Photochemically induced electron transfer between sulfur dioxide and tin (IV) mono-and di-phthalocyanines
- Nensala, Ngudiankama, Nzimande, Ayanda, Nyokong, Tebello
- Authors: Nensala, Ngudiankama , Nzimande, Ayanda , Nyokong, Tebello
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293402 , vital:57082 , xlink:href="https://doi.org/10.1016/1010-6030(96)04344-4"
- Description: Photolysis, using radiation from a tungsten lamp, of tin diphthalocyanine (Pc2Sn(IV)) in dichloromethane containing SO2 results in the one-electron oxidation of this species to [Pc(−2)Sn(IV)Pc(−1)]+. The relative quantum yields for the formation of the oxidized species were in the order of 10−3. The one-electron oxidized complex was also formed when Pc2Sn was photolysed in an acetonitrile/dichloromethane solvent mixture. Photolysis of the monomeric (L)2Sn(IV)Pc(LOH−, Cl−, Br− and F−) in pyridine and in the presence of SO2 resulted in the reduction of these species to (L)2Sn(IV)Pc(−3)]− with quantum yields in the order of 10−2.
- Full Text:
- Date Issued: 1996
- Authors: Nensala, Ngudiankama , Nzimande, Ayanda , Nyokong, Tebello
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293402 , vital:57082 , xlink:href="https://doi.org/10.1016/1010-6030(96)04344-4"
- Description: Photolysis, using radiation from a tungsten lamp, of tin diphthalocyanine (Pc2Sn(IV)) in dichloromethane containing SO2 results in the one-electron oxidation of this species to [Pc(−2)Sn(IV)Pc(−1)]+. The relative quantum yields for the formation of the oxidized species were in the order of 10−3. The one-electron oxidized complex was also formed when Pc2Sn was photolysed in an acetonitrile/dichloromethane solvent mixture. Photolysis of the monomeric (L)2Sn(IV)Pc(LOH−, Cl−, Br− and F−) in pyridine and in the presence of SO2 resulted in the reduction of these species to (L)2Sn(IV)Pc(−3)]− with quantum yields in the order of 10−2.
- Full Text:
- Date Issued: 1996
Spectroelectrochemical studies of tin (IV) diphthalocyanine
- Nensala, Ngudiankama, Nyokong, Tebello
- Authors: Nensala, Ngudiankama , Nyokong, Tebello
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293436 , vital:57085 , xlink:href="https://doi.org/10.1016/0277-5387(95)00325-1"
- Description: Cyclic voltammetry of tin(IV) diphthalocyanine (Pc2Sn) in dichloromethane containing TEAP shows two reduction couples at −0.56 and −0.89 versus saturated calomel electrode (SCE) and one oxidation couple at 0.35 V versus SCE; all were quasireversible one-electron couples. The oxidation couple corresponds to [Pc(−1)SnIVPc(−2)+/Pc(−2)SnIVPc(−2) and the reduction couples to Pc(−2)SnIVPc(−2)/[Pc(−3)SnIVPc(−2)]− and [Pc(−3)SnIVPc(−2)]−/[Pc(−3)SnIVPc(−3)]2−, respectively. The electronic absorption spectra of the various reduced or oxidized tin(IV) diphthalocyanine species are reported.
- Full Text:
- Date Issued: 1996
- Authors: Nensala, Ngudiankama , Nyokong, Tebello
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293436 , vital:57085 , xlink:href="https://doi.org/10.1016/0277-5387(95)00325-1"
- Description: Cyclic voltammetry of tin(IV) diphthalocyanine (Pc2Sn) in dichloromethane containing TEAP shows two reduction couples at −0.56 and −0.89 versus saturated calomel electrode (SCE) and one oxidation couple at 0.35 V versus SCE; all were quasireversible one-electron couples. The oxidation couple corresponds to [Pc(−1)SnIVPc(−2)+/Pc(−2)SnIVPc(−2) and the reduction couples to Pc(−2)SnIVPc(−2)/[Pc(−3)SnIVPc(−2)]− and [Pc(−3)SnIVPc(−2)]−/[Pc(−3)SnIVPc(−3)]2−, respectively. The electronic absorption spectra of the various reduced or oxidized tin(IV) diphthalocyanine species are reported.
- Full Text:
- Date Issued: 1996
Suppositories: An underutilized dosage form
- Webster, Jessica A, Dowse, Roslind, Walker, Roderick B
- Authors: Webster, Jessica A , Dowse, Roslind , Walker, Roderick B
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184697 , vital:44264 , xlink:href="https://hdl.handle.net/10520/AJA16836707_911"
- Description: The rectal route is useful for the delivery of both local acting and systemic drugs. In certain cases suppositories are the best form of therapy, or else they are an effective alternative when oral therapy is not possible. However; doctors rarely prescribe them and patients are often reluctant to use them. Understanding how suppositories work, and their numerous uses, can overcome the aversion to this particular dosage form. Pharmacists are in an ideal position to educate doctors, other health care providers, and patients, on the benefits of using suppositories and their correct use, and to offer advice on any problems associated with their use.
