Computational studies, synthesis and characterization of ruthenium (ii) anticancer complexes
- Authors: Adeniyi, Adebayo Azeez
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD (Chemistry)
- Identifier: vital:11338 , http://hdl.handle.net/10353/d1015577
- Description: This thesis is centred on the application of Ru-based complexes as a promising alternative to cis-platin in cancer chemotherapy. Cis-platin is known to be the most prescribed chemotherapy which has more than 70% application in cancer cases especially the testicular cancer. An insight is provided in Chapter One and Two into the literatures reports on the application of Ru(II)-based complexes in cancer chemotherapy. In order to address some of the pressing challenges in rational design of Ru-based anticancer complexes, section 3.3 and 3.4 deal with efforts to elucidate the complication of their chemistry and instability while in section 3.5 efforts are made to find solution to the lack of proper knowledge of their targets using different theoretical approaches as presented in Chapter Three. In addition to the theoretical study, this thesis also comprises of the synthesis of the bis-pyrazole derivatives type of ligands and the derivatives of their Ru(II)-based complexes as provided in Chapter Four and Five respectively. Also the computational methods were used to elucidate the structural and spectroscopic properties of the synthesised ligands and their Ru(II)-based complexes. The geometrical and electronic properties are studied in relation to the stability and the reported anticancer activities of Ru(II)-based complexes in section 3.3. In subsection 3.3.1, several quantum properties including the natural energy decomposition analysis (NEDA) and quantum theory of atoms in a molecule (QTAIM) are computed on three models of RAPTA-C complexes using DFT with hybrid functional and basis set with ECP and without ECP. The higher stability of Carbo-RAPTA-C and Oxalo-RAPTA-C over RAPTA-C comes from the lower exchange repulsion and higher polarization contributions to their stability which gives insight into experimental observation. A similar study was carried out in subsection 3.3.2 on half-sandwich Ru(II)-based anticancer complexes with 6-toluene and 6-trifluorotoluene.
- Full Text:
- Date Issued: 2014
- Authors: Adeniyi, Adebayo Azeez
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD (Chemistry)
- Identifier: vital:11338 , http://hdl.handle.net/10353/d1015577
- Description: This thesis is centred on the application of Ru-based complexes as a promising alternative to cis-platin in cancer chemotherapy. Cis-platin is known to be the most prescribed chemotherapy which has more than 70% application in cancer cases especially the testicular cancer. An insight is provided in Chapter One and Two into the literatures reports on the application of Ru(II)-based complexes in cancer chemotherapy. In order to address some of the pressing challenges in rational design of Ru-based anticancer complexes, section 3.3 and 3.4 deal with efforts to elucidate the complication of their chemistry and instability while in section 3.5 efforts are made to find solution to the lack of proper knowledge of their targets using different theoretical approaches as presented in Chapter Three. In addition to the theoretical study, this thesis also comprises of the synthesis of the bis-pyrazole derivatives type of ligands and the derivatives of their Ru(II)-based complexes as provided in Chapter Four and Five respectively. Also the computational methods were used to elucidate the structural and spectroscopic properties of the synthesised ligands and their Ru(II)-based complexes. The geometrical and electronic properties are studied in relation to the stability and the reported anticancer activities of Ru(II)-based complexes in section 3.3. In subsection 3.3.1, several quantum properties including the natural energy decomposition analysis (NEDA) and quantum theory of atoms in a molecule (QTAIM) are computed on three models of RAPTA-C complexes using DFT with hybrid functional and basis set with ECP and without ECP. The higher stability of Carbo-RAPTA-C and Oxalo-RAPTA-C over RAPTA-C comes from the lower exchange repulsion and higher polarization contributions to their stability which gives insight into experimental observation. A similar study was carried out in subsection 3.3.2 on half-sandwich Ru(II)-based anticancer complexes with 6-toluene and 6-trifluorotoluene.
