A unique tetranuclear nickel(II) complex containing pyridine-2-carboxaldehyde derivative bearing an intramolecular acetato: Synthesis, crystal structure and magnetic property

The novel tetranuclear nickel(II) carboxylate complex formulated as [Ni4(L)2(m2-OAc)2 (m3-OAc)2]·CH3OH·H2O, (1) (where L = 2-oxo-1,2-di(pyridin-2-yl)ethyl picolinate) has been synthesized and characterized systematically. The complex crystallizes in orthorhombic system, consisting of a tetranuclear Ni(II) distorted cubane-like core, in which four Ni(II) ions are bridged by four acetato groups. Each Ni(II) ion is further ligated with nitrogen atoms of bridging pyridine-2-carboxaldehyde derivative, forming either Ni, N, N, O- or Ni, N, O-chelate macro-rings. Magnetic susceptibility studies indicate that the weak antiferromagnetic interaction is operating between the adjacent nickel ions bridged via the carboxylate oxygen atoms within the complex.

Graphical AbstractA novel tetranuclear Ni(II) carboxylate complex [Ni4(L)2(μ2-OAc)2 (μ3-OAc)2]⋅ CH3OH⋅H2O, (1) has been synthesized and characterized systematically. The complex consists of a tetranuclear Ni(II) distorted cubane-like core, in which four Ni(II) ions are bridged by two kinds of acetato groups, and each Ni(II) ion is further ligated with nitrogen atoms forming either N, N, O- or N, O-chelate rings, simultaneously. Magnetic susceptibility measurements for 1 in the temperature range of 2.0–300 K studies indicate the presence of apparent weak antiferromagnetic interaction dominates in the complex.Figure optionsDownload as PowerPoint slideResearch Highlights
► A novel tetranuclear nickel(II) carboxylate complex has been synthesized and characterized.
► The novel poly-pyridine ligand was formed unprecedentedly during the synthesis process.
► Four Ni(II) ions are bridged simultaneously by the pyridine-2-carboxaldehyde derivative and acetate
► The weak antiferromagnetic interaction was operating between adjacent nickel ions.
► The magnetic result is consistent with the bite angle of Ni- O-Ni.