- Full Text:
- Date Issued: 1996
- Authors: Webster, Jessica A , Dowse, Roslind , Walker, Roderick B
- Date: 1996
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184697 , vital:44264 , xlink:href="https://hdl.handle.net/10520/AJA16836707_911"
- Description: The rectal route is useful for the delivery of both local acting and systemic drugs. In certain cases suppositories are the best form of therapy, or else they are an effective alternative when oral therapy is not possible. However; doctors rarely prescribe them and patients are often reluctant to use them. Understanding how suppositories work, and their numerous uses, can overcome the aversion to this particular dosage form. Pharmacists are in an ideal position to educate doctors, other health care providers, and patients, on the benefits of using suppositories and their correct use, and to offer advice on any problems associated with their use.
- Full Text:
- Date Issued: 1996
Tectonic and structural aspects at the Otjihase Mine, Matchless Belt, Namibia: A Systematic Review
- Authors: Hartmann, K
- Date: 1995-04
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190232 , vital:44976
- Description: The Otjihase pyritic massive sulphide deposit occurs within a 10km thick metasedimentary sequence of the Kuiseb Formation. The Kuiseb metasediments were deposited within the Khomas Trough, which forms the southernmost rift of the intracontinental arm of the Damara orogen. Amphibolite units of the Matchless member at Otjihase have a MORB-type geochemical character and occur within the Kuiseb schists, about 200m above the ore zone. The Otjihase mine is the largest of many Besshi-type deposits that occur in close proximity to the Matchless amphibolites. A depositional environment in a rift, slightly more advanced than the present-day Red Sea is envisaged. The five parallel, ruler-shaped, mineralised shoots at Otjihase occur on the same stratigraphic level. They have a plunge of approximately 6° to the west and a dip of approximately 16° to the northwest. The largest and best mineralised, is the northernmost shoot (the Main Shoot) which is ±250m wide, up to 12m thick and has a known length of 7,5km. The large length/breadth ratio is ascribed to the original setting along faults and thickening of the ore zone during thrusting. Intense ductile deformation has affected the ore bodies, with isoclinal refolding, boudinaging, duplexes of more competent bands and smearing of the schists. Squeezing and remobilisation of the sulphides into the schistosity and low pressure pods has taken place. Successive folding and thrusting during the D2 deformational event resulted in the dominant structural style. Fold axes of drag folds plot onto a great circle in stereographic projection, indicating the formation of sheath folds. The axial planar cleavages of competent layers is steeper than the S(0,1) foliation and suggests a structural right way-up. The presence of chloritic alteration above the ore shoots, is suggestive of footwall alteration indicating that the sequence was overturned during the D1 deformational event. Ore zone lithologies include stringery-, massive- and semi-massive sulphides, mineralised magnetite- quartzites and disseminated sulphide mineralisation within quartz-biotite-chlorite schists. Chalcopyrite is the main economic mineral and mainly occurs as matrix to pyrite and in coarse-grained pods. Lithological and metal zoning within the Main Shoot is distinct and is an indication that the macroscopic shape of the orebody is largely unaffected by later ductile deformation. North-south trending normal faults of the Windhoek Graben have disrupted the continuity of the ore shoots. In section, the faults appear to have a listric shape. The major faults have pronounced scissor movements and as a result the dips of the blocks within fault zones are affected. , Thesis (MSc) -- Faculty of Science, Exploration Geology, 2021
- Full Text:
- Date Issued: 1995-04
- Authors: Hartmann, K
- Date: 1995-04
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190232 , vital:44976
- Description: The Otjihase pyritic massive sulphide deposit occurs within a 10km thick metasedimentary sequence of the Kuiseb Formation. The Kuiseb metasediments were deposited within the Khomas Trough, which forms the southernmost rift of the intracontinental arm of the Damara orogen. Amphibolite units of the Matchless member at Otjihase have a MORB-type geochemical character and occur within the Kuiseb schists, about 200m above the ore zone. The Otjihase mine is the largest of many Besshi-type deposits that occur in close proximity to the Matchless amphibolites. A depositional environment in a rift, slightly more advanced than the present-day Red Sea is envisaged. The five parallel, ruler-shaped, mineralised shoots at Otjihase occur on the same stratigraphic level. They have a plunge of approximately 6° to the west and a dip of approximately 16° to the northwest. The largest and best mineralised, is the northernmost shoot (the Main Shoot) which is ±250m wide, up to 12m thick and has a known length of 7,5km. The large length/breadth ratio is ascribed to the original setting along faults and thickening of the ore zone during thrusting. Intense ductile deformation has affected the ore bodies, with isoclinal refolding, boudinaging, duplexes of more competent bands and smearing of the schists. Squeezing and remobilisation