Novel gallium (III) phthalocyanine derivatives–Synthesis, photophysics and photochemistry
- Chauke, Vongani, Ogunsipe, Abimbola, Durmus, Mahmut, Nyokong, Tebello
- Authors: Chauke, Vongani , Ogunsipe, Abimbola , Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283118 , vital:55912 , xlink:href="https://doi.org/10.1016/j.poly.2007.01.016"
- Description: The syntheses of gallium(III) chloride phthalocyanine {(Cl)GaPc}, octaphenoxyphthalocyaninato gallium(III) chloride {(Cl)GaOPPc} and octakis(4-tert-butylphenoxy)phthalocyaninato gallium(III) chloride {(Cl)GaOTBPPc}; as well as their photophysical and photochemical parameters are hereby presented. Fluorescence quantum yields do not vary much among the three metallophthalocyanines (MPcs); therefore it was concluded that the effect of the substituents is not significant amongst (Cl)GaPc, (Cl)GaOPPc and (Cl)GaOTBPPc. Solvents effects, however, had an effect on the results. Triplet quantum yields were found to be lower in DMSO than in DMF and toluene. The rate constants for fluorescence, intersystem crossing and internal conversion as well as fluorescence and triplet lifetimes are reported. We have also reported photodegradation and singlet oxygen quantum yields. There was no clear correlation between the later parameters. It was, however, established that the three MPcs were stable.
- Full Text:
- Date Issued: 2007
- Authors: Chauke, Vongani , Ogunsipe, Abimbola , Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283118 , vital:55912 , xlink:href="https://doi.org/10.1016/j.poly.2007.01.016"
- Description: The syntheses of gallium(III) chloride phthalocyanine {(Cl)GaPc}, octaphenoxyphthalocyaninato gallium(III) chloride {(Cl)GaOPPc} and octakis(4-tert-butylphenoxy)phthalocyaninato gallium(III) chloride {(Cl)GaOTBPPc}; as well as their photophysical and photochemical parameters are hereby presented. Fluorescence quantum yields do not vary much among the three metallophthalocyanines (MPcs); therefore it was concluded that the effect of the substituents is not significant amongst (Cl)GaPc, (Cl)GaOPPc and (Cl)GaOTBPPc. Solvents effects, however, had an effect on the results. Triplet quantum yields were found to be lower in DMSO than in DMF and toluene. The rate constants for fluorescence, intersystem crossing and internal conversion as well as fluorescence and triplet lifetimes are reported. We have also reported photodegradation and singlet oxygen quantum yields. There was no clear correlation between the later parameters. It was, however, established that the three MPcs were stable.
- Full Text:
- Date Issued: 2007
Photocatalysis of 4-nitrophenol using zinc phthalocyanine complexes
- Marais, Eloïse A, Klein, Rosalyn, Antunes, Edith M, Nyokong, Tebello
- Authors: Marais, Eloïse A , Klein, Rosalyn , Antunes, Edith M , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281286 , vital:55709 , xlink:href="https://doi.org/10.1016/j.molcata.2006.07.055"
- Description: Photodegradation of 4-nitrophenol (4-Np) in the presence of zinc tetrasulfophthalocyanine (ZnPcS4), zinc octacarboxyphthalocyanine (ZnPc(COOH)8) and a sulfonated ZnPc containing a mixture of differently sulfonated derivatives (ZnPcSmix), as photocatalysts is reported. ZnPcSmix is the most effective catalyst in terms of a high quantum yield for 4-Np degradation and the stability of the catalyst. However ZnPc(COOH)8 degrades readily during the catalysis, but it has a higher quantum yield (Φ4-Np) for 4-Np degradation than the rest of the complexes. The Φ4-Np values were closely related to the singlet oxygen quantum yields ΦΔ and hence aggregation. The rate constants for the reaction with 4-Np were kr = 0.67 × 106 mol−1 dm3 s−1 for ZnPcSmix and 2.8 × 108 mol−1 dm3 s−1 for ZnPc(COOH)8.
- Full Text:
- Date Issued: 2007
- Authors: Marais, Eloïse A , Klein, Rosalyn , Antunes, Edith M , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281286 , vital:55709 , xlink:href="https://doi.org/10.1016/j.molcata.2006.07.055"
- Description: Photodegradation of 4-nitrophenol (4-Np) in the presence of zinc tetrasulfophthalocyanine (ZnPcS4), zinc octacarboxyphthalocyanine (ZnPc(COOH)8) and a sulfonated ZnPc containing a mixture of differently sulfonated derivatives (ZnPcSmix), as photocatalysts is reported. ZnPcSmix is the most effective catalyst in terms of a high quantum yield for 4-Np degradation and the stability of the catalyst. However ZnPc(COOH)8 degrades readily during the catalysis, but it has a higher quantum yield (Φ4-Np) for 4-Np degradation than the rest of the complexes. The Φ4-Np values were closely related to the singlet oxygen quantum yields ΦΔ and hence aggregation. The rate constants for the reaction with 4-Np were kr = 0.67 × 106 mol−1 dm3 s−1 for ZnPcSmix and 2.8 × 108 mol−1 dm3 s−1 for ZnPc(COOH)8.
- Full Text:
- Date Issued: 2007
Photochemistry, photophysics and nonlinear optical parameters of phenoxy and tert-butylphenoxy substituted indium (III) phthalocyanines
- Chauke, Vongani, Durmus, Mahmut, Nyokong, Tebello
- Authors: Chauke, Vongani , Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268823 , vital:54235 , xlink:href="https://doi.org/10.1016/j.jphotochem.2007.05.022"
- Description: This work hereby presents the syntheses, photochemistry and photophysics of octaphenoxy ((Cl)InOPPc) and octakis(4-tert-butylphenoxy)chloroindium ((Cl)InOTBPPc) phthalocyanines. Calculated nonlinear parameters of these complexes are compared with those of the corresponding GaPc derivatives and tetrasubstituted GaPc and InPc complexes. Fluorescence quantum yields do not vary much between (Cl)InOPPc and (Cl)InOTBPPc complexes in different solvents. High quantum yields of triplet state (ΦT ranging from 0.70 to 0.91 in dimethysulphoxide, DMSO) and singlet oxygen generation (ΦΔ, ranging from 0.61 to 0.79 in DMSO) were obtained. Short triplet lifetimes 50–60 μs were obtained in DMSO). The optical limiting threshold intensity (Ilim) for the InPc derivatives were calculated and compared with those of corresponding tetrasubstituted InPc and GaPc complexes. The latter were found to be better optical limiters.
