Novel Tetranuclear Heterometallic Mn₃Ni and Mononuclear Ni Complexes with an ONO Schiff Base Ligand: Synthesis, Crystal Structures, and Magnetic Properties

A mononuclear Ni(II) complex, [Ni(HL1)(2)], (1) and a novel tetranuclear heterometal Mn-Ni complex, [Mn3Ni(L1)(4)Cl-2(EtOH)(2)], (2) [H(2)L1 = N-(2-hydroxymethylphenyl)salicylideneimine], have been synthesized and characterized via X-ray crystal structure analyses, infrared spectra, and elemental analyses. The structure analyses revealed that the tridentate ligand, H(2)L1, coordinates in a facial mode for Ni and a mer mode for Mn, respectively. Complex 2 includes Mn(II)Mn(III)(2)Ni(II) tetranuclear metal core bridged by mu-phenoxo and mu-alkoxo oxygens. Magnetic measurements for 2 indicate that weak ferromagnetic interactions (J(Mn(III)Ni(II)) = 2.23, J(Mn(III)Mn(II)) = 0.46, J(Mn(II)Ni(II)) = 1.78, and J(Mn(III)Mn(III)) = 0.58 cm(-1)) dominate in the tetranuclear core. Additionally, in alternating current (AC) magnetic measurements, frequency-dependent out-of-phase responses were observed.