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Theoretical investigations of polyhedral inorganic moleculesJohnston, Roy Luigi January 1986 (has links)
This Thesis describes some theoretical studies on cluster compounds of the main group and transition metal elements. Chapter 1 presents a review of the theoretical aspects of cluster chemistry. Three major theoretical approaches are identified, namely the localised, delocalised and free electron models and their historical development is described. The research described in this Thesis is based on extensions of Stone's Tensor Surface Harmonic (TSH) methodology, supported by Extended Huckel molecular orbital calculations. In Chapter 2, the TSH approach is used to describe the skeletal bonding in 3- and 4-connected polyhedral clusters. Like the deltahedral clusters, 4-connected molecules are generally characterised by (n+1) Skeletal Electron Pairs (SEP's). 3- connected clusters, however, possess 3n/2 SEP's. This difference is attributed to the occurrence of additional non-bonding orbitals in the 3-connected case. In Chapter 3, the bonding in a novel class of deltahedral metallaborane clusters is discussed. These hyper-closo or iso-closo species are studied from a fragment orbital viewpoint, regarding the structures as metal-capped fragments of a borane icosahedron. In this way, the problem of whether these clusters possess n or (n+1) SEP's is studied for n=9, 10 and 11. Although most deltahedral clusters conform to the (n+1) SEP rule, there are a significant number which do not. In Chapter 4, these deviations are rationalised from a group theoretical/topological viewpoint. A group theoretical paradigm is developed which simplifies the derivation of the frontier orbitals for these molecules. Chapter 5 extends the TSH methodology to clusters with bispherical topologies. To discuss these clusters, the TSH wavefunctions are modified to include radial, as well as angular nodes. The methodology is also applied to clusters with toroidal topologies, where the capping atoms form a ring around the equator of the inner cluster sphere. The bonding in π-donor- and π-acceptor-bridged clusters of the transition metals are compared in Chapter 6. Although the symmetry aspects are identical and lead to similar bonding patterns, the ir-donor clusters are characterised by a number of unoccupied d<sup>δ</sup>-based orbitals. The bonding in a series of closo, nido and arachno π-donor clusters, based on edge- and face-bridged octahedral molecules is considered and a relationship between the cluster electron count and the number of unavailable d<sup>δ</sup>-based orbitals is identified.
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The oxidation of olefins promoted by transition metal complexesJohn, Robert Alun January 1981 (has links)
The oxidation of olefins by transition metal complexes leading to epoxide or ketonic products has been reviewed, with an emphasis on non-free radical processes. The formation of cycloadducts by reaction of <u>bis</u> (triphenylphosphine )- platinum(O)dioxygen with the α,β-unsaturated carbonyl compounds <u>trans</u> but-2-enal, propenal, cyclohex-2-en-1-one, <u>exo</u> 2-methvlenecyclohexan-1-one and 3-phenylprop- 2-enal was investigated by H- and <sup>31</sup>P- nuclear magnetic resonance (n.m.r.). The cycloadducts derived from <u>trans</u> but-2-enal and propenal were thermally unstable in solution and further reacted to form stable, isolable complexes. The mechanism by which the cycloadduct <u>cis</u> [4-<u>trans</u>(prop-2-enyl )-1,1-bis( triphenyl - phosphine)platina-2,3» 5-trioxacyclopentane] , I , was transformed into <u>cis</u> [<u>trans</u>- (5-formyl-4-methyl)-1,1-bis(triphenylphosphine )platina-2 t 3-dioxacyclopentane] , II , was investigated by H- and H-n.m.r. utilising <u>trans</u> 4-[<sup>2</sup>H<sub>3</sub>]but-2-enal. A mechanism which involved both exchange of free <u>trans</u> but-2-enal with I and reaction to give II was proposed; a computer model, based upon numerical integration of the alternative rate equations was in good agreement with this proposition. The chemical reactivity of II with a variety of reagents was explored. In particular, the reaction of II with trifluoroacetic acid gave <u>trans</u> 2-formyl- 3-methyloxirane in high yield and stereoselectivity. The dynamic behaviour of <u>cis</u>[<i>bis</u>(triphenylphosphine)(2<sub>3</sub>,3'-m)(<u>trans</u> - but-2-enal )platinum(0)] was observed by variable temperature P-n.m.r. and explained by the interconversion of carbonyl rotamers. The preparation of iridium(I) olefin and peroxo complexes has been described Chloro<u>bis</u> triphenylphosphine) (1,2-m) (ethene )dioxygen iridium( I) , III , and related complexes were found to oxidise terminal olefins to their methyl ketones stoichiometrically, by a non-free radical process. The mechanism has been discussed.
