Synthesis Characterization and Biological Activities of an Enamine Derivative and Its Coordination Compounds

The medicinal uses and applications of metal complexes are of increasing clinical and commercial importance;this is as a result of some level of success achieved so far. In this regard, novel enamine free-base ligands were synthesized by the condensation of terephthalaldehyde and 2-(methylamino)ethanol. This afforded a dinegative ONNO donor enamine, free base, characterized using 1H and 13C NMR, Fourier-transformed infrared and UV-vis spectroscopy. Coordination compounds of the enamine were also synthesized using Cu(II), Ni(II), Co(II) and VO(IV) ions. These complexes were characterized by electronic, IR spectrophotometry, mass spectrometry, magnetic susceptibility and EDX. The compounds were thereafter evaluated for their antimicrobial and cytotoxic activities. The data obtained were supportive of an octahedral geometry for the Cu(II) complex, a square-pyramidal geometry for the vanadium complex and a 4-coordinate square-planar geometry for both the cobalt and nickel complexes. The magnetic susceptibility data revealed that the complexes are magnetically dilute and mononuclear with exception of the cobalt complex. The ligands and the complexes did not exhibit significant antimicrobial and cytotoxic assays, indicative of the nontoxicity of the ligand and complexes.

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 with two diamines: ethane-1,2-diamine and propane-1,2-diamine was carried out to give Ligands 1 and 2. Additionally, template [1 + 2] condensation of benzene-1,4-dicarboxaldehyde with ethane-1,2-diamine and propane-1,2-diamine were also carried out to give Ligands 3 and 4. These were characterized using 1H and 13C NMR, UV-Vis and infra-red spectroscopy and mass spectrometry. Coordination compounds of each ligand were further synthesized using Ni(II) and Cu(II) ions. They were characterized by Uv-vis, infrared spectroscopy, mass spectrometry, magnetic susceptibility and energy dispersion X-ray spectroscopy EDX. The ligands and complexes were further analyzed for their antimicrobial activities and extraction efficiency. The results obtained suggested that tetraaza macrocyclic and linear compounds were obtained for [2 + 2] and [1 + 2] condensation reactions respectively. Coordination compounds of the macrocyclic ligand yielded octahedral geometry for Ni(II) and Cu(II) complexes of Ligand 1 and square planar geometry for Ni(II) and Cu(II) complexes of Ligand 2. On the other hand square planar 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 metal ion in a tetradentate fashion. In some cases chelation enhanced the antimicrobial activity of some of the ligands. The results further showed that Ligands 1-4 effectively extracted cadmium(II). zinc(II) and lead(II) ions in solution.