Réaction d’amination intramoléculaire de liens C-H à partir de N-mésyloxycarbamates catalysée par des complexes de rhodium et d’autres métaux de transition : s ynthèse verte d’oxazolidinones

La réaction d’amination de liens C-H, impliquant la transformation directe d’un lien C-H en lien C-N constitue une approche synthétique d’avenir pour la préparation de composés azotés. L’application de cette stratégie de manière intramoléculaire apparaît comme une approche puissante pour la synthèse de composés hétérocycliques. En particulier, les oxazolidinones, carbamates cycliques à cinq chaînons, constituant une nouvelle classe d’antibiotiques très prometteuse, pourraient être synthétisées par cette méthode. Il y a moins d’une dizaine d’années, notre groupe de recherche a travaillé sur le développement de méthodologies utilisant des espèces nitrènes métalliques pour l’amination intra et intermoléculaire. Les N-tosyloxycarbamates, en présence d’une base et d’un catalyseur dimère de rhodium (II) tétracarboxylate sont les précurseurs de ces espèces nitrènes métalliques, capables de faire l’insertion de liens C(sp3)-H. Dans ces travaux de thèse, nous avons travaillé sur le développement d’une méthode plus « verte » d’amination intramoléculaire. Les N-mésyloxycarbamates, plus légers que leurs homologues N-tosyloxycarbamates, ont été identifiés comme d’excellents précurseurs de nitrènes. La méthodologie développée ne nécessite que 3 mol % de dimère de rhodium Rh2(tpa)4 et de 1,5 équivalents de solution aqueuse saturée de K2CO3, le tout dans l’acétate d’éthyle et donne de bons rendements de cyclisation. Une étude de l’étendue réactionnelle a été effectuée, montrant la tolérance et les limitations de notre système catalytique : les hétéroatomes ne posent pas de problèmes hormis l’atome d’azote, qui doit être protégé afin de garantir la transformation. En outre, nous avons constaté que les liens C-H aliphatiques secondaires sont moins réactifs que les liens tertiaires. Après avoir tenté de développer des conditions réactionnelles spécifiques aux liens C-H non activés, nous avons montré la possibilité d’aminer des liens C-H propargyliques de manière chimiosélective ; la triple liaison C-C peut ensuite être dérivatisée efficacement, donnant accès à la formule saturée correspondante ainsi qu’à d’autres motifs. Dans un désir de substituer les complexes de rhodium par d’autres complexes de métaux plus abondants et moins dispendieux, nous nous sommes tournés, dans un premier temps, vers les complexes de fer et par la suite, vers les pinceurs de nickel. Les phtalocyanines de fer ont été identifiées comme étant de bons catalyseurs de l’amination intramoléculaire de N-mésyloxycarbamates. Le chlorure de phtalocyanine de fer (III), en présence d’un sel de AgBF4 et de K2CO3, dans le 1,1,2,2-tétrachloroéthane anhydre, permet l’obtention de la 4-phenyloxazolidin-2-one avec 63% de rendement. En outre, il est possible d’atteindre un rendement de 49% à partir du même substrat N-mésyloxycarbamate, par catalyse avec un pinceur de nickel de type POCN, en présence d’un sel de mésylate. Des indices sur le mécanisme des ces deux transformations ont pu être recueillis lors de la courte étude de ces systèmes.

Comorbidity Between Major Depression and Alcohol Use Disorder From Adolescence to Adulthood

Background—Limited information exists regarding the long-term development of comorbidity between Major Depressive Disorder (MDD) and Alcohol Use Disorder (AUD; abuse/dependence). Using a representative prospective study, we examine multiple aspects pertaining to MDD+AUD comorbidity, with a focus on the relation between disorders across periods (adolescence, early adulthood, adulthood) and cumulative impairments by age 30. Method—816 participants were diagnostically interviewed at ages 16, 17, 24, and 30. Results—Rates of comorbid MDD+AUD were low in adolescence (2%), but increased in early adulthood (10%) and adulthood (7%). Rates of cumulative comorbidity were elevated (21%). Most individuals with a history of MDD or AUD had the other disorder, except for women with MDD. Prospectively, adolescent AUD predicted early adult MDD, while early adult MDD predicted adult AUD. Compared to pure disorders, MDD+AUD was associated with higher risk of alcohol dependence, suicide attempt, lower global functioning, and life dissatisfaction. Conclusions—Lifetime rates of comorbid MDD+AUD were considerably higher than in crosssectional studies. Comorbidity was partly explained by bidirectional and developmentally-specific associations and predicted selected rather than generalized impairments. Clinically, our findings emphasize the need to always carefully assess comorbidity in patients with MDD or AUD, taking into account concurrency and developmental timing.

Lithology and approximate sub-bottom depths and ages of the transition of soft to firm ooze and of firm ooze to chalk at DSDP Leg 89 and 90 Sites

Leg 90 recovered approximately 3705 m of core at eight sites lying at middle bathyal depths (1000-2200 m) (Sites 587 to 594) in a traverse from subtropical to subantarctic latitudes in the southwest Pacific region, chiefly on Lord Howe Rise in the Tasman Sea. This chapter summarizes some preliminary lithostratigraphic results of the leg and includes data from Site 586, drilled during DSDP Leg 89 on the Ontong-Java Plateau that forms the northern equatorial point of the latitudinal traverse. The lithofacies consist almost exclusively of continuous sections of very pure (>95% CaCO3) pelagic calcareous sediment, typically foraminifer-bearing nannofossil ooze (or chalk) and nannofossil ooze (or chalk), which is mainly of Neogene age but extends back into the Eocene at Sites 588, 592, and 593. Only at Site 594 off southeastern New Zealand is there local development of hemipelagic sediments and several late Neogene unconformities. Increased contents of foraminifers in Leg 90 sediments, notably in the Quaternary interval, correspond to periods of enhanced winnowing by bottom currents. Significant changes in the rates of sediment accumulation and in the character and intensity of sediment bioturbation within and between sites probably reflect changes in calcareous biogenic productivity as a result of fundamental paleoceanographic events in the region during the Neogene. Burial lithification is expressed by a decrease in sediment porosity from about 70 to 45% with depth. Concomitantly, microfossil preservation slowly deteriorates as a result of selective dissolution or recrystallization of some skeletons and the progressive appearance of secondary calcite overgrowths, first about discoasters and sphenoliths, and ultimately on portions of coccoliths. The ooze/chalk transition occurs at about 270 m sub-bottom depth at each of the northern sites (Sites 586 to 592) but is delayed until about twice this depth at the two southern sites (Sites 593 and 594). A possible explanation for this difference between geographic areas is the paucity of discoasters and sphenoliths at the southern sites; these nannofossil elements provide ideal nucleation sites for calcite overgrowths. Toward the bottom of some holes, dissolution seams and flasers appear in recrystallized chalks. The very minor terrigenous fraction of the sediment consists of silt- through clay-sized quartz, feldspar, mica, and clay minerals (smectite, illite, kaolinite, and chlorite), supplied as eolian dust from the Australian continent and by wind and ocean currents from erosion on South Island, New Zealand. Changes in the mass accumulation rates of terrigenous sediment and in clay mineral assemblages through time are related to various external controls, such as the continued northward drift of the Indo-Australian Plate, the development of Antarctic ice sheets, the increased desertification of the Australian continent after 14 m.y. ago, and the progressive increase in tectonic relief of New Zealand through the late Cenozoic. Disseminated glass shards and (altered) tephra layers occur in Leg 90 cores. They were derived from major silicic eruptions in North Island, New Zealand, and from basic to intermediate explosive volcanism along the Melanesian island chains. The tephrostratigraphic record suggests episodes of increased volcanicity in the southwest Pacific centered near 17, 13, 10, 5 and 1 m.y. ago, especially in the middle and early late Miocene. In addition, submarine basaltic volcanism was widespread in the southeast Tasman Sea around the Eocene/Oligocene boundary, possibly related to the propagation of the Southeast Indian Ridge through western New Zealand as a continental rift system.

Struggling for Educational Autonomy: The Significance of Schooling in New Mexico's Transition to Statehood

Thesis (Master's)--University of Washington, 2016-06

A comparison of the efficacy and safety of olanzapine versus haloperidol during transition from intramuscular to oral therapy

Background: Acutely agitated patients with schizophrenia who receive intramuscular (IM) medications typically are switched to oral (PO) antipsychotic maintenance therapy Objective: The goal of this study was to assess the efficacy and safety of olanzapine versus those of haloperidol during transition from IM to PO therapy We used additional data from a previously reported trial to test the hypothesis that the reduction in agitation achieved by IM olanzapine 10 mg or IM haloperidol 7.5 mg would be maintained following transition to 4 days of PO olanzapine or PO haloperidol (5-20 mg/d for both). We also hypothesized that olanzapine would maintain its more favorable extrapyramidal symptom (EPS) safety profile. Methods: This was a multinational (hospitals in 13 countries), double-blind, randomized, controlled trial. Acutely agitated inpatients with schizophrenia were treated with 1 to 3 IM injections of olanzapine 10 mg or haloperidol 7.5 mg over 24 hours and were entered into a 4-day PO treatment period with the same medication (5-20 mg/d for both). The primary efficacy measurement was reduction in agitation, as measured by the Positive and Negative Syndrome Scale-Excited Component (PANSS-EC) score. Adverse events and scores on EPS rating scales were assessed. Results: A total of 311 patients (204 men, 107 women; mean [SD] age, 38.2 [11.6] years) were enrolled (131, 126, and 54 patients in the olanzapine, haloperidol, and placebo groups, respectively). In all, 93.1% (122/131) of olanzapine-treated patients and 92.1% (116/126) of haloperidol-treated patients completed the IM period and entered the PO period; 85.5% (112/131) of olanzapine-treated patients and 84.1% (106/126) of haloperidol-treated patients completed the PO period. IM olanzapine and IM haloperidol effectively reduced agitation over 24 hours (mean [SD] PANSS-EC change, -7.1 [4.8] vs -6.7 [4.3], respectively). Reductions in agitation were sustained throughout the PO period with both study drugs (mean [SD] change from PO period baseline, -0.6 [4.8] vs -1.3 [4.4], respectively). During PO treatment, haloperidol-treated patients spontaneously reported significantly more acute dystonia than olanzapine-treated patients (4.3% [5/116] vs 0% [0/122], respectively; P = 0.026) and akathisia (5.2% [6/116] vs 0% [0/122], respectively; P = 0.013). Significantly more haloperidol-treated patients than olanzapine-treated patients met categorical criteria for treatment-emergent akathisia (18.5% [17/92] vs 6.5% [7/107], respectively; P = 0.015). Conclusions: In the acutely agitated patients with schizophrenia in this study, both IM olanzapine 10 mg and IM haloperidol 7.5 mg effectively reduced agitation over 24 hours. This alleviation of agitation was sustained following transition from IM therapy to 4 days of PO treatment (5-20 mg/d for both). During the 4 days of PO treatment, olanzapine-treated patients did not spontaneously report any incidences of acute dystonia, and olanzapine had a superior EPS safety profile to that of haloperidol. The combination of IM and PO olanzapine may help improve the treatment of acutely agitated patients with schizophrenia. Copyright (C) 2003 Excerpta Medica, Inc.

Using a matrix in life transition research

Life transitions can be planned or can occur unexpectedly. They can cause a major change to a person's life patterns and well-being. Older adulthood is a time for many life transitions as a result of changes in life roles and health status. In this exploratory study, the authors investigate the transition involved in driving cessation for older people. In analyzing and organizing the data, they develop a matrix that incorporated descriptive and temporal factors associated with the transition. This matrix is useful in organizing and communicating the findings as a whole and could be used in describing individual experiences. It might be of use for the organization of qualitative data about other life transitions such as illness, retirement, and the development and adoption of new behaviors.

Escalation and deceleration of offending behaviours from adolescence to early adulthood

Relatively little longitudinal research is available in Australia to describe I the age/crime relationship in much detail, particularly patterns of offending occurring during the transition from adolescence to early adulthood. This paper addresses this issue using self-reported criminal involvement from a school-based sample, a group of socially disadvantaged individuals, and a group of officially identified offenders. The findings support the widespread research that rates of offending peak during adolescence, at which time offending is widespread, and that the criminal career is of relatively short duration. However, the results also demonstrate that the age/crime curve is not a unitary phenomenon. The type of offending behaviour being considered, the gender of the population, and the perpetrator's exposure to the criminal justice system contribute to the variability in the curve. In this study, the prevalence and mean level of overall offending for the total sample was higher during early adulthood than adolescence for vehicle offences and drug-use, rates of theft were similar in both periods, and vandalism and serious offending were lower. In addition, socially disadvantaged young people reported involvement in crime that peaked and desisted earlier in the life course compared to the school-based sample, and gender differences within these groups were also found. For the school-based sample, offending for females began and desisted earlier than for males, but within the at-risk group, the opposite was true. Implications for crime-prevention programming are discussed.

Kallikrein 4 (hK4) and prostate-specific antigen (PSA) are associated with the loss of E-cadherin and an epithelial-mesenchymal transition (EMT)-like effect in prostate cancer cells

Prostate-specific antigen (PSA) and the related kallikrein family of serine proteases are current or emerging biomarkers for prostate cancer detection and progression. Kallikrein 4 (KLK4/hK4) is of particular interest, as KLK4 mRNA has been shown to be elevated in prostate cancer. In this study, we now show that the comparative expression of hK4 protein in prostate cancer tissues, compared with benign glands, is greater than that of PSA and kallikrein 2 (KLK2/hK2), suggesting that hK4 may play an important functional role in prostate cancer progression in addition to its biomarker potential. To examine the roles that hK4, as well as PSA and hK2, play in processes associated with progression, these kallikreins were separately transfected into the PC-3 prostate cancer cell line, and the consequence of their stable transfection was investigated. PC-3 cells expressing hK4 had a decreased growth rate, but no changes in cell proliferation were observed in the cells expressing PSA or hK2. hK4 and PSA, but not hK2, induced a 2.4-fold and 1.7-fold respective increase, in cellular migration, but not invasion, through Matrigel, a synthetic extracellular matrix. We hypothesised that this increase in motility displayed by the hK4 and PSA-expressing PC-3 cells may be related to the observed change in structure in these cells from a typical rounded epithelial-like cell to a spindle-shaped, more mesenchymal-like cell, with compromised adhesion to the culture surface. Thus, the expression of E-cadherin and vimentin, both associated with an epithelial-mesenchymal transition (EMT), was investigated. E-cadherin protein was lost and mRNA levels were significantly decreased in PC-3 cells expressing hK4 and PSA (10-fold and 7-fold respectively), suggesting transcriptional repression of E-cadherin, while the expression of vimentin was increased in these cells. The loss of E-cadherin and associated increase in vimentin are indicative of EMT and provides compelling evidence that hK4, in particular, and PSA have a functional role in the progression of prostate cancer through their promotion of tumour cell migration.

CXCR4/SDF1 interaction inhibits the primordial to primary follicle transition in the neonatal mouse ovary

