title: Inelastic neutron scattering study of electron reduction in Mn12 derivatives.
abstract: We report inelastic neutron scattering (INS) studies on a series of Mn(12) derivatives, [Mn(12)O(12)(O2CC6F5)16(H2O)4]z, in which the number of unpaired electrons in the cluster is varied. We investigated three oxidation levels: z = 0 for the neutral complex, z = -1 for the one-electron reduced species and z = -2 for the two-electron reduced complex. For z = 0, the ground state is S = 10 as in the prototypical Mn12-acetate. For z = -1, we have S = 19/2, and for z = - 2, an S = 10 ground state is retrieved. INS studies show that the axial zero-field splitting parameter D is strongly suppressed upon successive electron reduction: D = -0.45 cm(-1) (z = 0), D = -0.35 cm(-1) (z = -1), and D approximately -0.26 cm(-1) (z = -2). Each electron reduction step is directly correlated to the conversion of one anisotropic (Jahn-Teller distorted) Mn3+ (S = 2) to one nearly isotropic Mn2+ (S = 5/2).
authors.affiliation: Department of Chemistry and Biochemistry, University of Berne, Freiestrasse 3, CH-3000 Berne 9, Switzerland.
authors.forename: Reto
authors.initials: R
authors.lastname: Basler
authors.forename: Andreas
authors.initials: A
authors.lastname: Sieber
authors.forename: Grégory
authors.initials: G
authors.lastname: Chaboussant
authors.forename: Hans U
authors.initials: HU
authors.lastname: Güdel
authors.forename: Nicole E
authors.initials: NE
authors.lastname: Chakov
authors.forename: Monica
authors.initials: M
authors.lastname: Soler
authors.forename: George
authors.initials: G
authors.lastname: Christou
authors.forename: Arnaud
authors.initials: A
authors.lastname: Desmedt
authors.forename: Ruep
authors.initials: R
authors.lastname: Lechner