Reactivity of Rhenium (iii) and Rhenium (V) with multidentate NN-and no-donor ligands
- Yumata, Nonzaliseko Christine
- Authors: Yumata, Nonzaliseko Christine
- Date: 2010
- Subjects: Rhenium , Ligands
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10373 , http://hdl.handle.net/10948/1085 , Rhenium , Ligands
- Description: The reaction of the potentially tridentate Schiff-base chelate Hhaep [Haep = N’-(1- (2-hydroxyphenyl)ethylidene)benzohydrazide] with [ReCl3(benzil)(PPh3)] and trans-[ReOCl3(PPh3)2] produced the neutral oxorhenium(V) complexes cis- [ReOCl2(mep)] [Hmep = 2-(1-iminoethyl)phenol] and cis-[ReOCI2(meb)(PPh3)] [Hmeb = N’-(propan-2-ylidene)benzohydrazide] in ethanol and acetone respectively. In both reactions the Hhaep molecule cleaves to give different coordinated bidentate NO-donor chelates coordinated to the rhenium(V) centers. The X-ray studies reveal that mep is present as a bidentate, monoanionic Schiffbase coordinating through the neutral imino nitrogen and the deprotonated phenolate oxygen in cis-[ReOCl2(mep)]. The bond distances and angles in cis- [ReOCI2(meb)(PPh3)] confirm that meb coordinates to the metal in the enolate form. The distorted octahedral complex fac-[ReCl3(dpa)(PPh3)] was prepared by the reaction of trans-[ReCl3(MeCN)(PPh3)2] with a twofold molar excess of dpa in acetonitrile under a nitrogen atmosphere. The compound dpa.HCl.2H2O was obtained as a by-product in the reaction of dpa with trans-[ReCI3(MeCN)(PPh3)2] in acetonitrile. The reaction of trans-[ReCl3(MeCN)(PPh3)2] with a twofold molar excess of 6- amino-3-methyl-1-phenyl-4-azahept-2-ene-1-one (Hamp) in acetonitrile led to the isolation of cis-[ReCl2(bat)(PPh3)2]. On complexation to the metal center Hamp decomposed to give the coordinated benzoylacetone (bat). Bat is present as a monoanionic bidentate chelate. The complexes [ReVOCI(had)] and [ReIVCl(had)(PPh3)](ReO4) were prepared from the reaction of trans-[ReCl3(MeCN)(PPh3)2] with N,N-bis((2-hydroxybenzyl)-2- aminoethyl)dimethylamine (H2had) in ethanol under various reaction conditions. The treatment of [ReCl3(benzil)(PPh3)] with 2-[((2- pyridinylmethyl)amino)methyl]phenol (Hham) in a 2:1 molar ratio in acetonitrile led to the isolation of the hydrogen-bonded dimer [ReOCl2(ham)]2. The distorted octahedral complex [ReOCl(hap)] [H2hap = N,N-bis(2- hydroxybenzyl)aminomethylpyridine] was prepared from the reaction of trans- [ReCl3(MeCN)(PPh3)2] with a twofold molar excess of H2hap in acetonitrile. The X-ray crystal structure analysis shows that the chloride is coordinated trans to the tripodal tertiary amino nitrogen, with a phenolate oxygen trans to the oxo oxygen.
