Browsing by Author "Eke, U. B."
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Item A new heterobimetallic ruthenium(II) complex: synthesis, spectral studies and catalytic activity potential in the transfer hydrogenation of ketones(Chemical Society of Nigeria, 2019-06-07) Owalude, S. O.; Tella, A.C.; Eke, U. B.; Odebunmi, E.O.A new heterobimetallic ruthenium(II) complex with general formula [Ru(NCCH3)2(P(OMe)2Ph)2- (dppf)][BF4]2. {NCCH3 = acetonitrile P(OMe)2Ph = dimethylphenylphosphonite, dppf = 1,1’-bis-{diphenylphosphino}ferrocene} was synthesized from a one pot reaction of [Ru(COD)-(NCCH3)4][BF4]2, dimethylphenylphosphonite and 1,1’-bis{diphenylphosphino}ferroc-ene in dichloromethane under continuous stirring. The complex was characterized by NMR (31P{1H}, 1H and 13C), vibrational spectroscopy (FTIR) and elemental analysis. Catalytic performance of the complex in the transfer hydrogenation of cyclohexanone was investigated. An 80% conversion was achieved at a substrate to catalyst ratio of 1250 with 98% selectivity.Item Solvent-free synthesis, x-ray studies and in vitro inhibitory activities of copper(II) complexes of non-steroidal anti-inflammatory drugs(Springer, 2014-04-10) Tella, A. C.; Obaleye, J. A.; Eke, U. B.; Isaac, A. Y.; Ameen, MubarakSolid-state mechanochemical synthesis of [Cu(CAF)2(H2O)(OAc)]OAc co mplex 1a and [Cu(COD)2(H2O)(OAc)]OAc complex 2a were obtained by grinding stoichioetric amounts of Cu(CH3COO)2 H2O and corresponding non steroidal anti-inflammatory drugs[(caffeine (CAF) and codeine(COD)], respectively, in a mortar with pestle. Solvent-based synthesis of 1b and 2b was also carried out by reaction of metal acetate salt and each drug by refluxing at 70 C in CH3OH for 1 h for comparison purposes. The complexes 1a and 2a were characterized by comparison of elemental analysis, FT-IR, UV–Vis and 1H NMR spectra with those of the free ligand and solvent-based products (1b and 2b). The analytical and spectroscopic data of the complexes prepared via the two different methods are almost identical. X-ray diffraction patterns of the complexes prepared by mechanochemical method were different from that of the starting material suggesting formation of new metal complexes. In vitro inhibitory activities of both mechanochemical and solvent-based complexes were found to be higher than parent ligands, indicating that the antimicrobial effect of these drugs could be enhanced when they are chelated to the metal. The mechanochemical synthesis was carried out without the use of solvent or external heating. The method is faster and gives a higher yield than corresponding solvent-based reactions. The solid state reaction presented higher efficiency in terms of materials, energy and time compared to solvent-based synthesis.Item Synthesis and structural characterization of some ruthenium(II) alkoxide complexes(Faculty of Physical Sciences, University of Ilorin, 2014-01-03) Owalude, S. O.; Odebunmi, E. O.; Eke, U. B.; Tella, A. C.The complex [RuCl2(COD)(OR)2] (COD = cyclo-octa-1,5-diene and R = CH3 or C2H5) has been prepared by treatment of the polymeric specie [{RuCl2(COD)}x]) with appropriate LiOR solution and has been characterized by elemental analysis, IR and lH NMR spectroscopic analyses. The reaction of the alkoxide complex with two or more equivalent of phosphine ligands gave the complex [Ru(COD)(OR)2L2] (R = CH3 or C2H5; L = methoxyphenyldiphenylphosphine and tri(m-tolyl)phosphine) while the subsequent reaction with diphenylphosphine yielded [Ru(OR)2(Ph2P)4] (R = C2H5). Spectroscopic and elemental analysis data revealed symmetric alkoxide bridged diruthenium phosphine complexes.Item Synthesis of new ruthenium(II) complexes containing isocyanide and labile nitrile ligands(Ahmadu Bello University, Zaria, Nigeria, 