Synthesis, structure, and magnetic properties of a dinuclear antiferromagnetically coupled iron(II) complex

Abstract

A new dinuclear Fe(II) complex with the general formula [Fe2(1,4-tpbd)(dca)4(H2O)2] ( 1 ) (in which 1,4-tpbd = N,N,N′,N′-tetrakis(2-pyridylmethyl)benzene-1,4-diamine; dca = dicyanamide, [N(CN)2]−), has been prepared under hydrothermal conditions and fully characterized by elemental analysis, infrared spectroscopy, X-ray diffraction, and magnetic measurements. The compound crystallizes in the triclinic system and P-1 space group with Z = 1 and the following unit cell parameters: a = 8.165(5) Å, b = 10.236(5) Å, c = 13.105(5) Å, α = 81.421(5)°, β = 78.810(5)°, γ = 72.941(5)°, and V = 1022.2(9) Å3. The Fe(II) ions are six-coordinated, in distorted octahedral fashion, by three N atoms of tpbd ligand, one water oxygen atom and two N atoms of two dicyanamide anions. The intra-dinuclear Fe⋯Fe distance via the bridged μ2-tpbd ligand is 8.293(8) Å. In the molecular arrangement, the combination of OH⋯N and CH⋯N hydrogen bonds links the title complex to form a three-dimensional supramolecular structure. Magnetic susceptibility measurements (2–300 K) show that 1 presents weak antiferromagnetic exchange between the two nearest Fe2+ ions with the coupling constant J = −1.05 cm−1.