POLYHEDRON, vol.223, 2022 (SCI-Expanded)
From the reaction of pyridine-2,6-dicarboxylic acid (H2PDC) with 1,2-bis(pyridine-4-yl)ethane (BPE), a new proton transfer salt, 4,4 & PRIME;-(ethane-1,2-di-yl)bis(pyridin-1-ium) pyridine-2,6-dicarboxylate (H2BPE)(2+)(PDC)(2-)(1), has been obtained. Two copper complexes, [Cu-6(PDC)(6)(BPE)(3)(H2O)(4)].3H(2)O (2) and [Cu-2(PDC)2(BPE)(H2O)(2)]. H2O (3), were also synthesized. The first one was obtained from the proton transfer salt at room temperature, and the second one was obtained with mixed-ligand under hydrothermal conditions. Spectral (H-1, C-13 NMR, FT-IR and UV-VIS) and elemental analysis were performed for the structural analysis of the proton transfer salt. In order to determine the structures of the complexes, X-ray crystallography, spectral (AAS, UV-VIS and FT-IR), magnetic moment measurements and elemental analyses were carried out. Except for the Cu1 and Cu1(i) centers, which have a distorted square-planar geometry in 2, single-crystal X-ray analyzes of 2 and 3 revealed that the copper centers (Cu2-Cu2(i )and Cu3-Cu-3i for 2 and Cu1-Cu1(i) for 3) are five-coordinated and have a distorted square-pyramidal geometry. Antimicrobial evaluation of compounds (1-3) has been tested against Bacillus subtilis, Listeria monocytogenes (ATCC 7644), Enterococcus faecalis (ATCC 29212) (Gram positive), Staphylococcus aureus (NRRL B-767), Escherichia coli (ATCC 25922) (Gram negative), Pseudomonas aeruginosa (ATCC 27853) and Candida albicans (F89) (yeast) microorganisms. The Minimum Inhibitory Concentration (MIC) values of the new 1-3 were compared with the antibacterial reference compounds Levofloxacin Cefepime, Vancomycin and the antifungal compound Fluconazole.