The mechanism of redox reactions initiated by UV excitation of [Fe(bpy)(CN)4]2- in aqueous solutions has been investigated by continuous photolysis, laser kinetic spectroscopy and pulse radiolysis. Hydrated electrons formed in the light induced reaction are shown to react with ground state [Fe(bpy)(CN)4]2- to form [Fe(bpy)(CN)4]3- characterized by its absorption spectra and reactions. The back reaction between [Fe(bpy)(CN)4]- and [Fe(bpy)(CN)4]3- takes place with kl.8±4x1010 M-1 s-1. The quantum yield of solvated electron formation determined by using nitrate ions as electron scavenger is 0.14±0.01 and 0.068±0.007 at μ∼ 0.01 and μ∼ 1.0, respectively. Addition of methylviologen (MV2+) to the solution of iron(II) complex leads to production of MV+ via direct electron scavenging and an electron transfer reaction from [Fe(bpy)(CN)4]3-. The latter process takes place with k = 9.0±0.6 x 109 M-1 s-1. The decay of MV+ occurs in reactions with both iron(III) and iron(II) complexes.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry