- Title
- Ruthenium (II) complexes of mixed bipyridyl and dithiolate/thiourea ligands :|bsynthesis, characterization, photophysical and electrochemical studies
- Creator
- Nkombi, Pelokazi
- Subject
- Ruthenium Ruthenium compounds Ligands
- Date
- 2018
- Type
- Thesis
- Type
- Masters
- Type
- MSc
- Identifier
- http://hdl.handle.net/10353/10134
- Identifier
- vital:35358
- Description
- Energy is one of the most important factor to influence human lives. The increased in energy demand as well as the detrimental effects posed by emission of greenhouse gases due to continue use of fossil fuels for electricity generation has led to a renewed focus on energy production using renewable energy sources which are relatively cheap, clean and environmentally sustainable. Among the various renewable energy sources used so far, the Dye Synthesized Solar Cells (DSSCs), a form of photovoltaic device is reported for their better efficiencies despite their low cost of production and ability to work relatively under low light conditions. A recent report on the solar-to-electricity conversion efficiency of a typical DSSC sensitizer made from zinc based porphyrin dye coupled with sintered titanium(IV) oxide as semiconductor was 13 percent. In this study, 2,2-bipyridyl-4,4-dicarboxylic acid (bpydc) was used as mixed ligand and four dithiolate ligands; L1 = dipotassium ethoxycarbonyl-1-cyanoethylene-2,2-dithiolate, L2 = dipotassium bis(ethoxycarbonyl)ethane-2,2-dithiolate, L3 = dipotassium cyanodithio imidocarbonate and L4 = dipotassium 2,2-dicyanoethylene-2,2-dithiolate were synthesized while four alkyl thiourea ligands, L5 = 1,3-dimethyl thiourea, L6 = 1,3-diethyl thiourea, L7 = 1,3-diisopropyl thiourea and L8 = 1-methyl thiourea were purchased and used as supplied without further purification. These ligands were used to prepare eight ruthenium(II) complexes of mixed bipyridyl/dithiolate/thiourea. The compounds were characterised by elemental analysis and spectroscopic techniques, namely: Fourier transform infrared (FTIR), Nuclear Magnetic Resonance (NMR), ultraviolet-visible and photoluminescence (PL). Cyclic voltammetry (CV) and square wave voltammetry (SWV) were used for the electrochemical studies. Photoluminescence and UV-Vis spectroscopies were used for geometric and photophysical studies of the complexes respectively. FTIR spectra confirmed presence of functional groups in ligands and coordination of these ligands to ruthenium(II) ions to form complexes. The UV-Vis confirmed that the Ru(II) dithiolene complexes exhibited square planar geometries while the Ru(II) thiourea complexes gave octahedral geometries, this was deduced from the transitions assigned to the complexes. All the ruthenium(II) complexes synthesized showed photoluminescence properties that are suitable for light harvesting and application for dye-sensitized solar cells. Cyclic and square wave voltammetry show Ru(II) thiourea complexes have better redox properties when compared to Ru(II) dithiolate complexes which is ascribed to ligand strength field possibly due to contribution from the two bonded NCS groups.
- Format
- 118 leaves
- Format
- Publisher
- University of Fort Hare
- Publisher
- Faculty of Science and Agriculture
- Language
- English
- Rights
- University of Fort Hare
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UFH Department of Chemistry
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