The elucidation of nickel and zinc based Metal Organic Frameworks (MOFs) using a polycarboxylate-benzene ligand: a synthetic, spectroscopic, and thermoanalytical study
- Authors: Hodgson, Ivan Mark
- Date: 2022-04-06
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/290877 , vital:56795
- Description: Thesis (MSc) -- Faculty of Science, Chemistry, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Hodgson, Ivan Mark
- Date: 2022-04-06
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/290877 , vital:56795
- Description: Thesis (MSc) -- Faculty of Science, Chemistry, 2022
- Full Text:
- Date Issued: 2022-04-06
Publicising chemistry in a multicultural society through chemistry outreach
- Harrison, T G, Shallcross, D E, Norman, N C, Sewry, Joyce D, Davies-Coleman, Michael T
- Authors: Harrison, T G , Shallcross, D E , Norman, N C , Sewry, Joyce D , Davies-Coleman, Michael T
- Date: 2011
- Language: English
- Type: Article
- Identifier: vital:6573 , http://hdl.handle.net/10962/d1004136
- Description: Given the emphasis in Higher Education on community engagement in South Africa and the importance of international collaboration, we discuss a joint approach to chemistry outreach in two countries on two continents with widely differing target school audiences. We describe the history of the partnership between the chemistry departments at Rhodes University and the University of Bristol and provide an outline of the chemistry content of their outreach initiatives, the modes of delivery, the advantages to both departments and their students for involvement in various levels of outreach, the challenges they still face and additional opportunities that such work facilitated. The lecture demonstration 'A Pollutant's Tale' was presented to thousands of learners all over the world, including learners at resource-deprived schools in South Africa. Challenges to extend outreach activities in South Africa include long travelling distances, as well as a lack of facilities (such as school halls and electricity) at schools. Outreach activities not only impacted on the target audience of young learners, they also impacted upon the postgraduate and other chemistry students taking part in these initiatives. This collaboration strengthened both institutions and their outreach work and may also lead to chemistry research collaborations between the academics involved.
- Full Text:
- Date Issued: 2011
- Authors: Harrison, T G , Shallcross, D E , Norman, N C , Sewry, Joyce D , Davies-Coleman, Michael T
- Date: 2011
- Language: English
- Type: Article
- Identifier: vital:6573 , http://hdl.handle.net/10962/d1004136
- Description: Given the emphasis in Higher Education on community engagement in South Africa and the importance of international collaboration, we discuss a joint approach to chemistry outreach in two countries on two continents with widely differing target school audiences. We describe the history of the partnership between the chemistry departments at Rhodes University and the University of Bristol and provide an outline of the chemistry content of their outreach initiatives, the modes of delivery, the advantages to both departments and their students for involvement in various levels of outreach, the challenges they still face and additional opportunities that such work facilitated. The lecture demonstration 'A Pollutant's Tale' was presented to thousands of learners all over the world, including learners at resource-deprived schools in South Africa. Challenges to extend outreach activities in South Africa include long travelling distances, as well as a lack of facilities (such as school halls and electricity) at schools. Outreach activities not only impacted on the target audience of young learners, they also impacted upon the postgraduate and other chemistry students taking part in these initiatives. This collaboration strengthened both institutions and their outreach work and may also lead to chemistry research collaborations between the academics involved.
- Full Text:
- Date Issued: 2011
Electrocatalytic activity of ethynylbenzyl phthalocyanines when linked to quantum dots via click chemistry: Towards efficient oxygen reduction reaction and H2O2 oxidation
- Mpeta, Lekhetho S, Nyokong, Tebello
- Authors: Mpeta, Lekhetho S , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187037 , vital:44558 , xlink:href="https://doi.org/10.1016/j.jelechem.2019.03.064"
- Description: This work describes the conjugation of Co, Mn and Fe tetra ethynyl benzyl phthalocyanines to CdTe/ZnS quantum dots via click chemistry. The synthesized conjugates were then immobilised on glassy carbon electrode and their electrocatalytic activity towards hydrogen peroxide oxidation and oxygen reduction investigated. CoPc (1)-QDs showed superior electrocatalytic behaviour towards hydrogen peroxide catalysis with sensitivity of 2.8 × 105 μA/mM and limit of detection of 0.023 μM. On the other hand, FePc(3)-QDs showed the best oxygen reduction activity involving a direct 4-electron mechanism.
