Tuning the redox properties of metalloporphyrin-and metallophthalocyanine-based molecular electrodes for the highest electrocatalytic activity in the oxidation of thiols
- Bedioui, Fethi, Griveau, Sophie, Nyokong, Tebello, Appleby, A John, Caro, Claudia A, Gulppi, Miguel, Ochoa, Gonzalo, Zagal, José H
- Authors: Bedioui, Fethi , Griveau, Sophie , Nyokong, Tebello , Appleby, A John , Caro, Claudia A , Gulppi, Miguel , Ochoa, Gonzalo , Zagal, José H
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283988 , vital:56009 , xlink:href="https://doi.org/10.1039/B618767F"
- Description: In this work we discuss different approaches for achieving electrodes modified with N4 macrocyclic complexes for the catalysis of the electrochemical oxidation of thiols. These approaches involve adsorption, electropolymerization and molecular anchoring using self assembled monolayers. We also discuss the parameters that determine the reactivity of these complexes. Catalytic activity is associated with the nature of the central metal, redox potentials and Hammett parameters of substituents on the ligand. Correlations between catalytic activity (log i at constant E) and the redox potential of catalysts for complexes of Cr, Mn, Fe, Co, Ni and Cu are linear with an increase of activity for more positive redox potentials. For a great variety complexes bearing the same metal center (Co) correlations between log i and Eo′ of the Co(II)/Co(I) couple have the shape of an unsymmetric volcano. This indicates that the potential of the Co(II)/Co(I) couple can be tuned using the appropiate ligand to achieve maximum catalytic activity. Maximum activity probably corresponds to a ΔG of adsorption of the thiol on the Co center equal to zero, and to a coverage of active sites by the thiol equal to 0.5.
- Full Text:
- Date Issued: 2007
- Authors: Bedioui, Fethi , Griveau, Sophie , Nyokong, Tebello , Appleby, A John , Caro, Claudia A , Gulppi, Miguel , Ochoa, Gonzalo , Zagal, José H
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/283988 , vital:56009 , xlink:href="https://doi.org/10.1039/B618767F"
- Description: In this work we discuss different approaches for achieving electrodes modified with N4 macrocyclic complexes for the catalysis of the electrochemical oxidation of thiols. These approaches involve adsorption, electropolymerization and molecular anchoring using self assembled monolayers. We also discuss the parameters that determine the reactivity of these complexes. Catalytic activity is associated with the nature of the central metal, redox potentials and Hammett parameters of substituents on the ligand. Correlations between catalytic activity (log i at constant E) and the redox potential of catalysts for complexes of Cr, Mn, Fe, Co, Ni and Cu are linear with an increase of activity for more positive redox potentials. For a great variety complexes bearing the same metal center (Co) correlations between log i and Eo′ of the Co(II)/Co(I) couple have the shape of an unsymmetric volcano. This indicates that the potential of the Co(II)/Co(I) couple can be tuned using the appropiate ligand to achieve maximum catalytic activity. Maximum activity probably corresponds to a ΔG of adsorption of the thiol on the Co center equal to zero, and to a coverage of active sites by the thiol equal to 0.5.
- Full Text:
- Date Issued: 2007
Two issues, two groups:
- Authors: du Toit, Jeanne
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159299 , vital:40285 , https://hdl.handle.net/10520/EJC144677
- Description: One of the conference strategies that I found particularly valuable was that of the "syndicate teams" who met regularly to speak on focused topics. Delegates signed up for the topic they were interested in and stayed with that group for the duration of the conference. The list included topics such as the status of journalism education in the academy; the role of journalism in changing the media; adapting journalism education to a digital age, etc.
- Full Text:
- Date Issued: 2007
- Authors: du Toit, Jeanne
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159299 , vital:40285 , https://hdl.handle.net/10520/EJC144677
- Description: One of the conference strategies that I found particularly valuable was that of the "syndicate teams" who met regularly to speak on focused topics. Delegates signed up for the topic they were interested in and stayed with that group for the duration of the conference. The list included topics such as the status of journalism education in the academy; the role of journalism in changing the media; adapting journalism education to a digital age, etc.
