Critical literacy in South Africa : possibilities and constraints in 2002
- Authors: Prinsloo, J , Janks, H
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6330 , http://hdl.handle.net/10962/d1008475
- Description: This article examines the Curriculum documents produced in South Africa since the election of a democratic government in 1994 in order to consider the possibilities they create for the inclusion of critical literacy in the teaching of home languages. This discussion is set against an analysis of the apartheid curriculum documents prior to 1994 and a consideration of the ongoing inequalities in the provision of human and material resources across the system. Despite real constraints with regard to implementation, it is argued that the new Curriculum effects a significant break with the past and makes a positive contribution to transforming language education.
- Full Text:
- Date Issued: 2002
Making visible constructions of dis/advantage through genealogical investigation: South African schooled literacies
- Authors: Prinsloo, Jeanne
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147869 , vital:38680 , DOI: 10.1080/02560040701398889
- Description: In this paper I assume the relevance of Foucauldian insights for conducting socio-cultural critique and I argue the significance of genealogical work in relation to understanding the present. Thus, I seek both to establish what could constitute a genealogical investigation and to illustrate this by describing and discussing a study, undertaken within a genealogical frame, into literacy practices within a specifically South African context. I investigated the differing schooled literacies in KwaZulu-Natal province in South Africa over three decades along the language lines of Afrikaans, English and Zulu. The findings propose that the differing sets of literacy practices validate different subjects – and that they are implicated in constructing dis/advantage.
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- Date Issued: 2007
Gendering children's lives: TV fiction for South African kids
- Authors: Boshoff, Priscilla A , Prinsloo, Jeanne
- Date: 2008
- Language: English
- Type: text , book
- Identifier: vital:38264 , ISBN 9780868104508 , http://hdl.handle.net/10962/2476
- Description: Gendering children's lives: TV fiction for South African kids
- Full Text:
- Date Issued: 2008
Agreement and coordination in XiTsonga, SeSotho and IsiXhosa: an optimality theoretic perspective
- Authors: Mitchley, Hazel
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3423 , vital:20491
- Description: This thesis provides a unified Optimality Theoretic analysis of subject-verb agreement with coordinated preverbal subjects in three Southern Bantu languages: Xitsonga (S53), Sesotho (S33), and isiXhosa (S41). This analysis is then used to formulate a typology of agreement resolution strategies and the contexts which trigger them. Although some accounts in the Bantu literature suggest that agreement with coordinate structures is avoided by speakers (e.g. Schadeberg 1992, Voeltz 1971) especially when conjuncts are from different noun classes, I show that there is ample evidence to the contrary, and that the subject marker used is dependent on several factors, including (i) the [-HUMAN] specification on the conjuncts, (ii) whether the conjuncts are singular or plural, (iii) whether or not the conjuncts both carry the same noun class feature, and (iv) the order of the conjuncts. This thesis shows that there are various agreement resolution strategies which can beused: 1) agreement with the [+HUMAN] feature on the conjuncts, 2) agreement with the[-HUMAN] feature on the conjuncts, 3) agreement with the noun class feature on both conjuncts, 4) agreement with the noun class feature on the conjunct closest to the verb, and 5) agreement with the noun class feature on the conjunct furthest from the verb. Not all of these strategies are used by all languages, nor are these strategies interchangeable in the languages which do use them – instead, multiple factors conspire to trigger the use of a specific agreement strategy within a specific agreement featural context. I show that these effects can be captured using Optimality Theory (Prince and Smolensky 2004). The analysis makes use of seven constraints: RES#, MAX[+H], MAX[-H], DEP[-H], MAXNC, DEPNC, and AGREECLOSEST. The hierarchical ranking of these constraints not only accounts for the confinement of particular strategies to specific agreement featural contexts within a language, but also accounts for the cross-linguistic differences in the use of these strategies. I end off by examining the typological implications which follow from the OT analysis provided in this thesis.
