Syntheses, structures and magnetic properties of tetranuclear cubane-type and heptanuclear wheel-type nickel(ii) complexes with 3-methoxysalicylic acid derivatives†
Two ferromagnetic multinuclear Ni(II) clusters, [Ni4L14(μ3-OMe)4(CH3OH)4] (1) and [Ni7(HL2)6(μ3-OMe)6]Cl2 (2), and a mononuclear complex [NiL3]·2H2O (3) (HL1 = benzyl 2-hydroxy-3-methoxybenzoate; H2L2 = 1-(2-hydroxy-3-methoxybenzamido)-2-(benzylideneamino)ethane; H2L3 = 1-(2-hydroxy-3-methoxybenzamido)-2-(pyridylmethyleneamino)ethane) were synthesised, and their structures and magnetic behaviours were investigated in detail. 1 has a [Ni4O4] cubane structure while 2 has a wheel-like [Ni@Ni6] arrangement. The temperature-dependent magnetic susceptibilities for 1 and 2 are in accord with the presence of dominating intra-cluster ferromagnetic interactions between Ni(II) ions. The best fits for their behaviours gave the following parameters: J1 = 11.06 cm−1, J2 = 1.43 cm−1, g = 2.29 for 1, and J1 = 6.87 cm−1, J2 = −3.41 cm−1, g = 2.24 for 2.