A novel reactivity descriptor for MN4 molecular catalysts for the oxidation of 2-mercaptoethanol and of thioglycolic acid: The Electrochemical Hardness

Abstract

This manuscript describes a novel reactivity descriptor for Fe phthalocyanines molecular catalysts confined on the surface of OPG electrodes. The descriptor ΔE°’cat. is the gap in potential between the E°Fe(III)/(II) and E°Fe(II)/(I) redox processes for each FeN4 catalyst. This descriptor, labeled as the electrochemical hardness ΔE°’_cat. Was examined using FeN4 macrocyclic complexes for the electrooxidation of 2-mercaptoethanol (2-ME) and thioglycolic acid TGA. Our findings reveal that the reactivity as log log(j/Γ)E, plotted versus E°Fe(III)/(II) or E°Fe(II)/(I) give two linear correlations. The activity log(j/Γ)_E in both cases decreases with the redox potential of each FeN4 catalyst. In contrast log(j/Γ)_E, or log (TOF)_E, increase with ΔE°’_cat.. The FeS binding energy ΔE°’_cat. Correlates linearly with ΔE°’_cat. so the softer the system the greater the binding energy and the lower the catalytic activity.