New examples of metal coordination architectures of 4,4′- sulfonyldibenzoic acid: Syntheses, crystal structure and luminescence

Abstract

Seven metal-organic coordination polymers, namely [Cd(sfdb)(phen) 2]n·2nH2O (1), [Cd(sfdb)(bpy) 2]n·nH2O (2), [Cu(sfdb)(phen)(H 2O)]n·0.5nH2O (3), [Zn(sfdb)(bpy)(H 2O)]n·0.5nCH3OH (4), [Cd(sfdb)(quin)]n (5), [Cd3(sfdb)2(Hsfdb) 2-(phen)2]n (6), and [Cd(sfdb)(bpy)] n (7) [H2sfdb = 4,4′-sulfonyl-dibenzoic acid, phen = 1,10-phenanthroline, quin = 2,2′-biquinoline, bpy = 2,2′- bipyridine] have been synthesized according to the principles of crystal engineering and structurally characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction analyses. Compounds 1-3 form 1D zigzag chains. Two phen ligands chelate to one cadmium atom in 1, which is rare in similar polymers, while two 2,2′-bpy ligands coordinate one cadmium atom in 2. The zigzag chains in 3 propagate in two different directions (rotated by 75°) that are assembled by supramolecular forces into an intriguing three-dimensional network. Complexes 4 and 5 form square-wave-like 1D chains, although the results indicate a transformation of 2,2′-bpy into quin during the course of the hydrothermal synthesis of compound 5. Compound 6 is a 1D grid-chain based on a linear trinuclear unit, and compound 7 shows a 1D double chain containing 28-membered rings with sfdb2- ligands as bridges. Weak hydrogen bonding and intra- and/or intermolecular π⋯π stacking contacts in compounds 3-7 link the discrete 1D chains into high-dimensional supramolecular structures. The sfdb2- ligand displays multiple coordination modes in these seven complexes. Complexes 1, 2, and 4-7 show blue photoluminescence at room temperature. © Wiley-VCH Verlag GmbH & Co. KGaA, 2008.