- Full Text:
- Date Issued: 2007
- Authors: Chauke, Vongani , Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268823 , vital:54235 , xlink:href="https://doi.org/10.1016/j.jphotochem.2007.05.022"
- Description: This work hereby presents the syntheses, photochemistry and photophysics of octaphenoxy ((Cl)InOPPc) and octakis(4-tert-butylphenoxy)chloroindium ((Cl)InOTBPPc) phthalocyanines. Calculated nonlinear parameters of these complexes are compared with those of the corresponding GaPc derivatives and tetrasubstituted GaPc and InPc complexes. Fluorescence quantum yields do not vary much between (Cl)InOPPc and (Cl)InOTBPPc complexes in different solvents. High quantum yields of triplet state (ΦT ranging from 0.70 to 0.91 in dimethysulphoxide, DMSO) and singlet oxygen generation (ΦΔ, ranging from 0.61 to 0.79 in DMSO) were obtained. Short triplet lifetimes 50–60 μs were obtained in DMSO). The optical limiting threshold intensity (Ilim) for the InPc derivatives were calculated and compared with those of corresponding tetrasubstituted InPc and GaPc complexes. The latter were found to be better optical limiters.
- Full Text:
- Date Issued: 2007
Photochemistry, photophysics and nonlinear optical parameters of phenoxy and tert-butylphenoxy substituted indium (III) phthalocyanines
- Chauke, Vongani, Durmus, Mahmut, Nyokong, Tebello
- Authors: Chauke, Vongani , Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268787 , vital:54232 , xlink:href="https://doi.org/10.1016/j.jphotochem.2007.05.022"
- Description: This work hereby presents the syntheses, photochemistry and photophysics of octaphenoxy ((Cl)InOPPc) and octakis(4-tert-butylphenoxy)chloroindium ((Cl)InOTBPPc) phthalocyanines. Calculated nonlinear parameters of these complexes are compared with those of the corresponding GaPc derivatives and tetrasubstituted GaPc and InPc complexes. Fluorescence quantum yields do not vary much between (Cl)InOPPc and (Cl)InOTBPPc complexes in different solvents. High quantum yields of triplet state (ΦT ranging from 0.70 to 0.91 in dimethysulphoxide, DMSO) and singlet oxygen generation (ΦΔ, ranging from 0.61 to 0.79 in DMSO) were obtained. Short triplet lifetimes 50–60 μs were obtained in DMSO). The optical limiting threshold intensity (Ilim) for the InPc derivatives were calculated and compared with those of corresponding tetrasubstituted InPc and GaPc complexes. The latter were found to be better optical limiters.
- Full Text:
- Date Issued: 2007
- Authors: Chauke, Vongani , Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268787 , vital:54232 , xlink:href="https://doi.org/10.1016/j.jphotochem.2007.05.022"
- Description: This work hereby presents the syntheses, photochemistry and photophysics of octaphenoxy ((Cl)InOPPc) and octakis(4-tert-butylphenoxy)chloroindium ((Cl)InOTBPPc) phthalocyanines. Calculated nonlinear parameters of these complexes are compared with those of the corresponding GaPc derivatives and tetrasubstituted GaPc and InPc complexes. Fluorescence quantum yields do not vary much between (Cl)InOPPc and (Cl)InOTBPPc complexes in different solvents. High quantum yields of triplet state (ΦT ranging from 0.70 to 0.91 in dimethysulphoxide, DMSO) and singlet oxygen generation (ΦΔ, ranging from 0.61 to 0.79 in DMSO) were obtained. Short triplet lifetimes 50–60 μs were obtained in DMSO). The optical limiting threshold intensity (Ilim) for the InPc derivatives were calculated and compared with those of corresponding tetrasubstituted InPc and GaPc complexes. The latter were found to be better optical limiters.
- Full Text:
- Date Issued: 2007
Photophysical and photochemical properties of zinc and aluminum phthalocyanines in the presence of magnetic fluid
- Idowu, Mopelola, Nyokong, Tebello
- Authors: Idowu, Mopelola , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281298 , vital:55710 , xlink:href="https://doi.org/10.1016/j.jphotochem.2006.12.013"
- Description: The effect of magnetic fluid (MF) on the photophysical and photochemical parameters of zinc and aluminum phthalocyanines are reported. The complexes studied are zinc (II) phthalocyanine (ZnPc), chloroaluminum phthalocyanine ((Cl)AlPc) and tetrasulfonated aluminum phthalocyanine ((Cl)AlTSPc). The parameters are studied in dimethylsulfoxide (DMSO) for all complexes and also in aqueous media for (Cl)AlTSPc. The triplet lifetimes for (Cl)AlTSPc and ZnPc decreased while the triplet quantum yields increased in the presence of MF. For (Cl)AlPc, the triplet lifetimes were found to increase with decrease in laser energy while there was photoreduction to the Pc−3 species. Singlet oxygen and photodegradation quantum yields decreased in the presence of MF, suggesting quenching.
- Full Text:
- Date Issued: 2007
- Authors: Idowu, Mopelola , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281298 , vital:55710 , xlink:href="https://doi.org/10.1016/j.jphotochem.2006.12.013"
- Description: The effect of magnetic fluid (MF) on the photophysical and photochemical parameters of zinc and aluminum phthalocyanines are reported. The complexes studied are zinc (II) phthalocyanine (ZnPc), chloroaluminum phthalocyanine ((Cl)AlPc) and tetrasulfonated aluminum phthalocyanine ((Cl)AlTSPc). The parameters are studied in dimethylsulfoxide (DMSO) for all complexes and also in aqueous media for (Cl)AlTSPc. The triplet lifetimes for (Cl)AlTSPc and ZnPc decreased while the triplet quantum yields increased in the presence of MF. For (Cl)AlPc, the triplet lifetimes were found to increase with decrease in laser energy while there was photoreduction to the Pc−3 species. Singlet oxygen and photodegradation quantum yields decreased in the presence of MF, suggesting quenching.
- Full Text:
- Date Issued: 2007
Photophysical and photochemical studies of long chain-substituted zinc phthalocyanines
- Durmus, Mahmut, Ahsen, Vefa, Nyokong, Tebello
- Authors: Durmus, Mahmut , Ahsen, Vefa , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281310 , vital:55711 , xlink:href="https://doi.org/10.1016/j.jphotochem.2006.08.025"
- Description: Photochemical and photophysical measurements were conducted on peripheral and non-peripheral tetra(13,17-dioxanonacosane-15-hydroxy)-substituted zinc phthalocyanines (1, 2). General trends are described for quantum yields of photodegradation, fluorescence yields, triplet lifetimes and triplet quantum yields as well as singlet quantum yields of these compounds in dimethylformamide (DMF) and toluene. The effects of the solvents on the photophysical and photochemical parameters of the zinc(II) phthalocyanines (1, 2) are reported.
