Mononuclear iron(III) complexes supported by tripodal N3O ligands: Synthesis, structure and reactivity towards DNA cleavage

A new synthetic route to the known tripodal tetradentate N3O ligand L-1 (HL1 = [N-(3,5-di-tert-butyl-2-hydroxybenzyl)-N,N-di-(2-pyridylmethyl)]amine) is reported. The related compounds HLn (n = 2, 3) were prepared by a similar procedure. Treatment of HLn (n = 1-3) with FeCl3 center dot 6H(2)O in hot methanol led to the mononuclear iron(III) complexes [Fe(Ln)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. (C) 2009 Elsevier B.V. All rights reserved.