- Full Text:
- Date Issued: 2019
- Authors: Mpeta, Lekhetho S , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187037 , vital:44558 , xlink:href="https://doi.org/10.1016/j.jelechem.2019.03.064"
- Description: This work describes the conjugation of Co, Mn and Fe tetra ethynyl benzyl phthalocyanines to CdTe/ZnS quantum dots via click chemistry. The synthesized conjugates were then immobilised on glassy carbon electrode and their electrocatalytic activity towards hydrogen peroxide oxidation and oxygen reduction investigated. CoPc (1)-QDs showed superior electrocatalytic behaviour towards hydrogen peroxide catalysis with sensitivity of 2.8 × 105 μA/mM and limit of detection of 0.023 μM. On the other hand, FePc(3)-QDs showed the best oxygen reduction activity involving a direct 4-electron mechanism.
- Full Text:
- Date Issued: 2019
Distinguished women in Chemistry Award (PACN)
- Authors: Nyokong, Tebello
- Date: 2011
- Identifier: vital:7223 , http://hdl.handle.net/10962/d1005901
- Description: Distinguished Women in Chemistry Award as part of the Pan Africa Chemistry Network (PACN) and Royal Society of Chemistry (RSC) International Year of Chemistry Celebration of the 100th Anniversary of Marie Curie’s Nobel Award in Chemistry.
- Full Text: false
- Date Issued: 2011
- Authors: Nyokong, Tebello
- Date: 2011
- Identifier: vital:7223 , http://hdl.handle.net/10962/d1005901
- Description: Distinguished Women in Chemistry Award as part of the Pan Africa Chemistry Network (PACN) and Royal Society of Chemistry (RSC) International Year of Chemistry Celebration of the 100th Anniversary of Marie Curie’s Nobel Award in Chemistry.
- Full Text: false
- Date Issued: 2011
4-Azidoaniline-based electropolymer as a building block for functionalisation of conductive surfaces
- Coates, Megan, Elamari, Hichem, Girard, Christian, Griveau, Sophie, Nyokong, Tebello, Bedioui, Fethi
- Authors: Coates, Megan , Elamari, Hichem , Girard, Christian , Griveau, Sophie , Nyokong, Tebello , Bedioui, Fethi
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244404 , vital:51254 , xlink:href="https://doi.org/10.1016/j.jelechem.2012.01.001"
- Description: We propose in this work to compare three approaches using 4-azidoaniline combined with “click” chemistry and electrochemistry to anchor ferrocene moieties at glassy carbon surfaces. The immobilisation of a newly synthesised molecule, 4-(4-ferrocenyl-1H-1,2,3-triazol-1-yl)aniline, through direct electropolymerisation or via in situ diazotization followed by electrografting is studied by analysing the samples by XPS and electrochemistry.
- Full Text:
- Date Issued: 2012
4-Azidoaniline-based electropolymer as a building block for functionalisation of conductive surfaces
- Authors: Coates, Megan , Elamari, Hichem , Girard, Christian , Griveau, Sophie , Nyokong, Tebello , Bedioui, Fethi
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244404 , vital:51254 , xlink:href="https://doi.org/10.1016/j.jelechem.2012.01.001"
- Description: We propose in this work to compare three approaches using 4-azidoaniline combined with “click” chemistry and electrochemistry to anchor ferrocene moieties at glassy carbon surfaces. The immobilisation of a newly synthesised molecule, 4-(4-ferrocenyl-1H-1,2,3-triazol-1-yl)aniline, through direct electropolymerisation or via in situ diazotization followed by electrografting is studied by analysing the samples by XPS and electrochemistry.
- Full Text:
- Date Issued: 2012
Harnessing the energy of the sun
- Authors: Matiwana, Zamuxolo
- Language: English
- Type: Article
- Identifier: vital:7207 , http://hdl.handle.net/10962/d1006410
- Description: Capturing solar energy was the theme of this year's Barker Lecture delivered by Professor Derek Sehlettwein, an expert electrochemist from Justus-Liebig University in Giessen. Germany
- Full Text:
- Authors: Matiwana, Zamuxolo
- Language: English
- Type: Article
- Identifier: vital:7207 , http://hdl.handle.net/10962/d1006410
- Description: Capturing solar energy was the theme of this year's Barker Lecture delivered by Professor Derek Sehlettwein, an expert electrochemist from Justus-Liebig University in Giessen. Germany
- Full Text:
Vice-Chancellor's Annual Review 2004
- Language: English
- Type: Article
- Identifier: vital:7169 , http://hdl.handle.net/10962/d1006071
- Description: The highlight of 2004 was the award of both the Vice-Chancellor's Senior Research Award and the SABC2 Shoprite-Checkers Woman of the Year Award (Science and Technology) to Professor Tebello Nyokong, whose research on the development of photosensitisers for photodynamic cancer therapy has received considerable attention.