of the sulphides into the schistosity and low pressure pods has taken place. Successive folding and thrusting during the D2 deformational event resulted in the dominant structural style. Fold axes of drag folds plot onto a great circle in stereographic projection, indicating the formation of sheath folds. The axial planar cleavages of competent layers is steeper than the S(0,1) foliation and suggests a structural right way-up. The presence of chloritic alteration above the ore shoots, is suggestive of footwall alteration indicating that the sequence was overturned during the D1 deformational event. Ore zone lithologies include stringery-, massive- and semi-massive sulphides, mineralised magnetite- quartzites and disseminated sulphide mineralisation within quartz-biotite-chlorite schists. Chalcopyrite is the main economic mineral and mainly occurs as matrix to pyrite and in coarse-grained pods. Lithological and metal zoning within the Main Shoot is distinct and is an indication that the macroscopic shape of the orebody is largely unaffected by later ductile deformation. North-south trending normal faults of the Windhoek Graben have disrupted the continuity of the ore shoots. In section, the faults appear to have a listric shape. The major faults have pronounced scissor movements and as a result the dips of the blocks within fault zones are affected. , Thesis (MSc) -- Faculty of Science, Exploration Geology, 2021
- Full Text:
- Date Issued: 1995-04
Addendum to the paper Landcare: New directions in professional development for environmental education
- Authors: Lotz-Sisitka, Heila
- Date: 1995
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/438672 , vital:73488 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/137475"
- Description: During 1994-1995, we received correspondence from Tania Sadler of the University of Tasmania and from Debbie Heck, about the latter's paper published in volume 14. In response we publish the following addendum, which includes a list of references inadvertently left out of her paper. Ms Heck did supply these references to the SAJEE originally, and we apologise for any inconvenience to readers as a result of the mistake. (Ed.)
- Full Text:
- Date Issued: 1995
- Authors: Lotz-Sisitka, Heila
- Date: 1995
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/438672 , vital:73488 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/137475"
- Description: During 1994-1995, we received correspondence from Tania Sadler of the University of Tasmania and from Debbie Heck, about the latter's paper published in volume 14. In response we publish the following addendum, which includes a list of references inadvertently left out of her paper. Ms Heck did supply these references to the SAJEE originally, and we apologise for any inconvenience to readers as a result of the mistake. (Ed.)
- Full Text:
- Date Issued: 1995
Editorial
- Authors: Janse van Rensburg, Eureta
- Date: 1995
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/438706 , vital:73493 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/137460"
- Description: This edition of the SAJEE focuses on EEASA' s conference-and-workshops held in July 1995, at Kearsney College in Kwazulu Natal, South Africa. ln the 1994 issue we invited readers to explore Progress and Paradox, as a conference theme reflecting a new perspective on education and environment. We received a very positive response and the conference featured an excellent range of papers. From amongst the many worthy contributions the reviewers selected those papers that addressed the theme most directly, for publication in this, arguably EEASA' s best journal yet.
- Full Text:
- Date Issued: 1995
- Authors: Janse van Rensburg, Eureta
- Date: 1995
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/438706 , vital:73493 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/137460"
- Description: This edition of the SAJEE focuses on EEASA' s conference-and-workshops held in July 1995, at Kearsney College in Kwazulu Natal, South Africa. ln the 1994 issue we invited readers to explore Progress and Paradox, as a conference theme reflecting a new perspective on education and environment. We received a very positive response and the conference featured an excellent range of papers. From amongst the many worthy contributions the reviewers selected those papers that addressed the theme most directly, for publication in this, arguably EEASA' s best journal yet.
- Full Text:
- Date Issued: 1995
Equilibrium and kinetic studies of the reaction between pyridine and cobalt (II) phthalocyanine in DMSO
- Authors: Nyokong, Tebello
- Date: 1995
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293380 , vital:57080 , xlink:href="https://doi.org/10.1016/0277-5387(95)00090-F"
- Description: Kinetics and equilibria for the reaction between pyridine and cobalt(II) phthalocyanine [CoPc] (H2Pc = phthalocyanine) in dimethyl sulphoxide (DMSO) were studied at 25°C. The complex, CoPc(py)2, is formed in two consecutive steps. The formation of the mono-substituted CoPc(py)(DMSO) occurs first with a pseudo-first-order rate constant of k1f = 7.7 ± 0.3 × 10−3 dm3 mol−1 s−1. The final disubstituted CoPc(py)2 complex is formed with k2f= 1.1 ± 0.1 × 10−4dm3mol−1−1. The equilibrium constants were found to be K1 = 160 ± 20dm3 mol−1 and K2 = 15 ± 3 dm3mol−1 for the formation of CoPc(py)(DMSO) and CoPc(py)2, respectively.
