Synthesis, characterization and biological evaluation of xanthate metal complexes
- Authors: Casa, Sandisiwe
- Date: 2014-01
- Subjects: Metal complexes , Ligands
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24250 , vital:62594
- Description: Ni(II), Ag(I), Cu(II), Pd(II) and Pt(II) complexes of xanthate were synthesized and characterized by elemental analysis, UV‒Vis, FTIR, conductivity measurements, decomposition temperatures, and Pd(II), Pt(II) complexes and the xanthate ligands were further characterized by 1H-NMR spectroscopy. Conductivity measurements displayed that the complexes are non‒electrolytes in solution with conductivity values in the range 0.05 ‒ 18.30 μS. Generally all the xanthate ligands are soluble in water and the complexes are insoluble both in non-polar solvents except polar coordinating solvents such as DMSO and DMF. The xanthate complexes are formulated as four coordinate (tetrahedral or square planar), and six coordinate (octahedral) compounds. However, in each of the complexes xanthate acted as bidentate ligand through the two sulfur atoms. The geometries around the metal ions are completed by triphenylphosphine. The ligands and complexes were screened against two bacterial isolates to determine their antibacterial activities. Antibacterial activity of the synthesized metal complexes shows a generally increased activity in comparison with that of their respective free ligands. At a lower concentration some of the complexes did not show any activity, a good number of complexes however showed activity at a higher concentration of 40 mg/ml. The degree of activity varies with metals. Silver complex have been observed to show the highest activity of MIC value of 1.25 mg/mL with regards to antibacterial strength, although it varies with different ligands. , Thesis (MSc) -- Faculty of Science and Agriculture, 2014
- Full Text:
- Date Issued: 2014-01
- Authors: Casa, Sandisiwe
- Date: 2014-01
- Subjects: Metal complexes , Ligands
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24250 , vital:62594
- Description: Ni(II), Ag(I), Cu(II), Pd(II) and Pt(II) complexes of xanthate were synthesized and characterized by elemental analysis, UV‒Vis, FTIR, conductivity measurements, decomposition temperatures, and Pd(II), Pt(II) complexes and the xanthate ligands were further characterized by 1H-NMR spectroscopy. Conductivity measurements displayed that the complexes are non‒electrolytes in solution with conductivity values in the range 0.05 ‒ 18.30 μS. Generally all the xanthate ligands are soluble in water and the complexes are insoluble both in non-polar solvents except polar coordinating solvents such as DMSO and DMF. The xanthate complexes are formulated as four coordinate (tetrahedral or square planar), and six coordinate (octahedral) compounds. However, in each of the complexes xanthate acted as bidentate ligand through the two sulfur atoms. The geometries around the metal ions are completed by triphenylphosphine. The ligands and complexes were screened against two bacterial isolates to determine their antibacterial activities. Antibacterial activity of the synthesized metal complexes shows a generally increased activity in comparison with that of their respective free ligands. At a lower concentration some of the complexes did not show any activity, a good number of complexes however showed activity at a higher concentration of 40 mg/ml. The degree of activity varies with metals. Silver complex have been observed to show the highest activity of MIC value of 1.25 mg/mL with regards to antibacterial strength, although it varies with different ligands. , Thesis (MSc) -- Faculty of Science and Agriculture, 2014
- Full Text:
- Date Issued: 2014-01
Group 12 metal chalcogenides as single source molecular precursors for the preparation of metal sulfide nanoparticles
- Osuntokun, Jejenija https://orcid.org/0000-0003-0886-2732
- Authors: Osuntokun, Jejenija https://orcid.org/0000-0003-0886-2732
- Date: 2013-01
- Subjects: Ligands , Chalcogenides , Chemistry, Inorganic
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27428 , vital:67295
- Description: Twelve Zn(II), Cd(II) and Hg(II) complexes of mixed ligands: alkyl thiourea, 1-ethoxylcarbonyl-1-cyanoethylene-2,2-dithiolate and tetramethylthiuram disulfide were synthesized by the reaction between the ligands and the respective metal salts. The compounds were characterized by elemental analysis, infrared (IR), 1H- and 13C-NMR spectroscopy. Four coordinate geometries were proposed for the compounds based on elemental and spectroscopic analyses. The metal complexes were at best sparingly soluble in polar coordinating solvents such as DMSO and DMF and insoluble in most organic solvents. This makes it practically impossible to grow single crystals suitable for X-ray crystallographic analysis and also resulted in extremely poor 13C-NMR spectra for some of the complexes. Thermogravimetric analysis on some of the complexes showed that they decomposed to their respective metal sulfides and thus suitable as single molecular precursors for the preparation of metal sulfide nanoparticles. Nine of the complexes with good yield were thermolysed and used as single source precursors to synthesized hexadexylamine capped metal sulfide nanoparticles. The optical and structural properties of the nanoparticles were studied using UV-Visible, photoluminescence (PL), scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD) and energy dispersive spectroscopy (EDX). The absorption and emission spectra of the nanoparticles show quantum confinement. The SEM showed the morphology of the particles as nearly spherical, the EDX spectra revealed peaks corresponding to respective metal and sulfur with traces of contaminants being phosphorus from tri-n-octylphosphine (TOP). , Thesis (MSc) -- Faculty of Science and Agriculture, 2013