- Full Text:
- Date Issued: 2016
RUL News, Quarter 1, 2012
- Authors: Rhodes Library Services
- Date: 2012
- Language: English
- Type: Text
- Identifier: vital:16122 , http://hdl.handle.net/10962/d1020856
- Description: [From Introduction] Message from Ujala: It is now two months since I joined Rhodes University Library on February 01 2012 as the latest Director in a list of respected professionals who have led this Library to what it is today. I feel extremely privileged to have inherited an amazingly beautiful library building that has all the trappings of a modern 21st century academic library. To this end I acknowledge the former Director Gwenda Thomas who drove this reconstruction and renewal process together with Ms Jeanne Berger, former Acting Director and Deputy Director. I believe that together we are poised to embark on a new trajectory that will redefine this institution. This redefinition will include a new vision, mission and values statement; an articulated organizational culture; staff enablement and development for consolidation and innovation; and increased visibility and appreciation of the Library. While we enjoy the physical Library environment, we also need to explore the frontiers of the digital library. Unprecedented growth in technology provides us with vast new opportunities for identifying appropriate or relevant models for library services and communication. We need to commence this conversation proactively so that we understand and embrace the newest technologies to enable and contribute to the success of our users and the University. I believe that we have an exciting future ahead of us and that collectively we can set the agenda for this future. The African proverb, “If you want to go fast, go alone; if you want to go far, go together” certainly holds true for us and I look forward to working with each one of you.
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- Date Issued: 2012
Madeline, David and Gavin Marsh
- Subjects: Class reunions -- South Africa -- Grahamstown -- Photographs Grahamstown Teachers' Training College (South Africa) -- Photographs
- Type: Image
- Identifier: http://hdl.handle.net/10962/28108 , vital:23615 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017. , PIC/A 2897_110
- Description: Photograph of Madeline, David and Gavin Marsh (presumably the children of Jeanne Joubert). The man in the photograph is presumably Jeanne's husband , Leila Kerr (Linington) (Donor)
- Full Text: false
Rhodes University Library Annual Report 2011 : acting Library Director’s Review
- Authors: Berger, Jeanne
- Date: 2012
- Language: English
- Type: Text
- Identifier: vital:7944 , http://hdl.handle.net/10962/d1011891
- Description: [From the Introduction] 2011 saw the consolidation of a number of changes to Library services implemented in 2010 as a result of the 2009 Review of the Library Services Division. These include: 1) Collection development operating as a collaborative effort between Library staff and the academic community. The Collection Development Policy also underwent a major revision and was approved by Senate in October as the “Collection Development and Management Policy and Guidelines”. 2) The Faculty Liaison Service – the librarians in these teams are now proactively liaising with academics, for example, playing a crucial role in collection development for the departments, ensuring that they spend their information resources grants, creating awareness of appropriate online information resources and offering information literacy workshops.
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- Date Issued: 2012
Critical media literacy: a design for the future
- Authors: Prinsloo, Jeanne
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6331 , http://hdl.handle.net/10962/d1008476
- Description: [From OPENSPACE Editor Alice Kanengoni's editorial]: Professor Jeanne Prinsloo notes in her article that "In fact, it has been argued that the significance of the media in people’s lives has increased to the extent that it has been described as their primary curriculum, thereby recasting formal education as the secondary curriculum." This therefore requires an incestment in media literacy; people's ability to to understand the world around them, as represented in the media. Thus, Professor Prinsloo argues for critical media literacy, citing the role that the media played in fuelling the genocide in Rwanda, as an illustrative case in point. She states that "While we can not attribute all blame in the Rwandan scenario to the radio use, it is clear that the media mattered." She indicates that "media representations and engagements play a significant role in the way we understand the world, its people and events, and ourselves therein." As such, societies should invest in building a critical citizenry that can read and deconstruct the various ideologies that are often carries in and through the media.
- Full Text:
- Date Issued: 2006
Expurgating the Monstrous: an analysis of the South African Daily Sun's coverage of gang rape
- Authors: Boshoff, Priscilla A , Prinsloo, Jeanne
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143436 , vital:38246 , DOI: 10.1080/14680777.2014.903286
- Description: The most widely read South African tabloid, the Daily Sun, covered the “Soweto gang rape” in 2012. These acts were recorded by the perpetrators on mobile phones and “went viral” as the media continuously noted. We draw on the concept of provider love that informs relations of intimacy in certain South African spaces, central to which is its materiality and the assumption that a “real” man is able to command material resources, a prerequisite for having both a girlfriend and sex. For working class and township youth these possibilities are constrained and their sense of being left behind is lived in gendered ways with violent masculinities becoming a marker of tough sexual masculinity. Informed by Foucauldian understandings of discourse, the paper undertakes a close reading of this coverage, including the reporting, editorials, and letters. If those arrested for rape are constituted as monstrous, the analysis indicates how the responses are similarly vengeful. These responses deny the forms of masculinity produced within these marginalised spaces and foreclose on other possibilities for understanding these violent acts.