The molecular mechanisms behind the entry of the primordial follicle into the growing follicle pool remain poorly understood. To investigate this process further, a microarray-based comparison was undertaken between 2-day postpartum mouse ovaries consisting of primordial follicles/naked oocytes only and those with both primordial follicles and newly activated follicles (7-day postpartum). Gene candidates identified included the chemoattractive cytokine stromal derived factor-1 (SDF1) and its receptor CXCR4. SDF1 and CXCR4 have been implicated in a variety of physiological processes including the migration of embryonic germ cells to the gonads. SDF1-alpha expression increased with the developmental stage of the follicle. Embryonic expression was found to be dichotomous post-genii cell migration, with low expression in the female. Immunohistochemical studies nonetheless indicate that the autocrine pattern of expression ligand and receptor begins during embryonic life. Addition of recombinant SDF1-alpha to neonatal mouse ovaries in vitro resulted in significantly higher follicle densities than for control ovaries. TUNEL analysis indicated no detectable difference in populations of apoptotic cells of treated or control ovaries. Treated ovaries also contained a significantly lower percentage of activated follicles as determined by measurement of oocyte diameter and morphological analysis. Treatment of cultured ovaries with an inhibitor of SDF1-alpha, AMD3100, ablated the effect of SDF1-alpha. By retaining follicles in an unactivated state, SDF1/CXCR4 signaling may play an important role in maintaining the size and longevity of the primordial follicle pool. (c) 2006 Elsevier Inc. All rights reserved.

The role of migration in urban transition : studies of the relationship between migration and modernisation for Brisbane and Stockholm

Wilbur Zelinsky formulated a Hypothesis of Mobility Transition in 1971,in which he tried to relate all aspects of mobility to the Demographic Transition and modernisation. This dissertation applies the theoretical framework, proposed by Zelinsky and extended to encompass a family of transitions, to understand migration patterns of city regions. The two city regions, Brisbane and Stockholm, are selected as case studies, representing important city regions of similar size, but drawn from contrasting historical settings. A comparison of the case studies with the theoretical framework aims to determine how the relative contributions of net migration, the source areas of migrants, and the migration intensity change with modernisation. In addition, the research also aims to identify aspects of modernisation affecting migration. These aspects of migration are analysed with a "historical approach" and a "multivariate approach". An extensive investigation into the city regions' historical background provides the source, from which evidence for a relationship between migration and modernisation is extracted. With this historical approach, similarities and differences in migration patterns are identified. The other research approach analyse multivariate data, from the last two decades, on migration flows and modernisation. Correlations between migration and key aspects of modernisation are tested with multivariate regression, based on an alternative version of a spatial interaction model. The project demonstrates that the changing functions of cities and the structural modernisation are influential on migration. Similar patterns are found, regarding the relative contributions of net migration and natural increase to population growth. The research finds links between these changes in the relative contribution of net migration and demographic modernisation. The findings on variations in urban and rural source areas of migrants to city regions do not contradict the expected pattern, but data limitations prevent definite conclusion to be drawn. The assessment of variations in migration intensity resulted in the expected pattern not being supported. Based on Swedish data, the hypothesised increase in migration intensity is rejected. Interactional migration data also show patterns different from those derived from the theoretical framework. The findings, from both research approaches, suggested that structural modernisation affected migration flows more than demographic modernisation. The findings lead to a formulation of hypothesised patterns for migration to city regions. The study provides an important research contribution by applying the two research approaches to city regions. It also combines the study of internal and international migration to address the research objectives within a framework of transitional change.

An investigation into children’s inductive reasoning strategies:What drives the development of category induction?