- Full Text:
- Language: English
- Type: Article
- Identifier: vital:7169 , http://hdl.handle.net/10962/d1006071
- Description: The highlight of 2004 was the award of both the Vice-Chancellor's Senior Research Award and the SABC2 Shoprite-Checkers Woman of the Year Award (Science and Technology) to Professor Tebello Nyokong, whose research on the development of photosensitisers for photodynamic cancer therapy has received considerable attention.
- Full Text:
Knowledge practices and student access and success in General Chemistry at a Large South African University
- Authors: Mtombeni, Thabile Nokuthula
- Date: 2018
- Subjects: Chemistry -- Study and teaching (Higher) -- South Africa , Knowledge management , Education, Higher -- Curricula -- South Africa , Critical realism , Social integration -- South Africa , Educational equalization -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62873 , vital:28305
- Description: This dissertation reports on an investigation into the structuring principles of the General Chemistry curriculum at a Large South African University (LSAU). Student learning in the introductory modules of General Chemistry is critical for access to a range of fields since it is a requisite course for a variety of degree programmes. However, there is ample evidence that success in this subject remains a major challenge, particularly for black students. My quest in this study was to explore how the curriculum could enable greater epistemic access and thus include more students in science programmes at the LSAU. I investigated the organising principles underlying the curriculum practices of the General Chemistry module and explored the effects of the curriculum structure on student learning. Theoretically and conceptually, the study was underpinned by a social realist approach which holds that knowledge is stratified, differentiated, and has real emergent properties, powers and effects. The research question that I attempted to answer in this study was: How do knowledge practices privileged in the General Chemistry curriculum at the LSAU enable or constrain student learning? I adopted an intensive research design approach to conduct a qualitative case study using social realism and LCT as theoretical and analytical lenses. I used empirical data such as curriculum documents and interviews with lecturers to uncover the underlying generative mechanisms of the curriculum. I adopted a multi-layered data analysis process to make visible the underlying organising principles informing knowledge practices in the curriculum so that I could explain their potential effects on student learning. The first level of analysis explored the context of the curriculum and associated knowledge practices, and examined the pedagogic discourse evident in the curriculum. The second level of analysis revealed the inner logic structuring the curriculum and the associated knowledge practices. I used Maton’s Legitimation Code Theory (LCT): Specialisation to identify the specialisation codes, gazes and insights generated by the curriculum. For the third level of analysis, LCT: Semantics was used to generate the semantic profiles of learning activities to determine the extent to which the curriculum structure made cumulative learning possible. From the findings, it is evident that the verticality of knowledge in General Chemistry points to a recontextualising principle that prescribes the selection and arrangement of knowledge, and the special relationship of actors and discourses. As a result, the strong framing of the instructional discourse of General Chemistry curriculum structure is likely to constrain epistemological access for large numbers of students. In order to improve epistemological access to the field, weaker framing of the instructional discourse in introductory science is necessary. Weaker framing of the General Chemistry curriculum would require, in particular, changes to pacing, and that the evaluative criteria are made explicit. This is especially necessary when certain abstract and complex curricular content is taught, especially in the first semester. The findings also indicate that the nature of the organising principles in the curriculum are significant for improving epistemological access to knowledge. In terms of LCT: Specialisation, the General Chemistry curriculum generated a knowledge code and downplayed differences among social categories of students, thus positioning all equally in relation to the knowledge and practices of the field. Therefore, the structuring of the curriculum emphasises and legitimates students who have attained specialist knowledge without considering the nature of the new student coming into the educational setting. Simply, what is privileged is both the object of study (theoretical knowledge) and how it is studied (procedural knowledge). This finding is in line with the general outcomes of Chemistry education. In addition, the purist insight generated by the curriculum further attests to where the emphasis is placed in the curriculum. I argue that the lack of social relations in the curriculum poses a challenge for the holistic development of students as science knowers. The analysis of the learning activities shows rapid code shifts that indicate changes in cognitive demand and modes of thinking required of students. I argue that signposting the changes in complexity of knowledge and in the mode of thinking required could make learning, and thus epistemological access, more possible. Given the imperative of access to powerful knowledge, I contend that the curriculum should be reshaped to enable epistemological access for more students.
