Synthesis, characterization and photophysical properties of an acenaphthalene fused-ring-expanded NIR absorbing aza-BODIPY dye
- Majumdar, Poulomi, Mack, John, Nyokong, Tebello
- Authors: Majumdar, Poulomi , Mack, John , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7283 , http://hdl.handle.net/10962/d1020328
- Description: The synthesis and characterization of an NIR absorbing acenaphthalene fused-ring-expanded aza-BODIPY dye are reported. In contrast with its naphtho-fused analogue, a stable complex is obtained when the corresponding phthalonitrile is used as the precursor. A comparison is made with the photophysical properties of 3,5-diphenyl-aza-dibenzoBODIPY. , Original publication is available at http://dx.doi.org/10.1039/C5RA14916A , Arbortext Advanced Print Publisher 9.1.510/W Unicode , Acrobat Distiller 8.1.0 (Windows); modified using iText� 5.3.3 �2000-2012 1T3XT BVBA (AGPL-version)
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- Authors: Majumdar, Poulomi , Mack, John , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7283 , http://hdl.handle.net/10962/d1020328
- Description: The synthesis and characterization of an NIR absorbing acenaphthalene fused-ring-expanded aza-BODIPY dye are reported. In contrast with its naphtho-fused analogue, a stable complex is obtained when the corresponding phthalonitrile is used as the precursor. A comparison is made with the photophysical properties of 3,5-diphenyl-aza-dibenzoBODIPY. , Original publication is available at http://dx.doi.org/10.1039/C5RA14916A , Arbortext Advanced Print Publisher 9.1.510/W Unicode , Acrobat Distiller 8.1.0 (Windows); modified using iText� 5.3.3 �2000-2012 1T3XT BVBA (AGPL-version)
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Synthesis, photophysical and nonlinear optical behavior of neodymium based trisphthalocyanine
- Sekhosana, Kutloano E, Amuhaya, Edith K, Khene, M Samson, Nyokong, Tebello
- Authors: Sekhosana, Kutloano E , Amuhaya, Edith K , Khene, M Samson , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7243 , http://hdl.handle.net/10962/d1020247
- Description: Tris-{1(4),8(11),15(18),22(25)-tetra(4-tertbutylphenoxy) phthalocyaninato} dineodymium (III) was synthesised and its nonlinear optical and fluorescence behavior was studied. Low fluorescence quantum yield (ФF = 0.03) was obtained with a fluorescence lifetime τF = 4.31 ns for this complex. Nonlinear optical parameters for the complex were determined using the Z-scan technique and the values of Im[χ(3)] and γ were of the order of 10−10 and 10−28 esu, respectively. Square wave voltammetry revealed three reduction and two oxidation couples for the complex. , Original publication is available at http://dx.doi.org/10.1016/j.ica.2014.11.029
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- Authors: Sekhosana, Kutloano E , Amuhaya, Edith K , Khene, M Samson , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7243 , http://hdl.handle.net/10962/d1020247
- Description: Tris-{1(4),8(11),15(18),22(25)-tetra(4-tertbutylphenoxy) phthalocyaninato} dineodymium (III) was synthesised and its nonlinear optical and fluorescence behavior was studied. Low fluorescence quantum yield (ФF = 0.03) was obtained with a fluorescence lifetime τF = 4.31 ns for this complex. Nonlinear optical parameters for the complex were determined using the Z-scan technique and the values of Im[χ(3)] and γ were of the order of 10−10 and 10−28 esu, respectively. Square wave voltammetry revealed three reduction and two oxidation couples for the complex. , Original publication is available at http://dx.doi.org/10.1016/j.ica.2014.11.029
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The effect of ascorbic acid on the photophysical properties and photodynamic therapy activities of zinc phthalocyanine-single walled carbon nanotube conjugate on MCF-7 cancer cells
- Ogbodu, Racheal O, Nyokong, Tebello
- Authors: Ogbodu, Racheal O , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7286 , http://hdl.handle.net/10962/d1020334
- Description: Zinc mono carboxy phenoxy phthalocyanine (1) was chemical modified with ascorbic acid via an ester bond to give ZnMCPPc-AA (2). Complexes 2 and 1 were coordinated to single walled carbon nanotubes via π–π interaction to give ZnMCPPc-AA-SWCNT (3) and ZnMCPPc-SWCNT (4) respectively. Complexes 2, 3 and 4 showed better photophysical properties: with improved triplet lifetimes and quantum yields, and singlet oxygen quantum yields when compared to 1 alone. The photodynamic therapy activities of complexes 1, 2, 3 and 4 were tested in vitro on MCF-7 breast cancer cells. Ascorbic acid suppresses the photodynamic therapy effect of 1, due to its ability to reduce oxidative DNA damage as a result of its potent reducing properties. The highest phototoxicity was observed for 4 which resulted in 77% decrease in cell viability, followed by 3 which resulted in 67% decrease in cell viability. This shows the importance of combination therapy, where the phthalocyanines are the photodynamic therapy agents and single walled carbon nanotubes are the photothermal therapy agents. , Original publication is available at http://dx.doi.org/10.1016/j.saa.2015.06.063
