Trinuclear-based coordination compounds of Mn(II) and Co(II) with 4-amino-3,5-dimethyl-1,2,4-triazole and azide and thiocyanate anions: Synthesis, structure and magnetic properties

A 2D layer complex 1 and a linear trinuclear complex 2 with mixed ligands have been synthesized and characterized by elemental analyses, IR and single-crystal X-ray diffraction. In 1, the Mn(II) ions are six-coordinated and lie in distorted octahedron coordination environments. Complex 1 is connected into a 2D layer structure based on a linear trinuclear Mn3(admtrz)4(N3)6 (admtrz = 4-amino-3,5-dimethyl-1,2,4-triazole) building unit with either (6,3) topology when Mn1 cations as three-connected nodes or (4,4) network when the coordination trinuclear units being regarded as four connected nodes. In 2, the Co(II) ions are in slightly distorted octahedron coordination geometries. The magnetic behaviors are investigated in the temperature range 1.8–300 K. The magnetic susceptibility measurements show that the Mn(II) ions of complex 1 are weakly antiferromagnetically coupled with g = 1.98(1), J1 = −6.31(5) cm−1 and J2 = −1.88(1) cm−1. There is dominant zero field splitting (ZFS) effects with g values, g// = 2.38(2) and g⊥ = 4.96(4), indicated a significant presence of the spin–orbit coupling and magnetization experiment reveals large, uniaxial zero-field splitting parameters of D = −29.55 cm−1 for 2.

A 2D layer complex 1 with a linear trinuclear Mn3(admtrz)4(N3)6 building unit and either (6,3) topology in Mn1 connected nodes or (4,4) topology when three polyhedra as a connected node and a linear trinuclear complex 2 with [Co3(NCS)6(admtrz)4(H2O)2]·2H2O have been isolated and characterized by X-ray diffraction methods. The magnetic susceptibility measurements show that the Mn(II) in 1 and Co(II) in 2 ions are weakly antiferromagnetically coupled.Figure optionsDownload as PowerPoint slideResearch highlights
► A 2D complex 1 has two bridges (admtrz and N3) linking Mn ions to form layer structure with either (6,3) topology when Mn1 cations as three-connected nodes or (4,4) network when the trinuclear units being regarded as four connected nodes.
► A 0D complex 2 has two bridges (admtrz and SCN) linking Co ions. The 3D structure was stabilized by weak interactions, such as N-HS, N-HO, O-HS, O-HN.
► The magnetic behavior both complexes was investigated in the temperature range 1.8-300 K. The magnetic susceptibility measurements show that the Mn(II) ions are weakly antiferromagnetically coupled with J1 = −6.31(5) cm−1 and J2 = −1.88(1) cm−1.