Browsing by Author "Owalude, S. O."
Now showing 1 - 9 of 9
Results Per Page
Sort Options
Item Kinetics and Mechanism of Mn (II) Catalyzed Oxidation of D-Arabinose and D-Xylose by Chromium (VI) Ions in Perchloric Acid Medium(Faculty of Science, Akamai University, USA., 2009-05-29) Ogunlaja, A.S.; Odebunmi, E. O.; Owalude, S. O.The present paper describes the kinetics and mechanism of oxidation of D-arabinose and D-xylose by acidic solution of Chromium (VI) in the presence of Mn (II). First-order dependence of the reaction rate was observed on sugars, HClO4 at low concentrations and a zero-order observed for sugars at a higher concentration. First-order kinetics with respect to Mn (II) throughout its variation was observed in the oxidation of both sugars. The Cl− and ionic strength effect was found to be negligible. Arrhenius activation energy and other thermodynamic activation parameters have been evaluated and lend further support to the proposed mechanism. Formic acid and erythronic acid were reported as the product of oxidation for both sugars.Item Kinetics of oxidation of D-Arabinose and D-Xylose by Vanadium (V) in the presence of Manganese II as homogeneous catalyst(Chilean Chemical Society, 2010-02-10) Odebunmi, E.O.; Ogunlaja, A.S.; Owalude, S. O.Kinetics of oxidation of D-arabinose and D-Xylose by acidic solution of Vanadium (V) ions in the presence of manganese (II) has been reported. First-order dependence of the reaction rate was observed on [sugars] and [H+] at low concentrations throughout the oxidation reaction and a zeroth-order dependence on [sugar] and [H+] was observed at high concentrations. First-order kinetics with respect to [Mn (II)] was also observed throughout the oxidation for both sugars. The effect of Cl− concentration was found to be negligible. The reaction rates increases with the ionic strength of the medium. Various activation parameters were evaluated and provide further support to the proposed mechanism. Formic acid was reported as one of the oxidation products of the sugars.Item Mechanism of Ru(III)-catalyzed oxidation of L-cystine by Ce(IV) ions in sulphuric acid medium(University of Nigeria, Nsukka, Nigeria, 2018-12-18) Owalude, S. O.; Odebunmi, E. O.; Bamigboye, C.A.; Adebayo, A.B.Mechanism of oxidation of L-cystine by acidic solution of Ce(IV) ions in the presence of Ru(III) ions as homogeneous catalyst was studied using kinetic approach. A first-order dependence of the reaction rate on [cystine] and [Ce(IV)] was observed. The rate is inversely proportional to [H+] and decreased with increasing ionic strength of the medium. The active species of the oxidant in sulphuric acid medium and that of the catalyst were Ce(SO4)2 and [RuCl2(H2O)4]+ respectively. A suitable mechanism based on the kinetic data is proposed. The activation parameters and the thermodynamic quantities were also evaluated which supported the proposed mechanisms.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 One pot synthesis of group 6 homo-bimetallic carbonyl complexes incorporating a Schiff base and bidentate phosphine ligands(Federal University Wukari, Nigeria, 2016-09-04) Owalude, S. O.; Tella, A.C.; Ohara, M.S.; Eke, U.B.A simple route to the synthesis of two homo-bimetallic molybdenum carbonyl complexes [Mo2(CO)6(HL)2(dppm] (1) and [Mo2(CO)4(HL)2(dppb)] (2) (HL = (E)-2-((2- hydroxybenzylidene)amino)phenol; dppm = bis(diphenylphosphino)methane, dppb = 1,4- bis(diphenylphosphino)butane) have been developed. The two compounds were obtained pure by thermal decarbonylation of Mo(CO)6 using a Schiff base ligand previously prepared by condensation reaction of salicylaldehyde and 2-aminophenol, in the presence of either dppm or dppb. Compounds 1 and 2 were characterized using elemental analysis, IR and NMR (1H, 13C and 31P) spectroscopy. Elemental analysis and spectroscopic data revealed bimetallic complexes with three and two carbonyl remaining in the structure of complex 1 and 2 respectively with diphosphines acting as bridge between the two metals.Item Synthesis and characterization of new unsymmetrical bis-Schiff bases(Faculty of Science, University of Ilorin, 2018-07-10) Owalude, S. O.; AbdulRaheem, A.M.O.; Alemika, D.Y.; Tella, A. C.The literature is replete with symmetrical tetradentate bis-Schiff bases of 1,2-diamines with o-hydroxyaldehyde or ketones, but less attention has been focused on the analogous unsymmetrical tetradentate ones. Unsymmetrical Schiff bases of aromatic diamines are very difficult to obtain and are not easily isolated. This class of Schiff bases have very simple synthetic procedure and versatile coordination behavior. Metal complexes containing these Schiff bases in their structure usually possess exceptional antibacterial, antifungal and antitumor activities including anti-HIV activity. In this regard, two new unsymmetrical bis-Schiff bases, (Z)-N-(2-nitrophenyl)-N'-(2-((Z)-(2-oxoindolin-3-ylidene)amino)phenyl)acetimidamide (1) and (Z)-N-(2-nitrophenyl)-N'-((Z)-N-(2-oxoindolin-3-ylidene)carbamimidoyl)acetimidamide (2), were prepared from the condensation reactions of 2’-nitroacetanilide and 1H-indole-2,3-dione with o-phenylenediamine and guanidinium ions in ethanol. The corresponding symmetrical bis-Schiff bases (Z,Z)-1,3-bis(2-oxoindolin-3-ylidene)guanidine (3) and N-((2-(1-iminoethyl)-2-(2-nitrophenyl)hydrazinyl)methyl)-N-(2-nitrophenyl)acetimidamide (4) were also prepared. The data obtained from the elemental, IR and NMR spectroscopic analyses were used to propose structures for the four compounds.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 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.