Mononuclear iron(III) complexes supported by tripodal N 3O ligands: Synthesis, structure and reactivity towards DNA cleavage

Abstract

A new synthetic route to the known tripodal tetradentate N 3O ligand L 1 (HL 1 = [ N-(3,5-di- tert-butyl-2-hydroxybenzyl)- N, N-di-(2-pyridylmethyl)]amine) is reported. The related compounds HL n ( n = 2, 3) were prepared by a similar procedure. Treatment of HL n ( n = 1–3) with FeCl 3·6H 2O in hot methanol led to the mononuclear iron(III) complexes [Fe(L n )Cl 2] ( 1: n = 1, 2: n = 2, 3: n = 3). The solid-state structures of complexes 1 and 2 were determined by X-ray crystallography. [Fe(L 1)Cl 2] ( 1) showed effective nuclease activity in the presence of hydrogen peroxide, converting supercoiled plasmid DNA to its linear form.