Electrode Reaction of Iron Phenanthroline Complexes in an Amide-type Ionic Liquid

摘要

The electrode kinetics of [Fe(phen)3]~(3+)/[Fe(phen)3]~(2+) (phen = 1,10-phenanthroline) on a platinum electrode was investigated in an amide-type room-temperature ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (BMPTFSA). The diffusion coefficients of [Fe(phen)3] and [Fe(phen)3] were found to be affected not only by charge density of the complex but also by the size of the complex. The standard rate constant of [Fe(phen)3]~(3+)/[Fe(phen)3]~(2+) in BMPTFSA was smaller than that of [Fe(bpy)3]~(3+)/[Fe(bpy)3]~(2+) (bpy = 2,2'-bipyridine), reflecting the difference in the inner reorganization energies between [[Fe(phen)3]~(3+)/[Fe(phen)3]~(2+) and [Fe(bpy)3]~(3+)/[Fe(bpy)3]~(2+).