Synthesis, crystal structure, magnetic property, and nuclease activity of a binuclear iron(III) complex

Abstract

A -oxo-di--carboxylato-bridged iron(III) complex containing two tridentate nitrogen ligands,, has been synthesized and determined by X-ray diffraction. Complex 1 crystallizes in the monoclinic space group P2 1 /c with a ¼ 10.9434(12) Å , b ¼ 23.118(3) Å , c ¼ 15.8721(18) Å , ¼ 92.736(2) and Z ¼ 4. In 1, each Fe(III) has a distorted octahedral geometry with a N 3 O 3 donor set. The Fe(III) atoms are bridged by two carboxyl groups and one -oxo oxygen with Fe1-Fe2 separation of 3.064 Å . Susceptibility data of 1 indicate strong intramolecular antiferromagnetic coupling of the high-spin Fe(III) atoms with J ¼ À121.0 cm À1 and g ¼ 2.04. The interaction with calf thymus DNA was investigated by UV absorption and fluorescent spectroscopy. Results show that the complex binds to ct-DNA with a moderate intercalative mode. The interaction between 1 and pBR322 DNA has also been investigated by submarine gel electrophoresis; the complex exhibits effective DNA cleavage activity in the absence of activating agents under similar physiological conditions.