- Full Text:
- Date Issued: 2007
Using the tutorial system to improve the quality of feedback to students in large class teaching
- Snowball, Jeanette D, Sayigh, E
- Authors: Snowball, Jeanette D , Sayigh, E
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70848 , vital:29752
- Description: In many universities, economics teachers now face the challenge of dealing with large, diverse classes, especially at undergraduate level. A common concern is the non-attendance at lectures of unmotivated (conscript) students. This paper presents the results of a student assessment of a macroeconomics 1 course, coupled with a self-assessment of their own input into the course. The results obtained, using an econometric model, suggest that what students do outside of lectures is equally, or more, important than lecture attendance itself. The paper concludes by examining the possibility of using peer assessed group learning as a feasible way to encourage deep learning in large classes.
- Full Text:
- Date Issued: 2007
- Authors: Snowball, Jeanette D , Sayigh, E
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70848 , vital:29752
- Description: In many universities, economics teachers now face the challenge of dealing with large, diverse classes, especially at undergraduate level. A common concern is the non-attendance at lectures of unmotivated (conscript) students. This paper presents the results of a student assessment of a macroeconomics 1 course, coupled with a self-assessment of their own input into the course. The results obtained, using an econometric model, suggest that what students do outside of lectures is equally, or more, important than lecture attendance itself. The paper concludes by examining the possibility of using peer assessed group learning as a feasible way to encourage deep learning in large classes.
- Full Text:
- Date Issued: 2007
Vice Chancellor New staff welcome address, 2007
- Authors: Badat, Saleem
- Date: 2007
- Subjects: Rhodes University
- Type: text
- Identifier: vital:7646 , http://hdl.handle.net/10962/d1015774
- Full Text:
- Date Issued: 2007
- Authors: Badat, Saleem
- Date: 2007
- Subjects: Rhodes University
- Type: text
- Identifier: vital:7646 , http://hdl.handle.net/10962/d1015774
- Full Text:
- Date Issued: 2007
Vice Chancellor's message to the Toronto Old Rhodian Reunion
- Authors: Badat, Saleem
- Date: 2007
- Subjects: Rhodes University
- Language: English
- Type: text
- Identifier: vital:7648 , http://hdl.handle.net/10962/d1015776
- Full Text:
- Date Issued: 2007
- Authors: Badat, Saleem
- Date: 2007
- Subjects: Rhodes University
- Language: English
- Type: text
- Identifier: vital:7648 , http://hdl.handle.net/10962/d1015776
- Full Text:
- Date Issued: 2007
Vice Chancellor's Oppidan Newspaper message, 2007
- Authors: Badat, Saleem
- Date: 2007
- Subjects: Rhodes University
- Language: English
- Type: text
- Identifier: vital:7649 , http://hdl.handle.net/10962/d1015777
- Full Text:
- Date Issued: 2007
- Authors: Badat, Saleem
- Date: 2007
- Subjects: Rhodes University
- Language: English
- Type: text
- Identifier: vital:7649 , http://hdl.handle.net/10962/d1015777
- Full Text:
- Date Issued: 2007
Voltammetric characterisation of the self-assembled monolayers (SAMs) of benzyl-and dodecyl-mercapto tetra substituted metallophthalocyanines complexes
- Agboola, Bolade, Westbroek, Philippe, Ozoemena, Kenneth I, Nyokong, Tebello
- Authors: Agboola, Bolade , Westbroek, Philippe , Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281414 , vital:55723 , xlink:href="https://doi.org/10.1016/j.elecom.2006.08.047"
- Description: Voltammetric characterisations of cobalt, iron, manganese, nickel and zinc phthalocyanine complexes tetra substituted with benzyl- and dodecyl-mercapto ring substituents and immobilisation on gold electrodes via the self-assembling technique are presented. The self-assembled films are stable and showed blocking characteristics towards the following Faradaic processes; gold surface oxidation, under potential deposition of copper and solution redox chemistry of [Fe(H2O)6 3+ ]/[Fe(H2O)6 2+ ]. The solution chemistry of [Fe(CN)6]−3/[Fe(CN)6]−4 redox process was used to study the orientation of the CoPcs-SAMs and this revealed a possible deviation from flat orientation of the complexes on the gold electrodes when the SAM formation times were greater than 24 h. For SAM formation time at 24 and 48 h, CoTDMPc-SAM showed more inhibition of the [Fe(CN)6]−3/[Fe(CN)6]−4 redox process than the CoTBMPc-SAM counterpart, indicating more blocking characteristics of the dodecylmercapto ring substituents compared to the benzylmercapto counterpart. To avoid SAM desorption, the potential application should be limited to −0.2 to +0.8 V vs. Ag∣AgCl (NaCl, sat’d) in acidic and neutral pH.