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- Authors: Ogbodu, Racheal O , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7286 , http://hdl.handle.net/10962/d1020334
- Description: Zinc mono carboxy phenoxy phthalocyanine (1) was chemical modified with ascorbic acid via an ester bond to give ZnMCPPc-AA (2). Complexes 2 and 1 were coordinated to single walled carbon nanotubes via π–π interaction to give ZnMCPPc-AA-SWCNT (3) and ZnMCPPc-SWCNT (4) respectively. Complexes 2, 3 and 4 showed better photophysical properties: with improved triplet lifetimes and quantum yields, and singlet oxygen quantum yields when compared to 1 alone. The photodynamic therapy activities of complexes 1, 2, 3 and 4 were tested in vitro on MCF-7 breast cancer cells. Ascorbic acid suppresses the photodynamic therapy effect of 1, due to its ability to reduce oxidative DNA damage as a result of its potent reducing properties. The highest phototoxicity was observed for 4 which resulted in 77% decrease in cell viability, followed by 3 which resulted in 67% decrease in cell viability. This shows the importance of combination therapy, where the phthalocyanines are the photodynamic therapy agents and single walled carbon nanotubes are the photothermal therapy agents. , Original publication is available at http://dx.doi.org/10.1016/j.saa.2015.06.063
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The effects of gold coated and uncoated zinc oxide nanohexagons on the photophysicochemical properties of the low symmetry zinc phthalocyanine
- D'Souza, Sarah, Ogbodu, Racheal O, Nyokong, Tebello
- Authors: D'Souza, Sarah , Ogbodu, Racheal O , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7280 , http://hdl.handle.net/10962/d1020317
- Description: A new low symmetry, Zn phthalocyanine monosubstituted with diethylaminoethanethiol (mDEAET ZnPc) was synthesized and characterized. This work reports on its photophysical and photochemical properties of mDEAET ZnPc alone and when conjugated to gold coated and uncoated zinc oxide nanohexagons (ZnO NHXs). The photophysicochemical properties generally improved in the presence of the ZnO NHXs. These complexes were also tested for their photodynamic antimicrobial activity against Staphylococcus aureus (S. aureus). The Pc alone showed remarkable growth inhibition even at concentrations as low as 0.05 mg/mL. The conjugates showed a high photoinactivation of S. aureus after 30 min at a fluence of 90 mW cm−2 at a concentration of 0.05 mg/mL. The ZnPc-ZnO NHX conjugates produced the best antimicrobial results. , Original publication is available at http://dx.doi.org/10.1016/j.molstruc.2015.06.088
- Full Text: false
- Authors: D'Souza, Sarah , Ogbodu, Racheal O , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7280 , http://hdl.handle.net/10962/d1020317
- Description: A new low symmetry, Zn phthalocyanine monosubstituted with diethylaminoethanethiol (mDEAET ZnPc) was synthesized and characterized. This work reports on its photophysical and photochemical properties of mDEAET ZnPc alone and when conjugated to gold coated and uncoated zinc oxide nanohexagons (ZnO NHXs). The photophysicochemical properties generally improved in the presence of the ZnO NHXs. These complexes were also tested for their photodynamic antimicrobial activity against Staphylococcus aureus (S. aureus). The Pc alone showed remarkable growth inhibition even at concentrations as low as 0.05 mg/mL. The conjugates showed a high photoinactivation of S. aureus after 30 min at a fluence of 90 mW cm−2 at a concentration of 0.05 mg/mL. The ZnPc-ZnO NHX conjugates produced the best antimicrobial results. , Original publication is available at http://dx.doi.org/10.1016/j.molstruc.2015.06.088
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The nonlinear absorption in new lanthanide double decker pyridine-based phthalocyanines in solution and thin films
- Sekhosana, Kutloano Edward, Nyokong, Tebello
- Authors: Sekhosana, Kutloano Edward , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7299 , http://hdl.handle.net/10962/d1020366
- Description: The optical behavior of bis-{2(3), 9(10), 16(17), 23(24)-(tetrapyridin-4-yloxy phthalocyaninato)} lanthanum (III) (2) and its ytterbium (3) counterpart in dimethyl sulfoxide are presented and compared to bis-{1(4), 8(11), 15(18), 22(25)-(tetrapyridin-4-yloxy phthalocyaninato)} ytterbium (III) (4). We report on the third-order susceptibility, second-order hyperpolarizability and the limiting threshold values. The nonlinear optical limiting threshold values of complexes 2, 3 and 4 showed improvement in the solid state (thin films), with complex 4 giving the best value at 0.033 J cm−2. , Original publication is available at http://dx.doi.org/10.1016/j.optmat.2015.05.022
