solvent interactions. The Kamlet-Taft solvatochromic comparison method was used to separate and quantify these effects. Increasing the percentage of organic co-solvent in the medium enhances both reduction processes; there exists good correlation between E 1/2 and φCo(II) suggesting a similar solvation in these redox processes. |
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Keywords: | Cobalt(III) complexes Photo-reduction Electrochemistry Solvent effect Hammett equation |
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