- Full Text:
- Date Issued: 2018
- Authors: Mtombeni, Thabile Nokuthula
- Date: 2018
- Subjects: Chemistry -- Study and teaching (Higher) -- South Africa , Knowledge management , Education, Higher -- Curricula -- South Africa , Critical realism , Social integration -- South Africa , Educational equalization -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62873 , vital:28305
- Description: This dissertation reports on an investigation into the structuring principles of the General Chemistry curriculum at a Large South African University (LSAU). Student learning in the introductory modules of General Chemistry is critical for access to a range of fields since it is a requisite course for a variety of degree programmes. However, there is ample evidence that success in this subject remains a major challenge, particularly for black students. My quest in this study was to explore how the curriculum could enable greater epistemic access and thus include more students in science programmes at the LSAU. I investigated the organising principles underlying the curriculum practices of the General Chemistry module and explored the effects of the curriculum structure on student learning. Theoretically and conceptually, the study was underpinned by a social realist approach which holds that knowledge is stratified, differentiated, and has real emergent properties, powers and effects. The research question that I attempted to answer in this study was: How do knowledge practices privileged in the General Chemistry curriculum at the LSAU enable or constrain student learning? I adopted an intensive research design approach to conduct a qualitative case study using social realism and LCT as theoretical and analytical lenses. I used empirical data such as curriculum documents and interviews with lecturers to uncover the underlying generative mechanisms of the curriculum. I adopted a multi-layered data analysis process to make visible the underlying organising principles informing knowledge practices in the curriculum so that I could explain their potential effects on student learning. The first level of analysis explored the context of the curriculum and associated knowledge practices, and examined the pedagogic discourse evident in the curriculum. The second level of analysis revealed the inner logic structuring the curriculum and the associated knowledge practices. I used Maton’s Legitimation Code Theory (LCT): Specialisation to identify the specialisation codes, gazes and insights generated by the curriculum. For the third level of analysis, LCT: Semantics was used to generate the semantic profiles of learning activities to determine the extent to which the curriculum structure made cumulative learning possible. From the findings, it is evident that the verticality of knowledge in General Chemistry points to a recontextualising principle that prescribes the selection and arrangement of knowledge, and the special relationship of actors and discourses. As a result, the strong framing of the instructional discourse of General Chemistry curriculum structure is likely to constrain epistemological access for large numbers of students. In order to improve epistemological access to the field, weaker framing of the instructional discourse in introductory science is necessary. Weaker framing of the General Chemistry curriculum would require, in particular, changes to pacing, and that the evaluative criteria are made explicit. This is especially necessary when certain abstract and complex curricular content is taught, especially in the first semester. The findings also indicate that the nature of the organising principles in the curriculum are significant for improving epistemological access to knowledge. In terms of LCT: Specialisation, the General Chemistry curriculum generated a knowledge code and downplayed differences among social categories of students, thus positioning all equally in relation to the knowledge and practices of the field. Therefore, the structuring of the curriculum emphasises and legitimates students who have attained specialist knowledge without considering the nature of the new student coming into the educational setting. Simply, what is privileged is both the object of study (theoretical knowledge) and how it is studied (procedural knowledge). This finding is in line with the general outcomes of Chemistry education. In addition, the purist insight generated by the curriculum further attests to where the emphasis is placed in the curriculum. I argue that the lack of social relations in the curriculum poses a challenge for the holistic development of students as science knowers. The analysis of the learning activities shows rapid code shifts that indicate changes in cognitive demand and modes of thinking required of students. I argue that signposting the changes in complexity of knowledge and in the mode of thinking required could make learning, and thus epistemological access, more possible. Given the imperative of access to powerful knowledge, I contend that the curriculum should be reshaped to enable epistemological access for more students.
- Full Text:
- Date Issued: 2018
Layer by Layer Electrode Surface Functionalisation Using Carbon Nanotubes, Electrochemical Grafting of Azide‐Alkyne Functions and Click Chemistry
- Coates, Megan, Griveau, Sophie, Bedioui, Fethi, Nyokong, Tebello
- Authors: Coates, Megan , Griveau, Sophie , Bedioui, Fethi , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243509 , vital:51159 , xlink:href="https://doi.org/10.1002/elan.201200240"
- Description: Ferrocene was covalently bonded to a layer of adsorbed single-walled carbon nanotubes on a glassy carbon electrode surface using electrochemical grafting and click chemistry. Grafting of the 4-azidobenzenediazonium salt onto the surface was accomplished by electrochemical reduction. The surface-bound azide groups, with the use of a copper(I) catalyst, were reacted with ethynylferrocene to form covalent 1,2,3-triazole bonds by click chemistry. This layer by layer construction of the electrode surface results in stable electrodes by combining good electrical conductivity and increased surface area of the nanotubes with the versatility of the Sharpless click reaction.
