The development of catalytic oxovanadium(IV)-containing microspheres for the oxidation of various organosulfur compounds
- Ogunlaja, Adeniyi S, Khene, M Samson, Antunes, Edith M, Nyokong, Tebello, Torto, Nelson, Tshentu, Zenixole R
- Authors: Ogunlaja, Adeniyi S , Khene, M Samson , Antunes, Edith M , Nyokong, Tebello , Torto, Nelson , Tshentu, Zenixole R
- Language: English
- Type: Article
- Identifier: vital:7324 , http://hdl.handle.net/10962/d1020574
- Description: The development of poly[allylSB-co-EGDMA] beads containing a tetradentate ligand was achieved via suspension polymerization. The catalyst poly[allylSB-co-EGDMA]-VO was synthesized by reacting VIVOSO4 with poly[allylSB-co-EGDMA]. XPS and EPR were used to confirm the presence of vanadium (V4+) on the beads. The synthesized catalyst (poly[allylSB-co-EGDMA]-VO) was found to have a BET surface area of 22 m2 g−1 and porosity of 135 Å, with the atomic force microscopy (AFM) showing more insight on the porous nature of the beads. Oxidation of thiophene (TH), benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) was carried out using tert-butyl hydroperoxide (t-BuOOH) as oxidant. An overall conversion of 60%, 82%, 98% and 87% was achieved for thiophene (TH), benzothiophene (BT), dibenzothiophene (DBT) and 4,6 dimethyldibenzothiophene (4,6-DMDBT) respectively at higher (t-BuOOH) to substrate ratio and at a temperature of 40 °C. The efficient oxidation of the various organosulfur compounds presents potential for the possible application of this catalyst in oxidative desulfurization (ODS) of crude oil. , Original publication is available at http://dx.doi.org/10.1016/j.apcata.2013.05.004
- Full Text: false
- Authors: Ogunlaja, Adeniyi S , Khene, M Samson , Antunes, Edith M , Nyokong, Tebello , Torto, Nelson , Tshentu, Zenixole R
- Language: English
- Type: Article
- Identifier: vital:7324 , http://hdl.handle.net/10962/d1020574
- Description: The development of poly[allylSB-co-EGDMA] beads containing a tetradentate ligand was achieved via suspension polymerization. The catalyst poly[allylSB-co-EGDMA]-VO was synthesized by reacting VIVOSO4 with poly[allylSB-co-EGDMA]. XPS and EPR were used to confirm the presence of vanadium (V4+) on the beads. The synthesized catalyst (poly[allylSB-co-EGDMA]-VO) was found to have a BET surface area of 22 m2 g−1 and porosity of 135 Å, with the atomic force microscopy (AFM) showing more insight on the porous nature of the beads. Oxidation of thiophene (TH), benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) was carried out using tert-butyl hydroperoxide (t-BuOOH) as oxidant. An overall conversion of 60%, 82%, 98% and 87% was achieved for thiophene (TH), benzothiophene (BT), dibenzothiophene (DBT) and 4,6 dimethyldibenzothiophene (4,6-DMDBT) respectively at higher (t-BuOOH) to substrate ratio and at a temperature of 40 °C. The efficient oxidation of the various organosulfur compounds presents potential for the possible application of this catalyst in oxidative desulfurization (ODS) of crude oil. , Original publication is available at http://dx.doi.org/10.1016/j.apcata.2013.05.004
- Full Text: false
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
- Full Text: false
- 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
- Full Text: false
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
- Full Text: false
The FAWU Research Unit
- Food and Allied Workers' Union
- Authors: Food and Allied Workers' Union
- Subjects: Uncatalogued
- Language: English
- Type: text , pamphlet
- Identifier: http://hdl.handle.net/10962/106408 , vital:32649
- Description: The FAWU research unit has been operating in the Head Office since 1998. It has established a resource centre and has two people working in it at this time - Thandi Yoli and Viva Mtai. The unit was jointly conceived in 1996/97 by FAWU and the Labour Research Service (LRS). The relationship between the two organisations continues presently, and will last until the research unit is properly established and resourced within FAWU's head office. The LRS successfully applied for funding for the project in 1996/97 from the FNV-Holland. This money goes to paying the salaries and overhead costs incurred by the LRS for providing a senior researcher (Reza Daniels) to supervise and establish the research unit in FAWU. It is a three-year project and we are currently in the third year of the project. We are, however, going to apply for an extension of the project (to the FNV-Holland) so that it is completed by the end of the year 2000. The original aim of the project in 1996 was to assist FAWU to increase its bargaining capacity by developing a research unit that was targeted to producing sectoral reports that could assist the bargaining department. It was felt that FAWU lacked the research capacity to fully support its bargaining structures because of several factors.
