Hydrothermal Synthesis, Crystal Structures and Fluorescent Properties of Two Complexes Based on 1,2-Phenylenedioxydiacetic Acid and Polypyridyl Ligands

Hydrothermal reactions of flexible 1,2-phenylenedioxydiacetic acid (H2pda) with zinc nitrate or cadmium nitrate in the presence of auxiliary 4,4′-bypyridine (bpy) or 1,3-bis(4-pyridyl)propane (bpp) ligands gave rise to two coordination polymers, {[Cd2(pda)2(bpy)(H2O)2]·4H2O} n (1) and [Zn(pda)(bpp)] n (2). The polymers were characterized by elemental analysis, IR, TG, and single-crystal X-ray diffraction methods. Compound 1 shows 1D ribbon structure and compound 2 displays twofold parallel interpenetrated 2D → 2D architecture. The different conformations of pda anions in these two compounds are mainly induced by different metal coordination configurations in compound 1 and 2. In addition, the photoluminescence emission of 1 and 2 has been investigated in the solid state at room temperature.