- Full Text:
- Date Issued: 2007
- Authors: Agboola, Bolade , Westbroek, Philippe , Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281414 , vital:55723 , xlink:href="https://doi.org/10.1016/j.elecom.2006.08.047"
- Description: Voltammetric characterisations of cobalt, iron, manganese, nickel and zinc phthalocyanine complexes tetra substituted with benzyl- and dodecyl-mercapto ring substituents and immobilisation on gold electrodes via the self-assembling technique are presented. The self-assembled films are stable and showed blocking characteristics towards the following Faradaic processes; gold surface oxidation, under potential deposition of copper and solution redox chemistry of [Fe(H2O)6 3+ ]/[Fe(H2O)6 2+ ]. The solution chemistry of [Fe(CN)6]−3/[Fe(CN)6]−4 redox process was used to study the orientation of the CoPcs-SAMs and this revealed a possible deviation from flat orientation of the complexes on the gold electrodes when the SAM formation times were greater than 24 h. For SAM formation time at 24 and 48 h, CoTDMPc-SAM showed more inhibition of the [Fe(CN)6]−3/[Fe(CN)6]−4 redox process than the CoTBMPc-SAM counterpart, indicating more blocking characteristics of the dodecylmercapto ring substituents compared to the benzylmercapto counterpart. To avoid SAM desorption, the potential application should be limited to −0.2 to +0.8 V vs. Ag∣AgCl (NaCl, sat’d) in acidic and neutral pH.
- Full Text:
- Date Issued: 2007
WET-Roadmap:
- Dada, Rehana, Kotze, Donovan C, Ellery, William F N, Uys, Mary, Breen, Charles, Dini, John, Mitchell, Steve
- Authors: Dada, Rehana , Kotze, Donovan C , Ellery, William F N , Uys, Mary , Breen, Charles , Dini, John , Mitchell, Steve
- Date: 2007
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/176596 , vital:40093 , ISBN 978-1-77005-632-9 , http://www.wrc.org.za/wp-content/uploads/mdocs/TT 321-07.pdf
- Description: The WET-Management Series is a set of integrated tools that can be used to guide well-informed and effective wetland management and rehabilitation. Wetland loss in South Africa has been significant and the need for wetland rehabilitation as part of good wetland stewardship and management is compelling. National policy and legislation provide clear direction and support for rehabilitation, but the very complex links between people and wetlands mean that actions aimed at sustainably rehabilitating and conserving wetlands will depend on the dedication and commitment of all stakeholders, especially landowners and wetland users.
- Full Text:
- Date Issued: 2007
- Authors: Dada, Rehana , Kotze, Donovan C , Ellery, William F N , Uys, Mary , Breen, Charles , Dini, John , Mitchell, Steve
- Date: 2007
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/176596 , vital:40093 , ISBN 978-1-77005-632-9 , http://www.wrc.org.za/wp-content/uploads/mdocs/TT 321-07.pdf
- Description: The WET-Management Series is a set of integrated tools that can be used to guide well-informed and effective wetland management and rehabilitation. Wetland loss in South Africa has been significant and the need for wetland rehabilitation as part of good wetland stewardship and management is compelling. National policy and legislation provide clear direction and support for rehabilitation, but the very complex links between people and wetlands mean that actions aimed at sustainably rehabilitating and conserving wetlands will depend on the dedication and commitment of all stakeholders, especially landowners and wetland users.
- Full Text:
- Date Issued: 2007
Written medicines information for South African HIV/AIDS patients: does it enhance understanding of co-trimoxazole therapy?