In a series of studies, I investigated the developmental changes in children’s inductive reasoning strategy, methodological manipulations affecting the trajectory, and driving mechanisms behind the development of category induction. I systematically controlled the nature of the stimuli used, and employed a triad paradigm in which perceptual cues were directly pitted against category membership, to explore under which circumstances children used perceptual or category induction. My induction tasks were designed for children aged 3-9 years old using biologically plausible novel items. In Study 1, I tested 264 children. Using a wide age range allowed me to systematically investigate the developmental trajectory of induction. I also created two degrees of perceptual distractor – high and low – and explored whether the degree of perceptual similarity between target and test items altered children’s strategy preference. A further 52 children were tested in Study 2, to examine whether children showing a perceptual-bias were in fact basing their choice on maturation categories. A gradual transition was observed from perceptual to category induction. However, this transition could not be due to the inability to inhibit high perceptual distractors as children of all ages were equally distracted. Children were also not basing their strategy choices on maturation categories. In Study 3, I investigated category structure (featural vs. relational category rules) and domain (natural vs. artefact) on inductive preference. I tested 403 children. Each child was assigned to either the featural or relational condition, and completed both a natural kind and an artefact task. A further 98 children were tested in Study 4, on the effect of using stimuli labels during the tasks. I observed the same gradual transition from perceptual to category induction preference in Studies 3 and 4. This pattern was stable across domains, but children developed a category-bias one year later for relational categories, arguably due to the greater demands on executive function (EF) posed by these stimuli. Children who received labels during the task made significantly more category choices than those who did not receive labels, possibly due to priming effects. Having investigated influences affecting the developmental trajectory, I continued by exploring the driving mechanism behind the development of category induction. In Study 5, I tested 60 children on a battery of EF tasks as well as my induction task. None of the EF tasks were able to predict inductive variance, therefore EF development is unlikely to be the driving factor behind the transition. Finally in Study 6, I divided 252 children into either a comparison group or an intervention group. The intervention group took part in an interactive educational session at Twycross Zoo about animal adaptations. Both groups took part in four induction tasks, two before and two a week after the zoo visits. There was a significant increase in the number of category choices made in the intervention condition after the zoo visit, a result not observed in the comparison condition. This highlights the role of knowledge in supporting the transition from perceptual to category induction. I suggest that EF development may support induction development, but the driving mechanism behind the transition is an accumulation of knowledge, and an appreciation for the importance of category membership.

Dielectric transition of polyacrylonitrile derived carbon nanofibers

The dielectric behavior of polyacrylonitrile derived carbon nanofibers formed at different carbonization temperatures was investigated using impedance spectroscopy. The impedance data are presented in the form of Cole-Cole plots and four equivalent electrical circuits are derived. It is found that by increasing carbonization temperature from 500 to 800 °C, a strong capacitive element in the parallel equivalent circuit is transformed into an inductive element, while the contact resistance and parallel resistance are significantly decreased. Along with the morphological and chemical structural evolution, respectively witnessed by scanning electron microscopy and Raman spectroscopy, the dielectric transition deduced from the transformation of electrical circuits can be correlated to the proposed microstructural changes of polyacrylonitrile derived carbon nanofibers and the interaction/interference among them.

Settling in:understanding the role and influence of parents on student transition to university

This paper will present details and findings to date collected as part of a research project currently being undertaken at Aston University, Birmingham, UK. The research focuses on the adjustment and experience of first year students and the role and influence of their parents and family during this time. In addition to Educational research literature, the research draws on “Emerging Adulthood” to assist in understanding the experience of students upon enrolling on a Higher Education degree. It is anticipated that the findings will contribute to the UK student retention debate as well as the adjustment literature.

Studies on the thermal decomposition behaviour, kinetics and electrical conductivity of the non-isothermal decomposition of pyridine mono carboxylic acids and some of their transition metal complexes

