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Search Results: 1 - 10 of 201906 matches for " Emmanuel N. Nfor "
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Corrosion Inhibitory Studies of Novel Schiff Bases Derived from Hydralazine Hydrochloride on Mild Steel in Acidic Media  [PDF]
Romanus N. Njong, Bridget N. Ndosiri, Emmanuel N. Nfor, Offiong E. Offiong
Open Journal of Physical Chemistry (OJPC) , 2018, DOI: 10.4236/ojpc.2018.81002
Abstract: The inhibition performance of 1-hydralazinophthalazine (HPZ) (1), and synthesized1-(2-[(5-methylfuran-2-yl)methylene)] hydrazono) phthalazine (MFHPZ) (2), 1-(phthalazin-1(2H)-one) [(pyridin-2-yl) ethylidene] hydrazone (ACPHPZ) (3) and (2-acetylthiophene hydrazono) phthalazine (ACTHPZ) (4) has been investigated for mild steel in 1 M HCl. Compound 4 shows maximum inhibition efficiency of 93% at 5.0 × 10-3 M concentration. The evaluation of thermodynamics and activation parameters indicated spontaneous adsorption of the inhibitor molecules which takes place through chemisorption. The adsorption of 3 and 2 follows Langmuir adsorption isotherm and Temkin adsorption isotherm for 4 and 1. The inhibitor efficiency was of the order 4 > 3 > 1
Synthesis, Molecular Structure and Anti-Onchocercal Studies of 1-(Phthalazin-1(2H)-one)[(Pyridin-2-yl)ethylidene]hydrazone  [PDF]
Joseph N. Yong, Felicite Majoumo-Mbe, Moses Samje, Emmanuel N. Nfor
International Journal of Organic Chemistry (IJOC) , 2016, DOI: 10.4236/ijoc.2016.61008
Abstract: The novel ligand, 1-(phthalazin-1(2H)-one)[(pyridin-2-yl)ethylidene]hydrazone,(APN), derived from the antihypertensive drug, hydralazine hydrochloride, was synthesized and characterized by spectroscopic methods (IR, 1H NMR). The X-ray crystallographic data indicates that APN has an exocyclic C=N bond on the hydralazine moiety. APN revealed significant anti-onchocercal activity with IC50 values of 0.3125 μg/mL on microfilaria and 10 μg/mL on adult worms compared to the standard drug, ivermectin.
Synthesis, Molecular Structure and Antibacterial Activity of Benzylmethyl-4-Methyl-3-Thiosemicarbazone  [PDF]
James A. Mbah, Godfred A. Ayimele, Elvis N. Eyonganyoh, Emmanuel N. Nfor
International Journal of Organic Chemistry (IJOC) , 2017, DOI: 10.4236/ijoc.2017.72007
Abstract: A novel Schiff base, benzylmethyl-4-methyl-3-thiosemicarbazone (BMM) de-rived from benzylmethylketone and 4-methylthiosemicarbazide was synthe-sized and characterized by elemental analysis, spectroscopic methods (IR, 1H NMR, 13C NMR) and physical means. The single crystal structure analysis of the Schiff base reveals that it crystallizes in a monoclinic system in the P21/c space group. BMM revealed moderate antibacterial activity on three bacterial strains with diameter zone of inhibition of 16 mm (E. coli), 14 mm (K. pneumonia) and 13 mm (S. epider-midis) compared with the standard drug, ciprofloxacin.
Synthesis and Crystal Structure of the First Example of a Tris-Chelated Co(II) Complex Based on Oxamide Dioxime Ligand  [PDF]
Gouet Bebga, Emmanuel N. Nfor, Yves A. Mbiangué, Patrick L. Djonwouo, Justin Nenwa
Crystal Structure Theory and Applications (CSTA) , 2015, DOI: 10.4236/csta.2015.42002
Abstract: A new cobalt(II) complex, [Co(H2 oxado)3 ]C2 O4 H2 oxado·2H2 O (H2 oxado = oxamide dioxime), has been synthesized in aqueous solution and characterized by elemental analysis and single crystal X-ray structure determination. The complex crystallizes in the triclinic space group P-1, with the parameters a = 9.46(4), b = 11.84(5), c = 12. 81(5)?Å, α = 104.94(6), β = 99.29(5), γ = 106.73(5), V = 1284(9) Å3, Z = 2. The central cobalt(II) cation is pseudo-octahedrally coordinated by six imino N atoms of the neutral oxamide dioxime ligand. In the solid state, each of the following bricks, namely the cationic complexes, the oxalate dianions as well as the oxamide dioxime crystallization molecules, pile up parallel to the a axis. The bulk structure is consolidated by an extended three-dimensional network of hydrogen bridgings—that link the ionic partners, oxamide dioxime and water molecules to one another—and by coulombic interactions.
