Syntheses, Characterization, Antimicrobial Activity and Extraction Studies of Tetraaza Macrocyclic/Linear Schiff Bases Derived from Benzene-1,4-Dicarboxaldehyde and Their Coordination Compounds

Non-template [2 + 2] condensation of benzene-1,4-dicarboxaldehyde\r\nwith two diamines: ethane-1,2-diamine and propane-1,2-diamine was carried out to give Ligands 1 and 2. Additionally,\r\ntemplate [1 + 2] condensation of benzene-1,4-dicarboxaldehyde\r\nwith ethane-1,2-diamine and propane-1,2-diamine were also carried out to\r\ngive Ligands 3 and 4. These were characterized using 1H\r\nand 13C NMR, UV-Vis and infra-red spectroscopy and mass\r\nspectrometry. Coordination compounds of each ligand were further synthesized\r\nusing Ni(II) and Cu(II) ions. They were characterized by Uv-vis, infrared spectroscopy, mass spectrometry,\r\nmagnetic susceptibility and energy dispersion X-ray spectroscopy EDX. The\r\nligands and complexes were further analyzed for their antimicrobial activities and extraction\r\nefficiency. The results obtained suggested that tetraaza macrocyclic and linear\r\ncompounds were obtained for [2 + 2] and [1 + 2] condensation reactions respectively.\r\nCoordination compounds of the macrocyclic ligand yielded octahedral geometry\r\nfor Ni(II) and Cu(II) complexes of Ligand 1 and square planar geometry\r\nfor Ni(II) and Cu(II) complexes of Ligand 2. On the other hand square\r\nplanar geometry was proposed for coordination compounds of Ligand 3 and 4 exception for the Ni(II) complex of Ligand 3. All ligands coordinated to the\r\nmetal ion in a tetradentate fashion. In some cases chelation enhanced the\r\nantimicrobial activity of some of the ligands. The results further showed that\r\nLigands 1-4 effectively extracted cadmium(II). zinc(II) and\r\nlead(II) ions in solution.