The thesis is divided into four chapters. They are: introduction, experimental, results and discussion about the free ligands and results and discussion about the complexes. The First Chapter, the introductory chapter, is a general introduction to the study of solid state reactions. The Second Chapter is devoted to the materials and experimental methods that have been used for carrying out tile experiments. TIle Third Chapter is concerned with the characterisations of free ligands (Picolinic acid, nicotinic acid, and isonicotinic acid) by using elemental analysis, IR spectra, X-ray diffraction, and mass spectra. Additionally, the thermal behaviour of free ligands in air has been studied by means of thermogravimetry (TG), derivative thermogravimetry (DTG), and differential scanning calorimetry (DSC) measurements. The behaviour of thermal decomposition of the three free ligands was not identical Finally, a computer program has been used for kinetic evaluation of non-isothermal differential scanning calorimetry data according to a composite and single heating rate methods in comparison with the methods due to Ozawa and Kissinger methods. The most probable reaction mechanism for the free ligands was the Avrami-Erofeev equation (A) that described the solid-state nucleation-growth mechanism. The activation parameters of the decomposition reaction for free ligands were calculated and the results of different methods of data analysis were compared and discussed. The Fourth Chapter, the final chapter, deals with the preparation of cobalt, nickel, and copper with mono-pyridine carboxylic acids in aqueous solution. The prepared complexes have been characterised by analyses, IR spectra, X-ray diffraction, magnetic moments, and electronic spectra. The stoichiometry of these compounds was ML2x(H20), (where M = metal ion, L = organic ligand and x = water molecule). The environments of cobalt, nickel, and copper nicotinates and the environments of cobalt and nickel picolinates were octahedral, whereas the environment of copper picolinate [Cu(PA)2] was tetragonal. However, the environments of cobalt, nickel, and copper isonicotinates were polymeric octahedral structures. The morphological changes that occurred throughout the decomposition were followed by SEM observation. TG, DTG, and DSC measurements have studied the thermal behaviour of the prepared complexes in air. During the degradation processes of the hydrated complexes, the crystallisation water molecules were lost in one or two steps. This was also followed by loss of organic ligands and the metal oxides remained. Comparison between the DTG temperatures of the first and second steps of the dehydration suggested that the water of crystallisation was more strongly bonded with anion in Ni(II) complexes than in the complexes of Co(II) and Cu(II). The intermediate products of decomposition were not identified. The most probable reaction mechanism for the prepared complexes was also Avrami-Erofeev equation (A) characteristic of solid-state nucleation-growth mechanism. The tempemture dependence of conductivity using direct current was determined for cobalt, nickel, Cl.nd copper isonicotinates. An activation energy (ΔΕ), the activation energy (ΔΕ ) were calculated.The ternperature and frequency dependence of conductivity, the frequency dependence of dielectric constant, and the dielectric loss for nickel isonicotinate were determined by using altemating current. The value of s paralneter and the value of'density of state [N(Ef)] were calculated. Keyword Thermal decomposition, kinetic, electrical conduclion, pyridine rnono~ carboxylic acid, cOlnplex, transition metal compJex.

Transition metal ion coordination in hydrophilic polymer membranes

The research described within this thesis is concerned with the investigation of transition metal ion complexation within hydrophilic copolymer membranes. The membranes are copolymers of 4-methyl-4'-vinyl-2,2'-bipyridine, the 2-hydroxyethyl ester of 4,4'- dicarboxy-2,2'-bipyridine & bis-(5-vinylsalicylidene)ethylenediamine with 2-hydroxyethyl methacrylate. The effect of the polymer matrix on the formation and properties of transition metal iron complexes has been studied, specifically Cr(III) & Fe(II) salts for the bipyridyl- based copolymer membranes and Co(II), Ni(II) & Cu(II) salts for the salenH2- based copolymer membranes. The concomitant effect of complex formation on the properties of the polymer matrix have also been studied, e.g. on mechanical strength. A detailed body of work into the kinetics and thermodynamics for the formation of Cu(II) complexes in the salenH2- based copolymer membranes has been performed. The rate of complex formation is found to be very slow while the value of K for the equilibrium of complex formation is found to be unexpectedly small and shows a slight anion dependence. These phenomena are explained in terms of the effects of the heterogeneous phase provided by the polymer matrix. The transport of Cr(III) ions across uncomplexed and Cr(III)-pre-complexed bipyridyl-based membranes has been studied. In both cases, no Cr(III) coordination occurs within the time-scale of an experiment. Pre-complexation of the membrane does not lead to a change in the rate of permeation of Cr(III) ions. The transport of Co(II), Ni(II) & Cu(II) ions across salenH2- based membranes shows that there is no detectable lag-time in transport of the ions, despite independent evidence that complex formation within the membranes does occur. Finally, the synthesis of a number of functionalised ligands is described. Although they were found to be non-polymerisable by the methods employed in this research, they remain interesting ligands which provide a startmg pomt for further functionalisation.