Applied Chemistry

Metal- ligand complexation in solutions was studied in water-methanol media by pH-metric titration with the standard glass electrode at ionic strength of 0.1M KNO_3. The titrations were carried out at various temperatures 35^oC, 45^oC, and 55^oC and the pKa values (stability constants) were determined. Copper (II) with benzimidazole gave pKa’s of 2.86, 2.52, and 2.46; Stability constant (logK) 338.80, 331.13 and 288.40 while Nickel (II) benzimidazole gave pKa’s 2.51, 2.60 and 2.38 and Stability constant (logK) 323.59, 398.11 and 239.85 respectively.  It was revealed that the stability constants of the metal complexes decreased as the temperature increases. Formation constants obtained for these complexes showed that metal- ligand ratio were in the range of 1:1 and 1:2. The thermodynamic parameters were also determined at the working temperatures and the results obtained showed negative ?H and Gibb’s free energy (?G) indicating exothermic and spontaneous reactions.

In arid and semi arid area, irrigation is very essential for successful agriculture. Quality of irrigation water is an important factor of crop production .Whatever may be the source of irrigation water, some soluble salts are always dissolved there in these are mostly sodium, calcium, magnesium and some time potassium as cations and chloride , carbonate, and bi-carbonate as anions. Salinity hazard which is associated with high soluble salts in water and measured in terms of electrical conductivity (EC), water having an EC value of more than 2.25m.mhos/cm² is always unsafe for irrigation use. The alkali hazard is related to the development of alkalinity in the soil and is expressed as SAR Residual Sodium Carbonate is an indirect expression of CO3^-2 and HCO3^-1 of Na⁺in ground water. Based on the RSC value the irrigation water are classified in conclusion.

The proximate, mineral, vitamins and phytochemical compositions of a sample of pili fruit kernel have been investigated. The result revealed low values of ether extract (12.77±0.3%), crude fibre (4.72 ±0.2 %) and a very low crude protein value of 3.94 ±0.002.. It has a high value of carbohydrate (65.91±0.7%). The calculated metabolizable energy value (1659.94KJ/100g) shows that pili fruit kernel flour is a good source of energy. The pili fruit kernel has high values of the essential mineral elements: sodium (158 mg/100g), potassium (513 mg/100g), calcium (230 mg/100g), magnesium (365 mg/100g) and phosphorus (131 mg/100g) as well as the trace elements: iron (229.75 mg/kg), zinc (72.01 mg/kg), copper (121.75 mg/kg) and manganese (156.25 mg/kg).These values indicate that pili fruit kernel is a very rich (good) source of dietary minerals. The Ca/P (1.75) and Na/K (0.308) ratios have favorable health implications. The pili fruit kernel sample has high values of vitamin A (455.1mg/kg), niacin (8.50mg/kg), riboflavin (5.50 mg/kg) but low values of thiamin (1.25 mg/kg), vitamin C (8.60 mg/100g) and vitamin E (8.98mg/100g). The pili fruit kernel sample has high values of alkaloid (3.94±0.008%), flavonoid (4.82±0.003%) but low values of saponin (0.62±0.05%) , tannin (0.28 ±0.001 mg/100g), cyanogenic glycoside as HCN (0.52±0.002mg/kg) , phytate (0.02±0.0007%) and trace amount of trypsin inhibitor.

Functional properties and anti-nutritional factors of five wild seeds (Borassus aethiopum, Bombacopsis glabra, Entada africana, Entada gigas and Myrianthus arboreus) were carried out using standard methods. Functional properties of` the flour showed that the least gelation concentration for B. aethiopum, B. glabra, E. africana and M. arboreus were 10%, 6% 6% and 18% respectively. E. gigas flour however did not gel at 20%. B. aethiopum had the least foaming capacity 1.85% while B. glabra had the highest 27.27 %. Water absorption capacity ranged between 3.00% in M. arboreus and 30.0% in E. africana. Oil absorption capacity was between 13.00 % in M. arboreus and 22.00% in E. africana. Protein solubility increased with increase in pH in acidic medium and reached the peak at pH 7 (E africana exempted) before solubility began to decrease with further increase in pH at alkaline medium. Antinutrient content showed that saponin ranged between 0.29% in E .africana and 0.42% in B. glabra. Phytate was between 0.14mg/g in E. africana and 6.56mg/g in E. gigas. E. gigas had tannin content of 0.45mg/g, while M. arboreus had 4.87mg/g , B. aethiopum had the lowest oxalate 2.25mg/g while M. arboreus had the highest of 7.19mg/g.

Organotin compounds have attracted global attention due to their extensive use for agricultural, industrial, medicinal, and domestic applications. These applications have made them enter the environment. This has caused environmental concerns due to the proven toxicological relevance of the compounds. Their toxic effects result in extensive damage to non-target organisms at ultratrace concentration levels (ppt) and accumulation in sediments and biota. This leads to the legislative restriction place on the uses of some of these compounds. Despite the legislative restriction, their environmental pollutions continue. Hence, this review which is aimed at providing an overview of the application of organotin compounds and their environmental toxicities.