- Full Text:
- Date Issued: 2010
- Authors: Yumata, Nonzaliseko Christine
- Date: 2010
- Subjects: Rhenium , Ligands
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10373 , http://hdl.handle.net/10948/1085 , Rhenium , Ligands
- Description: The reaction of the potentially tridentate Schiff-base chelate Hhaep [Haep = N’-(1- (2-hydroxyphenyl)ethylidene)benzohydrazide] with [ReCl3(benzil)(PPh3)] and trans-[ReOCl3(PPh3)2] produced the neutral oxorhenium(V) complexes cis- [ReOCl2(mep)] [Hmep = 2-(1-iminoethyl)phenol] and cis-[ReOCI2(meb)(PPh3)] [Hmeb = N’-(propan-2-ylidene)benzohydrazide] in ethanol and acetone respectively. In both reactions the Hhaep molecule cleaves to give different coordinated bidentate NO-donor chelates coordinated to the rhenium(V) centers. The X-ray studies reveal that mep is present as a bidentate, monoanionic Schiffbase coordinating through the neutral imino nitrogen and the deprotonated phenolate oxygen in cis-[ReOCl2(mep)]. The bond distances and angles in cis- [ReOCI2(meb)(PPh3)] confirm that meb coordinates to the metal in the enolate form. The distorted octahedral complex fac-[ReCl3(dpa)(PPh3)] was prepared by the reaction of trans-[ReCl3(MeCN)(PPh3)2] with a twofold molar excess of dpa in acetonitrile under a nitrogen atmosphere. The compound dpa.HCl.2H2O was obtained as a by-product in the reaction of dpa with trans-[ReCI3(MeCN)(PPh3)2] in acetonitrile. The reaction of trans-[ReCl3(MeCN)(PPh3)2] with a twofold molar excess of 6- amino-3-methyl-1-phenyl-4-azahept-2-ene-1-one (Hamp) in acetonitrile led to the isolation of cis-[ReCl2(bat)(PPh3)2]. On complexation to the metal center Hamp decomposed to give the coordinated benzoylacetone (bat). Bat is present as a monoanionic bidentate chelate. The complexes [ReVOCI(had)] and [ReIVCl(had)(PPh3)](ReO4) were prepared from the reaction of trans-[ReCl3(MeCN)(PPh3)2] with N,N-bis((2-hydroxybenzyl)-2- aminoethyl)dimethylamine (H2had) in ethanol under various reaction conditions. The treatment of [ReCl3(benzil)(PPh3)] with 2-[((2- pyridinylmethyl)amino)methyl]phenol (Hham) in a 2:1 molar ratio in acetonitrile led to the isolation of the hydrogen-bonded dimer [ReOCl2(ham)]2. The distorted octahedral complex [ReOCl(hap)] [H2hap = N,N-bis(2- hydroxybenzyl)aminomethylpyridine] was prepared from the reaction of trans- [ReCl3(MeCN)(PPh3)2] with a twofold molar excess of H2hap in acetonitrile. The X-ray crystal structure analysis shows that the chloride is coordinated trans to the tripodal tertiary amino nitrogen, with a phenolate oxygen trans to the oxo oxygen.
- Full Text:
- Date Issued: 2010
Resilience in families where a parent misuses alcohol
- Authors: Fisher, Ruth
- Date: 2009
- Subjects: Alcoholics -- South Africa -- Family relationships , Alcoholism -- South Africa -- Prevention , Family psychotherapy -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9909 , http://hdl.handle.net/10948/953 , Alcoholics -- South Africa -- Family relationships , Alcoholism -- South Africa -- Prevention , Family psychotherapy -- South Africa
- Description: Surveys have shown that alcohol misuse is the biggest substance misuse problem in the world today, affecting millions of people. With the disease being part of a family, all members of the family experience the distress of parental alcohol misuse. While the challenges that these families have to face are many, they seem to have the ability to “bounce back”, in other words, have resilience. There has been limited research to date on family relations and alcohol misuse in South Africa, especially in terms of the parental member as the alcohol misuser. The proposed research aimed to explore and describe the factors that facilitate adjustment and adaptation in families where a member misuses alcohol. The Resiliency Model of Family Stress, Adjustment and Adaptation was used to analyze the factors that enable a family to adapt to the alcohol misuse, as outlined in the broader study at the University of Stellenbosch. An exploratory descriptive research design was employed in the proposed study. For the purposes of this study, the researcher combined qualitative and quantitative research methods in order to use their complementary strengths to enrich the data obtained from the proposed study. Sixty three families were surveyed using a biographical questionnaire and seven pencil-and-paper questionnaires. These families were accessed via drug and alcohol rehabilitation facilities throughout South Africa. The data from the biographical questionnaire was analyzed using descriptive statistics, while the qualitative data was analyzed using content analysis. The quantitative data was analyzed using correlation and regression analysis. The findings of the proposed research allow for better management of the alcohol misuser’s condition through the understanding of what resiliency areas the family may improve upon. Furthermore, the study can be used as a stepping stone for future research of resilience in families living with a parental member who misuses alcohol, and ultimately contributes to the broader context of family resilience research in South Africa. Key words: alcohol misuse, alcohol abuse, alcohol dependence, family, resilience, adjustment, adaptability.
