title: Ferromagnetic Interactions in the Mn(N(3))(4)[Ni(en)(2)(NO(2))](2) Trinuclear Compound. Crystal Structure and Physical Properties.
abstract: The goal of this work was to design a ferromagnetically coupled Mn(2+)Ni(2+) species. For this, we attempted to combine nitro-nitrito and end-on azido bridges which are both known to be ferromagnetic couplers. This has led us to the compound of formula Mn(N(3))(4)[Ni(en)(2)NO(2)](2) (en = ethylenediamine). The crystal structure has been solved at room temperature. The compound crystallizes in the monoclinic system, space group C2, with a = 12.631(14) Å, b = 15.636(2) Å, c = 13.43(2) Å, beta = 90.14(6) degrees, and Z = 4. The structure consists of two very similar but crystallographically independent neutral trinuclear units with a MnNi(2) isoceles triangular shape. The Mn and Ni atoms are doubly bridged by an end-on azido and a nitro-nitrito (with respect to Ni and Mn, respectively) group. Both the temperature dependence of the magnetic susceptibility and the field dependence of the magnetization at 2 K have been investigated and have revealed Mn(2+)-Ni(2+) ferromagnetic interactions, which give rise to an S = (9)/(2) ground state for the triad. The quantitative interpretation of these magnetic properties has given an interaction parameter J between Mn(2+) and Ni(2+) ions equal to 1.4(1) cm(-)(1) (H = -JS(Mn)().(S(Ni1)() + S(Ni2)()). The electronic absorption spectrum has been recorded at various temperatures down to 20 K and interpreted.
authors.affiliation: Laboratoire des Sciences Moléculaires, Institut de Chimie de la Matière Condensée de Bordeaux, UPR CNRS No. 9048, 33608 Pessac, France, and Laboratoire de Chimie du Solide et Inorganique Moléculaire, UMR No. 6511, Université de Rennes I, 35042 Rennes, France.
authors.forename: T. M.
authors.initials: TM
authors.lastname: Rajendiran
authors.forename: Corine
authors.initials: C
authors.lastname: Mathonière
authors.forename: Stéphane
authors.initials: S
authors.lastname: Golhen
authors.forename: Lahcène
authors.initials: L
authors.lastname: Ouahab
authors.forename: Olivier
authors.initials: O
authors.lastname: Kahn