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New amine-substituted cyclopentadienyl and indenyl ligandsMarsh, Sarah Margaret Beatrice January 1997 (has links)
This thesis concerns the new amine-substituted cyclopentadiene and indene ligands C(_5)H(_5)(CH(_2))(_3)N((^t)Bu)H and C(_9)H(_7)(CH(_2))(_3)N((^t)Bu)H which can co-ordinate to a metal through all five carbon atoms of the five-membered ring (η(^5)) and/ or through the nitrogen (σ). Chapter 1 reviews the recent literature concerning Lewis-base functionalised cyclopentadienyl and indenyl ligands and their compounds with s-, p-, d- and f-block metals. Chapter 2 contains a brief review of possible synthetic routes to amine-substituted cyclopentadienyl and indenyl ligands with some examples from the recent literature, and a detailed account of the synthesis of C(_5)H(_5)(CH(_2))(_3)N((^t)Bu)H and C(_9)H(_7)(CH(_2))(_3)N((^t)Bu)H. The amino alcohol (^t)BuNH(CH(_2))(_3) OH was synthesised by the conjugate addition of (^t)BuNH(_2) to ethyl acrylate and reduction of the product ester (^t)BuNH(CH(_2))(_2)C0(_2)Et using LiAIH(_4). (^t)BuNH(CH(_2))(_3)OH was converted into (^t)BuNH(CH(_2))(_3)Br.HBr and (^t)BuNH(CH(_2)(_3)Cl.HCl by reaction with HBr or SOCI(_2). Reaction between (^t)BuNH(CH(_2))(_3)C1.HC1 and two equivalents of Na(C(_5)H(_5)) gave C(_5)H(_5)(CH(_2))(_3)N((^t)Bu)H in good yield. Treatment of (^1)BuNH(CH(_2))(_3)C1.HC1 with excess NaOH followed by reaction with Li(C(_9)H(_7)) gave C(_9)H(_7)(CH(_2))(_3)N((^t)Bu)H, also in good yield. Chapter 3 describes the synthesis of various main group and iron compounds of C(_5)H(_5)(CH(_2))(_3)N((^t)Bu)H and C(_9)H(_7)(CH(_2))(_3)N((^t)Bu)H. Lithium salts Li[C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)H], Li[C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)]Li, Li[C(_9)H(_6)(CH(_2))(_3)N((^t)Bu)H] and Li[C(_9)H(_6)(CH(_2))(_3)N((^t)Bu)]Li were prepared for use as reactive intermediates and Li[C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)H] was characterised as its THF-adduct by (^t)H NMR spectroscopy. The silyl derivatives (Me(_3)Si)C(_5)H(_4)(CH(_2))(_3)NH(^t)Bu and (Me(_3)Si)C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)SiMe(_3) were synthesised and characterised by NMR spectroscopy, and (Me(_3)Si)C(_9)H(_6)(CH(_6))(_3)N((^t)Bu)H and (Me(_3)Si)C(_9)H(_6)(CH(_2))(_3)N((^t)Bu)(SiMe(_3)) were also synthesised. The anune-substituted ferrocene Fe{η(^5)-C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)H}(_2) was synthesised and oxidised to the corresponding ferricenium ion which was isolated as its PF(_6)(^-) salt. Exploratory work was carried out into the preparation of heterobimetallic species by reaction between Fe{η(^5)-C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)H}(_2) and MX(_2) (M = Co, Ni, X = CI, M = Mn, X = Br). The substituted bis(indenyl) iron(II) complex Fe{η(^5)-C(_9)H(_6)(CH(_2))(_3)N((^t)Bu)H}(_2) was also synthesised. Chapter 4 is an account of the chemistry of {η(^5) :σ-C(_5)H(_4) (CH(_2))(_3)N(^t)Bu}Ti(NMe(-2))(_2) which was synthesised by an aminolysis reaction between C(_5)H(_5)(CH(_2))(_3)NH(^t)Bu and Ti(NMe(_2))(_4) Reaction between this compound and various weak acids gave a range of new compounds including{η(^5):σ-C(_5)H(_4)(CH(_2))(-3)N(^t)Bu} Ti(O(^t)Pr)(_2), {η(^5):σ-C(_5)H(_4)(CH(_2))(_3)N(^t)Bu)(_2), {η(^5):σC, {η(^5):σ-C(_5)H(_4)(CH(_2))(_3)N(^t)Bu}Ti(C(_5)H(_5))(NMe(_2)) , {η(^5):σ-C(_5)H(_4)(CH(_2))(_3)N(^t)Bu}Ti(SnBu(_3))(_z) and the imido-bridged dimer [{η(^5):σ-C(_5)H(_4)(CH(_2))(_3)N(^t)Bu}Ti(NHPh)](_2)(µ-NPh)2, the X-ray structure of which is reported. Chapter 5 describes the experimental procedures used, and chapter 6 gives lists of characterising data for each compound. Appendix A gives details of the methods used for magnetic susceptibility determinations; appendix B lists X-ray crystallographic data for [ {η(^5):σ-C(_5)H(_4)(CH(_2))(_3)N(^t)Bu}Ti(NHPh)](_2)(µ-NPh)(_2) and appendix C lists departmental colloquia attended.