- Full Text:
- Authors: Food and Allied Workers' Union
- Subjects: Uncatalogued
- Language: English
- Type: text , pamphlet
- Identifier: http://hdl.handle.net/10962/106408 , vital:32649
- Description: The FAWU research unit has been operating in the Head Office since 1998. It has established a resource centre and has two people working in it at this time - Thandi Yoli and Viva Mtai. The unit was jointly conceived in 1996/97 by FAWU and the Labour Research Service (LRS). The relationship between the two organisations continues presently, and will last until the research unit is properly established and resourced within FAWU's head office. The LRS successfully applied for funding for the project in 1996/97 from the FNV-Holland. This money goes to paying the salaries and overhead costs incurred by the LRS for providing a senior researcher (Reza Daniels) to supervise and establish the research unit in FAWU. It is a three-year project and we are currently in the third year of the project. We are, however, going to apply for an extension of the project (to the FNV-Holland) so that it is completed by the end of the year 2000. The original aim of the project in 1996 was to assist FAWU to increase its bargaining capacity by developing a research unit that was targeted to producing sectoral reports that could assist the bargaining department. It was felt that FAWU lacked the research capacity to fully support its bargaining structures because of several factors.
- Full Text:
The ICU
- Industrial and Commercial Union (I.C.U.)
- Authors: Industrial and Commercial Union (I.C.U.)
- Subjects: I.C.U
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/250706 , vital:52041
- Description: Black people live and work in very poor conditions in South Africa. They have always protested and resisted this. But at the beginning of this century, these protests were limited to a few groups of workers at any one time. There was no organisation for black workers. Then, soon after the First World War ended, a new movement appeared. It spread through the land like a veld fire. The people began to talk of their liberation, their new leaders and their organisation - the Industrial and Commercial Union (the I.C.U.). As a farm labourer from Standerton said:"Man we thought we were getting our country back through Kadalie."
- Full Text:
- Authors: Industrial and Commercial Union (I.C.U.)
- Subjects: I.C.U
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/250706 , vital:52041
- Description: Black people live and work in very poor conditions in South Africa. They have always protested and resisted this. But at the beginning of this century, these protests were limited to a few groups of workers at any one time. There was no organisation for black workers. Then, soon after the First World War ended, a new movement appeared. It spread through the land like a veld fire. The people began to talk of their liberation, their new leaders and their organisation - the Industrial and Commercial Union (the I.C.U.). As a farm labourer from Standerton said:"Man we thought we were getting our country back through Kadalie."
- Full Text:
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
- Full Text: false
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
- Full Text: false
The teacher as manager of resources
- Authors: Henderson, Derek Scott
- Language: English
- Type: Text
- Identifier: vital:7343 , http://hdl.handle.net/10962/d1017072
- Full Text:
- Authors: Henderson, Derek Scott
- Language: English
- Type: Text
- Identifier: vital:7343 , http://hdl.handle.net/10962/d1017072
- Full Text:
The University - concept and reality
- Authors: Henderson, Derek Scott
- Language: English
- Type: Text
- Identifier: vital:7346 , http://hdl.handle.net/10962/d1017075
- Full Text:
- Authors: Henderson, Derek Scott
- Language: English
- Type: Text
- Identifier: vital:7346 , http://hdl.handle.net/10962/d1017075
- Full Text:
The use of phthalocyanines in cancer therapy
- Nyokong, Tebello, Gledhill, Igle
- Authors: Nyokong, Tebello , Gledhill, Igle
- Language: English
- Type: Article
- Identifier: vital:7323 , http://hdl.handle.net/10962/d1020572
- Description: Phthalocyanines are synthetic analogues of porphyrins employed as photosensitizers in cancer therapy. We present the history of photodynamic therapy and developments in the use of phthalocyanines as photosensitizers. New efforts in the development of more cancer-specific phthalocyanines are presented. The combination of phthalocyanines with nanoparticles for "combination therapy" of cancer is also discussed. The nanoparticles employed are quantum dots, gold, and magnetic nanoparticles. , Original publication is available at http://dx.doi.org/10.10631.4794220
- Full Text: false
- Authors: Nyokong, Tebello , Gledhill, Igle
- Language: English
- Type: Article
- Identifier: vital:7323 , http://hdl.handle.net/10962/d1020572
- Description: Phthalocyanines are synthetic analogues of porphyrins employed as photosensitizers in cancer therapy. We present the history of photodynamic therapy and developments in the use of phthalocyanines as photosensitizers. New efforts in the development of more cancer-specific phthalocyanines are presented. The combination of phthalocyanines with nanoparticles for "combination therapy" of cancer is also discussed. The nanoparticles employed are quantum dots, gold, and magnetic nanoparticles. , Original publication is available at http://dx.doi.org/10.10631.4794220
- Full Text: false
The V-C's Awards
- Language: English
- Type: Article
- Identifier: vital:7170 , http://hdl.handle.net/10962/d1006074
- Description: Prof Tebello Nyokong, from the Department of Chemistry, receives the V-C' s Senior Distinguished Research Award in 2003 and 2004
- Full Text:
- Language: English
- Type: Article
- Identifier: vital:7170 , http://hdl.handle.net/10962/d1006074
- Description: Prof Tebello Nyokong, from the Department of Chemistry, receives the V-C' s Senior Distinguished Research Award in 2003 and 2004
- Full Text:
Toast to honorary graduates 1979
- Authors: Henderson, Derek Scott
- Language: English
- Type: Text
- Identifier: vital:7398 , http://hdl.handle.net/10962/d1017287
- Full Text:
- Authors: Henderson, Derek Scott
- Language: English
- Type: Text
- Identifier: vital:7398 , http://hdl.handle.net/10962/d1017287
- Full Text:
Toast to honorary graduates at luncheon, Graduation 1978
- Authors: Henderson, Derek Scott
- Language: English
- Type: Text
- Identifier: vital:7366 , http://hdl.handle.net/10962/d1017246
- Full Text:
- Authors: Henderson, Derek Scott
- Language: English
- Type: Text
- Identifier: vital:7366 , http://hdl.handle.net/10962/d1017246
- Full Text:
Toast to honorary graduates at luncheon, graduation 1979
- Authors: Henderson, Derek Scott
- Language: English
- Type: Text
- Identifier: vital:7397 , http://hdl.handle.net/10962/d1017286
- Full Text:
- Authors: Henderson, Derek Scott
- Language: English
- Type: Text
- Identifier: vital:7397 , http://hdl.handle.net/10962/d1017286
- Full Text:
Top accolade for Rhodes scientist
- Mkentane, Luyolo, Holmes, Mike
- Authors: Mkentane, Luyolo , Holmes, Mike
- Language: English
- Type: Article
- Identifier: vital:7214 , http://hdl.handle.net/10962/d1006425
- Description: A RHODES University research professor who is championing ground-breaking research into a new cancer diagnosIs and treatment methodology has received a prestigious award after being nominated one of 10 Women of Excellence in South Africa.
- Full Text:
- Authors: Mkentane, Luyolo , Holmes, Mike
- Language: English
- Type: Article
- Identifier: vital:7214 , http://hdl.handle.net/10962/d1006425
- Description: A RHODES University research professor who is championing ground-breaking research into a new cancer diagnosIs and treatment methodology has received a prestigious award after being nominated one of 10 Women of Excellence in South Africa.