- Full Text:
- Date Issued: 2014
Nancy Jazz Pulsations
- Authors: Unknown
- Subjects: McGregor, Chris -- 1936-1990 , Brotherhood of Breath (Musical group) , Jazz
- Language: French
- Type: Text
- Identifier: vital:13784 , http://hdl.handle.net/10962/d1012816
- Description: Original flier for the 10th Nancy Jazz Pulsations festival (France).
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Learning (dis)advantage in matriculation language classrooms
- Authors: Prinsloo, J
- Date: 2006
- Language: English
- Type: Book chapter
- Identifier: vital:529 , http://hdl.handle.net/10962/d1008479
- Description: During the first decade of democracy in South Africa formal education has been characterised by sweeping policy shifts and consequent curriculum revision. In many instances, curricular revisions are criticised for failing to effect desired or anticipated changes. In this chapter the focus is on the language curriculum and the associated practices, or what I refer to as the literacy practices that have become naturalised over decades and persist in the present. The argument that is presented here contends that to enable effective change, it is essential to understand better what has historically constituted literacy practices and to recognise their social, cultural and economic implications.
- Full Text:
- Date Issued: 2006
Folic acid-modified phthalocyanine-nanozyme loaded liposomes for targeted photodynamic therapy
- Authors: Nwahara, Nnamdi , Abrahams, Garth , Prinsloo, Earl , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/231369 , vital:49881 , xlink:href="https://doi.org/10.1016/j.pdpdt.2021.102527"
- Description: The hypoxic tumour microenvironment and poor spatiotemporal localization of photosensitizers are two significant obstacles that limit practical applications of photodynamic therapy. In response, a biocompatible, light-activatable liposome integrated with both a zinc phthalocyanine photodynamic component and Pt nanoparticles-decorated with MnO2 catalase-mimicking component are engineered. This multifunctional system was rationally designed using unsaturated phospholipids to achieve on-demand drug release following light irradiation. Specificity was achieved by folic acid functionalization resulting in folate-modified liposomes (FTLiposomes). We demonstrated its specific uptake by fluorescence imaging using folate receptor (FR) overexpressing HeLa and MCF-7 cells as in vitro models. This multifunctional liposome exhibits superior hypoxic anti-tumour effects and holds the potential to reduce side effects associated with untargeted therapy. Fluorescence of the constituent ZnPc and folate-receptor targeting could enable tracking and permit spatiotemporal regulation for improved cancer treatment.
- Full Text:
- Date Issued: 2021
The photophysicochemical properties and photodynamic therapy activity of phenyldiazenyl phenoxy substituted phthalocyanines when incorporated into Pluronic® F127 micelles
- Authors: Motloung, Banele M , Sekhosana, Kutloano E , Managa, Muthumuni , Prinsloo, Earl , Nyokong, Tebello
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186769 , vital:44532 , xlink:href="https://doi.org/10.1016/j.poly.2019.114157"
- Description: The synthesis, photophysicochemical properties and photodynamic activity (PDT) of 4(4-phenyldiazenyl) phenoxy substituted indium (III) (InPc) and zinc (ZnPc) phthalocyanines when alone or incorporated into Pluronic_ F127 micelles are presented in this study. The InPc exhibited higher singlet oxygen (UD) at 0.47 compared to the ZnPc at 0.20 in dimethylsulfoxide. The UD values in the presence of Pluronic_ F127 and in water, were 0.32 for InPc and 0.09 for ZnPc. The triplet quantum yields (UT) were 0.92 for InPc and 0.32 for ZnPc in DMSO. The PDT activity followed the same trend as the singlet oxygen quantum yields. At the highest concentration, InPc in Pluronic_ F127 gave 22% cell viability compared to 34% for complex ZnPc. The partition coefficient Kp values were determined using the water and octanol system. InPc had a larger Kp suggesting that it is more likely to be taken up by the cancer cells, hence it exhibited better PDT activity.
