Photophysical and photochemical properties of a novel thiol terminated low symmetry zinc phthalocyanine complex and its gold nanoparticles conjugate
- Mthethwa, Thandekile P, Durmus, Mahmut, Nyokong, Tebello
- Authors: Mthethwa, Thandekile P , Durmus, Mahmut , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/231474 , vital:49891 , xlink:href="https://doi.org/10.1039/C3DT32698E"
- Description: A novel thiol functionalized zinc phthalocyanine complex (ZnPcSH) is reported in this work. This complex was conjugated to gold nanoparticles. The photophysical and photochemical properties of the complex and the conjugate were investigated. Upon conjugation a blue shift was observed from the UV-Vis spectra. The conjugate showed a decrease in the fluorescence quantum yield and lifetime. An increase in the triplet quantum yield and lifetime was observed for ZnPcSH following conjugation to gold nanoparticles. Both ZnPcSH and its conjugate with gold nanoparticles showed high singlet oxygen quantum yields with the conjugate being higher than the Pc alone.
- Full Text:
- Date Issued: 2013
- Authors: Mthethwa, Thandekile P , Durmus, Mahmut , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/231474 , vital:49891 , xlink:href="https://doi.org/10.1039/C3DT32698E"
- Description: A novel thiol functionalized zinc phthalocyanine complex (ZnPcSH) is reported in this work. This complex was conjugated to gold nanoparticles. The photophysical and photochemical properties of the complex and the conjugate were investigated. Upon conjugation a blue shift was observed from the UV-Vis spectra. The conjugate showed a decrease in the fluorescence quantum yield and lifetime. An increase in the triplet quantum yield and lifetime was observed for ZnPcSH following conjugation to gold nanoparticles. Both ZnPcSH and its conjugate with gold nanoparticles showed high singlet oxygen quantum yields with the conjugate being higher than the Pc alone.
- Full Text:
- Date Issued: 2013
Physicochemical properties of a zinc phthalocyanine–pyrene conjugate adsorbed onto single walled carbon nanotubes
- Ogbodu, Racheal O, Antunes, Edith M, Nyokong, Tebello
- Authors: Ogbodu, Racheal O , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/242314 , vital:51029 , xlink:href="https://doi.org/10.1039/C3DT50335F"
- Description: A conjugate between zinc monoamino phthalocyanine (ZnMAPc) and pyrene (Py) represented as ZnMAPc–Py (complex 3) was synthesized and characterized by various spectroscopic techniques and by elemental analysis. This manuscript also reports on the photochemical and photophysical properties of 3. This new compound exhibited higher triplet, fluorescence and singlet oxygen quantum yields in comparison to the phthalocyanine alone, hence showing the advantages of attaching pyrene to the Pc without breaking the conjugation. We also observed a decrease in photophysical parameters upon adsorbing the ZnMAPc–Py complex onto single walled carbon nanotubes (SWCNT). However, ZnMAPc–Py still generated some singlet oxygen when adsorbed onto SWCNT.
- Full Text:
- Date Issued: 2013
- Authors: Ogbodu, Racheal O , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/242314 , vital:51029 , xlink:href="https://doi.org/10.1039/C3DT50335F"
- Description: A conjugate between zinc monoamino phthalocyanine (ZnMAPc) and pyrene (Py) represented as ZnMAPc–Py (complex 3) was synthesized and characterized by various spectroscopic techniques and by elemental analysis. This manuscript also reports on the photochemical and photophysical properties of 3. This new compound exhibited higher triplet, fluorescence and singlet oxygen quantum yields in comparison to the phthalocyanine alone, hence showing the advantages of attaching pyrene to the Pc without breaking the conjugation. We also observed a decrease in photophysical parameters upon adsorbing the ZnMAPc–Py complex onto single walled carbon nanotubes (SWCNT). However, ZnMAPc–Py still generated some singlet oxygen when adsorbed onto SWCNT.
- Full Text:
- Date Issued: 2013
Physicochemical properties of zinc monoamino phthalocyanine conjugated to folic acid and single walled carbon nanotubes
- Ogbodu, Racheal O, Antunes, Edith M, Nyokong, Tebello
- Authors: Ogbodu, Racheal O , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241761 , vital:50967 , xlink:href="https://doi.org/10.1016/j.poly.2013.05.025"
- Description: This study reports on the photophysical and photochemical behavior of the conjugates formed by covalent and non-covalent bonding between zinc monoamino phthalocyanine (ZnMAPc) and either single walled carbon nanotubes (SWCNTs) or folic acid (FA). The conjugates were characterized using FTIR, X-ray powder diffractometry, thermogravimetric analyses, transmission electron microscopy and Raman spectroscopy. 1H NMR and mass spectroscopies were only employed for ZnMAPc–FA conjugate. There was a slight increase in the triplet and singlet oxygen quantum yields on conjugating ZnMAPc to SWCNTs (or FA), while a decrease in the photophysical and photochemical parameters were observed upon adsorption of the ZnMAPc–FA conjugate to SWCNTs.
- Full Text:
- Date Issued: 2013
- Authors: Ogbodu, Racheal O , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241761 , vital:50967 , xlink:href="https://doi.org/10.1016/j.poly.2013.05.025"
- Description: This study reports on the photophysical and photochemical behavior of the conjugates formed by covalent and non-covalent bonding between zinc monoamino phthalocyanine (ZnMAPc) and either single walled carbon nanotubes (SWCNTs) or folic acid (FA). The conjugates were characterized using FTIR, X-ray powder diffractometry, thermogravimetric analyses, transmission electron microscopy and Raman spectroscopy. 1H NMR and mass spectroscopies were only employed for ZnMAPc–FA conjugate. There was a slight increase in the triplet and singlet oxygen quantum yields on conjugating ZnMAPc to SWCNTs (or FA), while a decrease in the photophysical and photochemical parameters were observed upon adsorption of the ZnMAPc–FA conjugate to SWCNTs.