- Full Text:
- Date Issued: 2012
- Authors: Coates, Megan , Griveau, Sophie , Bedioui, Fethi , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243509 , vital:51159 , xlink:href="https://doi.org/10.1002/elan.201200240"
- Description: Ferrocene was covalently bonded to a layer of adsorbed single-walled carbon nanotubes on a glassy carbon electrode surface using electrochemical grafting and click chemistry. Grafting of the 4-azidobenzenediazonium salt onto the surface was accomplished by electrochemical reduction. The surface-bound azide groups, with the use of a copper(I) catalyst, were reacted with ethynylferrocene to form covalent 1,2,3-triazole bonds by click chemistry. This layer by layer construction of the electrode surface results in stable electrodes by combining good electrical conductivity and increased surface area of the nanotubes with the versatility of the Sharpless click reaction.
- Full Text:
- Date Issued: 2012
Organosilicon compounds as fluorescent chemosensors for fluoride anion recognition
- Gai, Lizhi, Mack, John, Lu, Hua, Nyokong, Tebello, Li, Zhifang, Kobayashi, Nagao, Shen, Zhen
- Authors: Gai, Lizhi , Mack, John , Lu, Hua , Nyokong, Tebello , Li, Zhifang , Kobayashi, Nagao , Shen, Zhen
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241424 , vital:50938 , xlink:href="https://doi.org/10.1016/j.ccr.2014.10.009"
- Description: Recent developments in organosilicon-based chemosensors for F− recognition are reviewed. The design strategies for improving the photophysical properties of organosilicon-based chemosensors are elaborated, with an emphasis placed on their utility for biological applications. The photophysical properties and electronic structures are analyzed in depth with reference made to the results of molecular modeling calculation and possible future research directions are assessed.
- Full Text:
- Date Issued: 2015
- Authors: Gai, Lizhi , Mack, John , Lu, Hua , Nyokong, Tebello , Li, Zhifang , Kobayashi, Nagao , Shen, Zhen
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241424 , vital:50938 , xlink:href="https://doi.org/10.1016/j.ccr.2014.10.009"
- Description: Recent developments in organosilicon-based chemosensors for F− recognition are reviewed. The design strategies for improving the photophysical properties of organosilicon-based chemosensors are elaborated, with an emphasis placed on their utility for biological applications. The photophysical properties and electronic structures are analyzed in depth with reference made to the results of molecular modeling calculation and possible future research directions are assessed.
- Full Text:
- Date Issued: 2015
Crystal Structure, Hirshfeld Surface Analysis and Computational Studies of Two Benzo [b][1, 4] Diazepine Derivatives
- Odame, Felix, Madanhire, T, Hosten, Eric C, Lobb, Kevin A
- Authors: Odame, Felix , Madanhire, T , Hosten, Eric C , Lobb, Kevin A
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452689 , vital:75162 , xlink:href="https://doi.org/10.1134/S0022476623120041"
- Description: The DFT computational studies, crystal structures and Hirshfeld surface analysis of (E)-4-(2-chlorostyryl)-2,2-dimethyl-2,3-dihydro-1H-benzo[b][1,4]diazepine (1) and (E)-4-(2-(2,2-dimethyl-2,3-dihydro-1H-benzo[b][1,4]diazepin-4-yl)vinyl)phenol (2) have been presented. The compounds crystallized in the monoclinic space group P21/c with 4 molecules in their unit cells each. The experimental and computed bond lengths and bond angles deviated from each other to some extent but also showed good agreement with each other in some cases. Hirshfeld surface analysis of the compounds provided further information about the structural properties of the compounds.
- Full Text:
- Date Issued: 2023
- Authors: Odame, Felix , Madanhire, T , Hosten, Eric C , Lobb, Kevin A
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/452689 , vital:75162 , xlink:href="https://doi.org/10.1134/S0022476623120041"
- Description: The DFT computational studies, crystal structures and Hirshfeld surface analysis of (E)-4-(2-chlorostyryl)-2,2-dimethyl-2,3-dihydro-1H-benzo[b][1,4]diazepine (1) and (E)-4-(2-(2,2-dimethyl-2,3-dihydro-1H-benzo[b][1,4]diazepin-4-yl)vinyl)phenol (2) have been presented. The compounds crystallized in the monoclinic space group P21/c with 4 molecules in their unit cells each. The experimental and computed bond lengths and bond angles deviated from each other to some extent but also showed good agreement with each other in some cases. Hirshfeld surface analysis of the compounds provided further information about the structural properties of the compounds.
