Photoreduction of iron(III) tetraphenylporphyrin in ethanol studied by laser flash photolysis: effects of concentration on quantum yields

Abstract

Chloroiron(III) tetraphenylporphyrin, CIFe^IIITPP, in deaerated ethanol is photoreduced to yield iron(II) tetraphenylporphyrin, Fe^IITPP, upon irradiation with UV light. The 355 nm laser photolysis studies have confirmed that the initial yields for the formation of Fe^IITPP are markedly decreased with an increase in the concentration of CIFe^IIITPP: ϕ= 0.015 at 5.35 × 10^–6 mol dm^–3 CIFe^IIITPP and ϕ= 0.01 at 1.0 × 10^–4 mol dm^–3 CIFe^IIITPP. The effects of the concentration on the quantum yields were interpreted in terms of the formation of photoreactive iron(III) porphyrin at low concentrations of CIFe^IIITPP.