- Full Text:
Top UN award for leading scientist
- National Research Foundation (NRF)
- Authors: National Research Foundation (NRF)
- Language: English
- Type: Article
- Identifier: vital:7193 , http://hdl.handle.net/10962/d1006357
- Description: Professor Tebello Nyokong holds the DST/NRF funded chair in Medicinal Chemistry and Nanotechnology at Rhodes University
- Full Text:
- Authors: National Research Foundation (NRF)
- Language: English
- Type: Article
- Identifier: vital:7193 , http://hdl.handle.net/10962/d1006357
- Description: Professor Tebello Nyokong holds the DST/NRF funded chair in Medicinal Chemistry and Nanotechnology at Rhodes University
- Full Text:
Tuning the physico-electrochemical properties of novel cobalt (II) octa[(3,5-biscarboxylate)-phenoxy] phthalocyanine complex using phenylamine-functionalised SWCNTs
- Agboola, Bolade Oyeyinka, Ozoemena, Kenneth I., Nyokong, Tebello, Fukuda, Takamitsu, Kobayashi, Nagao
- Authors: Agboola, Bolade Oyeyinka , Ozoemena, Kenneth I. , Nyokong, Tebello , Fukuda, Takamitsu , Kobayashi, Nagao
- Language: English
- Type: Article
- Identifier: vital:7238 , http://hdl.handle.net/10962/d1019689
- Description: The integration of phenylamine-functionalised SWCNTs (SWCNT-phenylamine) with a novel cobalt (II) octa[(3,5-biscarboxylate)-phenoxy] phthalocyanine (CoOBPPc) complex has been described. The physical and electrochemical properties of the CoOBPPc-SWCNT-phenylamine hybrid were evaluated using spectroscopy (IR and UV–vis), field emission scanning electron microscopy and electrochemistry (cyclic voltammetry and electrochemical impedance spectroscopy). Integration of SWCNT-phenylamine resulted in the physical transformation of the CoOBCPPc from the usually bluish colour of cobalt phthalocyanine complexes to a beautiful bright green colour. In addition, the heterogeneous electron transfer kinetics and electrocatalytic properties of the CoOBCPPc were greatly enhanced following the attachment of the SWCNT-phenylamine. The potential electrocatalytic application of the hybrid was tested using β-nicotinamide adenine dinucleotide (NADH) as a model biological analyte. Interestingly, the onset oxidation potential of this analyte was significantly reduced (300 mV) by this hybrid compared to the bare electrode. , Original publication is available at http://dx.doi.org/doi:10.1016/j.carbon.2009.10.023
- Full Text: false
- Authors: Agboola, Bolade Oyeyinka , Ozoemena, Kenneth I. , Nyokong, Tebello , Fukuda, Takamitsu , Kobayashi, Nagao
- Language: English
- Type: Article
- Identifier: vital:7238 , http://hdl.handle.net/10962/d1019689
- Description: The integration of phenylamine-functionalised SWCNTs (SWCNT-phenylamine) with a novel cobalt (II) octa[(3,5-biscarboxylate)-phenoxy] phthalocyanine (CoOBPPc) complex has been described. The physical and electrochemical properties of the CoOBPPc-SWCNT-phenylamine hybrid were evaluated using spectroscopy (IR and UV–vis), field emission scanning electron microscopy and electrochemistry (cyclic voltammetry and electrochemical impedance spectroscopy). Integration of SWCNT-phenylamine resulted in the physical transformation of the CoOBCPPc from the usually bluish colour of cobalt phthalocyanine complexes to a beautiful bright green colour. In addition, the heterogeneous electron transfer kinetics and electrocatalytic properties of the CoOBCPPc were greatly enhanced following the attachment of the SWCNT-phenylamine. The potential electrocatalytic application of the hybrid was tested using β-nicotinamide adenine dinucleotide (NADH) as a model biological analyte. Interestingly, the onset oxidation potential of this analyte was significantly reduced (300 mV) by this hybrid compared to the bare electrode. , Original publication is available at http://dx.doi.org/doi:10.1016/j.carbon.2009.10.023
- Full Text: false
Ultrafast Photodynamics of the Indoline Dye D149 Adsorbed to Porous ZnO in Dye-Sensitized Solar Cells
- Rohwer, Egmont, Richter, Christoph, Heming, Nadine, Strauch, Kerstin, Litwinski, Christian, Nyokong, Tebello, Schlettwein, Derck, Schwoerer, Heinrich
- Authors: Rohwer, Egmont , Richter, Christoph , Heming, Nadine , Strauch, Kerstin , Litwinski, Christian , Nyokong, Tebello , Schlettwein, Derck , Schwoerer, Heinrich
- Language: English
- Type: Article
- Identifier: vital:7326 , http://hdl.handle.net/10962/d1020576
- Description: We investigate the ultrafast dynamics of the photoinduced electron transfer between surface-adsorbed indoline D149 dye and porous ZnO as used in the working electrodes of dye-sensitized solar cells. Transient absorption spectroscopy was conducted on the dye in solution, on solid state samples and for the latter in contact to a I−/I3− redox electrolyte typical for dye-sensitized solar cells to elucidate the effect of each component in the observed dynamics. D149 in a solution of 1:1 acetonitrile and tert-butyl alcohol shows excited-state lifetimes of 300±50 ps. This signature is severely quenched when D149 is adsorbed to ZnO, with the fastest component of the decay trace measured at 150±20 fs due to the charge-transfer mechanism. Absorption bands of the oxidized dye molecule were investigated to determine regeneration times which are in excess of 1 ns. The addition of the redox electrolyte to the system results in faster regeneration times, of the order of 1 ns. , Original publication is available at http://dx.doi.org/10.1002/cphc.201200715