- Full Text:
- Date Issued: 1995
- Authors: Nyokong, Tebello
- Date: 1995
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293380 , vital:57080 , xlink:href="https://doi.org/10.1016/0277-5387(95)00090-F"
- Description: Kinetics and equilibria for the reaction between pyridine and cobalt(II) phthalocyanine [CoPc] (H2Pc = phthalocyanine) in dimethyl sulphoxide (DMSO) were studied at 25°C. The complex, CoPc(py)2, is formed in two consecutive steps. The formation of the mono-substituted CoPc(py)(DMSO) occurs first with a pseudo-first-order rate constant of k1f = 7.7 ± 0.3 × 10−3 dm3 mol−1 s−1. The final disubstituted CoPc(py)2 complex is formed with k2f= 1.1 ± 0.1 × 10−4dm3mol−1−1. The equilibrium constants were found to be K1 = 160 ± 20dm3 mol−1 and K2 = 15 ± 3 dm3mol−1 for the formation of CoPc(py)(DMSO) and CoPc(py)2, respectively.
- Full Text:
- Date Issued: 1995
Resource materials development in environmental education : Exploring some of the myths and tensions in participatory resource development in the We Care Primary Project
- Authors: Lotz-Sisitka, Heila
- Date: 1995
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/438792 , vital:73500 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/137472"
- Description: This paper on environmental education resource materials development represents some of my 'lived experience' (Malone, 1994:20) as a researcher involved in clarifying the processes of materials development for junior primary classrooms. The sites of inquiry, action and reflection have been focussed around the development of the We Care Primary materials, shifts in orientations to environmental education and current educational change.
- Full Text:
- Date Issued: 1995
- Authors: Lotz-Sisitka, Heila
- Date: 1995
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/438792 , vital:73500 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/137472"
- Description: This paper on environmental education resource materials development represents some of my 'lived experience' (Malone, 1994:20) as a researcher involved in clarifying the processes of materials development for junior primary classrooms. The sites of inquiry, action and reflection have been focussed around the development of the We Care Primary materials, shifts in orientations to environmental education and current educational change.
- Full Text:
- Date Issued: 1995
The reaction of cyanide with iron (II) hexadecachlorophthalocyanine
- Authors: Nyokong, Tebello
- Date: 1995
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293447 , vital:57086 , xlink:href="https://doi.org/10.1016/0277-5387(94)00291-L"
- Description: Kinetics and equilibria for the reaction between cyanide and iron(II) hexadecachlorophthalocyanine ((Cl)16PcFe(DMSO)2, where Pc(−2) = phthalocyanine dianion) in dimethyl sulphoxide (DMSO) are reported. Only the spectrophotometric changes due to the formation of the dicyano, [(Cl)16PcFe(CN)2]2−, complex were observed. This complex is formed with the equilibrium constant, K3 = 1.6 × 103 dm3 mol−1 and a rate constant of k3f = 4.2 × 10−3 dm3 mol−1 s−1. The K2[(Cl)16PcFe(CN)2] complex dissolves in DMSO and dimethyl formamide (DMF) with ϵ = 110 000 and 92 000 dm3 mol−1 cm−1, respectively.
- Full Text:
- Date Issued: 1995
- Authors: Nyokong, Tebello
- Date: 1995
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293447 , vital:57086 , xlink:href="https://doi.org/10.1016/0277-5387(94)00291-L"
- Description: Kinetics and equilibria for the reaction between cyanide and iron(II) hexadecachlorophthalocyanine ((Cl)16PcFe(DMSO)2, where Pc(−2) = phthalocyanine dianion) in dimethyl sulphoxide (DMSO) are reported. Only the spectrophotometric changes due to the formation of the dicyano, [(Cl)16PcFe(CN)2]2−, complex were observed. This complex is formed with the equilibrium constant, K3 = 1.6 × 103 dm3 mol−1 and a rate constant of k3f = 4.2 × 10−3 dm3 mol−1 s−1. The K2[(Cl)16PcFe(CN)2] complex dissolves in DMSO and dimethyl formamide (DMF) with ϵ = 110 000 and 92 000 dm3 mol−1 cm−1, respectively.
- Full Text:
- Date Issued: 1995
Cyclic voltammetry and photooxidation of molybdenum (V) phthalocyanine
- Authors: Nyokong, Tebello
- Date: 1994
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295475 , vital:57344 , xlink:href="https://doi.org/10.1016/S0277-5387(00)86594-8"
- Description: Cyclic voltammetry of OMoV(OH)Pc in chloronaphthalene shows two quasi-reversible oxidation couples at 0.38 and 1.22 V and three quasi-reversible reduction couples at −0.74, −1.15 and −1.85 V vs S.C.E. Bulk electrolysis of OMoV(OH)Pc (Pc2 = phthalocyanine dianion) shows that the first oxidation couple is due to the oxidation of the central MoV metal to MoVI and the first reduction couple due to reduction to OMoIVPc. Cyclic voltammetry and spectroelectrochemistry in DMSO also showed redox activity at the metal. Further reductions or oxidations in OMoVPc complexes occur at the phthalocyanine ring. OMoV(OH)Pc is readily photooxidized at the metal in the presence dichloromethane or dichlorobenzene, with the formation of OMoVIPc species.
