Three trinuclear Ni(II)-Na(I) complexes, [Ni₂(L¹)₂NaCl₃(H₂O)]·H₂O (1), [Ni₂(L²)₂NaCl₃(H₂O)] (2), and [Ni₂(L³)₂NaCl₃(OC₄H₁₀)] (3) have been synthesized using three different NNO donor tridentate reduced Schiff base ligands, HL¹ = 2-[(3-methylamino-propylamino)-methyl]-phenol, HL² = 2-[(3-methylamino-propylamino)-methyl]-4-chloro-phenol, and HL³ = 2-[(3-methylamino-propylamino)-methyl]-6-methoxy-phenol that had been structurally characterized. Among these complexes, 1 and 2 are isostructural in which dinuclearNi(II) units act as metalloligands to bind Na(I) ions via phenoxido and chlorido bridges. The Na(I) atom is five-coordinated, and the Ni(II) atom possesses hexacordinated distorted octahedral geometry. In contrast, in complex 3, two -OMe groups from the dinuclear Ni(II) unit also coordinate to Na(I) to make its geometry heptacordinated pentagonal bipyramidal. The magnetic measurements of complexes 1–3 indicate ferromagnetic interactions between dimeric Ni(II) units with J = 3.97 cm⁻¹, 4.66 cm⁻¹, and 5.50 cm⁻¹ for 1–3, respectively, as is expected from their low phenoxido bridging angles (89.32°, 89.39°, and 87.32° for 1–3, respectively). The J values have been calculated by broken symmetry DFT method and found to be in good agreement with the experimental values.

Two new Ni(II) complexes, [Ni2L12(C6H5CH2COO)](ClO4)·2CH3CN (1) and [Ni2L12(C6H5CH2COO)2(H2O)]·2H2O (2) have been synthesized by using Ni(ClO4)2·6H2O, a tridentate NNO donor reduced Schiff base ligand, HL1 = [(3-dimethylamino-propylamino)-methyl]-phenol and phenylacetic acid as co-ligand. Both complexes have been characterized by single crystal X-ray crystallography, electronic and IR spectroscopy. Structural analysis reveals that Ni(II) ions possess distorted octahedral geometry in both complexes 1-2. Bis-µ2-phenoxido bridged complex 1 has one syn-syn phenylacetate bridging, whereas complex 2 possesses similar type of structure with addition terminal coordination (Syn-monodentate-h1 mode) by another phenylacetate molecule.