- Full Text:
- Date Issued: 2019
Photophysicochemical properties and photodynamic therapy activity of highly water-soluble Zn (II) phthalocyanines
- Authors: Oluwole, David O , Sari, Fatma Aslihan , Prinsloo, Earl , Dube, Edith , Yuzer, Abdulcelil , Nyokong, Tebello , Ince, Mine
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/234507 , vital:50203 , xlink:href="https://doi.org/10.1016/j.saa.2018.05.090"
- Description: The syntheses of two zinc(II) phthalocyanines (ZnPcs) having either imidazole (ZnPc 1) or pyridiloxy (ZnPc 2) moieties as their macrocycle substituents are reported. Quaternization of the ZnPcs with methyl iodide afforded water soluble cationic phthalocyanines. The photophysical, photochemical properties and photodynamic therapy (PDT) activity of the ZnPcs were studied in solution. The fluorescence quantum yield and lifetime of ZnPc 1 were higher as compared to ZnPc 2. ZnPc 2 afforded higher triplet state (ΦT) and singlet oxygen quantum yields (ΦΔ) in comparison to ZnPc 1. The PDT activity of ZnPcs was investigated against human breast adenocarcinoma cells (MCF–7). The two compounds afforded a very minimal in vitro dark cytotoxicity with 85% viable cells at concentration ≤80 μM. On irradiation of the cells having the ZnPcs, ≥50% cell death was recorded for ZnPc 1 which was also evidenced by the cells photo–micrograph.
- Full Text:
- Date Issued: 2018
Secrets, lies and redemption:
- Authors: Boshoff, Priscilla A , Prinsloo, Jeanne
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143381 , vital:38241 , DOI: 10.1080/00020184.2017.1285671
- Description: Confession is a central disciplining technology deployed in the second series of Intersexions, a popular South African TV series that seeks to change sexual and social behaviours that contribute to the risk of HIV infection. The article considers the ‘edu’ part of this edutainment programme, specifically with the nature of the lessons and with the form of ‘disciplining’ the narratives presuppose for gendered and sexual subjects. Central to this critical and constructivist exploration of the gender relationships that are validated and expurgated are Foucault’s notions of discourse and confession as a technology of self. We argue that the series presents a range of different gendered and sexual subjectivities but implicitly endorses a modern subjectivity and transformation at the level of the individual.
- Full Text:
- Date Issued: 2017
Engendering childhood: concerning the content of South African Television content
- Authors: Boshoff, Priscilla A , Prinsloo, Jeanne
- Date: 2008
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/143560 , vital:38257 , ISBN , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: The essays in this volume reflect a wide-range of issues and concerns related to children’s media culture in Africa. For example, several address the role of entertainment television in Addis Abba, Ghana, South Africa, Kenya, and Zambia and in the lives of Muslim children. Other essays introduce us to children-centered media from Ghana, South Africa, and Zimbabwe, and the innovative programs of PLAN-International. In addition to entertainment media and children-centered media, media education and digital media literacy are also discussed.
- Full Text:
- Date Issued: 2008
Petrographic and geochemical characterisation of the hangingwall and the footwall rocks (the Dipeta and R.A.T. stratigraphic units) to the Kinsevere and Nambulwa copper ore deposits of the Lufilian Arc, southern Democratic Republic of Congo
- Authors: Nkulu, Robert Kankomba
- Date: 2020
- Subjects: Petrogenesis -- Congo (Democratic Republic) , Analytical geochemistry -- Congo (Democratic Republic) , Copper ores -- Congo (Democratic Republic) , Ore deposits -- Congo (Democratic Republic) , Katangan Sequence , Geological mapping -- Congo (Democratic Republic) , Central African Copperbelt (Congo and Zambia) , Lufilian Arc , Neoproterozoic Katangan R.A.T. (Roches Argilo Talqueuse) Subgroup , Dipeta Subgroup
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/142772 , vital:38115
- Description: The Kinsevere and Nambulwa copper deposits in the Democratic Republic of Congo (D.R.C.) are set in the eastern side of the Neoproterozoic Katanga Supergroup, forming the Lufilian Arc, resulting from a cratonic collision between the Congo and the Kalahari Cratons (ca.620-570_Ma). The Katanga Supergroup was deposited in an extensional rift setting with a sedimentary thickness succession ranging between 7 to 10 km, sub-divided into: − the Roan, the Nguba and the Kundelungu Groups. The stratigraphic column of the Roan Group consists of the R.A.T. (Roche Argilo Talqueuse), the Mines, the Dipeta and the Mwashya Subgroups. Three major deformation phases have been described characterised by complex multiphase tectonics related to a curved superposition of folded, thrust and sheared blocks. The rocks of the R.A.T., Mines and Dipeta Subgroups are recognised as blocks that occur within a stratiform to discordant and diapiritic megabreccia. The blocks were rafted upward with salt tectonics, resulting in the juxtaposition with the hangingwall and the footwall terranes. Therefore, in that context it has been found that the Dipeta may appear overlying the R.A.T. Subgroup through the unconformity decollement