High-nuclearity mixed-chelate ferric complexes from a new family of polynuclear precursors

Abstract

The syntheses, structures, and magnetochemical characterization of two novel mixed-chelate undeca- and dodecanuclear ferric complexes are reported. Preformed tri- and pentanuclear ferric complexes that possess tridentate Schiff base (L2- and (L′)2-) and acetate ligands were reacted with 1,1,1-tris(hydroxymethyl)ethane (H3thme) to afford [Fe11O3(OH)(O2CMe)8(thme) 2(L)6] (1) and [Fe12O4(O 2CMe)8(thme)2(NH2(CH 2)2O)2(L′)6] (2),spectively, following structural agglomeration and rearrangement associated with ligand substitution. The incorporation of more than one type of ligand that can both chelate and bridge the Fe centers gives rise to the complicated molecular structures displayed by 1 and 2...