B. Kwak et al., Synthesis and characterization of a ferric complex of the tripodal ligand tris(2-benzimidazolylmethyl)amine - a superoxide dismutase mimic, INORG CHIM, 290(1), 1999, pp. 21-27
The mononuclear iron complex 1 was synthesized using a tripedal ligand, tri
s(2-benzimidazolylmethyl) amine (ntb), where ntb served as a neutral tetrad
entate chelating ligand for the distorted octahedral ferric ion. Three benz
imidazole groups of ntb and one chloride anion formed a base of octahedral
geometry. One of the two axial positions was occupied by an apical nitrogen
atom of ntb and the other site was occupied by another chloride anion. Two
of the chloride anions in complex 1 are in a cis arrangement. The decay of
the electrochemically generated superoxide radical (O-2(-)) by complex 1 w
as observed using cyclic voltammetry. The superoxide dismutase (SOD) activi
ty of complex 1 was also examined using a modified method of the light- and
riboflavin-driven hydroxylaminenitrate assay. Reaction of complex 1 with a
n O-2(-) radical in methanol gave the mu-oxo dinuclear iron complex 2. The
mu-oxo group was substituted for the basal chloride anion of complex 1 in c
omplex 2. Complex 2 could also be synthesized using weak bases instead of t
he O-2(-) radical. (C) 1999 Elsevier Science S.A. All rights reserved.