surface of heterogeneous breccia. The petrographic observations made of the R.A.T. and Dipeta samples indicates in both units the presence of detrital quartz and feldspar that have been altered and replaced by sericite and muscovite minerals. Gypsum is intimately associated with magnesite, showing an evaporitic environment domain, while magnesite is common as alteration phase both in the R.A.T. and Dipeta Subgroups. Pyrophyllite has been observed in the Dipeta, resulting from reaction of silica with the Kaolinite at low temperature. Accessory detrital minerals include zircon, as well as xenotime intergrown with altered Fe-Ti-oxide hematite, forming complex textures with disseminated Ti-oxides both in R.A.T. and Dipeta units. Major and trace element geochemistry indicates that the Dipeta is more dolomitic and magnesite while the R.A.T. is clay-rich. The Ti2O value of Dipeta and R.A.T samples is relatively low, ranging between 0.36 and 0.69 wt.% respectively, which suggest highly evolved felsic material in the protolith. This is consistent with interpretation based on the Al2O3/TiO2 ratio, which ranges between 18 and 23 for the R.A.T. and Dipeta respectively, indicating an intermediate to felsic granitoids as the protolith of R.A.T. and Dipeta siltstones. The Ti/Zr ratio of R.A.T. and Dipeta samples of less than 10, while, the higher La/Sc ratio of between 2.6 and 5.5 (for the R.A.T. and Dipeta respectively) indicate that both the R.A.T. and Dipeta are active continental and passive margin tectonic setting. Based on the geochemical variation with depth across the R.A.T. and Dipeta and their contact zone, a geochemical fingerprinting suggests that the ratio TiO2/Al2O3 appears to be useful and could be considered as a stratigraphic geochemical maker able to discriminate the R.A.T. and the Dipeta Subgroups during the geological mapping.
- Full Text:
- Date Issued: 2020
A self-reflexive investigation into effective translation strategies with reference to Jeanne Goosen's Louoond
- Authors: Minnaar, Rae-Ann
- Date: 2012
- Subjects: Translating and interpreting -- South Africa , Afrikaans fiction -- Translating -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:8364 , http://hdl.handle.net/10948/d1008401 , Translating and interpreting -- South Africa , Afrikaans fiction -- Translating -- South Africa
- Description: This dissertation is a self-reflexive study into effective translation strategies. The study focuses primarily on the translation strategies by Vinay and Darbelnet (1995), namely direct and oblique strategies of translation. The strategies are used in the translation of Jeanne Goosen‘s novel Louoond (1987). The novel was chosen on account of the writer‘s unique writing style and the challenges it poses for the prospective translator. One of the key objectives of this study was to comprehensively illustrate Vinay and Darbelnet‘s strategies of translation when translating the novel. The theoretical framework of this study is an analysis of Vinay and Darbelnet‘s translation strategies. The study also aims to give insight into what is meant by translation, translation theory, literary theory and literary translation. The translation of the novel is the final product, but in order to illustrate each procedure of Vinay and Darbelnet (1995) examples were taken from this final product. The chapters that follow illustrate the strategies of Vinay and Darbelnet (1995) as used in the translation of an Afrikaans text (SL) into English (TL). Conclusions can then be drawn as to whether full equivalence was obtained and whether the translation is deemed successful.
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- Date Issued: 2012
The in vitro photo-sonodynamic combinatorial therapy activity of cationic and zwitterionic phthalocyanines on MCF-7 and HeLa cancer cell lines
- Authors: Nene, Lindokuhle Cindy , Buthelezi, Khanyisile , Prinsloo, Earl , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/295891 , vital:57387 , xlink:href="https://doi.org/10.1016/j.jphotochem.2022.114116"
- Description: The syntheses and characterization studies of zwitterionic 2,9,16,23-tetrakis-(N-propane sultone-morpholino) zinc(II) (4) and 2,9,16,23-tetrakis-(2,5-dimethyl-4-(N-propane sultone-morpholinomethyl))-phenoxy zinc(II) (6) phthalocyanines are reported in this work. The photophysical properties, reactive oxygen species (ROS) generation and in vitro anticancer photodynamic (PDT), sonodynamic (SDT), and photo-sonodynamic combination (PSDT) therapy activities of the Pcs were studied and compared to their cationic counterparts: (2,9,16,23-tetrakis-(N-methyl-morpholino) Zn(II)Pc, 3), (2,9,16,23-tetrakis-(2,5-dimethyl-4-(N-methylmorpholine)-phenoxy) Zn(II)Pc, 5). The cationic Pcs maintained higher anticancer activity for all treatment types and had higher ROS generation compared to the zwitterionic Pcs. Singlet oxygen and hydroxyl radicals were generated during ultrasound and combination irradiations of the Pcs. The zwitterionic Pcs also generated carbon radicals under ultrasound and combination irradiations. The ability of the Pcs to generate ROS is essential for PDT, SDT and PSDT, thus making these Pcs potential anticancer probes for these treatment types. Furthermore, the Pcs demonstrated the ability to bind to bovine serum albumin protein.
