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

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.