- Full Text:
- Date Issued: 2007
- Authors: Durmus, Mahmut , Ahsen, Vefa , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281310 , vital:55711 , xlink:href="https://doi.org/10.1016/j.jphotochem.2006.08.025"
- Description: Photochemical and photophysical measurements were conducted on peripheral and non-peripheral tetra(13,17-dioxanonacosane-15-hydroxy)-substituted zinc phthalocyanines (1, 2). General trends are described for quantum yields of photodegradation, fluorescence yields, triplet lifetimes and triplet quantum yields as well as singlet quantum yields of these compounds in dimethylformamide (DMF) and toluene. The effects of the solvents on the photophysical and photochemical parameters of the zinc(II) phthalocyanines (1, 2) are reported.
- Full Text:
- Date Issued: 2007
Photophysical, photochemical and bovine serum albumin binding studies on water-soluble gallium (III) phthalocyanine derivatives
- Ogunsipe, Abimbola, Nyokong, Tebello, Durmus, Mahmut
- Authors: Ogunsipe, Abimbola , Nyokong, Tebello , Durmus, Mahmut
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/271239 , vital:54524 , xlink:href="https://doi.org/10.1142/S1088424607000746"
- Description: Spectral, photophysical, photochemical and bovine serum albumin binding studies on some gallium(III) derivatives - {1,(4)-(tetrapyridyloxyphthalocyaninato)gallium(III), (αGaPc); 2,(3)-(tetrapyridyloxyphthalocyaninato)gallium(III), (βGaPc); and their quaternized derivatives: QαGaPc and QβGaPc)} are hereby presented. β-Substituted complexes are more fluorescent, but show lower tendencies to undergo intersystem crossing than the α-substituted, as judged by their fluorescence and triplet quantum yield values. The quaternized derivatives (QGaPc) are water-soluble and non-aggregated, which makes them potential photosensitizers of choice for photodynamic therapy applications; these amphiphilic compounds also bind strongly to bovine serum albumin in 1:1 stoichiometries, and with binding constants (Kb) in the order of 106 M−1.
- Full Text:
- Date Issued: 2007
- Authors: Ogunsipe, Abimbola , Nyokong, Tebello , Durmus, Mahmut
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/271239 , vital:54524 , xlink:href="https://doi.org/10.1142/S1088424607000746"
- Description: Spectral, photophysical, photochemical and bovine serum albumin binding studies on some gallium(III) derivatives - {1,(4)-(tetrapyridyloxyphthalocyaninato)gallium(III), (αGaPc); 2,(3)-(tetrapyridyloxyphthalocyaninato)gallium(III), (βGaPc); and their quaternized derivatives: QαGaPc and QβGaPc)} are hereby presented. β-Substituted complexes are more fluorescent, but show lower tendencies to undergo intersystem crossing than the α-substituted, as judged by their fluorescence and triplet quantum yield values. The quaternized derivatives (QGaPc) are water-soluble and non-aggregated, which makes them potential photosensitizers of choice for photodynamic therapy applications; these amphiphilic compounds also bind strongly to bovine serum albumin in 1:1 stoichiometries, and with binding constants (Kb) in the order of 106 M−1.
- Full Text:
- Date Issued: 2007
Preliminary survey of indigenous, non-indigenous and cryptogenic benthic invertebrates in Burrard Inlet, Vancover, British Columbia
- Richoux, Nicole B, Froneman, P William
- Authors: Richoux, Nicole B , Froneman, P William
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/457981 , vital:75705 , xlink:href="https://doi.org/10.1016/j.ecss.2006.09.007"
- Description: In a preliminary investigation into the presence of non-indigenous invertebrates in Burrard Inlet, Vancouver, British Columbia, qualitative sampling on rocky shores, pilings and floating docks was conducted in July and August 2004. Twenty-nine sites were established, 34 samples were analysed, and 103 different taxa were identified. Data were also obtained on habitat characteristics including substrate type, salinity and temperature. Identification of polychaetes, mussels from four sites, all amphipods, isopods and patellogastropods have been confirmed by taxonomic specialists.
- Full Text:
- Date Issued: 2007
- Authors: Richoux, Nicole B , Froneman, P William
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/457981 , vital:75705 , xlink:href="https://doi.org/10.1016/j.ecss.2006.09.007"
- Description: In a preliminary investigation into the presence of non-indigenous invertebrates in Burrard Inlet, Vancouver, British Columbia, qualitative sampling on rocky shores, pilings and floating docks was conducted in July and August 2004. Twenty-nine sites were established, 34 samples were analysed, and 103 different taxa were identified. Data were also obtained on habitat characteristics including substrate type, salinity and temperature. Identification of polychaetes, mussels from four sites, all amphipods, isopods and patellogastropods have been confirmed by taxonomic specialists.
- Full Text:
- Date Issued: 2007
Realistic idealism
- Authors: Tabensky, Pedro
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/305700 , vital:58605 , xlink:href="https://doi.org/10.3167/th.2007.5411306"
- Description: Realists found in International Relations (IR) circles explicitly assign relatively minor importance to ethical ideals in their analyses of the international political domain, although a robust ethical ideal of sorts, implicitly for the most part qua ethical ideal, does guide their analysis of the international arena. For them, the key to order in the international arena is the balance of power reached between different nations aiming at asserting their wills, promoting their interests, in what is in effect perceived by IR realists as an international battle of wills guided primarily by the logic of power. As a purely descriptive claim regarding how nations, for the most part, actually behave, I have no axe to grind with the IR realist, or at least I do not have to grind an axe with them on this matter for the purposes of this paper, but the IR realist is committed to more than merely describing the behaviour of the international order. IR realists, implicitly and paradoxically, are forced, by the logic of their own position, to believe that the ethical ideal that ought to be guiding the international order is the balance of power between competing interests guiding the international behaviour of nations in their quest for power and (alleged) survival. The primary moral dictum of their position is that nations ought to pursue their self-interested interests relentlessly, but only to the extent that the fragile balance of power is not upset (which is, at any rate, a central ingredient for promoting national self-interest). IR realists do not altogether explicitly deny the role of ideals, but the role they assign to ideals is limited and, I will argue, ultimately incoherent, for ideals ought to be understood as flowing from the structure of our embodied existences and into every nook and cranny of our lives, understood individually and collectively, nationally and internationally. We are active creatures, as Aristotle observed, and activities are defined as such in relation to a functional ideal, an ideal of operation, which flows from our specific modes of embodiment. The norms or ends guiding the international political order ought to flow from this understanding of the human subject ideally conceived, as opposed to the largely Machiavellian pessimistic understanding of the human situation informing IR realism; a pessimism that stems from the fallacious move from raw observation to normative recommendation. To claim that our ends are Machiavellian, we shall see, is incoherent and this incoherence is at the heart of IR realism. The demands of reason, we shall see, should push us in the direction of a particular variety of optimism. By using a broadly Aristotelian teleological technique of analysis I will show that IR realists cannot be right. Without placing ideals at the centre of our understandings of our political lives we would be unable properly to understand the political domain, including the specific sphere of concern of IR specialists. The purely observational descriptions alluded to above do not provide the grounds for proper understanding. What does provide a proper understanding, we shall see, is observation through a conceptual lens informed by a teleological understanding of the human person (observation in the light of a conception of the good). That I think a robust conception of the good, of the set of ideals that out to be guiding rational human life, is necessary for properly understanding the international arena does not of course mean that I advocate any such conception of the good. As claimed above, the sort that I advocate, following Aristotle’s footsteps, flows from the specific configuration of our embodied lives. I refer to this form of idealism as realistic idealism.