- Full Text:
- Date Issued: 2013
Playing with the forest: Invasive alien plants, policy and protected areas in India
- Kannan, Ramesh, Shackleton, Charlie M, Shaanker, Ramanan U
- Authors: Kannan, Ramesh , Shackleton, Charlie M , Shaanker, Ramanan U
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182334 , vital:43821 , xlink:href="https://www.jstor.org/stable/24092395"
- Description: Protected areas (PAs) are inviolate and invaluable landscapes that promote the in situ conservation of endangered, threatened and rare species. Accordingly, and in keeping with this definition, PA managers ensure that PAs are free from fire, poaching, grazing, non-timber forest products collection, mining, etc. In India, following the Indian Wildlife (Protection) Act (1972), there are today 102 and 515 National Parks and Wildlife Sanctuaries respectively. Many of these have in recent decades been heavily threatened by the spread of invasive alien plant species, notable among them being Lantana and Eupatorium. These species may have usurped as yet unestimated number of native plants and fauna, besides depressing the reproduction of native plant species. In fact, it is realized that the threat to biodiversity by invasive alien species (IAS) may only be second to that of fragmentation. Yet there seems to be no major attempts to eradicate, contain or manage IAS in PAs. Ironically, the justification for the lack of action lies in the definition of PAs - that they need to be kept inviolate and therefore above any active intervention. In this article we bring home this serious contradiction in the approach to management of PAs in India and discuss the philosophical origins of this practice. We argue that if we are to protect our PAs from the serious scourge of invasive species, we would have to relook at the policy governing PA management and revise it to be more inclusive than exclusive.
- Full Text:
- Date Issued: 2013
- Authors: Kannan, Ramesh , Shackleton, Charlie M , Shaanker, Ramanan U
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182334 , vital:43821 , xlink:href="https://www.jstor.org/stable/24092395"
- Description: Protected areas (PAs) are inviolate and invaluable landscapes that promote the in situ conservation of endangered, threatened and rare species. Accordingly, and in keeping with this definition, PA managers ensure that PAs are free from fire, poaching, grazing, non-timber forest products collection, mining, etc. In India, following the Indian Wildlife (Protection) Act (1972), there are today 102 and 515 National Parks and Wildlife Sanctuaries respectively. Many of these have in recent decades been heavily threatened by the spread of invasive alien plant species, notable among them being Lantana and Eupatorium. These species may have usurped as yet unestimated number of native plants and fauna, besides depressing the reproduction of native plant species. In fact, it is realized that the threat to biodiversity by invasive alien species (IAS) may only be second to that of fragmentation. Yet there seems to be no major attempts to eradicate, contain or manage IAS in PAs. Ironically, the justification for the lack of action lies in the definition of PAs - that they need to be kept inviolate and therefore above any active intervention. In this article we bring home this serious contradiction in the approach to management of PAs in India and discuss the philosophical origins of this practice. We argue that if we are to protect our PAs from the serious scourge of invasive species, we would have to relook at the policy governing PA management and revise it to be more inclusive than exclusive.
- Full Text:
- Date Issued: 2013
Poly methyl methacrylate films containing metallophthalocyanines in the presence of CdTe quantum dots
- Britton, Jonathan, Durmus, Mahmut, Chauke, Vongani, Nyokong, Tebello
- Authors: Britton, Jonathan , Durmus, Mahmut , Chauke, Vongani , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241629 , vital:50956 , xlink:href="https://doi.org/10.1016/j.molstruc.2013.09.017"
- Description: Non-linear optical (NLO) parameters were determined for phthalocyanine complexes containing In, Ga and Zn as central metals when embedded in poly (methyl methacrylate) polymer in the absence and presence of quantum dots (QDs) in an effort to create the most optimal optical limiting material. The QDs employed were CdTe–TGA (TGA = thioglylcolic acid). Triplet lifetimes generally increased as the value of the ratio of absorption cross sections of the excited state to that of the ground state (k) decreased on addition of CdTe–TGA to the phthalocyanines. The saturation energy density (Fsat) values were generally smaller in the films when compared to the solutions. Fsat, Ilim, Im[χ(3)]/α and γ all gave values which were of optimal range (i.e. the Im[χ(3)]/α and γ values were high enough to ensure adequate optical limiting but not too high to make the compounds behave like optical filters. Also, the Fsat and Ilim values were small enough to mean that the optical limiting process started at an intensity which was not too high) for complex 10 containing Zn central metal and tetrasubstituted with amino groups.
- Full Text:
- Date Issued: 2013
- Authors: Britton, Jonathan , Durmus, Mahmut , Chauke, Vongani , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241629 , vital:50956 , xlink:href="https://doi.org/10.1016/j.molstruc.2013.09.017"
- Description: Non-linear optical (NLO) parameters were determined for phthalocyanine complexes containing In, Ga and Zn as central metals when embedded in poly (methyl methacrylate) polymer in the absence and presence of quantum dots (QDs) in an effort to create the most optimal optical limiting material. The QDs employed were CdTe–TGA (TGA = thioglylcolic acid). Triplet lifetimes generally increased as the value of the ratio of absorption cross sections of the excited state to that of the ground state (k) decreased on addition of CdTe–TGA to the phthalocyanines. The saturation energy density (Fsat) values were generally smaller in the films when compared to the solutions. Fsat, Ilim, Im[χ(3)]/α and γ all gave values which were of optimal range (i.e. the Im[χ(3)]/α and γ values were high enough to ensure adequate optical limiting but not too high to make the compounds behave like optical filters. Also, the Fsat and Ilim values were small enough to mean that the optical limiting process started at an intensity which was not too high) for complex 10 containing Zn central metal and tetrasubstituted with amino groups.
- Full Text:
- Date Issued: 2013
Probing the sensitive and selective luminescent detection of peroxynitrite using thiol-capped CdTe and CdTe@ ZnS quantum dots
- Adegoke, Oluwasesan, Nyokong, Tebello
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193757 , vital:45393 , xlink:href="https://doi.org/10.1016/j.jlumin.2012.08.002"
- Description: CdTe and CdTe@ZnS quantum dots (QDs) capped with 3-mercaptopropionic acid (MPA), thioglycolic acid (TGA), or glutathione (GSH) have been employed for the first time as luminescent probes for the sensitive and selective detection of peroxynitrite (ONOO−) in aqueous solution. The sensitivity of the proposed probe followed the order: MPA–TGA–CdTe@ZnS>GSH–TGA–CdTe@ZnS>MPA–CdTe QDs. The varying degree of quenching is elucidated based on the QD–thiolate bond of CdTe@ZnS being more sensitive to oxidation from ONOO− than CdTe. The selectivity of the probe in the presence of co-existing species followed the order: GSH–TGA–CdTe@ZnS>MPA–TGA–CdTe@ZnS>MPA–CdTe QDs. QDs capped with MPA showed less selectivity for ONOO− than GSH. The best limit of detection (LOD) of 12.6 nM was obtained for MPA–TGA–CdTe@ZnS QDs. Time-resolved fluorescence measurements indicated that the interaction between ONOO− and the QDs is static in nature.
