Synthesis and magnetic properties of heptadecametallic Fe(III) clusters.

Heptadecametallic, all-ferric pieces of molecular magnetite of general formula HLx[Fe17O16(OH)(12)(L)(12)Br-4]Br3+x (L = beta-picoline, isoquinoline, 3,5-lutidine; x = 0, 1) are made by the simple dissolution of FeBr3 in L. The beta-picoline (or equivalent) molecules act simultaneously as solvent, base and capping ligand. The resultant structure consists of a metal-oxygen core containing both octahedral and tetrahedral Fe(III) ions that is the exact analogue of the metal-oxygen positions seen in the magnetite lattice. Antiferromagnetic exchange between the tetrahedral and octahedral Fe(IIII) ions lead to the stabilization of an S = 35/2 spin ground state. (c) 2006 Elsevier Ltd. All rights reserved.