Antimicrobial Resistance Profile of Bacteria Isolated from Boreholes and Hand Dug Wells Water in Ngaoundere Municipality of Adamawa Region in Cameroon  [PDF]
Bernard Viban Tangwa, Horline Keubou, Emmanuel N. Nfor, Albert Ngakou
Advances in Microbiology (AiM) , 2019, DOI: 10.4236/aim.2019.97039
Abstract: Uncontrolled uses of antibiotics have led to rapid evolution of antibiotic-resistance bacteria and antibiotic resistance gene transfer, especially in a pool of aquatic system where resistance, intermediate and susceptible bacteria to some antibiotics strive together. Consequently, there is a transfer of resistance genes. In this study, bacteria of the Enterobacteriaceae family and some gram positive bacteria isolated from some boreholes and hand dug wells water of public use were tested on 19 antibiotics of different classes. This was achieved through a disk diffusion technique to determine the antimicrobial resistance profile of the said bacteria, microbial resistance index of the drugs used (and their ability to produce Beta-lactamase). These isolates were shown to demonstrate a very high resistance to the drugs used in the area. The resistance was highest in Escherichia coli 1 (73.68%) and lowest in Streptococcus pneumoniae (47.82%). These isolates also indicated very high levels of multi-drug resistance. The minimum resistance index was 0.47, indicating that bacteria isolates were of fecal origin. It is evident from the present study that multiple antibiotic-resistant bacteria can thrive in water as an environmental reservoir, and can therefore provide a route to multidrug-resistant pathogens to enter human and animal population.
A Novel Mixed Ligand Dinuclear Complex of Cobalt (II): Synthesis, Characterization and Magnetic Studies  [PDF]
Emmanuel N. Nfor, Luke L. Keenan, Justin Nenwa, Peter T. Ndifon, Romanus N. Njong, Christelle N. T. Dzesse, Offiong E. Offiong
Crystal Structure Theory and Applications (CSTA) , 2014, DOI: 10.4236/csta.2014.31003
Abstract:

A novel dinuclear complex [Co2(atr)3(mal)2(H2O)2]·4H2O(1) (atr = 4-amino-1,2,4-triazole and mal = malonic acid) containing mixed N and O-donor atoms has been prepared and structurally characterized. The structure is made up of the symmetrically 1, 2, 4-triazole bridged [Co2(atr)3(mal)2(H2O)2] moiety and four lattice water molecules. The single crystal X-ray analysis reveals that the complex has a distorted octahedral structure. Magnetic susceptibility measurements reveals that antiferromagnetic interactions exists between the high spin Co(II) ions within the dinuclear unit.

Nickel (II) and Iron (II) Complexes with Azole Derivatives: Synthesis, Crystal Structures and Antifungal Activities
Emmanuel N. Nfor,Peter F. Asobo,Justin Nenwa,Oswald N. Nfor,Julius N. Njapba,Romanus N. Njong,Offiong E. Offiong
International Journal of Inorganic Chemistry , 2013, DOI: 10.1155/2013/987574
Abstract: Two new complexes of nickel (II) with 4-amino-3, 5-bis(pyridyl)-1, 2, 4-triazole (abpt) and iron (II) with 2-(3-phenyl-1H-pyrazole-5-yl) pyridine (phpzpy) have been synthesized and characterized by elemental analysis and IR spectroscopy. The crystal structures of the complexes have been determined by single crystal X-ray diffraction techniques. In the nickel and iron complexes, the ligands are coordinated through nitrogen atoms in bidentate manner. The ligands and their respective complexes have been tested for their antifungal activity against Aspergillus niger, Aspergillus flavus, and Candida albicans. From the study, the complexes showed enhanced activities against the tested organisms compared to the ligands. 1. Introduction Aromatic nitrogen heterocycles represent an important class of compounds which can act as ligands towards metal ions [1]. Azoles belong to this class and are five-membered heterocyclic ligands containing two or more heteroatoms, one of which must be nitrogen. These compounds have been paid considerable attention due to their wide applicability in medicine [2–4]. Pyrazole and triazole derivatives are subject of many research studies due to their widespread potential biological activities such as antitumour [5, 6], anti-inflammatory [7], antipyretic [8], antivirial [9], antimicrobial [10, 11], anticonvulsant [12], antihistaminic [13], antidepressant [14, 15], insecticides, and fungicides. In coordination chemistry pyrazole-and triazole-derived ligands exhibit various coordination modes and have received considerable attention for the synthesis of transition metal complexes with various nuclearities [16]. Herein we report on the synthesis, structural determination, and antifungal activities of Ni(II) and Fe(II) complexes of abpt and phpzpy, respectively. The crystal structures of the complexes are described and compared with those of closely related structures. 