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

Three unique ZnII/4-sulfobenzoate complexes based on 2,2′-bipyridine and/or 4,4′-bipyridine, [Zn(4-sb)(2,2′-bipy)(H2O)3]·H2O (1), {[Zn(4,4′-bipy)(H2O)4]·(4-sb)}n (2), and {[Zn(4-sb)(2,2′-bipy)(4,4′-bipy)0.5(H2O)]·2H2O}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 π…π 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.