Photoreduction of aqueous ferrioxamine B by oxalate induced by outer-sphere charge transfer excitation

The Fe(III) siderophore cation [ferrioxamine B]+ and oxalate form an ion pair which shows an outer-sphere charge transfer (OSCT) absorption at λmax=262 nm. While ferrioxamine B is not light-sensitive the aqueous ion pair [ferrioxamine B]+C2O42− undergoes a photoreduction to Fe(II) upon OSCT excitation.