- Full Text:
- Date Issued: 1994
- Authors: Nyokong, Tebello
- Date: 1994
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295475 , vital:57344 , xlink:href="https://doi.org/10.1016/S0277-5387(00)86594-8"
- Description: Cyclic voltammetry of OMoV(OH)Pc in chloronaphthalene shows two quasi-reversible oxidation couples at 0.38 and 1.22 V and three quasi-reversible reduction couples at −0.74, −1.15 and −1.85 V vs S.C.E. Bulk electrolysis of OMoV(OH)Pc (Pc2 = phthalocyanine dianion) shows that the first oxidation couple is due to the oxidation of the central MoV metal to MoVI and the first reduction couple due to reduction to OMoIVPc. Cyclic voltammetry and spectroelectrochemistry in DMSO also showed redox activity at the metal. Further reductions or oxidations in OMoVPc complexes occur at the phthalocyanine ring. OMoV(OH)Pc is readily photooxidized at the metal in the presence dichloromethane or dichlorobenzene, with the formation of OMoVIPc species.
- Full Text:
- Date Issued: 1994
Cyclic voltammetry and spectroelectrochemistry of rhodium phthalocyanines
- Authors: Nyokong, Tebello
- Date: 1994
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295486 , vital:57346 , xlink:href="https://doi.org/10.1039/DT9940001359"
- Description: The electrochemistry of RhIII(pc)(pc = phthalocyanine dianion) complexes containing chloride, pyridine, dimethyl sulfoxide (dmso) and cyanide as axial ligands was investigated by cyclic voltammetry and UV/VIS spectroelectrochemistry. The compounds were K[Rh(pc)(CN)2], [Rh(pc)(Cl)(py)] and [Rh(pc)Cl(dmso)]. For all of these the first oxidation occurs at the phthalocyanine ligand with the formation of a π-cation radical species. The addition of one electron to the complexes leads to one of two different reduction products depending on the nature of the axial ligands. The first reduction of [Rh(pc)Cl(py)] and [Rh(pc)Cl(dmso)] occurs at the metal, followed by rapid dimerization of the reduced species. The first and subsequent reductions of K[Rh(pc)(CN)2] occur at the ring.
- Full Text:
- Date Issued: 1994
- Authors: Nyokong, Tebello
- Date: 1994
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295486 , vital:57346 , xlink:href="https://doi.org/10.1039/DT9940001359"
- Description: The electrochemistry of RhIII(pc)(pc = phthalocyanine dianion) complexes containing chloride, pyridine, dimethyl sulfoxide (dmso) and cyanide as axial ligands was investigated by cyclic voltammetry and UV/VIS spectroelectrochemistry. The compounds were K[Rh(pc)(CN)2], [Rh(pc)(Cl)(py)] and [Rh(pc)Cl(dmso)]. For all of these the first oxidation occurs at the phthalocyanine ligand with the formation of a π-cation radical species. The addition of one electron to the complexes leads to one of two different reduction products depending on the nature of the axial ligands. The first reduction of [Rh(pc)Cl(py)] and [Rh(pc)Cl(dmso)] occurs at the metal, followed by rapid dimerization of the reduced species. The first and subsequent reductions of K[Rh(pc)(CN)2] occur at the ring.
- Full Text:
- Date Issued: 1994
Editorial
- Janse van Rensburg, Eureta, Irwin, Pat
- Authors: Janse van Rensburg, Eureta , Irwin, Pat
- Date: 1994
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/438694 , vital:73491 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/137493"
- Description: In 1993 environmental education was looking forward to the first democratic election in South Africa - now it is in the midst of 'reconstructionand-development'. For many local environmental educators, this means a contrihution, in one way or another, to the new national curriculum. But the challenges of 1993 continue: processes of participative curriculum development are forcing us to clarify different orientations to environmental education in our efforts to shape a curriculum based on the best of our various visions.
- Full Text:
- Date Issued: 1994
- Authors: Janse van Rensburg, Eureta , Irwin, Pat
- Date: 1994
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/438694 , vital:73491 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/137493"
- Description: In 1993 environmental education was looking forward to the first democratic election in South Africa - now it is in the midst of 'reconstructionand-development'. For many local environmental educators, this means a contrihution, in one way or another, to the new national curriculum. But the challenges of 1993 continue: processes of participative curriculum development are forcing us to clarify different orientations to environmental education in our efforts to shape a curriculum based on the best of our various visions.
- Full Text:
- Date Issued: 1994
Photoassisted electron transfer between sulfur dioxide and tin (IV) phthalocyanines
- Authors: Nyokong, Tebello
- Date: 1994
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295520 , vital:57349 , xlink:href="https://doi.org/10.1039/C39940001983"
- Description: Photolysis of tin(IV) phthalocyanine complexes in the presence of sulfur dioxide shows a first-order kinetic dependence on sulfur dioxide, and a one-electron reduction of SnPc to an anion radical species.