- Mansoor, Leila E, Dowse, Roslind
- Authors: Mansoor, Leila E , Dowse, Roslind
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156860 , vital:40059 , https://0-doi.org.wam.seals.ac.za/10.1093/her/cyl039
- Description: Written information to promote patient education is being increasingly recognized as an integral part of quality health care. The main objective of this study was to evaluate the effect of distributing a patient information leaflet (PIL) on knowledge acquisition and recall. Two different PILs were designed for co-trimoxazole tablets: a simple, shorter PIL that incorporated pictograms and text and a text-only PIL that was longer and more complex. Human immunodeficiency virus-positive participants on chronic co-trimoxazole therapy were enrolled from five local primary health care clinics in Grahamstown, South Africa, and were randomly allocated to a Control Group (no PIL), Group A (text-only PIL) or Group B (simple PIL with pictograms).
- Full Text:
- Date Issued: 2007
- Authors: Mansoor, Leila E , Dowse, Roslind
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156860 , vital:40059 , https://0-doi.org.wam.seals.ac.za/10.1093/her/cyl039
- Description: Written information to promote patient education is being increasingly recognized as an integral part of quality health care. The main objective of this study was to evaluate the effect of distributing a patient information leaflet (PIL) on knowledge acquisition and recall. Two different PILs were designed for co-trimoxazole tablets: a simple, shorter PIL that incorporated pictograms and text and a text-only PIL that was longer and more complex. Human immunodeficiency virus-positive participants on chronic co-trimoxazole therapy were enrolled from five local primary health care clinics in Grahamstown, South Africa, and were randomly allocated to a Control Group (no PIL), Group A (text-only PIL) or Group B (simple PIL with pictograms).
- Full Text:
- Date Issued: 2007
Cognitive pharmaceutical services and the community pharmacist: are South African patients receiving them and are they willing to pay?
- Hill, Peter W, Dowse, Roslind
- Authors: Hill, Peter W , Dowse, Roslind
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156829 , vital:40054 , DOI 10.1211/ijpp.15.2.0007
- Description: The objectives of this study were to ascertain the opinions of randomly selected South African medical aid members regarding the provision by community pharmacists of patient counselling and information; member satisfaction with pharmacist services; their rating of pharmacist accessibility; and if pharmacists should be reimbursed for providing cognitive pharmaceutical services. Setting A South African private healthcare insurance company.
- Full Text:
- Date Issued: 2006
- Authors: Hill, Peter W , Dowse, Roslind
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156829 , vital:40054 , DOI 10.1211/ijpp.15.2.0007
- Description: The objectives of this study were to ascertain the opinions of randomly selected South African medical aid members regarding the provision by community pharmacists of patient counselling and information; member satisfaction with pharmacist services; their rating of pharmacist accessibility; and if pharmacists should be reimbursed for providing cognitive pharmaceutical services. Setting A South African private healthcare insurance company.
- Full Text:
- Date Issued: 2006
Shakespeare's Victorian Stage: performing history in the theatre of Charles Kean, Richard W. Schoch: book review
- Authors: Wright, Laurence
- Date: 2004
- Language: English
- Type: text , article
- Identifier: vital:7050 , http://hdl.handle.net/10962/d1007393 , http://hdl.handle.net/10520/EJC48030
- Description: preprint , This book is a primarily a study of Charles Kean’s productions of Shakespeare’s English chronicle plays at the Princess’s Theatre between 1852 and 1859, a period crucial to the development of ideas of English nationalism. Schoch focuses on these particular stagings as more than drama; as performances of nineteenth century theories of history and historical representation. His project operates under the aegis of the so-called ‘linguistic turn’ in cultural theory, and is suspicious of neo-marxian fundamentalism.
- Full Text:
- Date Issued: 2004
- Authors: Wright, Laurence
- Date: 2004
- Language: English
- Type: text , article
- Identifier: vital:7050 , http://hdl.handle.net/10962/d1007393 , http://hdl.handle.net/10520/EJC48030
- Description: preprint , This book is a primarily a study of Charles Kean’s productions of Shakespeare’s English chronicle plays at the Princess’s Theatre between 1852 and 1859, a period crucial to the development of ideas of English nationalism. Schoch focuses on these particular stagings as more than drama; as performances of nineteenth century theories of history and historical representation. His project operates under the aegis of the so-called ‘linguistic turn’ in cultural theory, and is suspicious of neo-marxian fundamentalism.
- Full Text:
- Date Issued: 2004