2017-10-30) Owalude, S. O.; Tella, A.C.; Eke, U. B.; Odebunmi, E.O.A new ruthenium(II) complex containing both acetonitrile and propionitrile moieties as coordinating ligands has been prepared. The treatment of the polymer [{RuCl2(COD)}x], (COD = cycloocta-1,5-diene) (1) with a mixture of acetonitrile and propionitrile under reflux produced a new precursor [RuCl2(COD)(NCCH3)(CH3CH2CN)] (2). Also the compound [RuCl2L4] (3) (L = 2,6-dimethylphenylisocyanide) was prepared through a ligand exchange of a derivative of 1, [RuCl2(COD)(NCCH3)2] (4), with 2,6-dimethylphenylisocyanide. The two compounds were characterized by elemental analyses, IR and NMR (1H and 13C) measurements. The ruthenium in both compounds has distorted octahedral coordination geometry.Item The synthesis of some organotin (IV) compounds in the melt-phase(Islamic Azad University, Arak Branch, Arak, Islamic Republic of Iran, 2010-10-28) Eke, U. B.; Abodunrin, T.O.; Owalude, S.O.The melt-phase synthesis of dioctyltin (IV) and triphenyltin (IV) benzoates were carried out using stoichiometric amounts of benzoic acids and the corresponding organotin (IV) compounds. The reagents were ground together in a mortar and fed into a boiling glass tube. A cannula tube was inserted into the boiling tube to discharge accumulated gaseous products. A syringe ensured a continuous flow of dry Nitrogen gas in the reaction vessel. The compounds are known using wet Chemistry. Their syntheses via the melt-phase were in good yields. The physical properties corresponded to those of the similar compounds prepared by wet chemistry. The IR, 1H and 13C NMR data indicate that coordination to the tin atom is via carboxylate group.Item Synthesis, characterization and biological activity screening of metal (II) complexes of some nitrogen and dioxygen donor ligands(Ahmadu Bello University, Zaria, Nigeria, 2016-05-30) Owalude, S. O.; Tella, A.C.; Duntoye, M.R.; Adimula, V.O.; Eke, U. B.; Odebunmi, E.O.A series of Ni(II) and Cu(II) complexes of Schiff base ligands derived from 4-aminobenzoic acid, 2- aminophenol, salicylaldehyde and 1H-indole-2,3-dione have been synthesized and characterized by elemental analysis, FT-IR, UV-vis and NMR spectroscopic analyses. Elemental analysis data were in agreement with a metal:ligand ratio of 1:1 for the complexes formed with HL1, HL3 and HL4 in a tetrahedral geometry fashion while those with HL2 results in complexes with metal:ligand ratio of 1:2 in octahedral arrangement. The antimicrobial activity of the Schiff base ligands and their metal complexes were investigated on the strains of gram positive bacteria (Staphylococcus aureus and Bacillus subtilis) and gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Salmonella typhi) as well as on the fungi strains (Candida albicans, Aspergillus niger, Rhizopus stolonifer and Penicillium notatum) using disc diffusion method. The results showed that the zones of inhibition of the metal complexes for both species were higher than that of the Schiff base ligands. This indicates that the metal complexes can be applied in drug design to control bacterial and fungal diseases.Item Transesterification Reaction of Palm Kernel Oil (PKO) on a Bed of Crushed Cashew Nut Shell (CCNS)(Usmanu Danfodiyo University, Sokoto, Nigeria, 2019-06-04) Eke, U. B.; Owalude, S.O.; Tella, A.C.; Adejoro, A.G.Biodiesel (GA1) was produced by the transesterification reaction of palm kernel oil (PKO) and methanol catalysed by crushed cashew nut shaft. Biodiesel samples GA2 – GA4 were also produced from the palm kernel oil using conventional base catalysis by NaOH and crushed cashew nut shaft combined with NaOH. The physico-chemical properties and spectroscopic data of the four samples were found to be similar and compared favourably to those of standard biodiesel.