Nothing but a mass of debris: urban evictions and the right of access to adequate housing in Kenya
- Authors: Juma, Laurence
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/128425 , vital:36108 , http://www.scielo.org.za/scielo.php?script=sci_arttextamp;pid=S1996-20962012000200008amp;lng=enamp;nrm=iso
- Description: The article explores the opportunities that the new constitutional dispensation in Kenya has created for the protection against unlawful eviction of poor populations living in urban centres. It analyses the content of the right to accessible and adequate housing as provided for in article 43 of the Constitution of Kenya and articulated in various international instruments, and traces how this provision has been applied in the eviction cases that the Kenyan courts have decided. From this analysis, the article suggests that the new constitutional dispensation has opened up possibilities for rights enforcement that the courts as well as administrative organs should take advantage of. It also makes tangible suggestions on how to improve rights litigation in this regard, such as affirming the rights of access to courts and seeking further judicial oversight prior to any eviction and the promulgation of enabling legislation.
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- Date Issued: 2012
Oxovanadium (IV)-catalysed oxidation of dibenzothiophene and 4, 6-dimethyldibenzothiophene
- Authors: Ogunlaja, Adeniyi S , Chidawanyika, Wadzanai J U , Antunes, Edith M , Fernandes, Manuel A , Nyokong, Tebello , Torto, Nelson , Tshentu, Zenixole R
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/246025 , vital:51429 , xlink:href="https://doi.org/10.1039/C2DT31433A"
- Description: The reaction between [VIVOSO4] and the tetradentate N2O2-donor Schiff base ligand, N,N-bis(o-hydroxybenzaldehyde)phenylenediamine (sal-HBPD), obtained by the condensation of salicylaldehyde and o-phenylenediamine in a molar ratio of 2 : 1 respectively, resulted in the formation of [VIVO(sal-HBPD)]. The molecular structure of [VIVO(sal-HBPD)] was determined by single crystal X-ray diffraction, and confirmed the distorted square pyramidal geometry of the complex with the N2O2 binding mode of the tetradentate ligand. The formation of the polymer-supported p[VIVO(sal-AHBPD)] proceeded via the nitrosation of sal-HBPD, followed by the reduction with hydrogen to form an amine group that was then linked to Merrifield beads followed by the reaction with [VIVOSO4]. XPS and EPR were used to confirm the presence of oxovanadium(IV) within the beads. The BET surface area and porosity of the heterogeneous catalyst p[VIVO(sal-AHBPD)] were found to be 6.9 m2 g−1 and 180.8 Å respectively. Microanalysis, TG, UV-Vis and FT-IR were used for further characterization of both [VIVO(sal-HBPD)] and p[VIVO(sal-AHBPD)]. Oxidation of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) was investigated using [VIVO(sal-HBPD)] and p[VIVO(sal-AHBPD)] as catalysts. Progress for oxidation of these model compounds was monitored with a gas chromatograph fitted with a flame ionization detector. The oxidation products were characterized using gas chromatography-mass spectrometry, microanalysis and NMR. Dibenzothiophene sulfone (DBTO2) and 4,6-dimethyldibenzothiophene sulfone (4,6-DMDBTO2) were found to be the main products of oxidation. Oxovanadium(IV) Schiff base microspherical beads, p[VIVO(sal-AHBPD)], were able to catalyse the oxidation of sulfur in dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) to a tune of 88.0% and 71.8% respectively after 3 h at 40 °C. These oxidation results show promise for potential application of this catalyst in the oxidative desulfurization of crude oils.