- Full Text:
- Date Issued: 2007
- Authors: Tabensky, Pedro
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/305700 , vital:58605 , xlink:href="https://doi.org/10.3167/th.2007.5411306"
- Description: Realists found in International Relations (IR) circles explicitly assign relatively minor importance to ethical ideals in their analyses of the international political domain, although a robust ethical ideal of sorts, implicitly for the most part qua ethical ideal, does guide their analysis of the international arena. For them, the key to order in the international arena is the balance of power reached between different nations aiming at asserting their wills, promoting their interests, in what is in effect perceived by IR realists as an international battle of wills guided primarily by the logic of power. As a purely descriptive claim regarding how nations, for the most part, actually behave, I have no axe to grind with the IR realist, or at least I do not have to grind an axe with them on this matter for the purposes of this paper, but the IR realist is committed to more than merely describing the behaviour of the international order. IR realists, implicitly and paradoxically, are forced, by the logic of their own position, to believe that the ethical ideal that ought to be guiding the international order is the balance of power between competing interests guiding the international behaviour of nations in their quest for power and (alleged) survival. The primary moral dictum of their position is that nations ought to pursue their self-interested interests relentlessly, but only to the extent that the fragile balance of power is not upset (which is, at any rate, a central ingredient for promoting national self-interest). IR realists do not altogether explicitly deny the role of ideals, but the role they assign to ideals is limited and, I will argue, ultimately incoherent, for ideals ought to be understood as flowing from the structure of our embodied existences and into every nook and cranny of our lives, understood individually and collectively, nationally and internationally. We are active creatures, as Aristotle observed, and activities are defined as such in relation to a functional ideal, an ideal of operation, which flows from our specific modes of embodiment. The norms or ends guiding the international political order ought to flow from this understanding of the human subject ideally conceived, as opposed to the largely Machiavellian pessimistic understanding of the human situation informing IR realism; a pessimism that stems from the fallacious move from raw observation to normative recommendation. To claim that our ends are Machiavellian, we shall see, is incoherent and this incoherence is at the heart of IR realism. The demands of reason, we shall see, should push us in the direction of a particular variety of optimism. By using a broadly Aristotelian teleological technique of analysis I will show that IR realists cannot be right. Without placing ideals at the centre of our understandings of our political lives we would be unable properly to understand the political domain, including the specific sphere of concern of IR specialists. The purely observational descriptions alluded to above do not provide the grounds for proper understanding. What does provide a proper understanding, we shall see, is observation through a conceptual lens informed by a teleological understanding of the human person (observation in the light of a conception of the good). That I think a robust conception of the good, of the set of ideals that out to be guiding rational human life, is necessary for properly understanding the international arena does not of course mean that I advocate any such conception of the good. As claimed above, the sort that I advocate, following Aristotle’s footsteps, flows from the specific configuration of our embodied lives. I refer to this form of idealism as realistic idealism.
- Full Text:
- Date Issued: 2007
Reflecting on the 2007 World Environmental Education Congress
- Authors: Lotz-Sisitka, Heila
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183047 , vital:43907 , xlink:href="https://doi.org/10.1177/097340820700100207"
- Description: What motivates more than 800 people from 101 countries around the world to meet at a World Environmental Education Congress? And how does one make the most of such an incredible gathering of people, cultures, thoughts and minds? What did people learn and was it worthwhile? These are just some of the questions that have been chasing through my mind in the weeks following the fourth World Environmental Education Congress held in Durban, South Africa, in July 2007. This short paper shares some preliminary reflections on the 2007 WEEC event, noting that in-depth analyses will only become possible as time passes.
- Full Text:
- Date Issued: 2007
- Authors: Lotz-Sisitka, Heila
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/183047 , vital:43907 , xlink:href="https://doi.org/10.1177/097340820700100207"
- Description: What motivates more than 800 people from 101 countries around the world to meet at a World Environmental Education Congress? And how does one make the most of such an incredible gathering of people, cultures, thoughts and minds? What did people learn and was it worthwhile? These are just some of the questions that have been chasing through my mind in the weeks following the fourth World Environmental Education Congress held in Durban, South Africa, in July 2007. This short paper shares some preliminary reflections on the 2007 WEEC event, noting that in-depth analyses will only become possible as time passes.
- Full Text:
- Date Issued: 2007
Rhodes University EE and Sustainability Unit
- Lotz-Sisitka, Heila, Schudel, Ingrid J
- Authors: Lotz-Sisitka, Heila , Schudel, Ingrid J
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/294423 , vital:57220 , xlink:href="https://doi.org/10.1177/097340820700100127"
- Description: In the early 1990s, in response to the emphasis laid on environment and development issues by the new South African Constitution, Rhodes University undertook several initiatives such as establishing the first Chair of Environmental Education (EE) in Africa. Another important initiative was the introduction of an open-entry participatory course for environmental educators. Owing to its flexible format and practice-based methodology, the course gained rapid popularity, necessitating the setting up of a Service Centre to help meet the increased demand. The Chair and the Service Centre have been providing a range of short courses in environment and sustainability education to professionals, and are today widely known as the Rhodes University Environmental Education and Sustainability Unit (RUEESU). The Unit offers PhD and Masters level programmes in EE, encourages meaningful research in key thematic areas, and is actively involved in publishing, and policy transformation. It also endeavours to define the role of Universities in enabling sustainability education.
- Full Text:
- Date Issued: 2007
- Authors: Lotz-Sisitka, Heila , Schudel, Ingrid J
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/294423 , vital:57220 , xlink:href="https://doi.org/10.1177/097340820700100127"
- Description: In the early 1990s, in response to the emphasis laid on environment and development issues by the new South African Constitution, Rhodes University undertook several initiatives such as establishing the first Chair of Environmental Education (EE) in Africa. Another important initiative was the introduction of an open-entry participatory course for environmental educators. Owing to its flexible format and practice-based methodology, the course gained rapid popularity, necessitating the setting up of a Service Centre to help meet the increased demand. The Chair and the Service Centre have been providing a range of short courses in environment and sustainability education to professionals, and are today widely known as the Rhodes University Environmental Education and Sustainability Unit (RUEESU). The Unit offers PhD and Masters level programmes in EE, encourages meaningful research in key thematic areas, and is actively involved in publishing, and policy transformation. It also endeavours to define the role of Universities in enabling sustainability education.