- Full Text:
- Date Issued: 1994
- Authors: Nyokong, Tebello
- Date: 1994
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295520 , vital:57349 , xlink:href="https://doi.org/10.1039/C39940001983"
- Description: Photolysis of tin(IV) phthalocyanine complexes in the presence of sulfur dioxide shows a first-order kinetic dependence on sulfur dioxide, and a one-electron reduction of SnPc to an anion radical species.
- Full Text:
- Date Issued: 1994
Photoreduction of tin (IV) phthalocyanines
- Authors: Nyokong, Tebello
- Date: 1994
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293413 , vital:57083 , xlink:href="https://doi.org/10.1016/S0277-5387(00)83491-9"
- Description: Photolysis of Sn(IV)Pc(OH)2 (Pc = phthalocyanine dianion) and Sn(IV)Pc(Cl)2 using a tungsten lamp, and in the presence of SnCl2·2H2O as an electron donor results in the reduction of these complexes of π anion radical species. The reduction shows second order dependence on the concentration of the Sn(IV)Pc complexes and a first order dependence on SnCl2·H2O.
- Full Text:
- Date Issued: 1994
- Authors: Nyokong, Tebello
- Date: 1994
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293413 , vital:57083 , xlink:href="https://doi.org/10.1016/S0277-5387(00)83491-9"
- Description: Photolysis of Sn(IV)Pc(OH)2 (Pc = phthalocyanine dianion) and Sn(IV)Pc(Cl)2 using a tungsten lamp, and in the presence of SnCl2·2H2O as an electron donor results in the reduction of these complexes of π anion radical species. The reduction shows second order dependence on the concentration of the Sn(IV)Pc complexes and a first order dependence on SnCl2·H2O.
- Full Text:
- Date Issued: 1994
Redox reactions of an Mo (V) tetrasulfophthalocyanine
- Ferraudi, Guillermo, Nyokong, Tebello, Feliz, Mario, Perkovic, Marc, Rillema, D Paul
- Authors: Ferraudi, Guillermo , Nyokong, Tebello , Feliz, Mario , Perkovic, Marc , Rillema, D Paul
- Date: 1994
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295530 , vital:57351 , xlink:href="https://doi.org/10.1016/0020-1693(93)03664-V"
- Description: The preparation of an Mo(V) tetrasulfophthalocyanine and some of its thermal and photochemical reactions have been investigated in this work. Electrochemical processes have been followed by means of the UVVis spectral changes and compared with those observed in flash photolysis. Mo(IV) and Mo(V)-ligand-radical species are common intermediates of the electrochemical and photochemical reactions. In 254 nm irradiations of the Mo(V) tetrasulfophthalocyanine in aqueous solutions of 2-propanol, the macrocycle can be photohydrogenated and the product of the photolysis can be reoxidized with O2 back to the parent complex.
- Full Text:
- Date Issued: 1994
- Authors: Ferraudi, Guillermo , Nyokong, Tebello , Feliz, Mario , Perkovic, Marc , Rillema, D Paul
- Date: 1994
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295530 , vital:57351 , xlink:href="https://doi.org/10.1016/0020-1693(93)03664-V"
- Description: The preparation of an Mo(V) tetrasulfophthalocyanine and some of its thermal and photochemical reactions have been investigated in this work. Electrochemical processes have been followed by means of the UVVis spectral changes and compared with those observed in flash photolysis. Mo(IV) and Mo(V)-ligand-radical species are common intermediates of the electrochemical and photochemical reactions. In 254 nm irradiations of the Mo(V) tetrasulfophthalocyanine in aqueous solutions of 2-propanol, the macrocycle can be photohydrogenated and the product of the photolysis can be reoxidized with O2 back to the parent complex.
- Full Text:
- Date Issued: 1994
Research priorities for environmental education in southern Africa: Preliminary report
- Authors: Janse van Rensburg, Eureta
- Date: 1994
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/438781 , vital:73499 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/137480"
- Description: In this preliminary research report I introduce initial interpretations of the results of a recently completed study on research priorities in southern Africa. The study has been sponsored by Murray and Roberts, Rhodes University and the HNRE (Human and Natural Resources in the Environment) Programme of the Human Sciences Research Council.
- Full Text:
- Date Issued: 1994
- Authors: Janse van Rensburg, Eureta
- Date: 1994
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/438781 , vital:73499 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/137480"
- Description: In this preliminary research report I introduce initial interpretations of the results of a recently completed study on research priorities in southern Africa. The study has been sponsored by Murray and Roberts, Rhodes University and the HNRE (Human and Natural Resources in the Environment) Programme of the Human Sciences Research Council.