2. Experimental 2.1. Materials and Physical Measurements Elemental analysis for carbon, hydrogen, and nitrogen was performed on a Thermo Flash EA-1112 Series CHNS-O Elemental Analyzer. The IR spectra were obtained from KBr pellets in the range 4000–400?cm?1 using a Perkin-Elmer Spectrum 100?FT-IR spectrometer. 2.2. Single Crystal X-Ray Diffraction Analysis and Structure Determination Suitable-single crystals of 1 and 2 were selected and mounted in air onto a loop. The data collection for 1 and 2 was carried out with a Bruker DUO APEX II CCD diffractometer at 173 ?K using an Oxford cryostream 700. Data reduction and cell refinement were performed using SAINT-Plus, [17–21] and
Anionic Nanochanneled Silver-Deficient Oxalatochromate(III) Complex with Hydroxonium as Counter Ion: Synthesis, Characterization and Crystal Structure  [PDF]
Clémence T. Eboga, Gouet Bebga, Yves A. Mbiangué, Emmanuel N. Nfor, Patrick L. Djonwouo, Michel M. Bélombé, Justin Nenwa
Open Journal of Inorganic Chemistry (OJIC) , 2017, DOI: 10.4236/ojic.2017.73005
Abstract: Reaction of Ba0.50[Ag2Cr(C2O4)3]·5H2O with Ag2SO4 in an aqueous solution of sulfuric acid (pH ≈ 3) yielded the silver(I)/chromium(III) oxalate salt H0.50[Ag2.50Cr(C2O4)3]·5H2O (1). Compound 1 can be best described as an anionic silver-deficient oxalatochromate(III) complex [Ag2.50Cr(C2O4)3]0.5- with nanochannels containing hydrogen-bonded water molecules and protons. Thermal analyses show significant weight losses corresponding to the elimination of water molecules of crystallization followed by the decomposition of the network.
Synthesis, stereochemistry and antimicrobial activity of copper(II) and nickel(II) complexes of 4-phenylsemicarbazones
Emmanuel N. Nfor,Seraphine N. Esemu,Godfred A. Ayimele,Ededet A. Eno
Bulletin of the Chemical Society of Ethiopia , 2011,
Abstract: 2-Acetylpyridine-(4-phenylsemicarbazone) and o-vanillin-(4-phenylsemicarbazone) have been prepared and characterized on the basis of elemental analyses, infrared, electronic, 1H and 13C NMR spectra. Several nickel(II) and copper(II) complexes have been obtained from these ligands. The IR spectra of the ligands as well as those of their complexes suggest that 2-acetylpyridine-(4-phenylsemicarbazone) is a neutral tridentate molecule while o-vanillin-(4-phenylsemicarbazone) is a monobasic tridentate molecule. On the basis of the analytical data, magnetic moments and spectral data, a square-planar geometry has been proposed for the nickel(II) and copper(II) complexes with these ligands. Some representative complexes of copper(II) and nickel(II) were found to have remarkable antifungal and antibacterial activity.
Synthesis, stereochemistry and antimicrobial activity of copper(II) and nickel(II) complexes of 4-phenylsemicarbazones
Emmanuel N. Nfor, Seraphine N. Esemu, Godfred A. Ayimele, Ededet A. Eno, Grace E. Iniama, Offiong E. Offiong
Bulletin of the Chemical Society of Ethiopia , 2011,
Abstract: 2-Acetylpyridine-(4-phenylsemicarbazone) and o-vanillin-(4-phenylsemicarbazone) have been prepared and characterized on the basis of elemental analyses, infrared, electronic, 1H and 13C NMR spectra. Several nickel(II) and copper(II) complexes have been obtained from these ligands. The IR spectra of the ligands as well as those of their complexes suggest that 2-acetylpyridine-(4-phenylsemicarbazone) is a neutral tridentate molecule while o-vanillin-(4-phenylsemicarbazone) is a monobasic tridentate molecule. On the basis of the analytical data, magnetic moments and spectral data, a square-planar geometry has been proposed for the nickel(II) and copper(II) complexes with these ligands. Some representative complexes of copper(II) and nickel(II) were found to have remarkable antifungal and antibacterial activity. KEY WORDS: 4-Phenylsemicarbazone, Metal complexes, Stereochemistry, Antimicrobial activity Bull. Chem. Soc. Ethiop. 2011, 25(3), 361-370.
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