- Full Text:
- Date Issued: 2007
Spectroscopic characterisation and interactions of sulfonated titanium and tantalum phthalocyanines with methyl viologen
- Tau, Prudence, Nyokong, Tebello
- Authors: Tau, Prudence , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283129 , vital:55913 , xlink:href="https://doi.org/10.1016/j.ica.2006.12.035"
- Description: Sulfonated OTiPc(S)n and (Cl3)TaPc(S)n complexes are prepared and characterised by spectroscopic methods in DMSO, methanol and PBS 7.4. The dominant sulfonated species was the disulfophthalocyanine. OTiPc(S)n is highly aggregated in PBS 7.4 solution and tends to partially monomerise, on addition of Triton X-100, while (Cl3)TaPc(S)n showed broadened spectra in all solvents and was not affected by Triton X-100. The absorption and excitation spectra of OTiPc(S)n are similar and are mirror images of their emission spectra in DMSO, but differ in PBS and methanol. The fluorescence quantum yields (ϕF) and lifetimes (τF) were larger in DMSO than in methanol. In PBS 7.4, however, the ϕF and τF values were significantly smaller for OTiPc(S)n, which is typical of aggregated species. Gradual addition of the electron-acceptor MV2+ to solutions of MPc(S)n complexes resulted in the fluorescence quenching of complexes with higher quenching observed for OTiPc(S)n. The interaction of the MPc(S)n complexes with MV2+, and hence the stoichiometry and association constants are evaluated by means of Job method.
- Full Text:
- Date Issued: 2007
- Authors: Tau, Prudence , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283129 , vital:55913 , xlink:href="https://doi.org/10.1016/j.ica.2006.12.035"
- Description: Sulfonated OTiPc(S)n and (Cl3)TaPc(S)n complexes are prepared and characterised by spectroscopic methods in DMSO, methanol and PBS 7.4. The dominant sulfonated species was the disulfophthalocyanine. OTiPc(S)n is highly aggregated in PBS 7.4 solution and tends to partially monomerise, on addition of Triton X-100, while (Cl3)TaPc(S)n showed broadened spectra in all solvents and was not affected by Triton X-100. The absorption and excitation spectra of OTiPc(S)n are similar and are mirror images of their emission spectra in DMSO, but differ in PBS and methanol. The fluorescence quantum yields (ϕF) and lifetimes (τF) were larger in DMSO than in methanol. In PBS 7.4, however, the ϕF and τF values were significantly smaller for OTiPc(S)n, which is typical of aggregated species. Gradual addition of the electron-acceptor MV2+ to solutions of MPc(S)n complexes resulted in the fluorescence quenching of complexes with higher quenching observed for OTiPc(S)n. The interaction of the MPc(S)n complexes with MV2+, and hence the stoichiometry and association constants are evaluated by means of Job method.
- Full Text:
- Date Issued: 2007
Study South Africa
- International Education Association of South Africa (IEASA), Higher Education South Africa (Organization), Kishun, Roshen
- Authors: International Education Association of South Africa (IEASA) , Higher Education South Africa (Organization) , Kishun, Roshen
- Date: 2007
- Subjects: Education, Higher -- South Africa , Universities and colleges -- South Africa , Technical Institutes -- South Africa , Vocational guidance -- South Africa
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/65090 , vital:28685 , ISBN 9780620391634
- Description: [Extract from message from Minister of Higher Education, Hon. Naledi Pandor]: It gives me great pleasure to endorse the 7th edition of Study South Africa. The International Education Association of South Africa (IEASA) has once again produced a publication that provides valuable insights and information about South African public universities and their place in the global higher education arena I welcome this publication and congratulate IEASA for its hard work in promoting our higher education institutions internationally. Study South Africa gives a comprehensive picture of higher education in our country. At a glance, the enquirer is able to see all that South African higher education has to offer diversity in terms of institutions, the wide range of affordable courses on offer, the international acceptability of South African qualifications as well as the rich multi-cultural experiences of our campuses. In short, the Guide provides a summary of everything that will assist the potential student to actualise his or her full potential. South African higher education is founded on broad social values such as respect for human life and dignity, commitment to equality and human rights, respect for diversity and nonsexism. Our education system seeks to construct citizens who are conscious of these values and therefore aware of their responsibilities in life and in the lives of others. These values are reflected in the diverse offerings by institutions covered in the Guide. In addition, we have specific mechanisms in place to facilitate internationalisation, and our immigration policies have been relaxed to make it easier for international students, academics and other higher education staff to enter the country and stay for the duration of their planned activity. We also subsidise students from the continent in terms of our policy on the state subsidisation of foreign students at higher education institutions. South Africa shares the global concern about the digital and information divide. We are of the view that access to information is empowering and would therefore like to see as many citizens of our country and the continent connected with the rest of the world, both digitally and in terms of knowledge. By staying in touch with the rest of the world through information sharing and exchange programmes, we minimise this information gap. It is for this reason, therefore, that the work of IEASA in the form of this publication is applauded, because it seeks to promote such exchanges and information sharing. There is no question that through internationalisation we can impact on our political, economic, cultural and social transformation. We can also address our skills shortage, build research capacity, enrich curricula and enhance the student experience. Collectively higher education institutions in South Africa offer an impressive array of information and communication technologies, well stocked and interconnected libraries and some scholars who are among the best in the world, making the country a destination of choice for both Africans and students from abroad. We aspire to make all our international partners, students and staff feel at home and content with what our institutions offer them, pleasant living and study or work environments. We want them to be proud of their association with South African higher education and be ambassadors for the system once they leave South Africa. , 7th Edition
- Full Text:
- Date Issued: 2007
- Authors: International Education Association of South Africa (IEASA) , Higher Education South Africa (Organization) , Kishun, Roshen
- Date: 2007
- Subjects: Education, Higher -- South Africa , Universities and colleges -- South Africa , Technical Institutes -- South Africa , Vocational guidance -- South Africa
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/65090 , vital:28685 , ISBN 9780620391634
