A new Fe6 ferric cluster: synthesis, crystal structure and magnetic properties

Abstract

A new Fe^III₆cluster, [Fe₃L₂(ida)(μ-OH)₃(μ-O)]₂·4ClO₄·2CH₃OH·8H₂O (1) (where L = N-methyl-N,N-bis(2-pyridylmethyl)amine; H₂ida = iminodiacetic acid), has been synthesized and magnetic properties are shown. The asymmetric unit of 1 contains a triangular [Fe₃L₂(ida)(μ-OH)₃(μ-O)]²⁺ unit and two such trinuclear units are further connected by two ida²⁻, generating a hexanuclear Fe^III core in 1. Variable temperature magnetic susceptibility studies reveal the presence of dominant antiferromagnetic exchange interactions and the variable-field and temperature magnetization measurements establish that each Fe₃ cluster has S = 5/2 ground state and the coupling between the two moieties is almost zero.