Poly[tetra­aqua­(μ₆-9,10-dioxo-9,10-dihydro­anthracene-1,4,5,8-tetra­carboxyl­ato)dimanganese(II)]

The title complex, [Mn₂(C₁₈H₄O₁₀)(H₂O)₄]_n, was synthesized from manganese(II) chloride tetra­hydrate and 9,10-dioxo-9,10-dihydro­anthracene-1,4,5,8-tetra­carb­oxy­lic acid (H₄AQTC) in water. The anthraquinone unit is located about a crystallographic center of inversion. Each asymmetric unit therefore contains one Mn^II atom, two water ligands and one half AQTC⁴⁻ anion. The Mn^II atom is coordinated in a distorted octa­hedral geometry by four O atoms from three AQTC⁴⁻ ligands and two water O atoms. Two of the carboxyl­ate groups coordinate one Mn^II atom in a chelating mode, whereas the others each coordinate two Mn^II atoms. Each AQTC⁴⁻ tetra-anion therefore coordinates six different Mn^II ions and, as a result, a three-dimensional coordination polymer is formed. O—H...O hydrogen bonds, some of them bifurcated, between water ligands and neighboring water or anthraquinone ligands are observed in the crystal structure.

N′-(3-Hy­droxy­benzyl­idene)-4-methyl­benzohydrazide

The title compound, C₁₅H₁₄N₂O₂, was obtained from the reaction of 3-hy­droxy­benzaldhyde and 4-methyl­benzo­hydrazide in methanol. In the mol­ecule, the benzene rings form a dihedral angle of 2.9 (3)°. In the crystal, N—H...O and O—H...O hydrogen bonds link the mol­ecules into layers parallel to (101). The crystal packing also exhibits π–π inter­actions between the aromatic rings [centroid–centroid distance = 3.686 (4) Å].