- Description: [Extract from message from Minister of Higher Education, Hon. Naledi Pandor]: It gives me great pleasure to endorse the 7th edition of Study South Africa. The International Education Association of South Africa (IEASA) has once again produced a publication that provides valuable insights and information about South African public universities and their place in the global higher education arena I welcome this publication and congratulate IEASA for its hard work in promoting our higher education institutions internationally. Study South Africa gives a comprehensive picture of higher education in our country. At a glance, the enquirer is able to see all that South African higher education has to offer diversity in terms of institutions, the wide range of affordable courses on offer, the international acceptability of South African qualifications as well as the rich multi-cultural experiences of our campuses. In short, the Guide provides a summary of everything that will assist the potential student to actualise his or her full potential. South African higher education is founded on broad social values such as respect for human life and dignity, commitment to equality and human rights, respect for diversity and nonsexism. Our education system seeks to construct citizens who are conscious of these values and therefore aware of their responsibilities in life and in the lives of others. These values are reflected in the diverse offerings by institutions covered in the Guide. In addition, we have specific mechanisms in place to facilitate internationalisation, and our immigration policies have been relaxed to make it easier for international students, academics and other higher education staff to enter the country and stay for the duration of their planned activity. We also subsidise students from the continent in terms of our policy on the state subsidisation of foreign students at higher education institutions. South Africa shares the global concern about the digital and information divide. We are of the view that access to information is empowering and would therefore like to see as many citizens of our country and the continent connected with the rest of the world, both digitally and in terms of knowledge. By staying in touch with the rest of the world through information sharing and exchange programmes, we minimise this information gap. It is for this reason, therefore, that the work of IEASA in the form of this publication is applauded, because it seeks to promote such exchanges and information sharing. There is no question that through internationalisation we can impact on our political, economic, cultural and social transformation. We can also address our skills shortage, build research capacity, enrich curricula and enhance the student experience. Collectively higher education institutions in South Africa offer an impressive array of information and communication technologies, well stocked and interconnected libraries and some scholars who are among the best in the world, making the country a destination of choice for both Africans and students from abroad. We aspire to make all our international partners, students and staff feel at home and content with what our institutions offer them, pleasant living and study or work environments. We want them to be proud of their association with South African higher education and be ambassadors for the system once they leave South Africa. , 7th Edition
- Full Text:
- Date Issued: 2007
Surface chemistry and electrocatalytic behaviour of tetra-carboxy substituted iron, cobalt and manganese phthalocyanine monolayers on gold electrode
- Mashazi, Philani N, Westbroek, Philippe, Ozoemena, Kenneth I, Nyokong, Tebello
- Authors: Mashazi, Philani N , Westbroek, Philippe , Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268806 , vital:54233 , xlink:href="https://doi.org/10.1016/j.electacta.2007.08.044"
- Description: Surface chemistry and electrocatalytic properties of self-assembled monolayers of metal tetra-carboxylic acid phthalocyanine complexes with cobalt (Co), iron (Fe) and manganese (Mn) as central metal ions have been studied. These phthalocyanine molecules are immobilized on gold electrode via the coupling reaction between the ring substituents and pre-formed mercaptoethanol self-assembled monolayer (Au-ME SAM). X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy confirmed chemisorption of mercaptoethanol via sulfur group on gold electrode and also coupling reaction between phthalocyanines and Au-ME SAM. Electrochemical parameters of the immobilized molecules show that these molecules are densely packed with a perpendicular orientation. The potential applications of the gold modified electrodes were investigated towards L-cysteine detection and the analysis at phthalocyanine SAMs. Cobalt and iron tetra-carboxylic acid phthalocyanine monolayers showed good oxidation peak for L-cysteine at potentials where metal oxidation (MIII/MII) takes place and this metal oxidation mediates the catalytic oxidation of L-cysteine. Manganese tetra-carboxylic acid phthalocyanine monolayer also exhibited a good catalytic oxidation peak towards L-cysteine at potentials where MnIV/MnIII redox peak occurs and this redox peak mediates L-cysteine oxidation. The analysis of cysteine at phthalocyanine monolayers displayed good analytical parameters with good detection limits of the orders of 10−7 mol L−1 and good linearity for a studied concentration range up to 60 μmol L−1.
- Full Text:
- Date Issued: 2007
- Authors: Mashazi, Philani N , Westbroek, Philippe , Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268806 , vital:54233 , xlink:href="https://doi.org/10.1016/j.electacta.2007.08.044"
- Description: Surface chemistry and electrocatalytic properties of self-assembled monolayers of metal tetra-carboxylic acid phthalocyanine complexes with cobalt (Co), iron (Fe) and manganese (Mn) as central metal ions have been studied. These phthalocyanine molecules are immobilized on gold electrode via the coupling reaction between the ring substituents and pre-formed mercaptoethanol self-assembled monolayer (Au-ME SAM). X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy confirmed chemisorption of mercaptoethanol via sulfur group on gold electrode and also coupling reaction between phthalocyanines and Au-ME SAM. Electrochemical parameters of the immobilized molecules show that these molecules are densely packed with a perpendicular orientation. The potential applications of the gold modified electrodes were investigated towards L-cysteine detection and the analysis at phthalocyanine SAMs. Cobalt and iron tetra-carboxylic acid phthalocyanine monolayers showed good oxidation peak for L-cysteine at potentials where metal oxidation (MIII/MII) takes place and this metal oxidation mediates the catalytic oxidation of L-cysteine. Manganese tetra-carboxylic acid phthalocyanine monolayer also exhibited a good catalytic oxidation peak towards L-cysteine at potentials where MnIV/MnIII redox peak occurs and this redox peak mediates L-cysteine oxidation. The analysis of cysteine at phthalocyanine monolayers displayed good analytical parameters with good detection limits of the orders of 10−7 mol L−1 and good linearity for a studied concentration range up to 60 μmol L−1.
- Full Text:
- Date Issued: 2007
Syntheses and photophysics of new phthalocyanine derivatives of zinc, cadmium and mercury
- Chidawanyika, Wadzanai J U, Ogunsipe, Abimbola, Nyokong, Tebello
- Authors: Chidawanyika, Wadzanai J U , Ogunsipe, Abimbola , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283940 , vital:56005 , xlink:href="https://doi.org/10.1039/B615663K"
- Description: The syntheses of novel tetra{2,(3)-pyridyloxyphthalocyaninato} complexes of zinc, cadmium and mercury (TPyZnPc, TPyCdPc and TPyHgPc) are presented. Their spectral and photophysical properties (as well as those of their unsubstituted counterparts: ZnPc, CdPc and HgPc) are investigated. TPyZnPc and TPyCdPc are aggregated in non-coordinating solvents such as chloroform, while TPyHgPc is demetallated, as evident from their respective absorption spectra. The trends in fluorescence (ΦF), triplet (ΦT) and singlet oxygen (ΦΔ) quantum yields are explained in terms of relative strengths of spin–orbit coupling induced by the respective central metal ions in the complexes. The effect of the pyridyloxy substituents is a decrease in ΦF and an increase in ΦT values. The complexes are less fluorescent in DMSO but possess higher ΦT, triplet lifetimes (τT) and ΦΔ therein.
- Full Text:
- Date Issued: 2007
- Authors: Chidawanyika, Wadzanai J U , Ogunsipe, Abimbola , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283940 , vital:56005 , xlink:href="https://doi.org/10.1039/B615663K"
- Description: The syntheses of novel tetra{2,(3)-pyridyloxyphthalocyaninato} complexes of zinc, cadmium and mercury (TPyZnPc, TPyCdPc and TPyHgPc) are presented. Their spectral and photophysical properties (as well as those of their unsubstituted counterparts: ZnPc, CdPc and HgPc) are investigated. TPyZnPc and TPyCdPc are aggregated in non-coordinating solvents such as chloroform, while TPyHgPc is demetallated, as evident from their respective absorption spectra. The trends in fluorescence (ΦF), triplet (ΦT) and singlet oxygen (ΦΔ) quantum yields are explained in terms of relative strengths of spin–orbit coupling induced by the respective central metal ions in the complexes. The effect of the pyridyloxy substituents is a decrease in ΦF and an increase in ΦT values. The complexes are less fluorescent in DMSO but possess higher ΦT, triplet lifetimes (τT) and ΦΔ therein.
