Mono- and Dinuclear Fe(III) Complexes With the N2O2 Donor 5-Chlorosalicylideneimine Ligands; Synthesis, X-Ray Structural Characterization and Magnetic Properties

Abstract

Two novel monomeric [C<inf>18</inf>H<inf>17</inf>Cl<inf>3</inf>N <inf>2</inf>O<inf>2</inf>Fe] (1) and dimeric [C<inf>38</inf>H<inf>36</inf>N <inf>4</inf>O<inf>4</inf>Cl<inf>6</inf>Fe<inf>2</inf>] (2) Fe(III) tetradentate Schiff base complexes have been synthesized and their crystal structures have been determined by single crystal X-ray diffraction analysis. In complex (1) the Schiff base ligand coordinates toward one iron atom in a tetradentate mode and each iron atom is five coordinated with the coordination geometry around iron atom which can be described as a distorted square pyramid. The presence of a short (2.89 ) non-bonding interatomic Fe···O distances between adjacent monomeric Fe(III) complexes results in the formation of a dimer. Structural analysis of compound (2) shows that the structure is a centrosymmetric dimer in which the six coordinated Fe(III) atoms are linked by μ-phenoxo bridges from one of the phenolic oxygen atoms of each Schiff base ligand to the opposite metal center. The variable-temperature (2-300 K) magnetic susceptibility (χ) data of these two compounds have been investigated. The results show that for both complexes Fe(III) centers are in the high spin configuration (S = 5/2) and indicate antiferromagnetic spin-exchange interaction between Fe(III) ions. The obtained results are briefly discussed using magnetostructural correlations developed for other class of iron(III) complexes. © 2010 Elsevier B.V. All rights reserved.