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- Date Issued: 2012
Part II Zef/poor white kitsch chique
- Authors: Krueger, Anton
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/225745 , vital:49255 , xlink:href="https://doi.org/10.1080/17533171.2012.715484"
- Description: Ninja, who fronts the freak hip-hop band Die Antwoord, might not be quite what Desmond Tutu had in mind when he described South Africans as the “Rainbow People of God,”24 a happy harmonious amalgamation of different races. In his introduction to their seminal comic track “Enter the Ninja,” Ninja presents himself, rather, as a mongrel gutter dog, both embracing and parodying a syncretic fusion of the many different cultures and races of South Africa, celebrating as well as subverting the rainbow nation discourse. As he said in an interview with News24: “South African culture is quite a fucking fruit salad … a fucking fucked rainbow nation. South Africa's totally fucked … but in a cool way.”25 The cool side of being “fucked” in this way is “Zef.” Zef denotes a particular style of vulgar humor (in the usual sense of the word “vulgar,” but also with a nod to its origin in the Latin vulgaris for “mob” or “commoners”), which has been emerging more and more in South Africa during the past decade. It involves a way of presenting a persona in a purposefully degrading way, exaggerating one's appearance and mannerisms as low class, ill bred, and boorish. I would like to consider the recent popularity of “Zef” and examine its connection specifically to popular Afrikaans folk rock culture, a lineage of white poverty, and the feeling of disgrace experienced by many white Afrikaners after the end of apartheid.
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- Date Issued: 2012
Patrick Hayes. JM Coetzee and the Novel: writing and politics after Beckett
- Authors: Marais, Mike
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144220 , vital:38322 , DOI: 10.1093/res/hgs014
- Description: According to Patrick Hayes, J. M. Coetzee's fiction, on a thematic level, ‘repeatedly suggests that the condition of modernity is made up of competing, equally important, and yet incommensurate ways of imagining the good community’ (p. 4). The first of these imaginings is grounded in the Kantian notion that the human individual is a rational and autonomous agent, and that it is precisely his or her rational autonomy, and capacity to direct life through neutral principles that commands the respect and recognition of other individuals. As is evident in its emphasis on rationality, this politic of equal dignity and recognition is universalistic in its claims. In contrast, the second imagining of community is based on the recognition of cultural specificity, and the argument that freedom and equal recognition are only possible through a revision of deleterious cultural stereotypes. In its terms, the good community ‘must be founded on the recognition, and active fostering of cultural particularity’ (p. 12). This politic of difference is highly suspicious of the universalizing claims of the politic of dignity, arguing that its appeal to equal dignity is itself a form of particularism masquerading as universalism.
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- Date Issued: 2012
Peat formation in the context of the development of the Mkuze floodplain on the coastal plain of Maputaland, South Africa:
- Authors: Ellery, William F N , Grenfell, Suzanne E , Grenfell, Michael C , Humphries, M S , Barnes, K , Dahlberg, S , Kindness, A
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144354 , vital:38338 , DOI: 10.1016/j.geomorph.2011.11.009
- Description: This paper examines the geomorphological and sedimentological development of blocked-valley lakes in the Mkuze floodplain on the coastal plain of Maputaland, northern KwaZulu-Natal, South Africa. Blocked tributary valley lakes north of the floodplain become progressively shorter, broader, and less linear toward the eastern (downstream) end of the east–west oriented Mkuze floodplain. Clastic sediment forms surface sedimentary fill in tributary valleys in the west, while peat predominates tributary valley fill in the east. Two contrasting adjacent tributary valleys were examined, the more western Yengweni dominated by clastic sediment at the surface, and the more eastern Totweni with peat.
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- Date Issued: 2012
PhDs by publications
- Authors: Niven, Penelope , Grant, Carolyn
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281108 , vital:55693 , xlink:href="https://doi.org/10.1080/13562517.2012.640086"
- Description: PhDs by publications are a relatively new model for doctoral research, especially in the context of the Humanities or Education. This paper describes two writers’ experiences of conducting doctoral studies in this genre and in these faculties. Each discover alternative ways of employing a body of published research papers in development of an overarching thesis. The writers argue that whilst it can be a pragmatic choice for some, PhDs by publications are more likely to be highly complex meta-narratives and that an overview of past research is fraught with theoretical, conceptual and epistemological challenges in the quest for coherence. They claim that the nomenclature ‘PhDs by publications’ or ‘through publications’ is misleading: in the epistemological space of Humanities or Education studies, this mode of doctoral research is more accurately represented as a ‘PhD with or alongside publications’. They conclude that the particular affordance of the model is that it privileges accounts of the process of knowledge building and of descriptions of the gradual emergence of ‘doctoralness’ in the person of the researcher.
