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

Three new metal coordination polymers constructed from adipic acid and 2–(pyridin–3–yl)–(1H)–benzimidazole ligands, [M(ADP)(3PBI)2(H2O)2]∙2H2O (M = Ni and Co for 1 and 2, respectively) and [Cd(ADP)(3PBI)(H2O)] (3) [ADP = adipic acid dianion; 3PBI = 2-(pyridin-3-yl)-(1H)-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 1 and 2 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 3 possesses a binuclear unit and displays a two-dimensional layer which is further extended to a 3D supramolecular architecture via hydrogen bonding and other weak packing interactions. The luminescent properties of 3 were investigated in the solid state at room temperature.