Synthesis, structure, and magnetism of a novel series of trinuclear nickel(ii) clusters

Abstract

Five novel trinuclear nickel(II) clusters were successfully synthesized, namely Ni₃(fshz)₂(L)₄·n(sol) (H₃fshz = N-formylsalicylhydrazide; L = pyridine, n = 0, 1; L = 4-methylpyridine, n = 1, sol = CH₃CN, 2; L = 4-ethylpyridine, n = 2, sol = CH₃OH, 3; L = 4-vinylpyridine, n = 1, sol = CH₃OH, 4; and L = 2,6-pyridinedimethanol, n = 2, sol = CH₃OH, 5). Single-crystal X-ray diffraction revealed that the metallic skeletons of 1–5 were built by three Ni(II) ions, two fshz³⁻ units, and four auxiliary ligands. The coordination geometry of the Ni(II) ions in 1–5 are followed in two modes: square-planar and/or octahedral. Magnetic studies showed that 1–5 displayed intermolecular antiferromagnetic behavior and all the square-planar Ni(II) ions were diamagnetic as certified. Moreover, 1–4 presented easy-axis anisotropy with D = −4.02, −5.31, −4.82, and −3.65 cm⁻¹, respectively, while 5 presented easy-plane anisotropy (D = 11.06 cm⁻¹) due to the different coordination mode.