A copper complex of the type [Cu(Phen)(L-Tyr)(TSC)](ClO4), where Phen = 1,10 Phenanthroline, Tyr = Tyrosine and TSC = Thiosemicarbazide, was synthesised and characterised by elemental analysis, IR, conductivity measurement and EPR studies. DNA-binding properties have been studied by electronic absorption, emission, viscosity and cyclic voltametric methods. The results suggest that the copper(II) complex bind to DNA via different modes. Gel electrophoresis study reveals the fact that the copper complex cleaves super coiled pBR 322 DNA to nicked and linear forms in the presence and absence of ascorbic acid. The in vitro antimicrobial study indicates that the complex has good activity against gram positive, gram negative bacteria and fungus.

The effects of stress ratio on the fatigue crack propagation of the 6061 T6 alloy aluminum with a thickness of 5 mm were investigated at room temperature. The fatigue crack growth rates were studied at stress ratios of 0.1with stress range, Ds=80 MPa using centre cracked-tension specimen M (T). The results are expressed in term of crack tip stress intensity factor range that was derived from linear elastic theory. From the collected data, the fatigue crack growth versus stress intensity factor range was plotted. It was obtained that the overall stress intensity factor range is within 6 to 19.5 MPaÖ m, and the value of fatigue crack growth rate is within 10^-7 to 10^-3 mm/cycle. For R=0.1 the stress intensity factor range is within 8 to 19.5 MPaÖ m, and the value of fatigue crack growth rate is within 10^-6 to 10^-4 mm/cycle. Finally, the value of (m) and (C) were determined from the graph using the Paris Law equation. The results showed that the increase in continuous crack length and load cycle will result to the acceleration of fatigue crack growth. Scanning Electron Microscope (SEM) was used to check the microscopic of fractured surface. From the fractography analysis, the material fails in ductile fracture. Hopefully this collection data’s will used as reference to the next researcher.

A novel and selective method for the fast determination of trace amounts of Co(II)ions in water samples has been developed.  The first organic-solution-processable functionalized-Multiwalled carbon nanotubes (MWNTs) (SPFMWNTs) hybrid material with porphyrins. porphyrin–Multiwalled carbon nanotubes (MWNTs)  nanohybrid, 5-4 (aminophenyl)-10, 15, 20-triphenyl porphyrin and its photophysical properties including optical (TPP) and grapheme oxide molecules covalently bonded together via an amide bond (TPP-NHCO- SPFMWNTs )were used as absorbent for extraction of Co(II)   ions by solid phase extraction method. The complexes were eluted with HNO₃ (2M)10% V.V^-1 mthanol in acetone and determined the analyte by flame atomic absorption spectrometry.  The procedure is based on the selective formation of Co(II)  at optimum pH by elution with organic eluents and determination by flame atomic absorption spectrometry.The method is based on complex formation on the surface of the ENVI-18 DISK^TM disks modified porphyrin–Multiwalled carbon nanotubes (MWNTs)  nanohybrid, 5-4 (aminophenyl)-10, 15, 20-triphenyl porphyrin (TPP) and grapheme oxide molecules covalently bonded together via an amide bond (TPP-NHCO- SPFMWNTs ) followed by stripping of the retained species by minimum amounts of appropriate organic solvents. The elution is efficient and quantitative. The effect of potential interfering ions, pH, TPP-NHCO- SPFMWNTs, amount, stripping solvent, and sample flow rate were also investigated. Under the optimal experimental conditions, the break-through volume was found to about 1000mL providing a preconcentration factor of 600. The maximum capacity of the disks was found to be 568± 3 µg for Co²⁺. The limit of detection of the proposed method is 5ng per 1000mL.The method was applied to the extraction and recovery of Co in different water samples.

Interaction of various process parameters like initial chromium concentration (VI) (5-30 mg/l), pH (1-10), and adsorbent dosage (6-10 g/l) for chromium adsorption using custard apple powder were evaluated using central composite design (CCD) in response surface methodology. The CCD design in response surface methodology has been applied for designing the experiments as well as for full response surface estimation and 19 experimental data as per the model were used. The optimum conditions for better percentage removal of chromium from waste water with the concentration of 20 mg/l were as adsorbent dosage (9.9966 g/l), pH (2.7877) and initial chromium concentration (15.18693 mg/l). The high correlation coefficient (R2 =0.98929) between the model and the experimental data showed that the model was able to predict the better percentage removal of chromium (VI) from waste water using custard apple peel powder efficiently

A copper (II) complex, [cu(phen)(L-Ala)U](ClO4) (phen=1,10- phenanthroline, L-Ala =L-alanine,U =urea ), has been synthesized and characterized by Infra-red, EPR spectral and elemental analysis methods. The interaction with calf-thymus DNA has been studied by means of electronic absorption spectroscopy, emission spectroscopy, viscosity and cyclic voltammetry has been conducted to assess their interaction between their complex and DNA. A sample of copper II complex was tested for its Antimicrobial Activities and it was found to have good antimicrobial activities.