- Full Text:
- Date Issued: 2013
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193757 , vital:45393 , xlink:href="https://doi.org/10.1016/j.jlumin.2012.08.002"
- Description: CdTe and CdTe@ZnS quantum dots (QDs) capped with 3-mercaptopropionic acid (MPA), thioglycolic acid (TGA), or glutathione (GSH) have been employed for the first time as luminescent probes for the sensitive and selective detection of peroxynitrite (ONOO−) in aqueous solution. The sensitivity of the proposed probe followed the order: MPA–TGA–CdTe@ZnS>GSH–TGA–CdTe@ZnS>MPA–CdTe QDs. The varying degree of quenching is elucidated based on the QD–thiolate bond of CdTe@ZnS being more sensitive to oxidation from ONOO− than CdTe. The selectivity of the probe in the presence of co-existing species followed the order: GSH–TGA–CdTe@ZnS>MPA–TGA–CdTe@ZnS>MPA–CdTe QDs. QDs capped with MPA showed less selectivity for ONOO− than GSH. The best limit of detection (LOD) of 12.6 nM was obtained for MPA–TGA–CdTe@ZnS QDs. Time-resolved fluorescence measurements indicated that the interaction between ONOO− and the QDs is static in nature.
- Full Text:
- Date Issued: 2013
Production and characterization of a bioflocculant from a consortium of bacteria belonging to the halomonas and micrococcus genera
- Okaiyeto, Kunle (https://orcid.org/0000-0002-7211-714X)
- Authors: Okaiyeto, Kunle (https://orcid.org/0000-0002-7211-714X)
- Date: 2013
- Subjects: Flocculents , Bacteria
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/25822 , vital:64489
- Description: The physicochemical properties of two bioflocculant producing bacteria; Halomonas sp. Okoh and Micrococcus sp. Leo were investigated. The optimum culture conditions for the individual species were determined. All the growth conditions examined for the individual bacteria were similar. Glucose and ammonium sulphate as sole carbon and nitrogen sources respectively resulted in optimum production of bioflocculant. The flocculating activity of the bioflocculants was stimulated when Al3+ was used as the coagulating aid under acidic medium. The information obtained from individual strains was used to produce a bioflocculant from the consortium of the two bacteria. After purification, the bioflocculant yields from 1L fermentation broths were 1.213 g from Halomonas sp. Okoh, 0.738 g from Micrococcus sp. Leo and 3.51 g from the consortium. The chemical analyses of the purified bioflocculants showed that they were glycoproteins. The thermostability property of the bioflocculants was investigated between 50-100oC and the results revealed that they are heat-stable. Fourier transform infrared revealed the presence of hydroxyl, carboxyl and amino groups in the bioflocculant molecules. Scaning electron microscope (SEM) images showed the structure of each bioflocculant(s) and kaolin clay before and after flocculation. From the results obtained, the idea of using the two strains in consortium for bioflocculant production resulted in an improvement in terms of flocculating activity and yield. The bioflocculants appears to have promise as an alternative to chemical flocculants used in various industrial processes such as wastewater treatment and drinking water purification. , Thesis (MA) -- Science and Agriculture, 2013
- Full Text:
- Date Issued: 2013
- Authors: Okaiyeto, Kunle (https://orcid.org/0000-0002-7211-714X)
- Date: 2013
- Subjects: Flocculents , Bacteria
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/25822 , vital:64489
- Description: The physicochemical properties of two bioflocculant producing bacteria; Halomonas sp. Okoh and Micrococcus sp. Leo were investigated. The optimum culture conditions for the individual species were determined. All the growth conditions examined for the individual bacteria were similar. Glucose and ammonium sulphate as sole carbon and nitrogen sources respectively resulted in optimum production of bioflocculant. The flocculating activity of the bioflocculants was stimulated when Al3+ was used as the coagulating aid under acidic medium. The information obtained from individual strains was used to produce a bioflocculant from the consortium of the two bacteria. After purification, the bioflocculant yields from 1L fermentation broths were 1.213 g from Halomonas sp. Okoh, 0.738 g from Micrococcus sp. Leo and 3.51 g from the consortium. The chemical analyses of the purified bioflocculants showed that they were glycoproteins. The thermostability property of the bioflocculants was investigated between 50-100oC and the results revealed that they are heat-stable. Fourier transform infrared revealed the presence of hydroxyl, carboxyl and amino groups in the bioflocculant molecules. Scaning electron microscope (SEM) images showed the structure of each bioflocculant(s) and kaolin clay before and after flocculation. From the results obtained, the idea of using the two strains in consortium for bioflocculant production resulted in an improvement in terms of flocculating activity and yield. The bioflocculants appears to have promise as an alternative to chemical flocculants used in various industrial processes such as wastewater treatment and drinking water purification. , Thesis (MA) -- Science and Agriculture, 2013
- Full Text:
- Date Issued: 2013
Production and characterization of a bioflocculant from a consortium of bacteria belonging to the halomonas and micrococcus genera.
