Syntheses, crystal structures, luminescent properties of three metal coordination polymers based on adipic acid and 2-(pyridine-3-yl)-(1<i>H</i>)-benzimidazole

<div><p>Three new metal coordination polymers constructed from adipic acid and 2–(pyridin–3–yl)–(1<i>H</i>)–benzimidazole ligands, [M(ADP)(3PBI)<sub>2</sub>(H<sub>2</sub>O)<sub>2</sub>]∙2H<sub>2</sub>O (M = Ni and Co for <b>1</b> and <b>2</b>, respectively) and [Cd(ADP)(3PBI)(H<sub>2</sub>O)] (<b>3</b>) [ADP = adipic acid dianion; 3PBI = 2-(pyridin-3-yl)-(1<i>H</i>)-benzimidazole], have been synthesized by hydrothermal reactions and were characterized by X-ray single-crystal diffraction, elemental analyses, IR, powder X-ray diffraction, and thermogravimetry (TGA). Complexes <b>1</b> and <b>2</b> are isostructural. Both form a one-dimensional (1D) linear chain structure, which is further assembled into a three-dimensional (3D) supramolecular framework by π∙∙∙π stacking and hydrogen bonding interactions. Complex <b>3</b> possesses a binuclear unit and displays a two-dimensional layer which is further extended to a 3D supramolecular architecture <i>via</i> hydrogen bonding and other weak packing interactions. The luminescent properties of <b>3</b> were investigated in the solid state at room temperature.</p></div>