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- Date Issued: 2012
Photooxidation of 4-chlorophenol sensitized by lutetium tetraphenoxy phthalocyanine anchored on electrospun polystyrene polymer fiber
- Authors: Zugle, Ruphino , Antunes, Edith M , Khene, Samson M , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/245787 , vital:51405 , xlink:href="https://doi.org/10.1016/j.poly.2011.11.005"
- Description: An electrospun polystyrene (PS) fiber incorporating tetraphenoxy phthalocyanine complex of lutetium (LuTPPc/PS) as a photosensitizer was applied for the degradation of 4-chlorophenol in aqueous solution in the presence of visible light. The photocatalytic activity of the LuTPPc in the fiber was compared to that of zinc phthalocyanine (ZnPc) incorporated into the PS fiber, and the former showed higher activity. UV–Vis spectral changes of sample solutions indicated transformation of the analyte with first order kinetics and half-lives that are within one and half hours for LuTPPc/PS. Products identified from the spectral changes and gas chromatography were benzoquinone, hydroquinone and 4,4′-dihydroxydiphenol suggesting that the photodegradation of 4-chlorophenol was through both Types I and II mechanisms.
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- Date Issued: 2012
Photophysical and photochemical properties of novel phthalocyanines bearing non-peripherally substituted mercaptoquinoline moiety
- Authors: Yaşa, Göknur , Erdoğmuş, Ali , Uğur, Ahmet Lütf , Şener, M Kasım , Avcıata, Ulvi , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244360 , vital:51250 , xlink:href="https://doi.org/10.1142/S1088424612500940"
- Description: The synthesis, photophysical and photochemical properties of nonperipherally (a) mercaptoquinoline substituted Zn(II), TiO(IV) and Mg(II) and quaternized Zn(II) phthalocyanines are described for the first time. These complexes (2 to 5) and their precursor are characterized by elemental analysis, FT-IR, 1 H NMR, electronic spectroscopy as well as mass spectroscopy. Complexes 2, 4 and 5 have good solubility in organic solvents such as CHCl3, DCM, DMSO, DMF, THF and toluene and are not aggregated in all solvents within a wide concentration range. Complex 3 showed very good solubility in water as well as DMSO and DMF. General trends are described for singlet oxygen, photodegradation and fluorescence quantum yields of these complexes in DMSO and DMF. While complex 2 has higher singlet oxygen and fluorescence quantum yields than 3, 4 and 5, complex 4 has higher fluorescence quantum yields in DMF and DMSO than 2, 3 and 5. The effect of the solvents and metal on the photophysical and photochemical parameters of the metallophthalocyanines are also reported.
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- Date Issued: 2012
Photophysical and photochemical studies of sulfur containing phthalocyanine derivatives in the presence of folic acid
- Authors: Nombona, Nolwazi , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243180 , vital:51124 , xlink:href="https://doi.org/10.1016/j.ica.2012.03.051"
- Description: The syntheses of zinc and magnesium 9,16,23-tris-(5-trifluoromethyl-2-mercaptopyridine)-2-(carboxy)phthalocyaninato complexes are described for the first time. The photophysical and photochemical parameters of these molecules in the absence or presence of folic acid are compared to the corresponding oxygen bridged complexes and to 2,9,17,23-tetrakis-[(1,6-hexanedithiol)phthalocyaninato]zinc(II), [8,15,22-tris-(naptho)-2-(amidoethanethiol)phthalocyaninato]zinc(II) and zinc phthalocyanine tetrasulfonate. In the absence of folic acid, the complexes show relatively good triplet quantum yields (ranging from 0.52 to 0.88) in DMSO with reasonable triplet lifetime between 140 and 470 μs. The complexes showed high singlet oxygen quantum yield values ranging from 0.27 to 0.66 in the absence of folic acid. In the presence of folic acid, the triplet quantum yield values were between 0.37 and 0.75 and the lifetimes were significantly reduced (70–320 μs).
