Preparation and properties of new Fe6 and Fe8 clusters of iron(iii) with tripodal ligands

Abstract

The syntheses, structures and magnetic properties are reported of new iron(III) complexes with Fe₆ wheel and Fe₈ cage topologies, and containing tripodal ligands. The compound [Fe₈O₃(O₂CPh)₉(tea)(teaH)₃]·MeCN (1·MeCN), where teaH₃ is triethanolamine, was obtained from the reaction of two equivalents of teaH₃ with [Fe₃O(O₂CPh)₆(H₂O)₃](O₂CPh) in MeCN. Similarly, the compound [Fe₆(bic)₆]·4H₂O·4MeOH (2·4H₂O·4MeOH), where bicH₃ is bicine, was prepared by the analogous reaction but with two equivalents of bicine. Variable-temperature solid-state magnetic susceptibility studies of 1 and 2 in the temperature range 5.00–300 K reveal that both complexes possess S = 0 ground state spins, consistent with the expected antiferromagnetic exchange interactions between the constituent iron(III) ions.