title: New binuclear Mn(II) and Fe(II) complexes supported by 1,4,8-triazacycloundecane.
abstract: Two new binuclear metal complexes supported by 1,4,8-triazacycloundecane (tacud) are reported. [Fe(2)(tacud)(2)(μ-Cl)(2)Cl(2)] (1) and [Mn(2)(tacud)(2)(μ-Cl)(2)Cl(2)] (2) are isomorphs consisting of bis(μ-chloro) bridged metal centers along with terminal chloro groups and tacud ligands. Both compounds 1 and 2 crystallize in the P1 space group. For 1, a = 7.7321(12) Å, b = 7.8896(12) Å, c = 11.4945(17) Å, α = 107.832(2)°, β = 107.827(2)°, γ = 92.642(2)°, V = 627.85(17) Å(3) and Z = 1. For 2, a = 7.7607(12) Å, b = 7.9068(12) Å, c = 11.6111(18) Å, α = 108.201(2)°, β = 108.041(2)°, γ = 92.118(3)°, V = 636.47(17) Å(3) and Z = 1. Variable-temperature and variable-field magnetic susceptibility studies on 1 indicate the presence of weak ferromagnetic interactions between the high-spin iron(ii) centers in the dimer (J = + 1.6 cm(-1)) and the crystalline field anisotropy of the ferrous ion (D = - 2.8, E = - 0.1 cm(-1)). Variable temperature magnetic susceptometry studies on 2 indicate that weak antiferromagnetic coupling exists between the manganese(ii) centers (J = - 1.8 cm(-1)). Compounds 1 and 2 retain their dinuclearity in weakly coordinating or low polarity solvents, while both become mononuclear in solvents such as methanol.
authors.affiliation: Department of Chemistry, Oakland University, Rochester, MI 48309-4477, USA.
authors.forename: Piotr L
authors.initials: PL
authors.lastname: Pawlak
authors.forename: Manashi
authors.initials: M
authors.lastname: Panda
authors.forename: Reza
authors.initials: R
authors.lastname: Loloee
authors.forename: Benjamin E
authors.initials: BE
authors.lastname: Kucera
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Costes
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Tuchagues
authors.forename: Ferman A
authors.initials: FA
authors.lastname: Chavez
mesh_terms: D000473:Alkanes / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D007501:Iron / Q000737:chemistry*; D008280:Magnetics; D008345:Manganese / Q000737:chemistry*; D008968:Molecular Conformation; D013696:Temperature
chemical_list: D000473:Alkanes; D056831:Coordination Complexes; D008345:Manganese; D007501:Iron; C022884:undecane