Construction of Planar Clusters Using Planar Aromatic Polyoxime Ligands: Synthesis, Structure, and Magnetic Properties

Abstract

The reactions of NiSO4·6H2O or Mn(CH3COO)2·4H2O with the planar ligands of indane-1,2,3-trione trioxime (H3Itto) or indane-1,2,3-trione-1,2-dioxime (H2Itdo) gave two planar pentanuclear clusters [Et3NH]2[Ni5(HItto)4(MeOH)2(H2O)6(SO4)2]·2H2O (1) and [Ni5(HItdo)2(Itdo)2(DMF)4(MeOH)(H2O)(SO4)2]·CH3OH·6H2O (2), one planar trinuclear cluster, [MnIII3(μ3-O)(Itdo)3(CH3COO)(DMF)2(H2O)2]·H2O (3), and one planar platelike trinuclear cluster, [MnIII3(μ3-O)(Itdo)3(CH3COO)(DMF)2(MeOH)(H2O)]·H2O (4). Five Ni(II) ions of 1 and 2 are consolidated by four indane-1,2,3-trione trioxime ligands and four indane-1,2,3-trione-1,2-dioxime ligands, respectively, to form square topological planar pentanuclear clusters with five Ni(II) ions and all atoms of the four oxime ligands nearly in one plane. However, 1 and 2 show some differences in the bridging of the central metal ion with the metal ions on the square corners. Both 3 and 4 feature a planar isosceles triangular [Mn3(μ3-O)]7+ core. Each edge of the triangular [Mn3(μ3-O)]7+ core in 3 and 4 is bridged by a μ2,η3-bridging indane-1,2,3-trione-1,2-dioxime ligand to construct a planar skeleton for 3 with the central oxygen atom, three Mn(III) ions, and all atoms of the indane-1,2,3-trione-1,2-dioxime ligands nearly in one plane, and a planar platelike skeleton for 4 with the ligand planes deviating from the triangular metal plane. Magnetic studies of 1−4 reveal the presence of antiferromagnetic interactions between the metal ions in 1−4.