title: Molecular-Based Magnetism in Bimetallic Two-Dimensional Oxalate-Bridged Networks. An X-ray and Neutron Diffraction Study.
abstract: Bimetallic, oxalate-bridged compounds with bi- and trivalent transition metals comprise a class of layered materials which express a large variety in their molecular-based magnetic behavior. Because of this, the availability of the corresponding single-crystal structural data is essential to the successful interpretation of the experimental magnetic results. We report in this paper the crystal structure and magnetic properties of the ferromagnetic compound {[N(n-C(3)H(7))(4)][Mn(II)Cr(III)(C(2)O(4))(3)]}(n)() (1), the crystal structure of the antiferromagnetic compound {[N(n-C(4)H(9))(4)][Mn(II)Fe(III)(C(2)O(4))(3)]}(n)() (2), and the results of a neutron diffraction study of a polycrystalline sample of the ferromagnetic compound {[P(C(6)D(5))(4)][Mn(II)Cr(III)(C(2)O(4))(3)]}(n)() (3). Crystal data: 1, rhombohedral, R3c, a = 9.363(3) Å, c = 49.207(27) Å, Z = 6; 2, hexagonal, P6(3), a = 9.482(2) Å, c = 17.827(8) Å, Z = 2. The structures consist of anionic, two-dimensional, honeycomb networks formed by the oxalate-bridged metal ions, interleaved by the templating cations. Single-crystal field dependent magnetization measurements as well as elastic neutron scattering experiments on the manganese(II)-chromium(III) samples show the existence of long-range ferromagnetic ordering behavior below T(c) = 6 K. The magnetic structure corresponds to an alignment of the spins perpendicular to the network layers. In contrast, the manganese(II)-iron(III) compound expresses a two-dimensional antiferromagnetic ordering.
authors.affiliation: Institut für Anorganische Chemie, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland, Laboratorium für Neutronenstreuung, Eidgenössische Technische Hochschule Zürich & Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland, Hahn-Meitner-Institut, Abteilung für Neutronenstreuung, Glienickerstrasse 100, D-1000 Berlin 39, Germany, and Institut Laue-Langevin, BP 156, F-38042 Grenoble Cedex 9, France.
authors.forename: René
authors.initials: R
authors.lastname: Pellaux
authors.forename: Helmut W.
authors.initials: HW
authors.lastname: Schmalle
authors.forename: Reto
authors.initials: R
authors.lastname: Huber
authors.forename: Peter
authors.initials: P
authors.lastname: Fischer
authors.forename: Thomas
authors.initials: T
authors.lastname: Hauss
authors.forename: Bachir
authors.initials: B
authors.lastname: Ouladdiaf
authors.forename: Silvio
authors.initials: S
authors.lastname: Decurtins