Monodentate function of the 4,49-bipyridine that systematically occurs in the 4-sulfobenzoate manganese(II) complexes: Syntheses, crystal structures, and properties

In this presentation, three topologically diverse complexes based on the Mn2+/4-sulfobenzoate/ 4,4'-bipyridine system, [Mn(4,4'-bipy)(2)(H2O)(4)](Hsb) ( 1), [Mn(4,4'-bipy)(2)(H2O)(4)](sb)(4H(2)O) ( 2), and {[Mn(4,4'-bipy)(sb)(H2O)(3)](2H(2)O)}(n) ( 3) [4,4'-bipy = 4,4'-bipyridine; sb = 4-sulfobenzoate dianion], have been prepared and characterized by single-crystal X-ray analyses, elemental analyses, IR spectra, TG analyses, and photoluminescence studies. The structures of complexes 1 and 2 are cation - anion species whereas complex 3 is a 1-D polymer. In all three complexes 4,4'-bipyridine ligands feature a monodentate coordination mode and the uncoordinated nitrogen donor of each 4,4'-bipyridine engages in the intermolecular hydrogen bonding, which blocks the metal - metal bridging by 4,4'-bipyridine. In contrast to monodentate 4,4'-bipyridine-containing complexes occasionally reported in the literature, the monodentate function for 4,4'-bipyridine ligands in complexes 1 - 3 systematically occurs, suggesting the sulfonate group can adjust the competitive coordination between the carboxylate and 4,4'-bipyridine ligands. Extensive hydrogen-bonding interactions including hydrogen-bonded 4,4'-bipyridine in these three complexes control their crystal packings and give rise to 3-D extended supramolecular architectures.