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Chioma Festus Anthony C. Ekennia Aderoju A. Osowole Lukman O. Olasunkanmi Damian C. Onwudiwe Oguejiofo T. Ujam 《Research on Chemical Intermediates》2018,44(10):5857-5877
The work reported the synthesis and characterisation of Fe2+, Co2+, and Ni2+ complexes of 2-(4,6-dihydroxypyrimidin-2-ylamino)naphthalene-1,4-dione (HL). The spectroscopic and elemental analysis results obtained were consistent with the adoption of the formulas, [ML2] (M = Fe and Co) and [ML2(H2O)] (M = Ni) for the metal complexes. Electronic spectra and magnetic moments of the metal complexes corroborated octahedral geometry for Ni(II) complex and tetrahedral geometry for Fe(II) and Co(II) complexes. However, quantum-chemical calculations using density functional theory predicted trigonal bipyramidal geometry for Ni(II) complex and provided corroborative explanations for the structures of the other complexes. Conductance measurements in dimethylsulfoxide indicate that the complexes are non-electrolytes. The antimicrobial potential of the compounds was evaluated against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Bacillus cereus, Proteus mirabilis, Klebsiella oxytoca, Aspergillus niger, A. flavus, and Rhizopus stolonifer. The compounds gave moderate to good antimicrobial activity. However, the bacterial and fungal organisms were more susceptible to the cobalt complex and ligand respectively than the other compounds at concentration of 10 mg/mL. The compounds were also assessed for their antioxidant potential using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. The compounds displayed good DPPH radical scavenging activities. The nickel complex exhibited the best DPPH radical scavenging activity compared to the other compounds. 相似文献
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Ekennia Anthony C. Onwudiwe Damian C. Osowole Aderoju A. Okpareke Obinna C. Olubiyi Olujide O. Lane Joseph R. 《Research on Chemical Intermediates》2019,45(3):1169-1205
Research on Chemical Intermediates - In this study, the geometry, spectroscopic characteristics and coordination patterns of three biologically active ligands and their... 相似文献
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Synthesis,characterization, molecular docking,biological activity and density functional theory studies of novel 1,4‐naphthoquinone derivatives and Pd(II), Ni(II) and Co(II) complexes
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Anthony C. Ekennia Aderoju A. Osowole Damian C. Onwudiwe Ilknur Babahan Collins U. Ibeji Sunday N. Okafor Oguejiofo T. Ujam 《应用有机金属化学》2018,32(5)
Two novel heterocyclic ligands, 2‐[(5‐fluoro‐1,3‐benzothiazol‐2‐yl)amino]naphthalene‐1,4‐dione (HL1) and 2‐[(5‐methyl‐1,3‐benzothiazol‐2‐yl)amino]naphthalene‐1,4‐dione (HL2), and their Pd(II), Ni(II) and Co(II) complexes were prepared and characterized using 1H NMR, 13C NMR, infrared and UV–visible spectroscopic techniques, elemental analysis, magnetic susceptibility, thermogravimetry and molar conductance measurements. The infrared spectral data showed that the chelation behaviours of the ligands towards the transition metal ions were through one of the carbonyl oxygen and deprotonated nitrogen atom of the secondary amine group. Molar conductance results confirmed that the complexes are non‐electrolytes in dimethylsulfoxide. The geometries of the complexes were deduced from magnetic susceptibility and UV–visible spectroscopic results. Second‐order perturbation analysis using density functional theory calculation revealed a stronger intermolecular charge transfer between ligand and metal ion in [NiL1(H2O)2(CH3COO‐)] and CoL1 compared to the other complexes. The in vitro antibacterial activity of the compounds against some clinically isolated bacteria strains showed varied activities. [NiL1(H2O)2(CH3COO‐)] exhibited the best antibacterial results with a minimum inhibitory concentration of 50 μg mL?1. The molecular interactions of the compounds with various drug targets of some bacterial organisms were established in a bid to predict the possible mode of antibacterial action of the compounds. The ferrous ion chelating ability of the ligands indicated that HL1 is a better Fe2+ ion chelator, with an IC50 of 29.79 μg mL?1, compared to HL2 which had an IC50 of 98.26 μg mL?1. 相似文献
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Anthony C. Ekennia Aderoju A. Osowole Lukman O. Olasunkanmi Damian C. Onwudiwe Eno E. Ebenso 《Research on Chemical Intermediates》2017,43(7):3787-3811
Two Schiff bases, HL1 and HL2, were synthesized in two different reactions involving 2-hydroxynaphthaldehyde with 2-amino-6-methylbenzothiazole and 2-amino-6-florobenzothiazole respectively. Copper(II) and nickel(II) complexes of the Schiff bases were subsequently prepared in 1:1 metal-to-ligand stoichiometric reactions. The compounds were characterized extensively by 1H NMR, 13C NMR, Dept-90, UV–Vis, and IR spectroscopic techniques, magnetic susceptibility, TGA, DTG, and molar conductivity analysis. The spectroscopic results confirm bidentate nature of the Schiff bases and a four coordinate geometry for all the complexes: [CuL1ClH2O], [NiL1ClH2O], [Cu(L2)2], and [NiL2ClH2O]. Quantum chemical studies gave fully optimized geometries of the Schiff bases and metal complexes using the 6-31+g(d,p) basis set. The compounds were studied for their in vitro antibacterial activities against some selected Gram-positive and Gram-negative bacteria, using agar well diffusion. The metal complexes exhibited better antibacterial activities compared to the free ligand due to the effects of chelation, which improved the lipophilicity. Furthermore, the antioxidant potentials of the compounds were ascertained using DPPH radical scavenging and ferrous chelating assay. The copper complexes had the best antioxidant properties of all the tested compounds. The results of the biological analysis were in agreement with the theoretical data from quantum chemical calculations. The study presented biologically active coordination compounds with benzothiazole moiety that could be used as compounds of interest in the drug discovery processes. 相似文献
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Osowole Aderoju A. Ekennia Anthony C. Olubiyi Olujide O. Olagunju Maryam 《Research on Chemical Intermediates》2017,43(4):2565-2585
Research on Chemical Intermediates - The ketoamine, 2-(1,3-benzothiazol-2-ylamino)naphthalene-1,4-dione(HL) and its Mn(II), Co(II), Ni(II), Cu(II), Pd(II) and Zn(II) complexes were synthesized and... 相似文献
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