- Okaiyeto, Kunle (https://orcid.org/0000-0002-7211-714X)
- Authors: Okaiyeto, Kunle (https://orcid.org/0000-0002-7211-714X)
- Date: 2013
- Subjects: Flocculants , Bacteria
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/26119 , vital:64917
- Description: The physicochemical properties of two bioflocculant producing bacteria; Halomonas sp. Okoh and Micrococcus sp. Leo were investigated. The optimum culture conditions for the individual species were determined. All the growth conditions examined for the individual bacteria were similar. Glucose and ammonium sulphate as sole carbon and nitrogen sources respectively resulted in optimum production of bioflocculant. The flocculating activity of the bioflocculants was stimulated when Al3+ was used as the coagulating aid under acidic medium. The information obtained from individual strains was used to produce a bioflocculant from the consortium of the two bacteria. After purification, the bioflocculant yields from 1L fermentation broths were 1.213 g from Halomonas sp. Okoh, 0.738 g from Micrococcus sp. Leo and 3.51 g from the consortium. The chemical analyses of the purified bioflocculants showed that they were glycoproteins. The thermostability property of the bioflocculants was investigated between 50-100oC and the results revealed that they are heat-stable. Fourier transform infrared revealed the presence of hydroxyl, carboxyl and amino groups in the bioflocculant molecules. Scaning electron microscope (SEM) images showed the structure of each bioflocculant(s) and kaolin clay before and after flocculation. From the results obtained, the idea of using the two strains in consortium for bioflocculant production resulted in an improvement in terms of flocculating activity and yield. The bioflocculants appears to have promise as an alternative to chemical flocculants used in various industrial processes such as wastewater treatment and drinking water purification. , Thesis (MA) -- Faculty Science and Agriculture, 2013
- Full Text:
- Date Issued: 2013
- Authors: Okaiyeto, Kunle (https://orcid.org/0000-0002-7211-714X)
- Date: 2013
- Subjects: Flocculants , Bacteria
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/26119 , vital:64917
- Description: The physicochemical properties of two bioflocculant producing bacteria; Halomonas sp. Okoh and Micrococcus sp. Leo were investigated. The optimum culture conditions for the individual species were determined. All the growth conditions examined for the individual bacteria were similar. Glucose and ammonium sulphate as sole carbon and nitrogen sources respectively resulted in optimum production of bioflocculant. The flocculating activity of the bioflocculants was stimulated when Al3+ was used as the coagulating aid under acidic medium. The information obtained from individual strains was used to produce a bioflocculant from the consortium of the two bacteria. After purification, the bioflocculant yields from 1L fermentation broths were 1.213 g from Halomonas sp. Okoh, 0.738 g from Micrococcus sp. Leo and 3.51 g from the consortium. The chemical analyses of the purified bioflocculants showed that they were glycoproteins. The thermostability property of the bioflocculants was investigated between 50-100oC and the results revealed that they are heat-stable. Fourier transform infrared revealed the presence of hydroxyl, carboxyl and amino groups in the bioflocculant molecules. Scaning electron microscope (SEM) images showed the structure of each bioflocculant(s) and kaolin clay before and after flocculation. From the results obtained, the idea of using the two strains in consortium for bioflocculant production resulted in an improvement in terms of flocculating activity and yield. The bioflocculants appears to have promise as an alternative to chemical flocculants used in various industrial processes such as wastewater treatment and drinking water purification. , Thesis (MA) -- Faculty Science and Agriculture, 2013
- Full Text:
- Date Issued: 2013
Reconstructing the history of introduction and spread of the invasive species, Lantana, at three spatial scales in India
- Kannan, Ramesh, Shackleton, Charlie M, Shaanker, Ramanan U
- Authors: Kannan, Ramesh , Shackleton, Charlie M , Shaanker, Ramanan U
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181015 , vital:43687 , xlink:href="https://doi.org/10.1007/s10530-012-0365-z"
- Description: This study sought to reconstruct the history of Lantana invasion and spread in India by considering two questions; (a) from where, by who, and when were Lantana species introduced into India? and (b) given its long history in the country, is it still spreading or more or less stable? We critically evaluated the archival and historical information on plant imports by the European powers into India during the period before and after British colonization. We then reconstructed the path of spread by analyzing the spatio-temporal patterns of occurrence and distribution of Lantana in India at both the national and local scale using a GIS platform. The spread of Lantana across the globe started as early as the 1690s. The European colonial powers moved the plants from Latin America to Europe and to their colonial countries in the early 1800s. Lantana species were introduced in India from 1807 onwards and thereafter the colonial powers moved this plant across the country. Following its introduction into India, the spread of Lantana across the country, either through subsequent multiple introductions from Europe to different British cantonments, or through moving the plants between cantonments within India, were reasonably rapid spanning only a few decades. In the absence of a rigorous control program, the spread of Lantana has gone on unabated and thereby impacting both wildlife and biodiversity.
- Full Text:
- Date Issued: 2013
- Authors: Kannan, Ramesh , Shackleton, Charlie M , Shaanker, Ramanan U
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181015 , vital:43687 , xlink:href="https://doi.org/10.1007/s10530-012-0365-z"
- Description: This study sought to reconstruct the history of Lantana invasion and spread in India by considering two questions; (a) from where, by who, and when were Lantana species introduced into India? and (b) given its long history in the country, is it still spreading or more or less stable? We critically evaluated the archival and historical information on plant imports by the European powers into India during the period before and after British colonization. We then reconstructed the path of spread by analyzing the spatio-temporal patterns of occurrence and distribution of Lantana in India at both the national and local scale using a GIS platform. The spread of Lantana across the globe started as early as the 1690s. The European colonial powers moved the plants from Latin America to Europe and to their colonial countries in the early 1800s. Lantana species were introduced in India from 1807 onwards and thereafter the colonial powers moved this plant across the country. Following its introduction into India, the spread of Lantana across the country, either through subsequent multiple introductions from Europe to different British cantonments, or through moving the plants between cantonments within India, were reasonably rapid spanning only a few decades. In the absence of a rigorous control program, the spread of Lantana has gone on unabated and thereby impacting both wildlife and biodiversity.
- Full Text:
- Date Issued: 2013
Seeing Fictions in Film
- Authors: Jones, Ward E
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275711 , vital:55072 , xlink:href="https://doi.org/10.1080/00048402.2013.818044"
- Description: Although its subtitle refers to an ‘epistemology of movies’, the claim at the heart of George M. Wilson’s dense and penetrating book is a bit of sophisticated phenomenology concerning our experience of narrative fiction films [Chs 2–4]. This phenomenological claim he calls the ‘Imagined Seeing Thesis’. When we watch narrative fiction films, we imagine that we are seeing real motion picture shots of the fictional events being portrayed.