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Structure and agency in youth transitions : student perspectives on vocational further educationRudd, Peter W. January 1996 (has links)
No description available.
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Vibrational spectra of some transition metal organometallic complexes.Barna, Gabriel George January 1972 (has links)
No description available.
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Silent Partners in Care: Examining Care Transitions for Caregivers of Hip Fracture and Stroke PatientsToscan, Justine January 2011 (has links)
Background: Quality of care and patient safety have been demonstrated to be at increased risk during care transitions; making older adults with complex medical issues especially vulnerable due to the multifaceted care they require (Coleman, 2003; Cook et al., 2000; Forster et al., 2003; Murtaugh & Litke, 2002; Picker Institute, 1999; van Walraven et al., 2004). While a strong focus on patient issues during care transitions exists in current literature, there is a dearth of knowledge surrounding the role of informal caregivers in this process. As the senior population continues to grow in Canada, it is inevitable that the health system will be increasingly reliant upon informal caregivers to meet the demanding and complex care needs of older adults. This research explored informal caregiver experiences following an older patient’s medical crisis in order to foster a deeper understanding of caregiver needs during transitional care. This work will support efforts to develop viable interventions within formal care settings to better support and prepare individuals for informal care responsibilities (Canadian Caregiver Coalition, 2008; National Centre for Social and Economic Modelling, 2004).
Methods: A qualitative, post-positivist grounded theory study was employed to acquire an understanding of the role and needs of informal caregivers during transitional care. Semi-structured interviews were conducted with six community and resource case managers, and informal caregivers of eight hip fracture and two stroke caregivers. Two additional interviews were conducted with hip replacement caregivers. Questions explored individual experiences interacting with and/or providing informal care, and honed in on observed and experienced challenges, support received, and recommendations for future efforts to support care. NVivo8 software facilitated qualitative data analysis through hierarchical coding (Glaser & Strauss, 1967).
Results: Six properties of caregiver needs arose from the data, each consisting of several important ideas fostering its understanding. The core concept threading across all properties was building capacity to care. Combined, thematic interpretations were integrated into a comprehensive theory of caregiver needs to support a successful care transition from hospital to home, consisting of three layers: 1) Timeline of caregiver needs; 2) Instrumental needs; and 3) Emotional needs. A member-checking process of the theory consisting of both a focus group and individual interviews indicated high face and content validity, and highlighted priority areas for future interventions.
Discussion: The developed substantive theory is a valuable tool for which to understand the instrumental and emotional needs of hip fracture and stroke caregivers along a timeline of transitional care between hospital and home. Focus group and individual feedback indicate strong endorsement for theory adoption as a guiding framework for an intervention strategy to support informal caregivers within formal care settings and throughout the transition home. Results suggest the potential to broaden the conceptualization of the substantive theory to a formal explanation of transitional care needs for other medical crises across numerous types of transitions between formal hospital settings and the community.
