Applied Chemistry

The tridentate Schiff base, 3-{[(6-methoxypyridin-3-yl)imino]methyl}naphthalen-2-ol, formed by condensation of 5-amino-2-methoxypyridine and 2-hydroxy-1-napthaldehyde coordinates to some Metal(II) ions, forming complexes of the type [M(L2)]½H2O {where M = Mn, Co, Ni, Cu, Zn, Pd}. These complexes are characterized by percentage metal, melting point, conductance measurements, electronic and IR spectroscopies. The IR data confirms that coordination is via the imine nitrogen and napthanenol oxygen atoms; while electronic data support a 4-coordinate tetrahedral/squareplanar geometry for the metal complexes. The complexes are air-stable solids which melt/decompose on heating in the temperature range 196-232oC; and none is an electrolyte in nitromethane. The in-vitro antibacterial activities of the complexes against Staphylococcus aureus, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa and Klebsiella oxytoca are reported. Notably, the Pd(II) complex exhibits broad-spectrum antibacterial activity against these bacteria with the exception of Pseudomonas aeruginosa with inhibitory zones range in the range 8.0-12.0 mm.

A total of 14 different Petroleum samples comprising of 4 crude oil blends, 7 refined products and 3 wastes from the Tema oil refinery were analyzed for 27 elements using Instrumental Neutron Activation Analysis (INAA). Based on the results obtained and analytical procedure used in this work, pattern of occurrence of the metal contaminants in the petroleum products and waste suggest they are native to the crude oil and its origin as no external contamination was established. It was observed from the study and previous ones that the Brass and Bonny crude oil from Nigeria have low metal contents. However, despite the low concentrations, trace amounts of these metals could be deleterious in the refinery as they can cause corrosion, catalytic poisoning, and affect the quality of refined products. They could also contribute to environmental pollution as results of combustion of fuel products and hence should be reduced or removed.

2, 2-dihydroxy biphenyl-thiourea-formaldehyde (2, 2-DHBTF) terpolymer resin was synthesized by an eco-friendly technique in dimethyl formamide medium. The resin was characterized by elemental analysis, UV-Visible, FTIR, 1H NMR, 13C-NMR and viscometric measurement. The surface morphology of the terpolymer resin was established by scanning Electron Microscopy. The number average molecular weight was determined by non-aqueous conductometric titration. One of the important applications of these types of polymer is their capability to act as chelating ion-exchanger. The chelation ion-exchange properties of the terpolymer showed a powerful adsorption towards specific metal ions like Fe3+, Cu2+, Ni2+, Co2+ and Zn2+ . A batch equilibrium method was adopted to study the selectivity of the metal ion uptake involving the measurement of the distribution of the given metal ion between the polymer sample and a solution containing the metal ion over a wide range of concentrations and pH of different electrolytes.

This study is aimed at assessing & comparing the levels of some heavy metals in most commonly sold and/or consumed soft and alcoholic drinks in Iwo, Osun State, Nigeria. Three brands each of soft drink (Coke, 7Up & Maltina) and alcoholic drinks (Orijin, Trophy & Goldberg) were bought and analyzed for copper, chromium & lead using Flame Atomic Absorption Spectrophotometric technique. 30 mL of each of the sample was digested, after allowing the sample to stand for 24 hrs for gas evaporation, using dry ashing method; 10 mL of concentrated HNO3 was added to the ash, filtered and made up to 30 mL mark with 0.1 M HNO3. The digested samples were analyzed for Cu, Cr & Pb using Buck Scientific Model 210VGP Flame Atomic Absorption Spectrophotometer. Results showed that overall mean levels of Cu were 0.05 ± 0.03 mg/L and 0.09 ± 0.04 mg/L for soft & alcoholic drinks respectively. Chromium was below detection limit of the FAAS and can be inferred to be below tolerance limit set by NIS (0.05mg/L). Lead was detected in both sampled drinks at a concentration ranging from 0.010 - 0.140 mg/L for soft drinks and