- Full Text:
- Date Issued: 1994
The search for daily meaning: A technique for career counselling
- Authors: Rainier, Markseller Garrett
- Date: 1994
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193003 , vital:45289
- Description: Because work is such a tremendous potential source of meaning in an individual’s life, techniques which turn career choice into technical talent matching are inadequate. The individual’s search for authentic meaning needs to be the focus of career counselling, but few approaches have been able to addressed this relationship between working and living. Major developments in career theory are reviewed to highlight the distinction between the more technical logical positivist and the phenomenological approaches. Super’s Career- Development Assessment and Counselling (C-DAC) model is described in detail as it is the first significant attempt to move beyond the technical approaches by incorporating developmental theory into career counselling and by stressing the role of counsellee readiness to use the information provided. However, especially in South Africa, any test-based approach to career counselling runs the risk of shifting the locus of control from the counsellee to the counsellor, so an autobiographical non-test approach, the life-line, is introduced to assist counsellees in their search for personal meaning without running the risks associated with test-based assessments. The life-line helps to contextualise the choice of work within the counsellee’s subjective life experience and turns career counselling into a shared search for a range of personal meanings rather than the provision, by the counsellor, of a limiting interpretation. Three case studies are presented to demonstrate the use of the life-line, and the conclusions arrived at are shown to be essentially1 similar to conclusions obtained from using the C-DAC battery. The advantages and limitations of the life-line are discussed and its ability to combat problems associated with school based career counselling is outlined as well as its usefulness with mid-life career changers, in cross-cultural contexts, and in group counselling. , Thesis (MA) -- Faculty of Humanities, Psychology, 1990
- Full Text:
- Date Issued: 1994
- Authors: Rainier, Markseller Garrett
- Date: 1994
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193003 , vital:45289
- Description: Because work is such a tremendous potential source of meaning in an individual’s life, techniques which turn career choice into technical talent matching are inadequate. The individual’s search for authentic meaning needs to be the focus of career counselling, but few approaches have been able to addressed this relationship between working and living. Major developments in career theory are reviewed to highlight the distinction between the more technical logical positivist and the phenomenological approaches. Super’s Career- Development Assessment and Counselling (C-DAC) model is described in detail as it is the first significant attempt to move beyond the technical approaches by incorporating developmental theory into career counselling and by stressing the role of counsellee readiness to use the information provided. However, especially in South Africa, any test-based approach to career counselling runs the risk of shifting the locus of control from the counsellee to the counsellor, so an autobiographical non-test approach, the life-line, is introduced to assist counsellees in their search for personal meaning without running the risks associated with test-based assessments. The life-line helps to contextualise the choice of work within the counsellee’s subjective life experience and turns career counselling into a shared search for a range of personal meanings rather than the provision, by the counsellor, of a limiting interpretation. Three case studies are presented to demonstrate the use of the life-line, and the conclusions arrived at are shown to be essentially1 similar to conclusions obtained from using the C-DAC battery. The advantages and limitations of the life-line are discussed and its ability to combat problems associated with school based career counselling is outlined as well as its usefulness with mid-life career changers, in cross-cultural contexts, and in group counselling. , Thesis (MA) -- Faculty of Humanities, Psychology, 1990
- Full Text:
- Date Issued: 1994
An understanting of mirrors and mirroring in a schizophrenic patient obsessed with his appearance
- Authors: Zworestine, Barry John
- Date: 1993-04
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/191702 , vital:45149
- Description: This work addresses the role of mirroring and mirrors encountered while working with a patient obsessed with his appearance. At the same time, however, it also attempts to provide an understanding of the process of mirroring from the developing unborn child to the adult. It examines the womb as a reflective space, the mirroring role of the mother, psychological work as mirror work, the psychopathologies of disruptive mirroring and the nature of reflection as a story, confusion and a ghostly other, and finally, the relationship between mirror reflection and psychological life. What is examined and described in this process applies not only to the specific case in study but is relevant at a universal level to all of mankind regardless of race or religion. The case-study method was used to examine the process of therapy that took place over three months. The patient’s identifying data, reasons for referral, presenting problem, family background, basic personality, interpersonal relationships, mental state, diagnosis, dynamic formulation and rationale for psychotherapy were covered in detail. The process of psychotherapy over 27 sessions was recounted and discussed in detail. Theoretical understandings drawn on to facilitate an understanding of the case were from Davis and Walbridge on Winnicolt, Winnicot, Liedloff, Kay, Romanyshyn, Bettelheim, Schwartz and others. , Thesis (MA) -- Faculty of Humanities, Psychology, 1993