- Full Text:
- Date Issued: 2013-01
- Authors: Osuntokun, Jejenija https://orcid.org/0000-0003-0886-2732
- Date: 2013-01
- Subjects: Ligands , Chalcogenides , Chemistry, Inorganic
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27428 , vital:67295
- Description: Twelve Zn(II), Cd(II) and Hg(II) complexes of mixed ligands: alkyl thiourea, 1-ethoxylcarbonyl-1-cyanoethylene-2,2-dithiolate and tetramethylthiuram disulfide were synthesized by the reaction between the ligands and the respective metal salts. The compounds were characterized by elemental analysis, infrared (IR), 1H- and 13C-NMR spectroscopy. Four coordinate geometries were proposed for the compounds based on elemental and spectroscopic analyses. The metal complexes were at best sparingly soluble in polar coordinating solvents such as DMSO and DMF and insoluble in most organic solvents. This makes it practically impossible to grow single crystals suitable for X-ray crystallographic analysis and also resulted in extremely poor 13C-NMR spectra for some of the complexes. Thermogravimetric analysis on some of the complexes showed that they decomposed to their respective metal sulfides and thus suitable as single molecular precursors for the preparation of metal sulfide nanoparticles. Nine of the complexes with good yield were thermolysed and used as single source precursors to synthesized hexadexylamine capped metal sulfide nanoparticles. The optical and structural properties of the nanoparticles were studied using UV-Visible, photoluminescence (PL), scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD) and energy dispersive spectroscopy (EDX). The absorption and emission spectra of the nanoparticles show quantum confinement. The SEM showed the morphology of the particles as nearly spherical, the EDX spectra revealed peaks corresponding to respective metal and sulfur with traces of contaminants being phosphorus from tri-n-octylphosphine (TOP). , Thesis (MSc) -- Faculty of Science and Agriculture, 2013
- Full Text:
- Date Issued: 2013-01
Synthesis, characterization and antibacterial studies of metal complexes of substituted thiourea
- Authors: Zulu, Happy Nonkululeko
- Date: 2012-03
- Subjects: Complex compounds , Halides , Ligands
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24327 , vital:62636
- Description: Eighteen complexes Co(II), Cu(II), Zn(II), and Fe(III) with phenylthiourea, diethylthiourea, disopropylthiourea and dimethylthiourea were synthesized and characterized by elemental analysis, UV-Vis, FTIR, conductivity measurements. The complexes were formulated as either four coordinate for the metal(II) or six coordinate for Fe(III). The proposed formulations are consistent with the spectroscopic data for the complexes. The single crystal X-ray structure of the Zn(II) complex of phenylthiourea, Co(II) complex of diethylthiourea and Zn(II) complex of diisopropylthiourea are also reported. The X-ray crystal structures for these complexes revealed distorted tetrahedral geometry around the metal ions showed that the metal ions are coordinated to two molecules of the substituted thiourea through the sulphur atom and two either acetates or chlorides ions complete the four-coordinate geometry. The in vitro antibacterial activity of the complexes was studied against six bacterial strains using disc diffusion and broth micro-dilution methods. The complexes showed selective antibacterial activity. , Thesis (MSc) -- Faculty of Science and Agriculture, 2012
- Full Text:
- Date Issued: 2012-03
- Authors: Zulu, Happy Nonkululeko
- Date: 2012-03
- Subjects: Complex compounds , Halides , Ligands
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24327 , vital:62636
- Description: Eighteen complexes Co(II), Cu(II), Zn(II), and Fe(III) with phenylthiourea, diethylthiourea, disopropylthiourea and dimethylthiourea were synthesized and characterized by elemental analysis, UV-Vis, FTIR, conductivity measurements. The complexes were formulated as either four coordinate for the metal(II) or six coordinate for Fe(III). The proposed formulations are consistent with the spectroscopic data for the complexes. The single crystal X-ray structure of the Zn(II) complex of phenylthiourea, Co(II) complex of diethylthiourea and Zn(II) complex of diisopropylthiourea are also reported. The X-ray crystal structures for these complexes revealed distorted tetrahedral geometry around the metal ions showed that the metal ions are coordinated to two molecules of the substituted thiourea through the sulphur atom and two either acetates or chlorides ions complete the four-coordinate geometry. The in vitro antibacterial activity of the complexes was studied against six bacterial strains using disc diffusion and broth micro-dilution methods. The complexes showed selective antibacterial activity. , Thesis (MSc) -- Faculty of Science and Agriculture, 2012
- Full Text:
- Date Issued: 2012-03
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