- Full Text:
- Date Issued: 2022
Synthesis and characterisation of lanthanide complexes with nitrogen- and oxygen-donor ligands
- Authors: Madanhire, Tatenda
- Date: 2016
- Subjects: Rare earth metals
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/13127 , vital:27154
- Description: The reactions of Ln(NO3)3∙6H2O (Ln = Pr, Nd or Er) with the potentially tridentate O,N,O chelating ligand 2,6-pyridinedimethanol (H2pydm) were investigated, and complexes with the formula, [Ln(H2pydm)2(NO3)2](NO3) (Ln = Pr or Nd) and [Er(H2pydm)3](NO3)3 were isolated. The ten-coordinate Pr(III) and Nd(III) compounds crystallise in the triclinic space group P-1 while the nine-coordinate Er(III) complex crystallises in the monoclinic system (P21/n). The reaction of PrCl3∙6H2O with H2pydm yielded the compound, [Pr(H2pydm)3](Cl)3, that crystallises in the monoclinic system, space group P21/c with α = 90, β = 98.680(1) and γ = 90°. The nine-coordinate Pr(III) ion is bound to three H2pydm ligands, with bond distances Pr-O 2.455(2)-2.478(2) Å and Pr-N 2.6355(19)-2.64(2) Å. X-ray crystal structures of all the H2pydm complexes reveal that the ligand coordinates tridentately, via the pyridyl nitrogen atom and the two hydroxyl oxygen atoms. The electronic absorption spectra of complexes show 4f-4f transitions. Rare-earth complexes, [Ln(H2L1)2(NO3)3] [Ln = Gd, Ho or Nd], were also prepared from a Schiff base. The X-ray single-crystal diffraction studies and SHAPE analyses of the Gd(III) and Ho(III) complexes shows that the complexes are ten-coordinate and exhibit distorted tetradecahedron geometries. With proton migration occurring from the phenol group to the imine function, complexation of the lanthanides to the ligand gives the ligand a zwitterionic phenoxo-iminium form. A phenolate oxygen-bridged dinuclear complex, [Ce2(H2L1)(ovan)3(NO3)3], has been obtained by reacting Ce(NO3)3∙6H2O with an o-vanillin derived Schiff base ligand, 2-((E)-(1-hydroxy-2-methylpropan-2-ylimino)methyl)-6-methoxyphenol (H2L1). Hydrolysis of the Schiff base occurred to yield o-vanillin, which bridged two cerium atoms with the Ce∙∙∙Ce distance equal to 3.823 Å. The Ce(III) ions are both tencoordinate, but have different coordination environments, showing tetradecahedron and staggered dodecahedron geometries, respectively. The reaction of salicylaldehyde-N(4)-diethylthiosemicarbazone (H2L2) in the presence of hydrated Ln(III) nitrates led to the isolation of two novel compounds: (E)-2[(ortho-hydroxy)benzylidene]-2-(thiomethyl)-thionohydrazide (1) and bis[2,3-diaza4-(2-hydroxyphenyl)-1-thiomethyl-buta-1,3-diene]disulfide. The latter is a dimer of the former. For this asymmetric Schiff base, 1 and the symmetric disulfide, classical hydrogen bonds of the O–H∙∙∙N as well as N–H∙∙∙S (for 1) type are apparent next to C–H∙∙∙O contacts. 4-(4-Bromophenyl)-1-(propan-2-ylidene)thiosemicarbazide was also prepared upon reacting 4-(4-bromophenyl)-3-thiosemicarbazide with acetone in the presence of ethanol and La(NO3)3∙6H2O. The C=S bond length was found to be 1.6686(16) Å which is in good agreement with other thioketones whose metrical parameters have been deposited with the Cambridge Structural Database. Classical hydrogen bonds of the N–H∙∙∙N and the N–H∙∙∙Br type are observed next to C–H∙∙∙S contacts. All synthesised compounds were characterised by microanalyses, single-crystal X-ray diffraction (except for [Nd(H2L1)2(NO3)3]), 1H NMR and IR spectroscopy.
- Full Text:
- Date Issued: 2016