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- Date Issued: 2012
Photophysics and photochemistry of octaglucosylated zinc phthalocyanine derivatives
- Authors: Iqbal, Zafar , Ogunsipe, Abimbola , Nyokong, Tebello , Lyubimtsev, Alexey , Hanack, Michael , Ziegler, Thomas
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244416 , vital:51255 , xlink:href="https://doi.org/10.1142/S1088424612500630"
- Description: The ground state electronic absorption spectra, photophysics and photochemistry of amphiphilic octaglucosylated zinc phthalocyanines containing oxygen or sulfur bridges are presented. Triplet quantum yield values for the two dyes (in DMF and DMSO) vary between 0.71 and 0.84, while singlet quantum yield values lie between 0.63 and 0.75. Fluorescence lifetimes were determined experimentally by time correlated single photon counting and semi-empirically by fluorescence quenching techniques; and values from both methods were within the same range. Kinetic data were obtained for the quenching of the triplet state of the phthalocyanines by ground state molecular oxygen; the bimolecular collisional quenching rate constant range between 2.35 × 108 and 1.13 × 109 M-1.s-1. These values suggest that triplet states of the dyes are effectively quenched by ground molecular oxygen.
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- Date Issued: 2012
Physico-chemical properties of lutetium phthalocyanine complexes in solution and in solid polystyrene polymer fibers and their application in photoconversion of 4-nitrophenol
- Authors: Zugle, Ruphino , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243520 , vital:51160 , xlink:href="https://doi.org/10.1016/j.molcata.2012.02.010"
- Description: The photophysical and photochemical behavior of two phthalocyanine complexes of lutetium peripherally substituted with tetraphenoxy and tetra-2-pyridiloxy groups were studied in solution and when dispersed in polystyrene polymer fiber. The phthalocyanines were found not to fluoresce significantly in solution and not at all within the fiber matrix as compared with standard unsubstituted zinc phthalocyanine. They showed very promising photoactivity in solution with high singlet oxygen quantum yields. Their photoactivity within the polymer fiber matrix was also demonstrated with the photoconversion of 4-nitrophenol, a water pollutant. The photodegradation process with both phthalocyanines follows first order kinetics similar to that observed for the zinc phthalocyanine and the photo-products were found to be hydroquinone, benzoquinone and 4-nitrocatechol.
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- Date Issued: 2012
Quality of life in Grahamstown, East London and Mdantsane: preliminary result
- Authors: Helliker, Kirk D , Bekker, Simon , Lambie, Eileen
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144756 , vital:38376 , DOI: 10.1080/02580144.1981.10428933
- Description: A quality of life survey amongst residents of three Eastern Cape towns, viz. Grahamstown, East London, and Mdantsane, shows that the attitudes to home and neighbourhood which urban residents in the Eastern Cape develop, are fashioned in large part by both the residential “group area” in which these urban dwellers live, and by their socio-economic status. White residents, overwhelmingly, are satisfied with their diets, their municipality, their homes. They feel safe in their homes and are satisfied that police protection is available if needed. For black residents fear of poverty and unemployment, of physical violence, and dissatisfaction with an inadequate diet is widespread. Indian and coloured urban residents who are generally perceived as minorities in Grahamstown and East London, occupy an intermediate position. Their residential areas are sited close to predominantly low income black residential areas. Higher income Indian and coloured households show lower rates of dissatisfaction with diet, housing, and municipal services than the black community.
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- Date Issued: 2012
Quinones and halogenated monoterpenes of algal origin show anti-proliferative effects against breast cancer cells in vitro:
- Authors: de la Mare, Jo-Anne , Lawson, Jessica C , Chiwakata, Maynard T , Beukes, Denzil R , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165165 , vital:41214 , DOI: 10.1007/s10637-011-9788-0
- Description: Red and brown algae have been shown to produce a variety of compounds with chemotherapeutic potential. A recent report described the isolation of a range of novel polyhalogenated monoterpene compounds from the red algae Plocamium corallorhiza and Plocamium cornutum collected off the coast of South Africa, together with the previously described tetraprenylquinone, sargaquinoic acid (SQA), from the brown algae Sargassum heterophyllum. In our study, the algal compounds were screened for anti-proliferative activity against metastatic MDA-MB-231 breast cancer cells revealing that a number of compounds displayed anti-cancer activity with IC50 values in the micromolar range. A subset of the compounds was tested for differential toxicity in the MCF-7/MCF12A system and five of these, including sargaquinoic acid, were found to be at least three times more toxic to the breast cancer than the non-malignant cell line.
