The syntheses, structural and biological studies of Co(II) complexes of 1,2-Bis(pyridin-4-yl)ethane with 2-aminobenzene-1,4-disulfonic acid and 2,6-pyridinedicarboxylic acid

Abstract

The newly synthesized salt named 4,4′-(ethane-1,2-diyl)bis(pyridin-1-ium) 2-aminobenzene-1,4-disulfonate, (H2BPE)2+(ADSA)2− (1), was prepared from the reaction of 1,2–bis(pyridin–4–yl)ethane (BPE) and 2–amino-benzene–1,4–disulfonic acid (H2ADSA). Two new metal complexes of 4,4′-(ethane-1,2-diyl)bis(pyridin-1-ium) 2-aminobenzene-1,4-disulfonate were also synthesized: The first complex [Co(BPE)2(H2O)4](ADSA).BPE (2) has been synthesized from the obtained proton transfer salt (1). The second complex, {[Co(BPE)(H2O)4]}n[Co(DPC)2].2H2O (4), is a one–dimensional coordination polymer and was synthesized using proton transfer salt (H2BPE)2+(DPC)2- (3). Elemental analysis, Nuclear Magnetic Resonance, Infrared and Ultraviolet–Visible spectra methods were used to elucidate the structure of 1. Elemental analysis, magnetic moment measurements, spectral (UV–Vis, AAS and IR) and X–ray crystallographic analysis were applied for structural manalysis of 2 and 4. X–ray crystallographic study for 2 and 4 revealed that in both complexes the BPE coordinated the Co(II). In compound 2, the coordination periphery of the Co(II) consists of two nitrogens from two BPE, four oxygens from four H2O molecules and forms the six–coordinated octahedral geometry. X–ray crystallographic analysis of 4 showed that the complex was polymer and the metal ions were linked by BPE ligand bridges. The molecular structure of coordination polymer 4 contains both cationic and anionic complexes, each with an octahedral geometry. The coordination sphere of the cationic complex consists of two nitrogens of two BPE and four oxygens of four aqua molecules. On the other hand, the two DPC2− ligands contribute two nitrogens and four oxygens to the coordination sphere of the anionic complex. The antibacterial and antifungal capabilities of the produced compounds were further investigated, and the MIC (Minimum Inhibitory Concentration) values were compared to those of related control substances.