‘There is nothing to hold onto here’:
- Shabangu, Samuel M, Babu, Balaji, Soy, Rodah C, Managa, Muthumuni, Sekhosana, Kutloano E, Nyokong, Tebello
- Authors: Shabangu, Samuel M , Babu, Balaji , Soy, Rodah C , Managa, Muthumuni , Sekhosana, Kutloano E , Nyokong, Tebello
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156410 , vital:39987 , DOI: 10.1080/00958972.2020.1739273
- Description: Asymmetric mono-carboxy-porphyrins, (5-(4-carboxyphenyl)−10,15,20-tris(pentafluorophenyl)porphyrinato zinc(II) (1), 5-(4-carboxyphenyl)−10,15,20-triphenylporphyrinato zinc(II) (2) and 5-(4-carboxyphenyl)−10,15,20-tris(2-thienyl)porphyrinato zinc(II) (3), were linked to Ag nanoparticles (AgNPs) through amide bonds and self-assembly (the latter only for 3). The porphyrins and conjugates were used for photodynamic antimicrobial chemotherapy (PACT) against Staphylococcus aureus. PACT uses singlet oxygen for antimicrobial activity. Complex 3 and its conjugates had higher singlet oxygen quantum yields and higher log reduction when compared with the rest of the porphyrins and corresponding conjugates. These high log reductions for 3 and its conjugate were attributed to the presence of sulfur groups whereby there was more interaction with the bacterial membrane.
- Full Text:
- Authors: Shabangu, Samuel M , Babu, Balaji , Soy, Rodah C , Managa, Muthumuni , Sekhosana, Kutloano E , Nyokong, Tebello
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156410 , vital:39987 , DOI: 10.1080/00958972.2020.1739273
- Description: Asymmetric mono-carboxy-porphyrins, (5-(4-carboxyphenyl)−10,15,20-tris(pentafluorophenyl)porphyrinato zinc(II) (1), 5-(4-carboxyphenyl)−10,15,20-triphenylporphyrinato zinc(II) (2) and 5-(4-carboxyphenyl)−10,15,20-tris(2-thienyl)porphyrinato zinc(II) (3), were linked to Ag nanoparticles (AgNPs) through amide bonds and self-assembly (the latter only for 3). The porphyrins and conjugates were used for photodynamic antimicrobial chemotherapy (PACT) against Staphylococcus aureus. PACT uses singlet oxygen for antimicrobial activity. Complex 3 and its conjugates had higher singlet oxygen quantum yields and higher log reduction when compared with the rest of the porphyrins and corresponding conjugates. These high log reductions for 3 and its conjugate were attributed to the presence of sulfur groups whereby there was more interaction with the bacterial membrane.
- Full Text:
Visible light transformation of Rhodamine 6G using tetracarbazole zinc phthalocyanine when embedded in electrospun fibers and in the presence of ZnO and Ag particles
- Khoza, Phindile, Nyokong, Tebello
- Authors: Khoza, Phindile , Nyokong, Tebello
- Date: 2015
- Language: English
- Type: Article
- Identifier: vital:7246 , http://hdl.handle.net/10962/d1020251
- Description: Herein, we report the photocatalytic transformation of Rhodamine 6G (Rh 6G) using tetracarbazole zinc phthalocyanine (TCbZnPc) when alone or when conjugated with ZnO macroparticles (ZnOMPs) and silver nanoparticles (AgNPs), represented as TCbZnPc–ZnOMPs and TCbZnPc–AgNPs, respectively. The photocatalysts were supported onto electrospun polystyrene fibers. The efficiency of TCbZnPc was improved by the presence of both ZnOMPs and AgNPs. HPLC equipped with UV–vis was used to study phototransformation products. The mechanism of transformation was via the N-de-ethylation of Rh 6G. , Original publication is available at http://dx.doi.org/10.1080/00958972.2015.1013944
- Full Text: false
- Authors: Khoza, Phindile , Nyokong, Tebello
- Date: 2015
- Language: English
- Type: Article
- Identifier: vital:7246 , http://hdl.handle.net/10962/d1020251
- Description: Herein, we report the photocatalytic transformation of Rhodamine 6G (Rh 6G) using tetracarbazole zinc phthalocyanine (TCbZnPc) when alone or when conjugated with ZnO macroparticles (ZnOMPs) and silver nanoparticles (AgNPs), represented as TCbZnPc–ZnOMPs and TCbZnPc–AgNPs, respectively. The photocatalysts were supported onto electrospun polystyrene fibers. The efficiency of TCbZnPc was improved by the presence of both ZnOMPs and AgNPs. HPLC equipped with UV–vis was used to study phototransformation products. The mechanism of transformation was via the N-de-ethylation of Rh 6G. , Original publication is available at http://dx.doi.org/10.1080/00958972.2015.1013944
- Full Text: false
Electrocatalysis of asulam on cobalt phthalocyanine modified multi-walled carbon nanotubes immobilized on a basal plane pyrolytic graphite electrode
- Siswana, Msimelelo P, Ozoemena, Kenneth I, Nyokong, Tebello
- Authors: Siswana, Msimelelo P , Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6595 , http://hdl.handle.net/10962/d1004344
- Description: This work describes the electrochemical properties of cobalt tetra-aminophthalocyanine (CoTAPc) complex electropolymerized at the surface of multi-walled carbon nanotube (MWCNT) abrasively immobilized onto a basal plane pyrolytic graphite electrode (BPPGE). The constructed electrode displayed excellent electrocatalytic behaviour towards the oxidation of the herbicide, asulam, as evidenced by the enhancement of the oxidation peak current (~6 times) and the shift in the oxidation potential to lower values (by ~120 mV) in comparison with the bare BPPGE. The chronoamperometric detection of asulam which was carried out in 0.10 M phosphate buffer (pH 7.0) at a fixed potential of 0.65 V (versus Ag|AgCl) yielded excellent analytical parameters; a linear concentration range of 4.5–20 μM, a sensitivity of 241 × 10[superscript −3] μA/μM, a detection limit of 1.15 μM asulam (using the Y[subscript B] + 3σ criterion) and a response time of ~2 s.
- Full Text:
- Authors: Siswana, Msimelelo P , Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6595 , http://hdl.handle.net/10962/d1004344
- Description: This work describes the electrochemical properties of cobalt tetra-aminophthalocyanine (CoTAPc) complex electropolymerized at the surface of multi-walled carbon nanotube (MWCNT) abrasively immobilized onto a basal plane pyrolytic graphite electrode (BPPGE). The constructed electrode displayed excellent electrocatalytic behaviour towards the oxidation of the herbicide, asulam, as evidenced by the enhancement of the oxidation peak current (~6 times) and the shift in the oxidation potential to lower values (by ~120 mV) in comparison with the bare BPPGE. The chronoamperometric detection of asulam which was carried out in 0.10 M phosphate buffer (pH 7.0) at a fixed potential of 0.65 V (versus Ag|AgCl) yielded excellent analytical parameters; a linear concentration range of 4.5–20 μM, a sensitivity of 241 × 10[superscript −3] μA/μM, a detection limit of 1.15 μM asulam (using the Y[subscript B] + 3σ criterion) and a response time of ~2 s.
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