- Full Text:
- Date Issued: 2013
- Authors: Jones, Ward E
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275711 , vital:55072 , xlink:href="https://doi.org/10.1080/00048402.2013.818044"
- Description: Although its subtitle refers to an ‘epistemology of movies’, the claim at the heart of George M. Wilson’s dense and penetrating book is a bit of sophisticated phenomenology concerning our experience of narrative fiction films [Chs 2–4]. This phenomenological claim he calls the ‘Imagined Seeing Thesis’. When we watch narrative fiction films, we imagine that we are seeing real motion picture shots of the fictional events being portrayed.
- Full Text:
- Date Issued: 2013
Silica nanoparticles grafted with phthalocyanines
- Fashina, Adebayo, Antunes, Edith M, Nyokong, Tebello
- Authors: Fashina, Adebayo , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/232545 , vital:50001 , xlink:href="https://doi.org/10.1039/C3NJ00439B"
- Description: Silica nanoparticles grafted with phthalocyanines (tetra-substituted non-peripherally with 4-carboxyphenoxy and 3-carboxyphenoxy groups) have been synthesized, characterized and their photophysical properties evaluated in solution. The phthalocyanine dyes have a free carboxyl group facilitating the covalent attachment of the dye onto the silica surface via ester bond formation. The photophysical properties of the hybrid nanoparticles show higher fluorescence and triplet quantum yields as well as longer triplet lifetimes as compared to the free phthalocyanines. The triplet quantum yields were found to be higher for the phthalocyanines with ester bonds as compared to the amide bonded linkages. The silica nanoparticles were also studied in artificial lysosomal fluid over a period of 96 h and the dissolution of the nanoparticles was monitored and confirmed using inductively coupled plasma optical emission spectrometry.
- Full Text:
- Date Issued: 2013
- Authors: Fashina, Adebayo , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/232545 , vital:50001 , xlink:href="https://doi.org/10.1039/C3NJ00439B"
- Description: Silica nanoparticles grafted with phthalocyanines (tetra-substituted non-peripherally with 4-carboxyphenoxy and 3-carboxyphenoxy groups) have been synthesized, characterized and their photophysical properties evaluated in solution. The phthalocyanine dyes have a free carboxyl group facilitating the covalent attachment of the dye onto the silica surface via ester bond formation. The photophysical properties of the hybrid nanoparticles show higher fluorescence and triplet quantum yields as well as longer triplet lifetimes as compared to the free phthalocyanines. The triplet quantum yields were found to be higher for the phthalocyanines with ester bonds as compared to the amide bonded linkages. The silica nanoparticles were also studied in artificial lysosomal fluid over a period of 96 h and the dissolution of the nanoparticles was monitored and confirmed using inductively coupled plasma optical emission spectrometry.
- Full Text:
- Date Issued: 2013
Spatial and temporal variations in stable carbon (δ13C) and nitrogen (δ15N) isotopic composition of symbiotic scleractinian corals
- Nahon, Sarah, Richoux, Nicole B, Kolasinski, Joanna, Desmalades, Martin, Ferrier Pages, Christine F, Lecellier, Gael, Planes, Serge, Berteaux Lecellier, Véronique
- Authors: Nahon, Sarah , Richoux, Nicole B , Kolasinski, Joanna , Desmalades, Martin , Ferrier Pages, Christine F , Lecellier, Gael , Planes, Serge , Berteaux Lecellier, Véronique
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/457309 , vital:75624 , xlink:href="https://doi.org/10.1371/journal.pone.0081247"
- Description: Tropical scleractinian corals are considered autotrophic as they rely mainly on photosynthesis-derived nutrients transferred from their photosymbionts. Corals are also able to capture and ingest suspended particulate organic matter, so heterotrophy can be an important supplementary trophic pathway to optimize coral fitness. The aim of this in situ study was to elucidate the trophic status of 10 coral species under contrasted environmental conditions in a French Polynesian lagoon. Carbon (δ13C) and nitrogen (δ15N) isotopic compositions of coral host tissues and photosymbionts were determined at 3 different fringing reefs during wet and dry seasons. Our results highlighted spatial variability in stable isotopic compositions of both coral host tissues and photosymbionts. Samples from the site with higher level of suspended particulate matter were 13C-depleted and 15N-enriched relative to corals and photosymbionts from less turbid sites. However, differences in both δ13C and δ15N between coral host tissues and their photosymbionts (Δhost-photosymbionts 13C and Δhost-photosymbionts 15N) were small (0.27 ± 0.76‰ and 1.40 ± 0.90‰, respectively) and similar at all sites, thus indicating no general increases in the heterotrophic pathway. Depleted δ13C and enriched δ15N values of coral host tissues measured at the most turbid site were explained by changes in isotopic composition of the inorganic nutrients taken up by photosymbionts and also by changes in rate of isotopic fractionation with environmental conditions. Our results also highlighted a lack of significant temporal variations in δ13C and δ15N values of coral host and photosymbiont tissues and in Δhost-photosymbionts 13C and Δhost-photosymbionts 15N values. This temporal stability indicated that corals remained principally autotrophic even during the wet season when photosymbiont densities were lower and the concentrations of phytoplankton were higher. Increased coral heterotrophy with higher food availability thus appears to be species-specific.
- Full Text:
- Date Issued: 2013
- Authors: Nahon, Sarah , Richoux, Nicole B , Kolasinski, Joanna , Desmalades, Martin , Ferrier Pages, Christine F , Lecellier, Gael , Planes, Serge , Berteaux Lecellier, Véronique
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/457309 , vital:75624 , xlink:href="https://doi.org/10.1371/journal.pone.0081247"
- Description: Tropical scleractinian corals are considered autotrophic as they rely mainly on photosynthesis-derived nutrients transferred from their photosymbionts. Corals are also able to capture and ingest suspended particulate organic matter, so heterotrophy can be an important supplementary trophic pathway to optimize coral fitness. The aim of this in situ study was to elucidate the trophic status of 10 coral species under contrasted environmental conditions in a French Polynesian lagoon. Carbon (δ13C) and nitrogen (δ15N) isotopic compositions of coral host tissues and photosymbionts were determined at 3 different fringing reefs during wet and dry seasons. Our results highlighted spatial variability in stable isotopic compositions of both coral host tissues and photosymbionts. Samples from the site with higher level of suspended particulate matter were 13C-depleted and 15N-enriched relative to corals and photosymbionts from less turbid sites. However, differences in both δ13C and δ15N between coral host tissues and their photosymbionts (Δhost-photosymbionts 13C and Δhost-photosymbionts 15N) were small (0.27 ± 0.76‰ and 1.40 ± 0.90‰, respectively) and similar at all sites, thus indicating no general increases in the heterotrophic pathway. Depleted δ13C and enriched δ15N values of coral host tissues measured at the most turbid site were explained by changes in isotopic composition of the inorganic nutrients taken up by photosymbionts and also by changes in rate of isotopic fractionation with environmental conditions. Our results also highlighted a lack of significant temporal variations in δ13C and δ15N values of coral host and photosymbiont tissues and in Δhost-photosymbionts 13C and Δhost-photosymbionts 15N values. This temporal stability indicated that corals remained principally autotrophic even during the wet season when photosymbiont densities were lower and the concentrations of phytoplankton were higher. Increased coral heterotrophy with higher food availability thus appears to be species-specific.