- Full Text: false
- Authors: Rohwer, Egmont , Richter, Christoph , Heming, Nadine , Strauch, Kerstin , Litwinski, Christian , Nyokong, Tebello , Schlettwein, Derck , Schwoerer, Heinrich
- Language: English
- Type: Article
- Identifier: vital:7326 , http://hdl.handle.net/10962/d1020576
- Description: We investigate the ultrafast dynamics of the photoinduced electron transfer between surface-adsorbed indoline D149 dye and porous ZnO as used in the working electrodes of dye-sensitized solar cells. Transient absorption spectroscopy was conducted on the dye in solution, on solid state samples and for the latter in contact to a I−/I3− redox electrolyte typical for dye-sensitized solar cells to elucidate the effect of each component in the observed dynamics. D149 in a solution of 1:1 acetonitrile and tert-butyl alcohol shows excited-state lifetimes of 300±50 ps. This signature is severely quenched when D149 is adsorbed to ZnO, with the fastest component of the decay trace measured at 150±20 fs due to the charge-transfer mechanism. Absorption bands of the oxidized dye molecule were investigated to determine regeneration times which are in excess of 1 ns. The addition of the redox electrolyte to the system results in faster regeneration times, of the order of 1 ns. , Original publication is available at http://dx.doi.org/10.1002/cphc.201200715
- Full Text: false
Unemployment Insurance Fund
- UIF
- Authors: UIF
- Subjects: UIF
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/160982 , vital:40574
- Description: U.I.F. (Unemployment Insurance Fund) is an insurance scheme. The scheme pays money to a worker who has contributed to the fund and who is temporarily unemployed. Money paid into the Fund is paid out to workers who have become unemployed and under certain other circumstances that we will set out below.
- Full Text:
- Authors: UIF
- Subjects: UIF
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/160982 , vital:40574
- Description: U.I.F. (Unemployment Insurance Fund) is an insurance scheme. The scheme pays money to a worker who has contributed to the fund and who is temporarily unemployed. Money paid into the Fund is paid out to workers who have become unemployed and under certain other circumstances that we will set out below.
- Full Text:
Unsymmetrically Substituted Nickel Triazatetra-Benzcorrole and Phthalocynanine Complexes: Conjugation to Quantum Dots and Applications as Fluorescent “Turn ON” Sensors
- Adegoke, Oluwasesan, Nyokong, Tebello
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7311 , http://hdl.handle.net/10962/d1020403
- Description: We report on the design and application of fluorescent nanoprobes based on the covalent linking of L-glutathione-capped CdSe@ZnS quantum dots (QDs) to newly synthesized unsymmetrically substituted nickel mercaptosuccinic acid triazatetra-benzcorrole (3) and phthalocyanine (4) complexes. Fluorescence quenching of the QDs occurred on conjugation to complexes 3 or 4. The nanoprobes were selectively screened in the presence of different cations and Hg2+ showed excellent affinity in “turning ON” the fluorescence of the nanoprobes. Experimental results showed that the sensitivity of QDs-4 towards Hg2+ was much higher than that of QDs-3 nanoprobe. The mechanism of reaction has been elucidated based on the ability of Hg2+ to coordinate with the sulphur atom of the Ni complex ring and apparently “turn ON” the fluorescence of the linked QDs. , Original publication is available at http://dx.doi.org/10.1007/s10895-013-1317-4
- Full Text: false
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello
- Language: English
- Type: Article
- Identifier: vital:7311 , http://hdl.handle.net/10962/d1020403
- Description: We report on the design and application of fluorescent nanoprobes based on the covalent linking of L-glutathione-capped CdSe@ZnS quantum dots (QDs) to newly synthesized unsymmetrically substituted nickel mercaptosuccinic acid triazatetra-benzcorrole (3) and phthalocyanine (4) complexes. Fluorescence quenching of the QDs occurred on conjugation to complexes 3 or 4. The nanoprobes were selectively screened in the presence of different cations and Hg2+ showed excellent affinity in “turning ON” the fluorescence of the nanoprobes. Experimental results showed that the sensitivity of QDs-4 towards Hg2+ was much higher than that of QDs-3 nanoprobe. The mechanism of reaction has been elucidated based on the ability of Hg2+ to coordinate with the sulphur atom of the Ni complex ring and apparently “turn ON” the fluorescence of the linked QDs. , Original publication is available at http://dx.doi.org/10.1007/s10895-013-1317-4
- Full Text: false