- Full Text:
- Date Issued: 2007
Synthesis and electrochemical properties of benzyl-mercapto and dodecyl-mercapto tetrasubstituted manganese phthalocyanine complexes
- Agboola, Bolade, Ozoemena, Kenneth I, Westbroek, Philippe, Nyokong, Tebello
- Authors: Agboola, Bolade , Ozoemena, Kenneth I , Westbroek, Philippe , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281321 , vital:55713 , xlink:href="https://doi.org/10.1016/j.electacta.2006.09.002"
- Description: Manganese tetrakis (benzyl-mercapto) phthalocyanine (MnTBMPc) and manganese tetrakis (dodecyl-mercapto) phthalocyanine (MnTDMPc) complexes were synthesized and their spectral and electrochemical properties are reported. Cyclic voltammetric data showed three reversible to quasi-reversible and two irreversible redox processes for both complexes. Ring substituents influenced the positions of both oxidation and reduction redox couples. Spectroelectrochemistry confirmed the first two reductions to be due to MnIIIPc2−/MnIIPc2− and MnIIPc3−/MnIIPc2− processes. The first example of a formation of self-assembled monolayers (SAMs) using thiol substituted MnPc complexes is presented, the SAMs were found to show blocking characteristics towards some faradaic reactions.
- Full Text:
- Date Issued: 2007
- Authors: Agboola, Bolade , Ozoemena, Kenneth I , Westbroek, Philippe , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281321 , vital:55713 , xlink:href="https://doi.org/10.1016/j.electacta.2006.09.002"
- Description: Manganese tetrakis (benzyl-mercapto) phthalocyanine (MnTBMPc) and manganese tetrakis (dodecyl-mercapto) phthalocyanine (MnTDMPc) complexes were synthesized and their spectral and electrochemical properties are reported. Cyclic voltammetric data showed three reversible to quasi-reversible and two irreversible redox processes for both complexes. Ring substituents influenced the positions of both oxidation and reduction redox couples. Spectroelectrochemistry confirmed the first two reductions to be due to MnIIIPc2−/MnIIPc2− and MnIIPc3−/MnIIPc2− processes. The first example of a formation of self-assembled monolayers (SAMs) using thiol substituted MnPc complexes is presented, the SAMs were found to show blocking characteristics towards some faradaic reactions.
- Full Text:
- Date Issued: 2007
Synthesis and electrochemical properties of purple manganese (III) and red titanium (IV) phthalocyanine complexes octa-substituted at non-peripheral positions with pentylthio groups
- Mbambisa, Gcineka, Tau, Prudence, Antunes, Edith M, Nyokong, Tebello
- Authors: Mbambisa, Gcineka , Tau, Prudence , Antunes, Edith M , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/271252 , vital:54525 , xlink:href="https://doi.org/10.1016/j.poly.2007.08.007"
- Description: The synthesis and electrochemical characterisation of octapentylthiophthalocyaninato manganese (III) acetate (4) and octapentylthiophthalocyaninato titanium (IV) oxide (5) complexes are reported. The complexes have an unusual purple (4) and red (5) colouration since the Q-band is shifted to the near infrared region with Q-band maxima at 893 nm and 808 nm in dichloromethane for 4 and 5, respectively. The structures of the complexes were confirmed by elemental analysis and interpretation of their spectroscopic data, including 2D NMR. The cyclic voltammetry (CV) of the Mn complex (4) showed four quasi reversible couples. The reduction processes are attributed to MnIIIPc−2/MnIIPc−2 and MnIIPc−2/MnIIPc−3 and the oxidation processes to MnIVPc−2/MnIIIPc−2 and MnIVPc−1/MnIVPc−2. The processes were confirmed by spectroelectrochemistry. A well-defined spectrum of the rare MnIVPc−2 species is reported. The CV of the Ti complex (5) showed two well-resolved reduction processes due to TiIVPc−2/TiIIIPc−2 and TiIIIPc−2/TiIIPc−2. However, oxidation processes of the complex revealed adsorption behaviour and resulted in decomposition on electrolysis using spectroelectrochemistry.
- Full Text:
- Date Issued: 2007
- Authors: Mbambisa, Gcineka , Tau, Prudence , Antunes, Edith M , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/271252 , vital:54525 , xlink:href="https://doi.org/10.1016/j.poly.2007.08.007"
- Description: The synthesis and electrochemical characterisation of octapentylthiophthalocyaninato manganese (III) acetate (4) and octapentylthiophthalocyaninato titanium (IV) oxide (5) complexes are reported. The complexes have an unusual purple (4) and red (5) colouration since the Q-band is shifted to the near infrared region with Q-band maxima at 893 nm and 808 nm in dichloromethane for 4 and 5, respectively. The structures of the complexes were confirmed by elemental analysis and interpretation of their spectroscopic data, including 2D NMR. The cyclic voltammetry (CV) of the Mn complex (4) showed four quasi reversible couples. The reduction processes are attributed to MnIIIPc−2/MnIIPc−2 and MnIIPc−2/MnIIPc−3 and the oxidation processes to MnIVPc−2/MnIIIPc−2 and MnIVPc−1/MnIVPc−2. The processes were confirmed by spectroelectrochemistry. A well-defined spectrum of the rare MnIVPc−2 species is reported. The CV of the Ti complex (5) showed two well-resolved reduction processes due to TiIVPc−2/TiIIIPc−2 and TiIIIPc−2/TiIIPc−2. However, oxidation processes of the complex revealed adsorption behaviour and resulted in decomposition on electrolysis using spectroelectrochemistry.