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Siblings of pediatric bone marrow transplant recipients: their lived experience as they transition through the bone marrow transplant trajectoryWilkins, Krista L. 20 October 2006 (has links)
Bone marrow transplantation (BMT) is the treatment of choice for many malignancies and other childhood disorders. Acknowledging that the entire family is affected when a child undergoes a BMT, increasing research attention has been given to understanding this experience from the perspectives of recipients, parents and the family as a whole. Yet, minimal attention has been directed at understanding the experience of healthy siblings as they transition through the BMT experience. Before intervention studies can be undertaken that will help healthy siblings transition through the BMT experience, knowledge about the impact of the experience on siblings is needed. Accordingly, a qualitative study guided by the philosophy of hermeneutic phenomenology was conducted to elicit detailed descriptions of the lived experience of siblings.
Participants were children, adolescents and young adults with a sibling who had undergone a BMT during childhood. Participants were recruited from a pediatric BMT clinic in Western Canada. Semi-structured, open-ended interviews that explored siblings’ memories about what it is like to be a sibling of a child who has had a BMT were conducted with each participant. Demographic data and field notes were recorded. All interviews and field notes were transcribed. The transcripts were reviewed repeatedly for significant statements in an attempt to find meaning and understanding through themes.
The data analysis revealed the essence of siblings’ lived experience of transitioning through the BMT trajectory as an interruption in family life. Four themes communicated the essence of siblings’ lived experience: (1) life goes on, (2) feeling more or less a part of a family, (3) faith in God that things will be okay, and (4) feelings around families. Differences between donor and non-donor siblings are highlighted. Siblings’ recommendations for health care professionals are also provided. Results from this study will help health professionals better anticipate the diverse and shifting needs and demands of siblings of pediatric BMT patients. Recommendations for future research and innovations in nursing interventions are provided.
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Transition metal complexes of α-aminothioacidsO'Halloran, Harry John January 1969 (has links)
Typescript. / Thesis (Ph. D.)--University of Hawaii, 1969. / Bibliography: leaves 129-137. / ix, 137 l illus
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Synthesis and characterization of novel anionic transition metal borohydridesEliseo, Jennifer R January 2007 (has links)
Thesis (M.S.)--University of Hawaii at Manoa, 2007. / Includes bibliographical references (leaves 87-92). / viii, 92 leaves, bound ill. 29 cm
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Nonlinear dynamics and smooth transition modelsGonzález Gómez, Andrés January 2004 (has links)
During the last few years nonlinear models have been a very active area of econometric research: new models have been introduced and existing ones generalized. To a large extent, these developments have concerned models in which the conditional moments are regime-dependent. In such models, the different regimes are usually linear and the change between them is governed by an observable or unobservable variable. These specifications can be useful in situations in which it is suspected that the behaviour of the dependent variable may vary between regimes. A classical example can be found the business cycle literature where it is argued that contractions in the economy are not only more violent but also short-lived than expansions. Unemployment, which tends to rise faster during recessions than decline during booms, constitutes another example. Two of the most popular regime-dependent models are the smooth transition and the threshold model. In both models cases the transition variable is observable but the specification of the way in which the model changes from one regime to the other is different. Particularly, in the smooth transition model the change is a continuous whereas in the threshold model it is abrupt. One of the factors that has influenced the development of nonlinear models are improvements in computer technology. They have not only permitted an introduction of more complex models but have also allowed the use of computer-intensive methods in hypothesis testing. This is particularly important in nonlinear models because there these methods have proved to be practical in testing statistical hypothesis such as linearity and parameter constancy. In general, these testing situation are not trivial and their solution often requires computer-intensive methods. In particular, bootstrapping and Monte Carlo testing are now commonly used. In this thesis the smooth transition model is used in different ways. In the first chapter, a vector smooth transition model is used as a device for deriving a test for parameter constancy in stationary vector autoregressive models. In the second chapter we introduce a panel model whose parameters can change in a smooth fashion between regimes as a function of an exogenous variable. The method is used to investigate whether financial constraints affect firms' \ investment decisions. The third chapter is concern with linearity testing in smooth transition models. New tests are introduced and Monte Carlo testing techniques are shown to be useful in achieving control over the size of the test. Finally, the last chapter is devoted to the Smooth Permanent Surge model. This is a nonlinear moving average model in which a shock can have transitory or permanent effects depending on its sign and magnitude. Test for linearity and random walk hypothesis are introduced. / Diss. Stockholm : Handelshögsk., 2004
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