- Full Text:
- Date Issued: 2014
Structural, optical and electrical characterization of nano-sized c-tio2 quamtum dots synthesized by spray pyrolysis
- Authors: Taziwa, Raymond Tichaona
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD (Chemistry)
- Identifier: vital:11342 , http://hdl.handle.net/10353/d1016089
- Description: In the 21st century, scientific communities face challenges and opportunities concerning future development, where innovations must be a key driver over the past, evolution of African societies were based on incomplete models, only taking into account economical growth and not paying attention to environmental deterioration as a consequence of anthropogenic activity and environmental pollution. We have to learn from our past mistakes in order not to repeat them. Education and research of today as the embryonic stages of the development models of tomorrow should be directed toward a sustainable mentality. In this sense, solar energy technologies have emerged as key instruments for minimizing environmental impact as well as reducing economic cost in the field of renewable energies. Titanium dioxide is a fascinating low cost material exhibiting unique properties of stability and photo catalytic activities, leading to clean technologies in water purification and energy conversion of sunlight. However, conventional techniques (high temperature, high vacuum, high pressures) of processing titanium dioxide are a technological limitation due to excessive energy consumption. This poses a handicap for practical applications in areas such as preparation of hybrid organic/Titanium dioxide materials or devices on thermo flexible substrates such as plastic material. It is for this reason that the investigation presented in this Ph.D thesis deals with the development of spray pyrolysis techniques for preparation of carbon doped titanium dioxide nano powders for solar cell applications. This thesis is therefore structured as follows: Chapter 1 gives a general overview of the work done in this thesis. This work relies greatly on the excellent structural optical and electrical properties of TiO2 thin films, as well as its chemical resistance and insulating properties. A summary of the physical, optical, electrical and chemical properties reported in the literature, with an emphasis on those relevant to solar cell fabrication, is presented in Chapter 2. Chapter 3 gives a concise literature review on models governing droplet formation in ultrasonic spray pyrolysis (USP) techniques, the limitations of these models have been exposed and a new relation model for estimating the final particle size given a set of initial reaction conditions has been proposed. The presently derived model is quite advantageous in that it does not require the investigator to look up values of surface tension and density for every precursor solution. Chapter 4 presents in detail the designed and constructed spray pyrolysis system capable of realizing desired nano structures for photovoltaic applications. The first system employed an ultrasonic atomization spray nozzle in order to create an aerosol of the TiO2 precursor. The reasons for choosing ultrasonic spray deposition (USP) and the TiO2 precursors, titanium iso propoxide and titanium tetra butoxide are discussed. Chapter 5 outlines experimental methodologies used in synthesis and characterization of the materials used in this study. Chapter 5 further provides experimental methodologies used in fabrication of a new type of photo electrochemical solar cells (PECs). Chapter 6 reveals the opto-electrical results of PECs solar cells fabricated. There are numerous properties that are affected by the size but emphasis will be placed on nano-size and confinement effects. Chapter 7 presents a confirmation of the phonon confinement effects in C-TiO2 QDs for the first time. In addition Chapter 7 also presents a new phonon confinement model. Chapter 8 reveals the optical, structural and electronic properties of C-TiO2 QDs synthesized by USP and PSP techniques. In addition the electrical properties of C-TiO2 QDs PEC solar cells devices are reported in Chapter 8. Concluding remarks, with potential future research projects are presented in Chapter 9. Through these 9 chapters, all research questions have been answered satisfactorily and all objectives met. Most of the work contained in this thesis has been subjected to external reviews through publication of these peer reviewed articles.
- Full Text:
- Date Issued: 2014
- Authors: Taziwa, Raymond Tichaona
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD (Chemistry)
- Identifier: vital:11342 , http://hdl.handle.net/10353/d1016089
- Description: In the 21st century, scientific communities face challenges and opportunities concerning future development, where innovations must be a key driver over the past, evolution of African societies were based on incomplete models, only taking into account economical growth and not paying attention to environmental deterioration as a consequence of anthropogenic activity and environmental pollution. We have to learn from our past mistakes in order not to repeat them. Education and research of today as the embryonic stages of the development models of tomorrow should be directed toward a sustainable mentality. In this sense, solar energy technologies have emerged as key instruments for minimizing environmental impact as well as reducing economic cost in the field of renewable energies. Titanium dioxide is a fascinating low cost material exhibiting unique properties of stability and photo catalytic activities, leading to clean technologies in water purification and energy conversion of sunlight. However, conventional techniques (high temperature, high vacuum, high pressures) of processing titanium dioxide are a technological limitation due to excessive energy consumption. This poses a handicap for practical applications in areas such as preparation of hybrid organic/Titanium dioxide materials or devices on thermo flexible substrates such as plastic material. It is for this reason that the investigation presented in this Ph.D thesis deals with the development of spray pyrolysis techniques for preparation of carbon doped titanium dioxide nano powders for solar cell applications. This thesis is therefore structured as follows: Chapter 1 gives a general overview of the work done in this thesis. This work relies greatly on the excellent structural optical and electrical properties of TiO2 thin films, as well as its chemical resistance and insulating properties. A summary of the physical, optical, electrical and chemical properties reported in the literature, with an emphasis on those relevant to solar cell fabrication, is presented in Chapter 2. Chapter 3 gives a concise literature review on models governing droplet formation in ultrasonic spray pyrolysis (USP) techniques, the limitations of these models have been exposed and a new relation model for estimating the final particle size given a set of initial reaction conditions has been proposed. The presently derived model is quite advantageous in that it does not require the investigator to look up values of surface tension and density for every precursor solution. Chapter 4 presents in detail the designed and constructed spray pyrolysis system capable of realizing desired nano structures for photovoltaic applications. The first system employed an ultrasonic atomization spray nozzle in order to create an aerosol of the TiO2 precursor. The reasons for choosing ultrasonic spray deposition (USP) and the TiO2 precursors, titanium iso propoxide and titanium tetra butoxide are discussed. Chapter 5 outlines experimental methodologies used in synthesis and characterization of the materials used in this study. Chapter 5 further provides experimental methodologies used in fabrication of a new type of photo electrochemical solar cells (PECs). Chapter 6 reveals the opto-electrical results of PECs solar cells fabricated. There are numerous properties that are affected by the size but emphasis will be placed on nano-size and confinement effects. Chapter 7 presents a confirmation of the phonon confinement effects in C-TiO2 QDs for the first time. In addition Chapter 7 also presents a new phonon confinement model. Chapter 8 reveals the optical, structural and electronic properties of C-TiO2 QDs synthesized by USP and PSP techniques. In addition the electrical properties of C-TiO2 QDs PEC solar cells devices are reported in Chapter 8. Concluding remarks, with potential future research projects are presented in Chapter 9. Through these 9 chapters, all research questions have been answered satisfactorily and all objectives met. Most of the work contained in this thesis has been subjected to external reviews through publication of these peer reviewed articles.
