FACULTY OF PHYSICAL SCIENCE
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Item GREEN SYNTHESIS, CHARACTERIZATION, MODIFICATIONS AND APPLICATIONS OF ZINC OXIDE NANORODS(UNIVERSITY OF ILORIN, 2018) ADELEKE, JOSHUA TOYINThe demand for clean energy and clean water is becoming challenging issues having been greatly influenced by human’s lifestyle and the growing world population. Nanotechnology offers promising solution through the applications of nanomaterials. The orthodox methods of synthesizing nanomaterials are expensive and generate hazardous toxic chemicals. Green method route of synthesis has become an alternative to overcome such limitations. This research work therefore aimed at synthesising a multifunctional zinc oxide nanorod through green principle route of synthesis. The objectives were to: (i) synthesize Mangifra indicaleave extract-mediated zinc oxide nanorods (ZnO NR); (ii) synthesize spinel nickel ferrite nanorods (NF NR); (iii) modify the ZnO NR with NF NR by calcination to obtain a nickel ferrite-zinc oxide nanocomposite; (iv) characterize the synthesized nanostructures for structural, elemental composition, functional groups,morphological and optical studies using X – Ray Diffractometer XRD, Fourier Transform Infrared (FTIR), Energy Dispersive X-ray Spectrometer (EDX), Scanning Electron Microscope (SEM), UV-VIS Spectrophotometer, and Photoluminescence (PL) spectroscopy respectively; (v) examine the applications of the synthesized nanostructures for dielectric studies, solar cell nanocoating, biosensing, photodegradation and treatment of both domestic and industry waste water. Green principle route of synthesis was used for the synthesis of zinc oxide nanorods. The zinc oxide nanorods (ZnO NR) were modified with spinel nickel ferrite nanorods (NF NR) by calcination both at 850 0C for ten hours to obtain zinc oxide-nickel ferrite (ZnO/NF) nanocomposite. Both unmodified and modified ZnO NR were characterized and examined for applications in dielectrics, solar cell nanocoating, glucose sensing, photodegradation and waste water treatment. The findings of this research work showed that: (i) ZnO NR have been synthesized by green synthesis route and had been successfully modified with nickel ferrite nanorods synthesized by coprecipitation method. (ii) the dielectric constantε/ of the green synthesized ZnO NR is very high (750) with capacitance value of 0.78 pF. Its dielectric loss Ԑ//, dielectric loss angle, σdecreases with increasing frequency and then reaches a constant value, hence a good dielectric. (iii) the fill factor of a silver solar cell coated with the green synthesized ZnO NR by drop-casting method was enhanced showing improved solar cell efficiency up to 5%. (iv) the modified ZnO NR was successfully used as a biosensor for glucose. (v) the photocatalytic studies reveal that the ZnO/NF nanocomposite exhibits high degradation efficiency under UV light and that •OH and photoproduced holes h+ are the main species in the removal of the organic dyes solution. (vi) for the treatment of domestic and industrial waste water, the green synthesized ZnO NR showed 93.95% and 93.95% of chemical oxygen demand (COD) reduction in 75 minutes. This research work concluded that green synthesis route is suitable for the synthesis of ZnO NR, appropriate modification of which makes it multifunctional. It is recommended that, green synthesis method should be adopted for the synthesis of ecofriendly, cost effective and multifunctional ZnO NR.Item SYNTHESIS AND CHARACTERIZATION OF 1, 1-DIARYL VINYL SULFONES AS POTENTIAL ANTICANCER AGENTS(UNIVERSITY OF ILORIN, 2018-03) EGHAREVBA, GOD’SHELP OSASCancer has become a major health concern globally. Interestingly, anticancer agents are being synthesized from small molecules derived from either plants or aquatic organisms. For example, Combretastatin A-4 (CA-4) isolated from the bark of the South African tree Combretum caffrum. CA-4 is one of such important anticancer agents which have gained the attention of a vast majority of investigators. However, it has problems of bioavailability and isomerisation of the biologically active Z-configured double bond into the inactive E-configuration. There is therefore the need to synthesize a new library of CA-4 analogues. The objectives were to: (i) synthesize 1,1-diarylethene derivatives having a sulfonyl (SO2R) group at the 2 - carbon position; (ii) characterize all synthesized compounds; and (iii)determine the cytotoxicity of the synthesized compounds using various human cancer cell lines. The desired target molecules were obtained from 3,4,5-trimethoxy benzaldehyde prepared by Corey-Fuchs olefination to yield 5-(2,2-dibromovinyl)-1,2,3-trimethoxybenzene. This was reacted with 1, 8- diazabicyclo[5.4.0]undec-7-ene (DBU) in acetonitrile to give 5-ethynyl-1,2,3- trimethoxybenzene. Further treatment of the product with diacetoiodobenzene (DIB), sodium-p-toluenesulfonate and potassium iodide in acetonitrile yielded (E)-5-(1-iodo-2-tosylvinyl)-1,2,3-trimethoxybenzene). This was made to undergo Suzuki-Miyaura coupling with different substituted arylboronic acids in tetrahydrofuran (THF) to give different combretastatin sulfonyl compounds. The compounds were characterized using proton (1H) and carbon-13 (13C) Nuclear Magnetic Resonance (NMR) Spectroscopy, Fourier Transform Infra Red Spectroscopy (FTIR), Electro Spray Ionization Mass Spectrometry (ESI-MS) and High Resolution Mass Spectrometry (HRMS). The in vitro cytotoxicity assay was carried out against four human cancer cell lines MDA-MB 231(breast cancer), HeLa (cervical cancer), A549 (lung cancer), and IMR-32 (neuroblast cancer), along with normal cell line HEK-293 (human embryonic kidney cell)by employing 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. The following results were obtained: (i) twenty novel 1,1, diaryl sulfones analogues of combretastatin CA-4 were successfully synthesized; (ii) the sulfonyl group was fully characterized with the following signals: 1H and 13C NMR at ẟ2.36 ppm and ẟ21.50 ppm respectively, which confirmed the presence of the methyl group attached to the aryl sulfonyl group. Proton resonating around ẟ7.14 ppm - 7.46 ppm also established the presence of the aromatic protons attached to the aryl sulfonyl group. Infra red (IR) band around 1361cm-1 and 1150cm-1 signified the presence of SO2 in the compound. HRMS molecular formula C26H28O7NaS also supported the presence of SO2 in the compound; (iii) the compounds showed significant cytotoxicity with IC50 values ranging from 4.10 - 23.94 µM when compared to the standard, doxorubicin (IC50 values ranging from 0.23 – 2.06 µM); (iv) conjugate (Z)-1,2,3-trimethoxy-5-(1-(4-methoxyphenyl)-2-tosylvinyl)benzene displayed potent antiproliferative activity against A549 and IMR-32 cancer cell lines; and (v) all the synthesized compounds were non toxic to normal cell line HEK-293.with the exception of 4-methylphenyl(3,4,5-trimethoxyphenyl)ethynyl sulfone. In conclusion, the synthesized CA-4 analogues were found to be effective against A549 cancer cell lines especially compound (Z)-1,2,3-trimethoxy-5-(1-(4-methoxyphenyl)-2-tosylvinyl)benzene. It is therefore recommended for consideration as a possible drug for lung cancer treatment.