- Full Text:
- Date Issued: 2009
- Authors: Fisher, Ruth
- Date: 2009
- Subjects: Alcoholics -- South Africa -- Family relationships , Alcoholism -- South Africa -- Prevention , Family psychotherapy -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9909 , http://hdl.handle.net/10948/953 , Alcoholics -- South Africa -- Family relationships , Alcoholism -- South Africa -- Prevention , Family psychotherapy -- South Africa
- Description: Surveys have shown that alcohol misuse is the biggest substance misuse problem in the world today, affecting millions of people. With the disease being part of a family, all members of the family experience the distress of parental alcohol misuse. While the challenges that these families have to face are many, they seem to have the ability to “bounce back”, in other words, have resilience. There has been limited research to date on family relations and alcohol misuse in South Africa, especially in terms of the parental member as the alcohol misuser. The proposed research aimed to explore and describe the factors that facilitate adjustment and adaptation in families where a member misuses alcohol. The Resiliency Model of Family Stress, Adjustment and Adaptation was used to analyze the factors that enable a family to adapt to the alcohol misuse, as outlined in the broader study at the University of Stellenbosch. An exploratory descriptive research design was employed in the proposed study. For the purposes of this study, the researcher combined qualitative and quantitative research methods in order to use their complementary strengths to enrich the data obtained from the proposed study. Sixty three families were surveyed using a biographical questionnaire and seven pencil-and-paper questionnaires. These families were accessed via drug and alcohol rehabilitation facilities throughout South Africa. The data from the biographical questionnaire was analyzed using descriptive statistics, while the qualitative data was analyzed using content analysis. The quantitative data was analyzed using correlation and regression analysis. The findings of the proposed research allow for better management of the alcohol misuser’s condition through the understanding of what resiliency areas the family may improve upon. Furthermore, the study can be used as a stepping stone for future research of resilience in families living with a parental member who misuses alcohol, and ultimately contributes to the broader context of family resilience research in South Africa. Key words: alcohol misuse, alcohol abuse, alcohol dependence, family, resilience, adjustment, adaptability.
- Full Text:
- Date Issued: 2009
The effects of hyperinflation on the Zimbabwean construction industry
- Authors: Moyo, Admire
- Date: 2010
- Subjects: Inflation (Finance) -- Zimbabwe , Zimbabwe -- Economic conditions , Construction industry -- Economic aspects -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9687 , http://hdl.handle.net/10948/1197 , Inflation (Finance) -- Zimbabwe , Zimbabwe -- Economic conditions , Construction industry -- Economic aspects -- Zimbabwe
- Description: Less than two decades ago, Zimbabwe was a symbol for the rest of the world of what Africa could become (Dell, 2005). DiSilvio (2007) contends that independent Zimbabwe was an economic success on route to attaining status of the most “developed country” in Africa. Contrary to expectations, by 2003 the Zimbabwean economy was shrinking faster than any other economy in the world at 18 percent per year (Richardson, 2005). Reports indicate that the Zimbabwean economy is in crisis and has since been set back by more than 50 years (Matikinye, 2005). This phenomenon necessitated the need for an investigation to ascertain its cause in Zimbabwe. As a result, the research identifies and presents hyperinflation as the root cause of the crisis in Zimbabwe and illustrates the validity of this assertion with a focus on the Zimbabwean construction industry. As part of the research inquiry, a review of related literature was conducted. The literature review illustrated the generic effects of hyperinflation as well as the effects of this phenomenon in action in Zimbabwe. The literature study was followed by a questionnaire survey. The questionnaire was completed by 23 contractors and 7 clients from a census of contractors and clients in Zimbabwe. The questionnaire consisted of a number of variables, which the respondents were asked to rate vis-à-vis the effects of hyperinflation in the construction industry. In summary, the questionnaire sought to determine the causes of hyperinflation in Zimbabwe, its specific effects on the construction industry and how respondents thought the phenomenon could be mitigated so as to revive the Zimbabwean construction industry. The techniques of re-scaling, in conjunction with descriptive and inferential statistics, ranking and quadrant analysis were applied to the data. Results from these analyses revealed a high degree of agreement among respondents vis-à-vis the effects of hyperinflation on the Zimbabwean construction industry. The interpretation of the results further revealed that hyperinflation has undoubtedly led to the collapse of the Zimbabwean construction industry. In conclusion, the research, applying the interpretations of v the survey findings, prescribes a number of ways in which the Zimbabwean construction sector may be resurrected. Among the recommended prescriptions, there are a number of debatable issues that arise that the researcher proposes should be subject to future study.