- Full Text:
- Date Issued: 2013
Stock returns and Friday the 13th effect in five African countries
- Authors: Botha, Ferdi
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/396127 , vital:69152 , xlink:href="https://www.ajol.info/index.php/aref/article/view/91060"
- Description: This study is concerned with Friday the 13th and daily stock market returns in five African countries. Using the MSCI Global Equity Indices during various periods, the evidence overwhelmingly suggests that there is no Friday the 13th effect.
- Full Text:
- Date Issued: 2013
- Authors: Botha, Ferdi
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/396127 , vital:69152 , xlink:href="https://www.ajol.info/index.php/aref/article/view/91060"
- Description: This study is concerned with Friday the 13th and daily stock market returns in five African countries. Using the MSCI Global Equity Indices during various periods, the evidence overwhelmingly suggests that there is no Friday the 13th effect.
- Full Text:
- Date Issued: 2013
Study South Africa
- International Education Association of South Africa (IEASA), Jooste, Nico
- Authors: International Education Association of South Africa (IEASA) , Jooste, Nico
- Date: 2013
- Subjects: Education, Higher -- South Africa , Education and globalization -- South Africa Student mobility -- Africa International education -- South Africa Education, Higher -- International cooperation , Universities and colleges -- South Africa , Technical Institutes -- South Africa , Vocational guidance -- South Africa
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/64878 , vital:28623
- Description: [Editor's Letter]: Study South Africa has been the global mouthpiece of the International Education Association of South Africa (IEASA) and South African Higher Education since the publication of its first edition in 1999. It grew from a publication that served as a guide to South African Higher Education to a comprehensive source of information for the international academic community and others interested in South Africa’s tertiary education sector. This annual publication requires knowledgeable contributors as well as skilful editorial and other technical support. For the past number of years the editorial team was ably supported by Loveness Kaunda from the University of Cape Town (UCT). She provided the publication with her time, energy and knowledge. However, as she retired from her UCT position, she will no longer be available to consult with on a regular basis. This edition of Study South Africa is dedicated to her as a token of gratitude for all her time and passion. Another source of knowledge and inspiration is Patrick Fish - a higher education specialist who does research on topics relevant to the South African Higher Education landscape and provides us with up-to-date information. His writing skills turn the first number of pages of this publication into a real source of information. The knowledge about South African universities will be incomplete without the contributions of the universities themselves. A common trend this year is the focus on excellence of teaching and research as well as the relevance of South African Higher Education to local students functioning in an ever globalising world. It is also evident that most of the South African universities are aware of the need to be globally competitive, not only to attract the best international students, but also to be able to compete in a very competitive global knowledge driven environment. Study South Africa is again proudly presented by IEASA. This edition, focussing on Internationalisation of Higher Education, with a specific focus on South Africa in a changing world, again illustrates the interconnectedness of global higher education. It is envisaged that future editions will explore and document the collaboration between IEASA and similar organisations that is promoting the Internationalisation of Higher Education as well as global trends in international higher education affecting internationalisation of higher education in emerging countries. , 13th Edition
- Full Text:
- Date Issued: 2013
- Authors: International Education Association of South Africa (IEASA) , Jooste, Nico
- Date: 2013
- Subjects: Education, Higher -- South Africa , Education and globalization -- South Africa Student mobility -- Africa International education -- South Africa Education, Higher -- International cooperation , Universities and colleges -- South Africa , Technical Institutes -- South Africa , Vocational guidance -- South Africa
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/64878 , vital:28623
- Description: [Editor's Letter]: Study South Africa has been the global mouthpiece of the International Education Association of South Africa (IEASA) and South African Higher Education since the publication of its first edition in 1999. It grew from a publication that served as a guide to South African Higher Education to a comprehensive source of information for the international academic community and others interested in South Africa’s tertiary education sector. This annual publication requires knowledgeable contributors as well as skilful editorial and other technical support. For the past number of years the editorial team was ably supported by Loveness Kaunda from the University of Cape Town (UCT). She provided the publication with her time, energy and knowledge. However, as she retired from her UCT position, she will no longer be available to consult with on a regular basis. This edition of Study South Africa is dedicated to her as a token of gratitude for all her time and passion. Another source of knowledge and inspiration is Patrick Fish - a higher education specialist who does research on topics relevant to the South African Higher Education landscape and provides us with up-to-date information. His writing skills turn the first number of pages of this publication into a real source of information. The knowledge about South African universities will be incomplete without the contributions of the universities themselves. A common trend this year is the focus on excellence of teaching and research as well as the relevance of South African Higher Education to local students functioning in an ever globalising world. It is also evident that most of the South African universities are aware of the need to be globally competitive, not only to attract the best international students, but also to be able to compete in a very competitive global knowledge driven environment. Study South Africa is again proudly presented by IEASA. This edition, focussing on Internationalisation of Higher Education, with a specific focus on South Africa in a changing world, again illustrates the interconnectedness of global higher education. It is envisaged that future editions will explore and document the collaboration between IEASA and similar organisations that is promoting the Internationalisation of Higher Education as well as global trends in international higher education affecting internationalisation of higher education in emerging countries. , 13th Edition
- Full Text:
- Date Issued: 2013
Subterranean control of an arboreal pest: EPNs and EPFs for FCM
- Moore, Sean D, Coombes, Candice A, Manrakhan, Aruna, Kirkman, Wayne, Hill, Martin P, Ehlers, Ralf-Udo, Daneel, John-Henry, De Waal, Jeanne, Dames, Joanna F, Malan, Antoinette P
- Authors: Moore, Sean D , Coombes, Candice A , Manrakhan, Aruna , Kirkman, Wayne , Hill, Martin P , Ehlers, Ralf-Udo , Daneel, John-Henry , De Waal, Jeanne , Dames, Joanna F , Malan, Antoinette P
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/425450 , vital:72241 , xlink:href="https://www.cabdirect.org/cabdirect/abstract/20133257699"
- Description: Control measures against the false codling moth (FCM), Thaumatotibia leucotreta, have traditionally ignored the soil-borne pupal stage. Recent trials with entomopathogenic nematodes (EPNs) and entomopathogenic fungi (EPFs) have targeted this life-stage. Application of Heterorhabditis bacteriophora to a citrus orchard floor, reduced T. leucotreta infestation of fruit by up to 81%. Conservation of H. zealandica through non-usage of a nematicide also resulted in dramatically lower fruit infestation. Dose-response and exposure time-response bioassays identified the three most promising fungal isolates against pupating T. leucotreta. Orchard trials showed persistence of these fungi in orchard soil for at least six months.
