| Abstract: By the introduction of protonated 1, 3-di(4-pyridyl)propane (1, 3-dppH22+) and protonated bis(imidazol-1- ylmethyl)benzene (1, 4-bixH22+) as a cationic template, three new cobalt naphthalene-diphosphate coordination poly- mers based on 1, 4-naphthalenediphosphonic acid (1, 4-ndpaH4), namely (1, 3-dppH2)2[Co4(1, 4-ndpa)(1, 4-ndpaH)2(1, 4-ndpaH2)]·6H2O (1), (1, 4-bixH2)0.5[Co(1, 4-ndpaH)] (2), and (1, 4-bixH2)0.5[Co2(1, 4-ndpaH)(1, 4-ndpaH2)(H2O)2] (3), have been hydrothermally synthesized. complexes 1-3 were characterized by elemental analysis, infrared spectroscopy, single crystal X-ray diffraction, powder X-ray diffraction, and thermogravimetric analysis, respectively. In complexes 1 and 2, inorganic chains of corner-sharing {CoO4} and {PO3C} tetrahedron are cross-linked by naphthalene ligands into 3D open-framework structures. The protonated di-pyridinium/imidazolium moieties, 1, 3-dppH22+ for 2 and 1, 4-bixH22+ for 2, lie inside the skeletal voids of the crystal structure, respectively. Interestingly, complex 3 with similar chemical composition to 2 except for an additional 1, 4-ndpaH22- ligand and two coordinated water molecules shows a 2D undulating layer structure, where the chains of corner-sharing {CoO5} trigonal bipyramid, {CoO6} octahedron, and {PO3C} tetrahedron are cross-linked by naphthalene groups. Adjacent layers are packed in AB stacking into the supramolecular structure, in which 1, 4-bixH22+ ions fill and balance the charge of 3. Magnetic studies reveal that dominant antiferromagnetic interactions between the magnetic centers are propagated in complexes 1 and 2. |