- Full Text: false
- Authors: Sekhosana, Kutloano Edward , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7299 , http://hdl.handle.net/10962/d1020366
- Description: The optical behavior of bis-{2(3), 9(10), 16(17), 23(24)-(tetrapyridin-4-yloxy phthalocyaninato)} lanthanum (III) (2) and its ytterbium (3) counterpart in dimethyl sulfoxide are presented and compared to bis-{1(4), 8(11), 15(18), 22(25)-(tetrapyridin-4-yloxy phthalocyaninato)} ytterbium (III) (4). We report on the third-order susceptibility, second-order hyperpolarizability and the limiting threshold values. The nonlinear optical limiting threshold values of complexes 2, 3 and 4 showed improvement in the solid state (thin films), with complex 4 giving the best value at 0.033 J cm−2. , Original publication is available at http://dx.doi.org/10.1016/j.optmat.2015.05.022
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The Photophysical Properties of Multi-Functional Quantum Dots-Magnetic Nanoparticles—Indium Octacarboxyphthalocyanine Nanocomposite
- Tshangana, Charmaine, Nyokong, Tebello
- Authors: Tshangana, Charmaine , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7248 , http://hdl.handle.net/10962/d1020254
- Description: This work presents the development of a multifunctional hybrid nanoparticle made of L-glutathione capped quantum dots (GSH-CdSe@ZnS), amino functionalized Fe3O4 magnetic nanoparticles and indium octacarboxy phthalocyanine (ClInPc(COOH)8). In this work we investigate the photophysical properties of the individual components and the hybrid nanoparticle, in addition we study the energy transfer (Förster Resonance Energy Transfer (FRET)) in the complex. FRET efficiencies of ~48 % were obtained for energy transfer between the QDs (when alone or linked to MNPs). Both triplet yields and lifetimes of ClInPc(COOH)8 increase in the nanocomposite, with a decrease in fluorescence lifetime. The hybrid nanoparticle showed improved photophysical properties and as a result can be used in photodynamic therapy. , Original publication is available at http://dx.doi.org/10.1007/s10895-014-1497-6
- Full Text: false
- Authors: Tshangana, Charmaine , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7248 , http://hdl.handle.net/10962/d1020254
- Description: This work presents the development of a multifunctional hybrid nanoparticle made of L-glutathione capped quantum dots (GSH-CdSe@ZnS), amino functionalized Fe3O4 magnetic nanoparticles and indium octacarboxy phthalocyanine (ClInPc(COOH)8). In this work we investigate the photophysical properties of the individual components and the hybrid nanoparticle, in addition we study the energy transfer (Förster Resonance Energy Transfer (FRET)) in the complex. FRET efficiencies of ~48 % were obtained for energy transfer between the QDs (when alone or linked to MNPs). Both triplet yields and lifetimes of ClInPc(COOH)8 increase in the nanocomposite, with a decrease in fluorescence lifetime. The hybrid nanoparticle showed improved photophysical properties and as a result can be used in photodynamic therapy. , Original publication is available at http://dx.doi.org/10.1007/s10895-014-1497-6
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Utilising new technology to enable sustainable chemical and drug manufacturing in Africa
- Authors: Watts, Paul
- Subjects: Drug development , Pharmacology , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/21000 , vital:29426
- Description: Over the last few decades organic chemists have developed highly sophisticated chemical reactions to prepare very complex molecules. The pharmaceutical industry uses the methodology that academics develop within research programmes to manufacture drugs to treat a plethora of medical conditions. When unwell, all citizens expect treatment, however it needs to be remembered that the pharmaceutical industry is a business in order to make a profit for its shareholders, and consequently only rich nations can afford access to the most modern treatments available.
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- Authors: Watts, Paul
- Subjects: Drug development , Pharmacology , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/21000 , vital:29426
- Description: Over the last few decades organic chemists have developed highly sophisticated chemical reactions to prepare very complex molecules. The pharmaceutical industry uses the methodology that academics develop within research programmes to manufacture drugs to treat a plethora of medical conditions. When unwell, all citizens expect treatment, however it needs to be remembered that the pharmaceutical industry is a business in order to make a profit for its shareholders, and consequently only rich nations can afford access to the most modern treatments available.
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