- Full Text:
- Date Issued: 2023
Development of biosensor systems for the detection of anti-cancer drugs and prostate cancer
- Authors: Mwanza, Daniel
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/365929 , vital:65803
- Description: Thesis embargoed. Expected release date early 2025. , Thesis (PhD) -- Faculty of Science, Chemistry, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Mwanza, Daniel
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/365929 , vital:65803
- Description: Thesis embargoed. Expected release date early 2025. , Thesis (PhD) -- Faculty of Science, Chemistry, 2022
- Full Text:
- Date Issued: 2022-10-14
Electrode modification using alkynyl substituted Fe (II) phthalocyanine via electrografting and click chemistry for electrocatalysis
- Nxele, Siphesihle R, Mashazi, Philani N, Nyokong, Tebello
- Authors: Nxele, Siphesihle R , Mashazi, Philani N , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189296 , vital:44835 , xlink:href="https://doi.org/10.1002/elan.201500212"
- Description: In this work, tetrakis(5-hexyn-oxy)Fe(II) phthalocyanine was synthesised in order to perform a click reaction between the terminal alkyne groups and an azide group on a glassy carbon electrode (GCE) surface. An azide group was formed on the electrode surface following electrografting using 4-azidobenzene diazonium tetrafluoroborate by electrochemical reduction. The Cu(I) catalyzed alkyne-azide Huisgen cycloaddition reaction was then employed in order to react the terminal alkyne groups on the phthalocyanine with the azide groups on the GCE surface. The modified electrode was employed to catalyse the oxidation of hydrazine. The electrode showed good electrocatalytic ability towards the detection of hydrazine with a sensitivity of 15.38 µA mM−1 and a limit of detection of 1.09 µM.
- Full Text:
- Date Issued: 2015
- Authors: Nxele, Siphesihle R , Mashazi, Philani N , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189296 , vital:44835 , xlink:href="https://doi.org/10.1002/elan.201500212"
- Description: In this work, tetrakis(5-hexyn-oxy)Fe(II) phthalocyanine was synthesised in order to perform a click reaction between the terminal alkyne groups and an azide group on a glassy carbon electrode (GCE) surface. An azide group was formed on the electrode surface following electrografting using 4-azidobenzene diazonium tetrafluoroborate by electrochemical reduction. The Cu(I) catalyzed alkyne-azide Huisgen cycloaddition reaction was then employed in order to react the terminal alkyne groups on the phthalocyanine with the azide groups on the GCE surface. The modified electrode was employed to catalyse the oxidation of hydrazine. The electrode showed good electrocatalytic ability towards the detection of hydrazine with a sensitivity of 15.38 µA mM−1 and a limit of detection of 1.09 µM.
- Full Text:
- Date Issued: 2015
Basic Chemistry: PAC 101
- Authors: Maqanda, V , Tichagwa, L
- Date: 2011-02
- Subjects: Chemistry
- Language: English
- Type: Examination paper
- Identifier: vital:17801 , http://hdl.handle.net/10353/d1010352
- Description: Basic Chemistry: PAC 101, supplementary February 2011.
- Full Text: false
- Date Issued: 2011-02
- Authors: Maqanda, V , Tichagwa, L
- Date: 2011-02
- Subjects: Chemistry
- Language: English
- Type: Examination paper
- Identifier: vital:17801 , http://hdl.handle.net/10353/d1010352
- Description: Basic Chemistry: PAC 101, supplementary February 2011.
- Full Text: false
- Date Issued: 2011-02
Investigation of electrocatalytic behaviour of low symmetry cobalt phthalocyanines when clicked to azide grafted carbon electrodes
- Mpeta, Lakethe S, Sen, Pinar, Nyokong, Tebello
- Authors: Mpeta, Lakethe S , Sen, Pinar , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186304 , vital:44483 , xlink:href="https://doi.org/10.1016/j.jelechem.2020.113896"
- Description: This work describes the electrochemical properties of low symmetry cobalt phthalocyanines namely, tris-[(4-tert-butylphenoxy)-4-(pent-4-yn-1-yloxy) phthalocyaniato] cobalt (II) (3) and tris-[(4-tert-butylphenoxy)-4-(4-ethybylbenzyl-oxy) phthalocyaniato] cobalt (II) (5). The complexes were characterized by a number of techniques including UV–Vis, mass, and infrared spectra, as well as elemental analysis. The glassy carbon electrodes were first azide functionalized then clicked to low symmetry phthalocyanines. The click reaction was confirmed using X-ray photoelectron spectra. The constructed electrodes showed excellent electrocatalytic activity towards hydrazine oxidation. Oxidation peaks with low potentials of 0.21 V and 0.26 V, for complexes 3 and 5, respectively were obtained. Complex-5 gave a better detection limit of 0.94 μM and electrocatalytic rate constant of 5.6 × 106 M−1 s−1.