- Full Text:
- Date Issued: 2010
- Authors: Moyo, Admire
- Date: 2010
- Subjects: Inflation (Finance) -- Zimbabwe , Zimbabwe -- Economic conditions , Construction industry -- Economic aspects -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9687 , http://hdl.handle.net/10948/1197 , Inflation (Finance) -- Zimbabwe , Zimbabwe -- Economic conditions , Construction industry -- Economic aspects -- Zimbabwe
- Description: Less than two decades ago, Zimbabwe was a symbol for the rest of the world of what Africa could become (Dell, 2005). DiSilvio (2007) contends that independent Zimbabwe was an economic success on route to attaining status of the most “developed country” in Africa. Contrary to expectations, by 2003 the Zimbabwean economy was shrinking faster than any other economy in the world at 18 percent per year (Richardson, 2005). Reports indicate that the Zimbabwean economy is in crisis and has since been set back by more than 50 years (Matikinye, 2005). This phenomenon necessitated the need for an investigation to ascertain its cause in Zimbabwe. As a result, the research identifies and presents hyperinflation as the root cause of the crisis in Zimbabwe and illustrates the validity of this assertion with a focus on the Zimbabwean construction industry. As part of the research inquiry, a review of related literature was conducted. The literature review illustrated the generic effects of hyperinflation as well as the effects of this phenomenon in action in Zimbabwe. The literature study was followed by a questionnaire survey. The questionnaire was completed by 23 contractors and 7 clients from a census of contractors and clients in Zimbabwe. The questionnaire consisted of a number of variables, which the respondents were asked to rate vis-à-vis the effects of hyperinflation in the construction industry. In summary, the questionnaire sought to determine the causes of hyperinflation in Zimbabwe, its specific effects on the construction industry and how respondents thought the phenomenon could be mitigated so as to revive the Zimbabwean construction industry. The techniques of re-scaling, in conjunction with descriptive and inferential statistics, ranking and quadrant analysis were applied to the data. Results from these analyses revealed a high degree of agreement among respondents vis-à-vis the effects of hyperinflation on the Zimbabwean construction industry. The interpretation of the results further revealed that hyperinflation has undoubtedly led to the collapse of the Zimbabwean construction industry. In conclusion, the research, applying the interpretations of v the survey findings, prescribes a number of ways in which the Zimbabwean construction sector may be resurrected. Among the recommended prescriptions, there are a number of debatable issues that arise that the researcher proposes should be subject to future study.
- Full Text:
- Date Issued: 2010
Unaccompanied refugee children's experiences in migration to South Africa
- Nthako, Matsedeso Emily Delle
- Authors: Nthako, Matsedeso Emily Delle
- Date: 2019
- Subjects: Refugee children -- South Africa -- Psychological aspects , Refugee children -- South Africa -- Social conditions Emigration and immigration -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/42738 , vital:36686
- Description: An increasing number of children from countries as far as Zimbabwe, Somalia, Democratic of Congo are migrating across South African's borders in the absence of their parents, relatives or care givers. Such children face a myraid of life-threatening experiences that are different from those of adult refugees in migration. While a great deal of research covered the experiences of adult refugees, those unaccompanied refugee children generally understudied. Valuable lessons can be derived from conducting studies to gain insight into their subjective experiences. This study explores and describes psychological experiences of URC in migration to South Africa. This is a qualitative study that follows an exploratory-descriptive research design. Purposive non-probability selection of participants. Data collection is derived from individual, semi-structured interviews and is analysed using thematic analysis. The findings are an exploration of the URC's experiences include detaching from the environment, family separation and loss, psychological challenges and coping mechanisms dealing with the inner being and children's perceptions of migration.
- Full Text: false
- Date Issued: 2019
- Authors: Nthako, Matsedeso Emily Delle
- Date: 2019
- Subjects: Refugee children -- South Africa -- Psychological aspects , Refugee children -- South Africa -- Social conditions Emigration and immigration -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/42738 , vital:36686
- Description: An increasing number of children from countries as far as Zimbabwe, Somalia, Democratic of Congo are migrating across South African's borders in the absence of their parents, relatives or care givers. Such children face a myraid of life-threatening experiences that are different from those of adult refugees in migration. While a great deal of research covered the experiences of adult refugees, those unaccompanied refugee children generally understudied. Valuable lessons can be derived from conducting studies to gain insight into their subjective experiences. This study explores and describes psychological experiences of URC in migration to South Africa. This is a qualitative study that follows an exploratory-descriptive research design. Purposive non-probability selection of participants. Data collection is derived from individual, semi-structured interviews and is analysed using thematic analysis. The findings are an exploration of the URC's experiences include detaching from the environment, family separation and loss, psychological challenges and coping mechanisms dealing with the inner being and children's perceptions of migration.
- Full Text: false
- Date Issued: 2019
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