title: Heterobimetallic oxalato-bridged M(II)Re(IV) complexes (M = Mn, Fe, Co, Ni): synthesis, crystal structure, and magnetic properties.
abstract: Four rhenium(IV)-M(II) bimetallic complexes of formula [ReCl(4)(mu-ox)M(dmphen)(2)].CH(3)CN with M = Mn (1), Fe (2), Co (3), and Ni (4) (ox = oxalate anion, dmphen = 2,9-dimethyl-1,10-phenanthroline) have been synthesized and the crystal structures of 1 and 3 determined by single-crystal X-ray diffraction. 1 and 3 are isostructural and crystallize in the monoclinic system, space group P2(1)/c, with a = 16.008(4) A, b = 12.729(2) A, c = 18.909(5) A, beta = 112.70(2) degrees, and Z = 4 for 1 and a = 15.998(4) A, b = 12.665(2) A, c = 18.693(5) A, beta = 112.33(2) degrees, and Z = 4, for 3. The structure of 1 and 3 is made up of neutral [ReCl(4)(mu-ox)M(dmphen)(2)] bimetallic units (M = Mn (1), Co (3)) and acetonitrile molecules of crystallization. M(II) and Re(IV) metal ions exhibit distorted octahedral coordination geometries being bridged by a bis(bidentate) oxalato ligand. The magnetic behavior of 1-4 has been investigated over the temperature range 2.0-300 K. A very weak antiferromagnetic coupling between Re(IV) and Mn(II) occurs in 1 (J = -0.1 cm(-)(1)), whereas a significant ferromagnetic interaction between Re(IV) and M(II) is observed in 2-4 [J = +2.8 (2), +5.2 (3), and +5.9 cm(-)(1) (4)].
authors.affiliation: Cátedra de Química Inorgánica, Facultad de Química de la Universidad de la República, Montevideo, Uruguay.
authors.forename: Raúl
authors.initials: R
authors.lastname: Chiozzone
authors.forename: Ricardo
authors.initials: R
authors.lastname: González
authors.forename: Carlos
authors.initials: C
authors.lastname: Kremer
authors.forename: Giovanni
authors.initials: G
authors.lastname: De Munno
authors.forename: Donatella
authors.initials: D
authors.lastname: Armentano
authors.forename: Francesc
authors.initials: F
authors.lastname: Lloret
authors.forename: Miguel
authors.initials: M
authors.lastname: Julve
authors.forename: Juan
authors.initials: J
authors.lastname: Faus