- Full Text:
- Date Issued: 2020
- Authors: Mpeta, Lakethe S , Sen, Pinar , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186304 , vital:44483 , xlink:href="https://doi.org/10.1016/j.jelechem.2020.113896"
- Description: This work describes the electrochemical properties of low symmetry cobalt phthalocyanines namely, tris-[(4-tert-butylphenoxy)-4-(pent-4-yn-1-yloxy) phthalocyaniato] cobalt (II) (3) and tris-[(4-tert-butylphenoxy)-4-(4-ethybylbenzyl-oxy) phthalocyaniato] cobalt (II) (5). The complexes were characterized by a number of techniques including UV–Vis, mass, and infrared spectra, as well as elemental analysis. The glassy carbon electrodes were first azide functionalized then clicked to low symmetry phthalocyanines. The click reaction was confirmed using X-ray photoelectron spectra. The constructed electrodes showed excellent electrocatalytic activity towards hydrazine oxidation. Oxidation peaks with low potentials of 0.21 V and 0.26 V, for complexes 3 and 5, respectively were obtained. Complex-5 gave a better detection limit of 0.94 μM and electrocatalytic rate constant of 5.6 × 106 M−1 s−1.
- Full Text:
- Date Issued: 2020
""Of molecules and men"" : inaugural lecture delivered at Rhodes University
- Authors: Kaye, Perry T
- Date: 1989
- Subjects: Biochemistry , Chemistry, Organic , Chemistry
- Language: English
- Type: Text
- Identifier: vital:643 , http://hdl.handle.net/10962/d1020712 , ISBN 0868101842
- Description: Inaugural lecture delivered at Rhodes University , Rhodes University Libraries (Digitisation)
- Full Text:
- Date Issued: 1989
- Authors: Kaye, Perry T
- Date: 1989
- Subjects: Biochemistry , Chemistry, Organic , Chemistry
- Language: English
- Type: Text
- Identifier: vital:643 , http://hdl.handle.net/10962/d1020712 , ISBN 0868101842
- Description: Inaugural lecture delivered at Rhodes University , Rhodes University Libraries (Digitisation)
- Full Text:
- Date Issued: 1989
Chemistry and the white knight : inaugural lecture delivered at Rhodes University
- Authors: Letcher, T.M.
- Date: 1981
- Subjects: Chemistry, Physical and theoretical
- Language: English
- Type: Text
- Identifier: vital:647 , http://hdl.handle.net/10962/d1020716 , ISBN 0868100749
- Description: Inaugural lecture delivered at Rhodes University , Rhodes University Libraries (Digitisation)
- Full Text:
- Date Issued: 1981
- Authors: Letcher, T.M.
- Date: 1981
- Subjects: Chemistry, Physical and theoretical
- Language: English
- Type: Text
- Identifier: vital:647 , http://hdl.handle.net/10962/d1020716 , ISBN 0868100749
- Description: Inaugural lecture delivered at Rhodes University , Rhodes University Libraries (Digitisation)
- Full Text:
- Date Issued: 1981
Conjugation of azide-functionalised CdSe/ZnS quantum dots with tetrakis (5-hexyn-oxy) Fe (II) phthalocyanine via click chemistry for electrocatalysis
- Nxele, Siphesihle R, Nyokong, Tebello
- Authors: Nxele, Siphesihle R , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188755 , vital:44782 , xlink:href="https://doi.org/10.1016/j.electacta.2016.01.234"
- Description: In this work, azide-funtionalised CdSe/ZnS QDs are conjugated with tetrakis(5-hexyn-oxy) Fe(II) phthalocyanine for the electrocatalytic detection of paraquat. The conjugate was fully characterised using various techniques to confirm the success of the reaction. They also showed good electrocatalytic ability towards the electroreduction of paraquat with limits of detection (LoD) of 5.9 × 10−9 μM which is a great improvement compared to other reported sensors for this analyte.
