Dimeric iron(III) complexes with salicylaldimine ligands:: structures, magnetic properties, and activity of H2O2 disproportionation

The preparations. characterizations, structures, magnetic properties and catalase-like activities of four new alkoxy bridged dimeric five-coordinate iron(III) salicylaldimine complexes, [(FeLCl)-Cl-1](2) (1) (H2L1 = N-(3-hydroxypropyl)(5-bromosalicylaldimine)), [(FeLCl)-Cl-2](2) (2) (H2L2 = N-(3-hydroxypropyl)(3-methoxysalicylaldimine)), [(FeLCl)-Cl-3](2) (3) (H2L3 = N-(3-hydroxypropyl)(4-diethylaminosalicylaldimine)), and [(FeLCl)-Cl-4](2) (4) (H2L4 = N-(3-hydroxypropyl)(3,5-diiodosalicyaldimine)) are reported. The crystal structure of complexes 1-3 show an alkoxy bridged dimeric iron(III) complex, which occupies a site of inversion symmetry, and each iron atom is five-coordinate with square-pyramidal arrangements. Mossbauer spectra reveal the presence of high-spin iron(III) ions in complexes 1-4. The magnetic susceptibility (300-2 K) indicate an antiferromagnetic interaction between the two oxygen-bridged iron(III) ions with J = - 17.5, - 12.40, - 19.0 and - 21.0 cm(-1) for the complexes of 1-4, respectively. The H2O2 disproportionation of complexes 1-4 in acetonitrile at 25 degreesC show the rate law of k(obs)[H2O2[complex]. (C) 2001 Elsevier Science B.V. All rights reserved.