- Full Text:
- Date Issued: 1993-04
- Authors: Zworestine, Barry John
- Date: 1993-04
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/191702 , vital:45149
- Description: This work addresses the role of mirroring and mirrors encountered while working with a patient obsessed with his appearance. At the same time, however, it also attempts to provide an understanding of the process of mirroring from the developing unborn child to the adult. It examines the womb as a reflective space, the mirroring role of the mother, psychological work as mirror work, the psychopathologies of disruptive mirroring and the nature of reflection as a story, confusion and a ghostly other, and finally, the relationship between mirror reflection and psychological life. What is examined and described in this process applies not only to the specific case in study but is relevant at a universal level to all of mankind regardless of race or religion. The case-study method was used to examine the process of therapy that took place over three months. The patient’s identifying data, reasons for referral, presenting problem, family background, basic personality, interpersonal relationships, mental state, diagnosis, dynamic formulation and rationale for psychotherapy were covered in detail. The process of psychotherapy over 27 sessions was recounted and discussed in detail. Theoretical understandings drawn on to facilitate an understanding of the case were from Davis and Walbridge on Winnicolt, Winnicot, Liedloff, Kay, Romanyshyn, Bettelheim, Schwartz and others. , Thesis (MA) -- Faculty of Humanities, Psychology, 1993
- Full Text:
- Date Issued: 1993-04
Interaction of cyanide with iron (II) phthalocyanine
- Authors: Nyokong, Tebello
- Date: 1993
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295497 , vital:57347 , xlink:href="https://doi.org/10.1039/DT9930003601"
- Description: The kinetics and equilibria for the reaction between cyanide and iron (II) phthalocyanine [Fe(pc)](H2pc = phthalocyanine) in dimethyl sulfoxide (dmso) were studied at 25 °C. The complex [Fe(pc)(CN)2]2– is formed in two consecutive pseudo-first-order processes with k2f= 17.5 ± 0.8 dm3 mol–1 s–1 and k3f= 0.20 ± 0.05 dm3 mol–1 s–1, where k2f and k3f are the rate constants for the binding of the first and second cyanide ligands, respectively. The equilbrium constants were fund to be K2= 3.0 × 103 dm3 mol–1 and K3= 5.7 × 102 dm3 mol–1, for the formation of [Fe(pc)(CN)(dmso)]– and [Fe(pc)(CN)2]2–, respectively.
- Full Text:
- Date Issued: 1993
- Authors: Nyokong, Tebello
- Date: 1993
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295497 , vital:57347 , xlink:href="https://doi.org/10.1039/DT9930003601"
- Description: The kinetics and equilibria for the reaction between cyanide and iron (II) phthalocyanine [Fe(pc)](H2pc = phthalocyanine) in dimethyl sulfoxide (dmso) were studied at 25 °C. The complex [Fe(pc)(CN)2]2– is formed in two consecutive pseudo-first-order processes with k2f= 17.5 ± 0.8 dm3 mol–1 s–1 and k3f= 0.20 ± 0.05 dm3 mol–1 s–1, where k2f and k3f are the rate constants for the binding of the first and second cyanide ligands, respectively. The equilbrium constants were fund to be K2= 3.0 × 103 dm3 mol–1 and K3= 5.7 × 102 dm3 mol–1, for the formation of [Fe(pc)(CN)(dmso)]– and [Fe(pc)(CN)2]2–, respectively.
- Full Text:
- Date Issued: 1993
Kinetics of the reaction of cyanide with ruthenium phthalocyanine complexes
- Nyokong, Tebello, Guthrie-Strachan, Jeffry
- Authors: Nyokong, Tebello , Guthrie-Strachan, Jeffry
- Date: 1993
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295509 , vital:57348 , xlink:href="https://doi.org/10.1016/S0020-1693(00)85128-2"
- Description: Kinetic studies of the reaction of cyanide with (CO)(DMF)RuPc and (DMSO)2RuPc in DMF are reported. In the presence of a large excess of cyanide, the (CN)2RuPc complex is formed by pseudo first order kinetics. The reaction is first order in both cyanide and phthalocyanine, with specific rate constants of 5.2×10−2 and 7.2×10−2 M−1 s−1 for reactions of cyanide with (CO)(DMF)RuPc and (DMSO)2RuPc, respectively. The rate constants correspond to the coordination of the second cyanide ligand to the ruthenium phthalocyanine species.
- Full Text:
- Date Issued: 1993
- Authors: Nyokong, Tebello , Guthrie-Strachan, Jeffry
- Date: 1993
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295509 , vital:57348 , xlink:href="https://doi.org/10.1016/S0020-1693(00)85128-2"
- Description: Kinetic studies of the reaction of cyanide with (CO)(DMF)RuPc and (DMSO)2RuPc in DMF are reported. In the presence of a large excess of cyanide, the (CN)2RuPc complex is formed by pseudo first order kinetics. The reaction is first order in both cyanide and phthalocyanine, with specific rate constants of 5.2×10−2 and 7.2×10−2 M−1 s−1 for reactions of cyanide with (CO)(DMF)RuPc and (DMSO)2RuPc, respectively. The rate constants correspond to the coordination of the second cyanide ligand to the ruthenium phthalocyanine species.
- Full Text:
- Date Issued: 1993