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- Date Issued: 2012
Radical thinking in South Africa’s age of retreat
- Authors: Helliker, Kirk D , Vale, Peter C J
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71214 , vital:29818 , https://doi.org/10.1177/0021909612442654
- Description: This article traces the rise and fall of radical praxis in South Africa and offers a critique of the prevailing practices of former Marxists under post-apartheid conditions. Western Marxism emerged in the 1970s in South Africa and Marxist activists became deeply involved in the liberation movements. With the unravelling of apartheid, the main liberation forces made a social pact with capitalist forces and former Marxists embraced a statist project. In the context of the rise of ‘new’ social movements, radical thinking of a more Libertarian kind is emerging in contemporary South Africa.
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- Date Issued: 2012
Reverse saturation absorption spectra and optical limiting properties of chlorinated tetrasubstituted phthalocyanines containing different metals
- Authors: Tuhl, Ahmad , Manaa, Hacene , Makhseed, Saad , Al-Awadi, Nouria , Matthew, Jacob , Ibrahim, Hamada Mohamed , Nyokong, Tebello , Behbehani, Haider
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243498 , vital:51158 , xlink:href="https://doi.org/10.1016/j.optmat.2012.05.018"
- Description: A highly non-aggregated series of peripherally tetra(2,6-diisopropylphenoxy) substituted phthalocyanines (Pcs) containing different metals (Al, Ga, In and Zn) were prepared and their nonlinear optical properties (NLO), including the optical limiting behavior were investigated. This study explores the effect of the implanted metals along with the peripheral chlorine atoms on the NLO of the prepared complexes, thereby improving their optical limiting performance. The best wavelength at which the Pc complex exhibits the strongest nonlinear effect was determined over the low absorption window region (420–590 nm) comprised between the Q and B bands using a nanosecond pulsed laser with the aid of a Z-scan technique. The excited state absorption cross sections (σeff) have been found to be wavelength dependent with common double peaks at 505 nm and around 485 nm and the highest value was calculated for Pc1–In (1.1 × 10−16 cm2). The figure of merit spectra show different spectral structure when compared to the excited state absorption spectra and the largest figure of merit value was found to be around 107 for Pc1–In derivative. In full agreement with reverse saturation results, the optical limiting measurements, carried out at 485 nm and 532 nm for each derivative, show very low optical limiting thresholds at the former wavelength. In the continuous wave excitation regime, the Z-scan measurements, which were carried out at 632.8 and 532 nm, showed strong refractive and absorptive nonlinear effects.
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- Date Issued: 2012
Richard T. Carson: Contingent valuation: a comprehensive bibliography and history
- Authors: Snowball, Jeanette D
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71504 , vital:29859 , https://link.springer.com/content/pdf/10.1007/s10824-012-9165-7.pdf
- Description: For those of us who have been involved in willingness to pay studies for some time, Contingent Valuation: A comprehensive bibliography and history by Richard Carson is a fascinating read, tracking the early development of the method and debates around it from an insider’s perspective. As someone who has not only been involved in contingent valuation research over many years, but who has also been instrumental in shaping it, Richard Carson is the ideal author of this carefully crafted book.
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- Date Issued: 2012
Schottky barrier diode parameters of Ag/MgPc/p-Si structure
- Authors: Canlıca, Mevlüde , Coskun, Mustafa , Altındal, Ahmet , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/245820 , vital:51408 , xlink:href="https://doi.org/10.1142/S1088424612500824"
- Description: An Ag/Pc/p-Si Schottky barrier (SB) diode was fabricated. The current-voltage (I-V), capacitance-voltage (C-V) and conductance-voltage (G-V) measurements were carried out to determine the characteristic parameters such as barrier height, ideality factor and series resistance of the SB diode. The non-linear behavior of ln (I) vs. ln (V) and ln (I/V) vs. V1/2 plots indicated that the thermoionic emission theory can be applied to evaluate junction parameters for the investigated SB diode rather than space-charge limited conduction (SCLC) mechanism and bulk-limited Poole–Frenkel emission. The bulk doping concentration NB and fixed oxide charges Nf was determined from the measured high frequency C-V curve and was found to be 9.5 × 1014 cm-3 and 2.3 × 1013 cm-2, respectively. The values of barrier height obtained from Norde's function were compared with those from the forward bias current-voltage characteristic, and it was seen that there was a good agreement between barrier heights from both methods.
