Browsing by Author "Yunus-Issa, M. T."

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    Synthesis, Characterization and Antimicrobial activities of some Mixed Ascorbic acid –Nicotinamide Metal Complexes
    (Faculty of Science, Bayero University Kano. Nigeria, 2015-01-25) Lawal, A.; Amolegbe, S. A.; Rajee, A. O.; Babamale, H. F.; Yunus-Issa, M. T.
    The present study aimed at synthesizing copper(II) and zinc(II) complexes of mixed ascorbic acid and nicotinamide and physiochemically characterize by solubility test, melting point, conductivity t e s t , i n f r a r e d , e l e c t r o n i c a n d p r o t o n n u c l e a r m a g n e t i c r e s o n a n c e t e c h n i q u e s . T h e r e s u l t o f t h e physiochemical studies indicated 1:1 stoichiometry and were supported by the spectroscopic data. T h e a n t i m i c r o b i a l a c t i v i t i e s o f t h e m i x e d c o m p l e x e s w e r e c a r r i e d o u t a g a i n s t B a c i l l u s s u b t i l i s , Escherichia coli, Staphylococcus aureus, Penicillum , spp Aspergillus flavus and Aspergillus niger. The result of the infrared data showed that ascorbi c acid coordinates through the oxygen of the carbonyl group and that of enolic C-2 hydroxyl grou p, while nicotinamide coordinates through the nitrogen atom of the pyridine ring. The result of t he antimicrobial studies showed that the mixed complexes have higher inhibitory activity than the original ligands against the tested bacteria and fu ngi species
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    Synthesis, Characterization and Antimicrobial activity of Mixed Transition Metal Complexes of salicylic acid with 1,10 - Phenanthroline
    (World Bank Assisted National Agricultural Research Project (NARD), Faculty of Science, University of Port-Harcourt, Nigeria, 2017) Lawal, A.; Shodeinde, A. S.; Amolegbe, S. A.; Elaigwu, S. E.; Yunus-Issa, M. T.
    A new series of Mn(II), Fe(II), Co(II), Cu(II) and Zn(II) mixed ligands-metal complexes derived from salicylic acid (SA) and 1,10-phenanthroline (PHEN) have been synthesized and characterized by spectroscopic studies. The coordination of the two ligands towards central metal ions has been proposed in the light of elemental analysis, IR, UV–vis spectroscopic studies. The results of the physical and spectroscopic data confirmed that the ligands are chelating agents. In 1, 10-phenanthroline, coordination occurred through the two pyridinic nitrogen groups, while in the salicylic acid coordination occurred through the oxygen of the hydroxyl and the carboxylic groups. All the complexes synthesized were of octahedral geometry.Antimicrobial activity of the mixed ligands metal complexes and the free ligands were carried out against the bacterial Escherichia coli, staphylococcus aureus, klebsiella pneumonia, pseudomonas aeruginosa and the fungi candida spp. The mixed ligands metal complexes showed higher activities when compared to the free ligands of salicylic acid but were less active than the free 1,10-phenanthroline ligand. The complexes of Cu (II) showed the highest antimicrobial activity while the Fe(II ) complex showed the least activity against the bacterial and fungi organisms
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    Synthesis, Characterization and Biological activity of Metal Complexes Mixed Citric acid and Amodiaquine
    (Faculty of Science, Bayero University Kano. Nigeria, 2017-05-20) Lawal, A.; Olowude, S.; Bamigboye, M. O.; Sa`ad, H. O.; Nnabuike, G. G.; Yunus-Issa, M. T.; Amolegbe, S. A.
    A range of d-block transition metals complexes of mixed amodiaquine and citric acid have been synthesized and characterised using microanalytical technique , elemental analysis, FT-IR spectroscopy and magnetic measurement. The results of the analytical and spectroscopic data revealed that both amodiaquine and citric acid acted as bidentate ligands in the ir mode of coordination with the metal ions.The citric acid bound through the carbonyl (C=O) and hydroxyl groups to the metal ions while, amodiaquine coordinated through the nitrogen atom of the amine and oxygen donor atom of hydroxyl group; resulted in structures with octahedral geometry. Percentage composition and magnetic Bohr moment data indicated that all metal complexes were paramagnetic. Molar conductance measurement indicates that the complexes are non-electrolytes in nature. The antimicrobial activity of the ligands and their mixed complexes was carried out against g(+)Pseudomonas aeruginosa, g(+)E. coli, g( +)Klebsiella pneumonia, g(+)Staphylococcus aureus and g(+)Candida using Muller Hinton diffusion method. The citric acid and amodiaquine result showed low or moderate value from (0.6-0.8) for all the metal complexes with the exception of the Cu(II) complex having inhibitory zones ranging from 1-0-1. 3 , 0 . 7 - 0 . 9 at 200 ppm respectively. Moreover, the free ligands were found being less active compared with their mixed complexes.