The polymeric membrane using naturally occurring aloe-vera pulp as host and for filler, fine powdered natural waste egg shell was used which served the purpose of second component of the composite. The ratio of the aloe pulp and egg shell (ES) was kept 90:10. The membrane was characterized by different spectroscopic methods, viz., X-ray diffraction, Fourier transformed infra-red spectroscopy and conductivity by impedance spectroscopy. There is a sharp increase in the resistivity with temperature around melting temperature of the crystalline polymer. The attraction of this work is that the ingredients used for constructing the polymer matrix are natural , biocompatible and fully biodegradable.

The synthesis and Biological activity of 2,4,5-trimethoxy benzaldehyde Thiosemicarbazone ligands have been reported. The Infrared and Elemental analysis have been assigned. The data agree quite well with the proposed structures. The group sensitive fundamentals are compared with those of similar molecules already reported in the literature. Ligand were screened for antimicrobial activities by the disc diffusion technique using DMSO as solvent. These Schiff base has been studied for their anti-bacterial ,anti-fungal, and anti oxidant activity. The antifungal activity of the said ligand has been screened against Aspergillus flavus, Asperjillus niger and Antibacterial activity tested against Vibrio harveyi , VibrioVulnificus, Escherichia Coli, Bacillus pumilus.The anti oxidant activity againt catalase assay.

The Corrosion inhibition of a inhibitor namely Zn complex of 1-(8-hydroxy quinolin-2yl-methyl) urea (Zn-HUF) in controlling corrosion of mild steel immersed in aqueous solution containing 60 ppm Cl- has investigated using weight loss method. The corrosion inhibition efficiency offered by 50 ppm of Zn-HUF is 74 %. The corrosion inhibition was observed due to the formation of more stable and compact protective film on the metal surface. Fluorescence spectral analysis was used to detect the presence of iron-inhibitor complex. Polarization study and Electrochemical Impedance spectra confirm the formation of a protective film formed on the metal surface.

A new heteropolyacid-based cation exchanger [Bismuth(III) tungstomolybdate (BTM)] has been synthesized and characterized using chemical stability, pH titration, distribution studies, thermal stability, FTIR, X-Ray analysis and TGA curve analysis. It exhibits 1.05 meq/g ion exchange capacity for sodium ions. The chemical stability of the material has been tested in acidic, neutral and basic media. Its distribution behaviour for nine metal ions has been studied. Ion exchanger column was used for binary separation and hardness causing metal ions removal.

The study includes the determination of Ni (II) using azo reagent Benzenesulfonate, 4,4’-[3-(2-pyridinyl)-1,2,4-triazine-5,6-diyl]bis-, hydrogen sodium salt (1:1:1) spectrophotometric at (?max 562 nm) wave length. The effect of different parameters on determination is evaluated. The study shows that best PH=(7±0.1). The study includes obey concentration of Beer-Lambert law to determination of the calibration graph of Ni(II) by reagent. From this graph we note obey the concentration of law was between (2-50) µg of Ni(II) after this values the absorbance increased. The stoichiometry of complex Nickel ion determined by molar ratio method. Result indicated reagent to metal ratio was (1:2) the stability constant of the complex determination through mole ratio method and its value indicated good stability. The UV-Vis spectra and the IR spectra of the complex and reagent were measured. From all mentioned studies proposed structural formula of Ni(II) complex.

The ligand 2,5-bis(phenylcarbamoyl)terephthalicacid (bpctpa) was synthesized and characterized. Novel co-ordination polymers were prepared by using ligand (bpctpa) and transition metal ions viz. Mn(II), Co(II), Ni(II), Cu(II), and Zn(II). The co-ordination polymers and parent ligand were characterized by elemental analysis, spectral studies, thermogravimetry, number-average molecular weights ( ), diffuse reflectance spectral studies and magnetic susceptibilities. The biological activity of all the samples has also been monitored against plant pathogens.