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- Date Issued: 2012
Single walled carbon nanotubes functionalized with nickel phthalocyanines
- Authors: Khene, Samson , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/245843 , vital:51410 , xlink:href="https://doi.org/10.1142/S1088424611004439"
- Description: In this work we report on electrochemical behavior of nickel phthalocyanine derivatives tetrasubstituted peripherally and non-peripherally with hydroxy and used to modify single walled carbon nanotubes. Nickel phthalocyanine complex octasubstituted at the peripheral positions with hydroxy groups was also used to modify single walled carbon nanotubes. Nickel phthalocyanine complex tetrasubstituted with amino groups at peripheral position was covalently and non-covalently linked to single walled carbon nanotubes. All the conjugates of nickel phthalocyanine derivatives with single walled carbon nanotubes were used for the electro oxidation of 4-chlorophenol. The nickel phthalocyanine octabsubstituted with hydroxy groups at the non-peripheral positions gave the best current response and the best resistance against electrode fouling for the oxidation of 4-chlorophenol.
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- Date Issued: 2012
Spectral, photophysical and photochemical properties of tetra-and octaglycosylated zinc phthalocyanines
- Authors: Iqbal, Zafar , Masilela, Nkosiphile , Nyokong, Tebello , Lyubimtsev, Alexey , Hanack, Michael , Ziegler, Thomas
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244428 , vital:51256 , xlink:href="https://doi.org/10.1039/c2pp05348a"
- Description: Photophysical and photochemical properties of a series of tetra- and octaglycosylated zinc phthalocyanines (ZnPcs) substituted with glucose and galactose moieties have been reported. Spectral properties of these phthalocyanines are compared in DMSO. Absorption spectra of the non-peripherally tetra-substituted ZnPcs 2 showed a significant red shift in their Q-band maxima as compared to the peripherally substituted analog 1. All the complexes gave high triplet quantum yields ranging from 0.68 to 0.88, whereas triplet lifetimes were in the range of 100–430 µs in argon-saturated solutions. The octagalactosylated ZnPc 3b showed the highest triplet quantum yield and singlet oxygen quantum yield of 0.88 and 0.69, respectively. The fluorescence quantum yields and lifetimes of all the compounds under investigation were within the range of zinc phthalocyanine complexes.
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- Date Issued: 2012
Spectroscopic and physicochemical behavior of magnesium phthalocyanine derivatives mono-substituted with a carboxylic acid group
- Authors: Nombona, Nolwazi , Chidawanyika, Wadzanai J U , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244450 , vital:51258 , xlink:href="https://doi.org/10.1016/j.molstruc.2011.12.051"
- Description: This work reports on the synthesis of novel unsymmetrically substituted magnesium phthalocyanine complexes containing one carboxyl group. The physicochemical behavior of these complexes were compared with those of their unmetallated and zinc counterparts. The MgPcs showed interesting absorption spectra with [8,15,22-Tris-(naphtho)-4,5-(3-carboxy-1,2-dioxyphenyl)phthalocyaninato]magnesium (II) showing a large split in the Q band whereas [8,15,22-Tris-(naphtho)-2-(carboxy) phthalocyaninato]magnesium(II) presented only a small splitting. The magnesium phthalocyanine derivatives displayed higher fluorescence quantum yields compared to unmetallated and zinc phthalocyanine counterparts. The latter gave admirable triplet and singlet oxygen quantum yields. These molecules can distinctly be employed in the field of photodynamic therapy in combination with fluorescence imaging.
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- Date Issued: 2012