- Full Text:
- Date Issued: 2016
- Authors: Nxele, Siphesihle R , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188755 , vital:44782 , xlink:href="https://doi.org/10.1016/j.electacta.2016.01.234"
- Description: In this work, azide-funtionalised CdSe/ZnS QDs are conjugated with tetrakis(5-hexyn-oxy) Fe(II) phthalocyanine for the electrocatalytic detection of paraquat. The conjugate was fully characterised using various techniques to confirm the success of the reaction. They also showed good electrocatalytic ability towards the electroreduction of paraquat with limits of detection (LoD) of 5.9 × 10−9 μM which is a great improvement compared to other reported sensors for this analyte.
- Full Text:
- Date Issued: 2016
Electrode modification using alkyne manganese phthalocyanine and click chemistry for electrocatalysis
- O'Donoghue, Charles St John Nqwabuko, Fomo, Gertrude, Nyokong, Tebello
- Authors: O'Donoghue, Charles St John Nqwabuko , Fomo, Gertrude , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188541 , vital:44763 , xlink:href="https://doi.org/10.1002/elan.201600379"
- Description: In this work, azidobenzene diazonium salt is grafted onto a glassy carbon electrode (GCE) followed by clicking of manganese tetrahexynyl phthalocyanine for the electrocatalysis of hydrazine. The GCE was first grafted via the in situ diazotization of a diazonium salt, rendering the GCE surface layered with azide groups. From this point, the 1,3-dipolar cycloaddition reaction, catalyzed by a copper catalyst was utilized to ‘click’ the manganese tetrahexynyl phthalocyanine to the surface of the grafted GCE. This new platform was then characterized using cyclic voltammetry (CV), scanning electrochemical microscopy (SECM) and X-ray photoelectron spectroscopy (XPS). Based on the cyclic voltammetry calibration curve of electrocatalysis for hydrazine, the clicked Mn phthalocyanine electrode proved to be an effective sensor with a sensitivity of 27.38 µA mM−1 and the limit of detection (LoD) of 15.4 pM which is a great improvement compared to other reported sensors for this analyte.
- Full Text:
- Date Issued: 2016
- Authors: O'Donoghue, Charles St John Nqwabuko , Fomo, Gertrude , Nyokong, Tebello
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188541 , vital:44763 , xlink:href="https://doi.org/10.1002/elan.201600379"
- Description: In this work, azidobenzene diazonium salt is grafted onto a glassy carbon electrode (GCE) followed by clicking of manganese tetrahexynyl phthalocyanine for the electrocatalysis of hydrazine. The GCE was first grafted via the in situ diazotization of a diazonium salt, rendering the GCE surface layered with azide groups. From this point, the 1,3-dipolar cycloaddition reaction, catalyzed by a copper catalyst was utilized to ‘click’ the manganese tetrahexynyl phthalocyanine to the surface of the grafted GCE. This new platform was then characterized using cyclic voltammetry (CV), scanning electrochemical microscopy (SECM) and X-ray photoelectron spectroscopy (XPS). Based on the cyclic voltammetry calibration curve of electrocatalysis for hydrazine, the clicked Mn phthalocyanine electrode proved to be an effective sensor with a sensitivity of 27.38 µA mM−1 and the limit of detection (LoD) of 15.4 pM which is a great improvement compared to other reported sensors for this analyte.
- Full Text:
- Date Issued: 2016
Optically active BODIPYs
- Lu, Hua, Mack, John, Nyokong, Tebello, Kobayashi, Nagao, Shen, Zhen
- Authors: Lu, Hua , Mack, John , Nyokong, Tebello , Kobayashi, Nagao , Shen, Zhen
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240421 , vital:50833 , xlink:href="https://doi.org/10.1016/j.ccr.2016.03.015"
- Description: This review highlights and summarizes various optically active BODIPY molecules and describes the analysis of their circular dichroism (CD) and circularly polarized luminescence (CPL) spectroscopy, to provide a platform for the rational design of novel optically active BODIPY structures and the development of new chiroptical applications. Possible future research directions are also discussed.
- Full Text:
- Date Issued: 2016
- Authors: Lu, Hua , Mack, John , Nyokong, Tebello , Kobayashi, Nagao , Shen, Zhen
- Date: 2016
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240421 , vital:50833 , xlink:href="https://doi.org/10.1016/j.ccr.2016.03.015"
- Description: This review highlights and summarizes various optically active BODIPY molecules and describes the analysis of their circular dichroism (CD) and circularly polarized luminescence (CPL) spectroscopy, to provide a platform for the rational design of novel optically active BODIPY structures and the development of new chiroptical applications. Possible future research directions are also discussed.
- Full Text:
- Date Issued: 2016