Model compounds for microbial iron-transport compounds. Part IV. Further solution chemistry and Mössbauer studies on iron(II) and iron(III) catechol complexes

Abstract

Mössbauer spectroscopy and solution studies, together with Evans' Method to measure magnetic moments, on the complexes in the Iron(II)/Iron(III) catechol system are reported. A mechanism previously proposed for the reduction of Iron(III) to Iron(II) is modified by consideration of new evidence for the monoprotonation of the monocatecholato acid stable iron complex. The monoprotonated catechol moiety is the electron donor to the coordinated iron(III) and thus protonation of iron-containing hexadentate catecholate siderophores is probably essential for the reduction.