- Full Text:
- Date Issued: 2014
Synthesis, characterization, and biological studies of pyrazolone Schiff bases and their transition metal complexes
- Authors: Idemudia, Omoruyi Gold
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD (Chemistry)
- Identifier: vital:11340 , http://hdl.handle.net/10353/d1016068
- Description: Some new acylpyrazolone Schiff bases have been synthesized from the condensation reaction of two acylpyrazolone diketone precursors with phenylhydrazine, 2,4-dinitrophenylhydrazine and sulfanilamide. They have been fully characterized by elemental analysis and spectroscopic techniques (IR,1H and 13C NMR, and mass-spectra). The single crystal structure of the benzoyl derivative acylpyrazolone Schiff bases have been obtained and analyzed by X-ray crystallography technique. Solid state X-ray diffraction revealed a keto tautomer Schiff base in solid state. Mn(II), Co(II), Ni(II) and Cu(II) complexes with the Schiff bases have been synthesized and characterized by elemental analysis, IR and UV-VIS spectroscopy, magnetic susceptibility measurements, and thermal studies (TGA and DTG). An octahedral geometry around the transition metal ion, consisting of two bidentate Schiff base ligands bonding through the azometine nitrogen and ketonic oxygen have been proposed based on careful interpretation of available analytical and spectroscopic characterization results. Two water molecules as ligands complete the octahedral geometry in all cases. Using the invitro disc diffusion method for screening synthesized compounds against selected gram positive and gram negative bacterial at 40 mg/mL, and the DPPH free radical scavenging methods at 0.50, 0.25 and 0.13 mg/mL, the synthesized Schiff base and metal complexes showed varying biological activities. 4-benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-one sul29 fanilamide showed more activity generally, exhibiting a broad spectrum activity against all selected bacterial in some cases. Mn(II), Co(II) and Ni(II) complexes of sulfanilamide Schiff base with the acetylpyrazolone derivative 4-acetyl-3-methyl-1-phenyl-2-pyrazolin-5-one sulfanilamide, exhibited a stronger and very good DPPH radical scavenging activity as good as ascorbic acid on comparing, but not with Cu(II). As such they could be important antitumour candidates.
- Full Text:
- Date Issued: 2014
- Authors: Idemudia, Omoruyi Gold
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD (Chemistry)
- Identifier: vital:11340 , http://hdl.handle.net/10353/d1016068
- Description: Some new acylpyrazolone Schiff bases have been synthesized from the condensation reaction of two acylpyrazolone diketone precursors with phenylhydrazine, 2,4-dinitrophenylhydrazine and sulfanilamide. They have been fully characterized by elemental analysis and spectroscopic techniques (IR,1H and 13C NMR, and mass-spectra). The single crystal structure of the benzoyl derivative acylpyrazolone Schiff bases have been obtained and analyzed by X-ray crystallography technique. Solid state X-ray diffraction revealed a keto tautomer Schiff base in solid state. Mn(II), Co(II), Ni(II) and Cu(II) complexes with the Schiff bases have been synthesized and characterized by elemental analysis, IR and UV-VIS spectroscopy, magnetic susceptibility measurements, and thermal studies (TGA and DTG). An octahedral geometry around the transition metal ion, consisting of two bidentate Schiff base ligands bonding through the azometine nitrogen and ketonic oxygen have been proposed based on careful interpretation of available analytical and spectroscopic characterization results. Two water molecules as ligands complete the octahedral geometry in all cases. Using the invitro disc diffusion method for screening synthesized compounds against selected gram positive and gram negative bacterial at 40 mg/mL, and the DPPH free radical scavenging methods at 0.50, 0.25 and 0.13 mg/mL, the synthesized Schiff base and metal complexes showed varying biological activities. 4-benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-one sul29 fanilamide showed more activity generally, exhibiting a broad spectrum activity against all selected bacterial in some cases. Mn(II), Co(II) and Ni(II) complexes of sulfanilamide Schiff base with the acetylpyrazolone derivative 4-acetyl-3-methyl-1-phenyl-2-pyrazolin-5-one sulfanilamide, exhibited a stronger and very good DPPH radical scavenging activity as good as ascorbic acid on comparing, but not with Cu(II). As such they could be important antitumour candidates.
- Full Text:
- Date Issued: 2014
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