- Full Text:
- Date Issued: 2007
Synthesis and photodynamic potential of tetra-and octa-triethyleneoxysulfonyl substituted zinc phthalocyanines
- Atilla, Devrim, Savdan, Nil, Durmus, Mahmut, Gürek, Ayşe Gül, Khan, Tania, Rück, Angelika, Walt, Heinrich, Nyokong, Tebello, Ahsen, Vefa
- Authors: Atilla, Devrim , Savdan, Nil , Durmus, Mahmut , Gürek, Ayşe Gül , Khan, Tania , Rück, Angelika , Walt, Heinrich , Nyokong, Tebello , Ahsen, Vefa
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281342 , vital:55715 , xlink:href="https://doi.org/10.1016/j.jphotochem.2006.08.022"
- Description: Synthesis of the water soluble zinc phthalocyanines (3, 4) obtained from the phthalonitriles substituted with oligo(ethyleneoxy)thia groups are described. The new compounds have been characterized by elemental analysis, IR, 1H and 13C NMR spectroscopy, including HSQC, HMBC and COSY bidimensional correlation techniques, electronic spectroscopy and mass spectra. The aggregation behaviour of the phthalocyanine compounds (3, 4) was investigated using UV–vis spectroscopy in dimethylsulphoxide. Photochemical and photophysical measurements were conducted on oligo(ethyleneoxy)thia appended zinc phthalocyanines. General trends are described for quantum yields of photodegredation, fluorescence yields, triplet lifetimes and triplet quantum yields as well as singlet oxygen quantum yields of these compounds. The phototoxicity against cancer cells of the new compounds was investigated during several in vitro experiments. The dye-sensitized photooxidation of 1,3-diphenylisobenzofurane via 1O2 was studied in dimethylsulphoxide.
- Full Text:
- Date Issued: 2007
- Authors: Atilla, Devrim , Savdan, Nil , Durmus, Mahmut , Gürek, Ayşe Gül , Khan, Tania , Rück, Angelika , Walt, Heinrich , Nyokong, Tebello , Ahsen, Vefa
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281342 , vital:55715 , xlink:href="https://doi.org/10.1016/j.jphotochem.2006.08.022"
- Description: Synthesis of the water soluble zinc phthalocyanines (3, 4) obtained from the phthalonitriles substituted with oligo(ethyleneoxy)thia groups are described. The new compounds have been characterized by elemental analysis, IR, 1H and 13C NMR spectroscopy, including HSQC, HMBC and COSY bidimensional correlation techniques, electronic spectroscopy and mass spectra. The aggregation behaviour of the phthalocyanine compounds (3, 4) was investigated using UV–vis spectroscopy in dimethylsulphoxide. Photochemical and photophysical measurements were conducted on oligo(ethyleneoxy)thia appended zinc phthalocyanines. General trends are described for quantum yields of photodegredation, fluorescence yields, triplet lifetimes and triplet quantum yields as well as singlet oxygen quantum yields of these compounds. The phototoxicity against cancer cells of the new compounds was investigated during several in vitro experiments. The dye-sensitized photooxidation of 1,3-diphenylisobenzofurane via 1O2 was studied in dimethylsulphoxide.
- Full Text:
- Date Issued: 2007
Synthesis and solvent effects on the electronic absorption and fluorescence spectral properties of substituted zinc phthalocyanines
- Durmus, Mahmut, Nyokong, Tebello
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293279 , vital:57071 , xlink:href="https://doi.org/10.1016/j.poly.2007.01.018"
- Description: The synthesis and spectroscopic properties of the following tetra- and octa-substituted aryloxy zinc(II) phthalocyanines are reported for the first time: 1,(4)-(tetrabenzyloxyphenoxyphthalocyaninato) zinc(II) (7); 2,(3)-(tetrabenzyloxyphenoxyphthalocyaninato) zinc(II) (8); 2,3-(octabenzyloxyphenoxyphthalocyaninato) zinc(II) (9). The new compounds have been characterized by elemental analysis, IR, 1H NMR spectroscopy and electronic spectroscopy. Spectroscopic properties of these compounds were investigated in different solvents. Protonation of non-peripherally substituted complex 7 resulted in the splitting and red-shifting of the Q-band. The peripherally substituted derivatives 8 and 9, did not show the split in the Q-band. Fluorescence spectra of the derivatives show Stokes shifts typical of MPc complexes.
- Full Text:
- Date Issued: 2007
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293279 , vital:57071 , xlink:href="https://doi.org/10.1016/j.poly.2007.01.018"
- Description: The synthesis and spectroscopic properties of the following tetra- and octa-substituted aryloxy zinc(II) phthalocyanines are reported for the first time: 1,(4)-(tetrabenzyloxyphenoxyphthalocyaninato) zinc(II) (7); 2,(3)-(tetrabenzyloxyphenoxyphthalocyaninato) zinc(II) (8); 2,3-(octabenzyloxyphenoxyphthalocyaninato) zinc(II) (9). The new compounds have been characterized by elemental analysis, IR, 1H NMR spectroscopy and electronic spectroscopy. Spectroscopic properties of these compounds were investigated in different solvents. Protonation of non-peripherally substituted complex 7 resulted in the splitting and red-shifting of the Q-band. The peripherally substituted derivatives 8 and 9, did not show the split in the Q-band. Fluorescence spectra of the derivatives show Stokes shifts typical of MPc complexes.
- Full Text:
- Date Issued: 2007
Synthesis and solvent effects on the electronic absorption and fluorescence spectral properties of substituted zinc phthalocyanines
- Durmus, Mahmut, Nyokong, Tebello
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283140 , vital:55914 , xlink:href="https://doi.org/10.1016/j.poly.2007.01.018"
- Description: The synthesis and spectroscopic properties of the following tetra- and octa-substituted aryloxy zinc(II) phthalocyanines are reported for the first time: 1,(4)-(tetrabenzyloxyphenoxyphthalocyaninato) zinc(II) (7); 2,(3)-(tetrabenzyloxyphenoxyphthalocyaninato) zinc(II) (8); 2,3-(octabenzyloxyphenoxyphthalocyaninato) zinc(II) (9). The new compounds have been characterized by elemental analysis, IR, 1H NMR spectroscopy and electronic spectroscopy. Spectroscopic properties of these compounds were investigated in different solvents. Protonation of non-peripherally substituted complex 7 resulted in the splitting and red-shifting of the Q-band. The peripherally substituted derivatives 8 and 9, did not show the split in the Q-band. Fluorescence spectra of the derivatives show Stokes shifts typical of MPc complexes.
- Full Text:
- Date Issued: 2007
- Authors: Durmus, Mahmut , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283140 , vital:55914 , xlink:href="https://doi.org/10.1016/j.poly.2007.01.018"
- Description: The synthesis and spectroscopic properties of the following tetra- and octa-substituted aryloxy zinc(II) phthalocyanines are reported for the first time: 1,(4)-(tetrabenzyloxyphenoxyphthalocyaninato) zinc(II) (7); 2,(3)-(tetrabenzyloxyphenoxyphthalocyaninato) zinc(II) (8); 2,3-(octabenzyloxyphenoxyphthalocyaninato) zinc(II) (9). The new compounds have been characterized by elemental analysis, IR, 1H NMR spectroscopy and electronic spectroscopy. Spectroscopic properties of these compounds were investigated in different solvents. Protonation of non-peripherally substituted complex 7 resulted in the splitting and red-shifting of the Q-band. The peripherally substituted derivatives 8 and 9, did not show the split in the Q-band. Fluorescence spectra of the derivatives show Stokes shifts typical of MPc complexes.
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- Date Issued: 2007