Electronic structure, magnetic interactions, and the role of ligands in Mnn(n=4,12) single-molecule magnets -: art. no. 184421

We report our first principles calculation studies of electronic structure and magnetic properties of the Mn-n (n=4,12) single-molecule magnet, i.e., [Mn4O3Cl(OAc)(3)(dbm)(3)] (dbmH=dibenzoyl-methane) and [Mn12O12(CH3COO)(16)(H2O)(4)] molecules. For the calculations, we used the localized pseudoatomic orbital method based on the density functional theory within local density approximation. To investigate the role of ligand and its contribution to the determination of the magnetic properties, we calculated the electronic structures of Mn-n clusters with different ligand configurations. The detailed analysis reveals an important contribution of the bridging carbon atoms, connecting the Mn-O core and the outer ligand complex, to the magnetic ground states of the magnetic molecules. In addition, we calculated the effective exchange-coupling constants among Mn ions.