| Abstract: | The design and synthesis of 3d–4f heterometallic coordination polymers have attracted much interest due to the intriguing diversity of their architectures and topologies. Pyridine‐2,6‐dicarboxylic acid (H2pydc) has a versatile coordination mode and has been used to construct multinuclear and heterometallic compounds. Two isostructural centrosymmetric 3d–4f coordination compounds constructed from pyridine‐2,6‐dicarboxylic acid and 4,4′‐bipyridine (bpy), namely 4,4′‐bipyridine‐1,1′‐diium diaquabis(μ2‐pyridine‐2,6‐dicarboxylato)tetrakis(pyridine‐2,6‐dicarboxylato)bis4‐(pyridin‐4‐yl)pyridinium]cobalt(II)dieuropium(III) octahydrate, (C10H10N2)CoEu2(C10H9N2)2(C7H3NO4)6(H2O)2]·8H2O, (I), and 4,4′‐bipyridine‐1,1′‐diium diaquabis(μ2‐pyridine‐2,6‐dicarboxylato)tetrakis(pyridine‐2,6‐dicarboxylato)bis4‐(pyridin‐4‐yl)pyridinium]cobalt(II)diterbium(III) octahydrate, (C10H10N2)CoTb2(C10H9N2)2(C7H3NO4)6(H2O)2]·8H2O, (II), were synthesized under hydrothermal conditions and characterized by IR and fluorescence spectroscopy, thermogravimetric analysis and powder X‐ray diffraction. Both compounds crystallize in the triclinic space group P . The EuIII and TbIII cations adopt nine‐coordinated distorted tricapped trigonal–prismatic geometries bridged by three pydc2? ligands. The CoII cation has a six‐coordination environment formed by two pydc2? ligands, two bpy ligands and two coordinated water molecules. Adjacent molecules are connected by π–π stacking interactions to form a one‐dimensional chain, which is further extended into a three‐dimensional supramolecular network by multipoint hydrogen bonds. |
