Syntheses, crystal structures and properties of two new coordination complexes containing 1,2,4,5-benzenetetracarboxylate and imidazole: [Ni2(Him)12 · (bta) · 8H2O] and [Cd2(Him)4(μ4-bta)]

Two new coordination complexes, [Ni2(Him)12 · (bta) · 8H2O] 1 and [Cd2(Him)4(bta)] 2, (H4bta = 1,2,4,5-benzenetetracarboxylic acid, Him = imidazole) were prepared under hydrothermal conditions and their structures were determined by single-crystal X-ray diffraction. X-ray diffraction reveals that complex 1, consisting of two crystallographically independent [Ni(Him)6]2+ fragments, an uncoordinated bta4− anion and eight lattice water molecules, displays an interesting 3D supramolecular network constructed by cationic layers (layer A) and anionic layers (layer B) with ABAB sequence through hydrogen bonding interactions. In complex 2, each bta ligand links four metal ions to form a one dimensional (1D) double chain. The 1D double metal chains are assembled into a 3D supramolecular network through NH⋯O hydrogen bonding and CH⋯π interactions. Complex 2 shows strong blue fluorescence at room temperature.