- Full Text:
- Date Issued: 2013
- Authors: Moore, Sean D , Coombes, Candice A , Manrakhan, Aruna , Kirkman, Wayne , Hill, Martin P , Ehlers, Ralf-Udo , Daneel, John-Henry , De Waal, Jeanne , Dames, Joanna F , Malan, Antoinette P
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/425450 , vital:72241 , xlink:href="https://www.cabdirect.org/cabdirect/abstract/20133257699"
- Description: Control measures against the false codling moth (FCM), Thaumatotibia leucotreta, have traditionally ignored the soil-borne pupal stage. Recent trials with entomopathogenic nematodes (EPNs) and entomopathogenic fungi (EPFs) have targeted this life-stage. Application of Heterorhabditis bacteriophora to a citrus orchard floor, reduced T. leucotreta infestation of fruit by up to 81%. Conservation of H. zealandica through non-usage of a nematicide also resulted in dramatically lower fruit infestation. Dose-response and exposure time-response bioassays identified the three most promising fungal isolates against pupating T. leucotreta. Orchard trials showed persistence of these fungi in orchard soil for at least six months.
- Full Text:
- Date Issued: 2013
Surface patterning using scanning electrochemical microscopy to locally trigger a “click” chemistry reaction
- Quinton, Damien, Maringa, Audacity, Griveau, Sophie, Nyokong, Tebello, Bedioui, Fethi
- Authors: Quinton, Damien , Maringa, Audacity , Griveau, Sophie , Nyokong, Tebello , Bedioui, Fethi
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241805 , vital:50971 , xlink:href="https://doi.org/10.1016/j.elecom.2013.03.021"
- Description: We report on the surface micropatterning of conductive surfaces via the electrochemical triggering of a click reaction, the copper(I) catalyzed azide–alkyne cycloaddition reaction (CuAAC) by SECM via a two-step approach: (i) functionalization on the entire surface with azido-aryl groups by using the diazonium approach followed by (ii) the covalent linkage of alkyne-bearing ferrocene by CuAAC within a local area by SECM. More precisely, the click reaction was triggered by Cu(I) catalyst generation for 30 min at the SECM tip positioned ≈ 10 μm above the azido-aryl modified surface. The dimension of the spot obtained under these conditions was ≈ 75 μm. The electrochemical imaging by SECM of the ultra thin area locally clicked with ferrocene moieties was made thanks to the electrocatalytic properties of the ferrocene modified surface towards ferrocyanide electrooxidation. This local clicking procedure opens the gate to further controlled functionalization of restricted small substrates.
- Full Text:
- Date Issued: 2013
- Authors: Quinton, Damien , Maringa, Audacity , Griveau, Sophie , Nyokong, Tebello , Bedioui, Fethi
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241805 , vital:50971 , xlink:href="https://doi.org/10.1016/j.elecom.2013.03.021"
- Description: We report on the surface micropatterning of conductive surfaces via the electrochemical triggering of a click reaction, the copper(I) catalyzed azide–alkyne cycloaddition reaction (CuAAC) by SECM via a two-step approach: (i) functionalization on the entire surface with azido-aryl groups by using the diazonium approach followed by (ii) the covalent linkage of alkyne-bearing ferrocene by CuAAC within a local area by SECM. More precisely, the click reaction was triggered by Cu(I) catalyst generation for 30 min at the SECM tip positioned ≈ 10 μm above the azido-aryl modified surface. The dimension of the spot obtained under these conditions was ≈ 75 μm. The electrochemical imaging by SECM of the ultra thin area locally clicked with ferrocene moieties was made thanks to the electrocatalytic properties of the ferrocene modified surface towards ferrocyanide electrooxidation. This local clicking procedure opens the gate to further controlled functionalization of restricted small substrates.
- Full Text:
- Date Issued: 2013
Synthesis and nonlinear optical examination of 3 (4), 15 (16)-Bis-(4-tert-butyl-phenoxy)-10, 22-diaminohemiporphyrazinato chloroindium
- Britton, Jonathan, Antunes, Edith M, Nyokong, Tebello
- Authors: Britton, Jonathan , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241739 , vital:50965 , xlink:href="https://doi.org/10.1016/j.molstruc.2013.05.001"
- Description: 3(4),15(16)-Bis-(4-tert-butyl-phenoxy)-10,22-diaminohemiporphyrazinato chloroindium hemiporphyrazine was synthesized from 1,3,5-triaminobenzene and 4-tert-butyl-phenoxyisoindoline. The structure of the complex was confirmed using mass, nuclear magnetic resonance and infrared spectroscopies. The nonlinear parameters of the compound was also analyzed in dimethylformamide and found to be significantly greater than previously analyzed phthalocyanines.
