Structural, electronic and magnetic properties of neutral and anionic Fe2(BO2)n (n=1-3) clusters

Using Fe-2 dimer as a prototype of transition-metal cluster calculations based on density functional theory have been carried out to study the effect of ligand and charge states on the geometry, bonding feature and magnetic coupling of neutral and anionic Fe-2(BO2)(n) (n = 1-3) clusters. For neutral Fe-2(BO2)(n) clusters the spin multiplicity of the complex changes from 7 to 8 when n goes from 0 to 1, 2, and 3. With increasing number of ligands the Fe-Fe distance increases, the magnetic coupling between Fe-Fe changes from direct exchange to super exchange, and 3d-2p hybridization between Fe and O atoms becomes predominant. For anionic Fe-2(BO2)(n) (n = 1-3) clusters, the corresponding total magnetic moment is 0, 7 and 6 mu(B), respectively. Compared with neutral clusters the HOMO-LUMO gaps of anionic species increase rapidly as more BO2 units are introduced. This study sheds light on the potential of superhalogens to tune electronic and magnetic properties of Fe clusters. (C) 2014 Published by Elsevier B.V.