Syntheses, structures, and supra-molecular assembles of zinc 4-sulfobenzoate complexes with chelating and/or bridging ligands

Three unique Zn-II/4-sulfobenzoate complexes based on 2,2'-bipyridine and/or 4,4'-bipyridine, [Zn(4-sb)(2,2'-bipy)(H2O)(3)]center dot H2O (1), {[Zn(4,4'-bipy)(H2O)(4)]center dot(4-sb)}(n), (2), and {[Zn(4-sb)(2,2'-bipy)(4,4'-bipy)(0.5)(-H2O)]center dot 2H(2)O}(n) (3) [4-sb = 4-sulfobenzoate; 4,4'-bipy = 4,4'-bipyridine: 2,2'-bipy = 2,2'-bipyridine], have been prepared and characterized by single-crystal X-ray analyses, elemental analyses, IR, thermogravimetric analyses and fluorescent spectra. The molecular structure of the complex 1 is a monomer species, while the structures of complexes 2 and 3 are 1-D chains. The complex 2 is a cation-anion species. These extended hydrogen-bonding networks are 3-D architectures. In complexes 1 and 3 there are strong pi...pi stacking effects, while in complex 2 there is no such interaction. The thermal stability of complexes 1, 2. and 3 has the order of 2 > 1 > 3. (C) 2009 Elsevier B.V. All rights reserved.