Models for lipoxygenase with two alkoxide—Fe(III) centers: synthesis, structures, and properties

Abstract

[FeIII(OMe)(Hedtb)](ClO4)3·6.5CH3OH (1) and [FeIII(On-Bu)(Hedtb)](ClO4)3·3n-BuOH (2) (edtb = N,N,N',N'-tetrakis[(2-benzimidazolyl)methyl]-1,2-ethanediamine ) were prepared and display lipoxygenase activity. X-ray crystallography reveals that the FeIII centers in complexes 1 and 2 are ligated to three nitrogens of benzimidazole and two alkylamine nitrogen atoms from the edtb ligand, with a terminal alkyoxyl group occupying the sixth position. Complexes 1 and 2 both possess a FeIII—OR center (R = Me, 1; n-Bu, 2) with Fe—O bond distances of 1.799(3) Å and 1.789(5) Å, respectively. The UV-Vis spectra and electrochemical properties of the complexes were recorded. Both complexes have strong absorption peaks at around 375 nm and display lipoxygenase activity.