Syntheses, structures, and magnetic properties of tetranuclear NiII4 and NiII2MnIII2 complexes with ONO tridentate ligands

Tetranuclear Ni-4(11) and (Ni2Mn211)-Mn-11 complexes of Al-(2-hydroxymethylphenyl)salicylideneimine (H(2)L1), [Ni4Cl2)(L1)(2)(HL1)(2)] (1), [Mn2Ni2Cl2(L1)(4)(H2O)(2)] (2), and Ni(II)(4) Complex of N-(2-hydroxymethylphenyl)salicylamine (H(2)L2), [Ni-4(L2)(4)(CH3OH)(2)] (3) have been characterized by X-ray crystal structure analyses and magnetic measurements. The structure analyses revealed that complexes 1 and 2 have a defective double-cubane metal core connected by mu(3)-alkoxo bridges. Complex 1 contains two types of tridentate ligands coordinating as dianionic (L1(2-)) and monoanionic (HL1(-)). The double-cubane core of 1 is significantly distorted due to an effect of chloride anions as bridging atoms. Complex 2 consists of two mu-phenoxo Ni-II-Mn-III heteronuclear units making a dimer-of-dimers structure. Complex 3 contains dianionic (L2)(2-) ligands and forms Ni-4(II) cubane core. Magnetic measurements of complex 2 indicate that a weak ferromagnetic interactions (J(NiMn) = 1.5 cm(-1), J(NiNi) = 20 cm(-1)) are dominant in this hetero-metal core. (c) 2005 Elsevier Ltd. All rights reserved.