- Full Text:
- Date Issued: 2013
- Authors: Britton, Jonathan , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241739 , vital:50965 , xlink:href="https://doi.org/10.1016/j.molstruc.2013.05.001"
- Description: 3(4),15(16)-Bis-(4-tert-butyl-phenoxy)-10,22-diaminohemiporphyrazinato chloroindium hemiporphyrazine was synthesized from 1,3,5-triaminobenzene and 4-tert-butyl-phenoxyisoindoline. The structure of the complex was confirmed using mass, nuclear magnetic resonance and infrared spectroscopies. The nonlinear parameters of the compound was also analyzed in dimethylformamide and found to be significantly greater than previously analyzed phthalocyanines.
- Full Text:
- Date Issued: 2013
Synthesis and photophysicochemical properties of zinc phthalocyanine derivatized with benzothiazole or carbazole photosensitizers
- Khoza, Phindile, Antunes, Edith M, Nyokong, Tebello
- Authors: Khoza, Phindile , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241728 , vital:50964 , xlink:href="https://doi.org/10.1016/j.poly.2013.05.046"
- Description: The synthesis of new zinc phthalocyanine complexes containing 3-(2-benzothiazol-2-yloxy) (complex 3) and 3-(carbazol-2-yloxy) (complex 4) substituents at the non-peripheral positions are reported. The new compounds were characterized by elemental analysis, FT-IR, 1H NMR, mass spectrometry and UV–Vis spectroscopy. The effects of carbazole and benzothiazole substitutents on the photophysical and photochemical parameters of ZnPc are reported. These new phthalocyanines are non-aggregated in common solvents and show improved photophysicochemical properties. The 3-(2-benzothiazol-2-yloxy) substituted complex showed the longest triplet lifetime ever reported for a zinc phthalocyanine (1.7 ms).
- Full Text:
- Date Issued: 2013
- Authors: Khoza, Phindile , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241728 , vital:50964 , xlink:href="https://doi.org/10.1016/j.poly.2013.05.046"
- Description: The synthesis of new zinc phthalocyanine complexes containing 3-(2-benzothiazol-2-yloxy) (complex 3) and 3-(carbazol-2-yloxy) (complex 4) substituents at the non-peripheral positions are reported. The new compounds were characterized by elemental analysis, FT-IR, 1H NMR, mass spectrometry and UV–Vis spectroscopy. The effects of carbazole and benzothiazole substitutents on the photophysical and photochemical parameters of ZnPc are reported. These new phthalocyanines are non-aggregated in common solvents and show improved photophysicochemical properties. The 3-(2-benzothiazol-2-yloxy) substituted complex showed the longest triplet lifetime ever reported for a zinc phthalocyanine (1.7 ms).
- Full Text:
- Date Issued: 2013
Synthesis and photophysicochemical studies of a water soluble conjugate between folic acid and zinc tetraaminophthalocyanine
- Khoza, Phindile, Antunes, Edith M, Chen, Ji-Yao, Nyokong, Tebello
- Authors: Khoza, Phindile , Antunes, Edith M , Chen, Ji-Yao , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/242142 , vital:51005 , xlink:href="https://doi.org/10.1016/j.jlumin.2012.06.048"
- Description: This work reports on the synthesis of zinc tetraaminophthalocyanine (ZnTAPc) functionalized with folic acid (FA), forming ZnTAPcFA. The conjugate between FA and ZnTAPc was soluble in water whereas ZnTAPc alone is not. The structure of ZnTAPcFA conjugate was elucidated by 1H NMR, MALDI-TOF mass and FTIR spectra. Photophysical and photochemical studies of ZnTAPcFA were conducted in DMSO. The increase in fluorescence quantum yield of the conjugate was accompanied by a decrease in the triplet and singlet oxygen quantum yields. The changes in triplet quantum and singlet oxygen quantum yields were marginal when ZnTAPc was simply mixed with FA without a chemical bond.
- Full Text:
- Date Issued: 2013
- Authors: Khoza, Phindile , Antunes, Edith M , Chen, Ji-Yao , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/242142 , vital:51005 , xlink:href="https://doi.org/10.1016/j.jlumin.2012.06.048"
- Description: This work reports on the synthesis of zinc tetraaminophthalocyanine (ZnTAPc) functionalized with folic acid (FA), forming ZnTAPcFA. The conjugate between FA and ZnTAPc was soluble in water whereas ZnTAPc alone is not. The structure of ZnTAPcFA conjugate was elucidated by 1H NMR, MALDI-TOF mass and FTIR spectra. Photophysical and photochemical studies of ZnTAPcFA were conducted in DMSO. The increase in fluorescence quantum yield of the conjugate was accompanied by a decrease in the triplet and singlet oxygen quantum yields. The changes in triplet quantum and singlet oxygen quantum yields were marginal when ZnTAPc was simply mixed with FA without a chemical bond.
- Full Text:
- Date Issued: 2013
Synthesis and physicochemical behaviour of aluminium bis and tris (diammine platinum) octacarboxyphthalocyanine
- Malinga, Nduduzo, Antunes, Edith M, Nyokong, Tebello
- Authors: Malinga, Nduduzo , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241970 , vital:50988 , xlink:href="https://doi.org/10.1016/j.poly.2013.02.073"
- Description: Hydroxy aluminium octacarboxy phthalocyanine (Al(OH)OCPc) was conjugated with a diammine platinum complex to give conjugates containing two or three platinum complexes (represented as: Al(OH)OCPc(Pt)2 and Al(OH)OCPc(Pt)3). It was found that the complexes were soluble in water at a pH > 8.2. Both conjugates were found to have two fluorescence lifetimes. The triplet and singlet oxygen quantum yields increased for the conjugates compared to Al(OH)OCPc alone.
- Full Text:
- Date Issued: 2013
- Authors: Malinga, Nduduzo , Antunes, Edith M , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241970 , vital:50988 , xlink:href="https://doi.org/10.1016/j.poly.2013.02.073"
- Description: Hydroxy aluminium octacarboxy phthalocyanine (Al(OH)OCPc) was conjugated with a diammine platinum complex to give conjugates containing two or three platinum complexes (represented as: Al(OH)OCPc(Pt)2 and Al(OH)OCPc(Pt)3). It was found that the complexes were soluble in water at a pH > 8.2. Both conjugates were found to have two fluorescence lifetimes. The triplet and singlet oxygen quantum yields increased for the conjugates compared to Al(OH)OCPc alone.
- Full Text:
- Date Issued: 2013