Synthesis and structural studies of metallacarboranes

The properties of some new metallacarboranes are described in this thesis, along with the results of a study to determine structural patterns in compounds published by others. Chapter 1 introduces heteroborane cluster compounds and a description of the bonding in these compounds. The synthesis and structure of supraicosahedral heteroboranes are discussed in detail with reference to literature examples throughout. A brief description of the trans influence is also given. Chapter 2 describes the synthesis and structures of a series of thirteen vertex indenyl cobaltacarboranes and a single fourteen vertex bimetallic indenyl cobaltacarborane. The crystallographically-determined orientation of the exo-polyhedral indenyl ligand in each compound is used to probe the relative strengths of the metal-carborane bonds. Rotation of a related exo-polyhedral ligand about 360o is explored computationally and the results used to help rationalise the orientations of the indenyl ligands. Chapter 3 describes the synthesis and structures of a single twelve vertex and a series of thirteen vertex naphthalene ruthenacarboranes. As for the isoelectronic indenyl cobaltacarboranes, the orientations of the naphthalene ligands are explored crystallographically and computationally. The details of some unexpected side products are also discussed. Chapter 4 is an analysis of the results of a crystallographic database search which showed clear structural patterns in previously published metallacarboranes. Cage atoms which are relatively weakly bonded to the metal tend to lie trans to exo-polyhedral ligands which are relatively strongly bonded to the metal. Chapter 5 describes the structures of thirteen and fourteen vertex bimetallic pentamethylcyclopentadienyl ruthenacarboranes with unconventional electron counts, which were synthesised by metallation followed by direct electrophilic insertion. The structures of an exo-polyhedral metal-bound species and three solvent-bound zwitterionic metallacarboranes prepared from attempted direct electrophilic insertion reactions are also presented. Chapter 6 gives the experimental procedures used to synthesise and purify each new compound and provides details of how they were characterised. Appendix 1 lists the crystallographic data relevant to each compound. Appendix 2 gives details of the literature structures found during the structural database search described in chapter four. Appendix 3 (electronic appendix - see CD-ROM) contains rtf and CIF files (crystallographic data) for all compounds (where available). Appendix 4 (electronic appendix - see CD-ROM) contains CIF and mol2 files for all literature compounds discussed in chapter four.ESPR

Study of re-writing in the poetry of Arthur Hugh Clough

For all the recent interest in Clough's poetry, there has been little critical study of the numerous drafts and revisions that he made, although these are unusual, both in their number and in the radical nature of the differences between the various versions. Drawing on the published variants in the revised Oxford Poems of Arthur Hugh Clough, and on the Clough manuscripts at Oxford and at Harvard, this thesis attempts, through a mixture of literary, biographical, and textual criticism, a broadly chronological study of the kinds of re-writing Clough was doing at different periods of his life, concentrating on detailed study of the major poems. Chapter I outlines the changing attitudes of critics to the "unfinished" state of many of Clough's poems, and examines the role of re-writing in Clough's poetic theory. Chapter II, drawing on Clough's recently-released journals, shows how his Rugby poetry already showed traces of rewriting. Chapter III surveys Tractarian attitudes to the process of literary composition, and their appeal to Clough, and argues, through detailed study of three manuscript groups, that in his Oxford years re-writing became central to Clough's art. Chapters IV-VII give stage-by-stage analyses of the composition and re-writing of Adam and Eve, The Bothie, Amours -de Voyage, and Dipsychus, and suggest that the success of Amours de Voyage stems from Clough's incorporation into the later versions of divergent attitudes from his earlier drafts. Chapter VIII demonstrates the more stable pattern of composition in Clough's later work. A brief conclusion relates this study to the difficulty of editing the Clough texts. Appendices are devoted to (i) the texts of "The Longest Day"; (ii) the posthumous editions of Clough's Poems (1862); and (iii) a bibliography of early editions (1835-69). A published edition of Amours de Voyage is submitted in support of the thesis

Screen-printed flexible MRI receive coils.

Magnetic resonance imaging is an inherently signal-to-noise-starved technique that limits the spatial resolution, diagnostic image quality and results in typically long acquisition times that are prone to motion artefacts. This limitation is exacerbated when receive coils have poor fit due to lack of flexibility or need for padding for patient comfort. Here, we report a new approach that uses printing for fabricating receive coils. Our approach enables highly flexible, extremely lightweight conforming devices. We show that these devices exhibit similar to higher signal-to-noise ratio than conventional ones, in clinical scenarios when coils could be displaced more than 18 mm away from the body. In addition, we provide detailed material properties and components performance analysis. Prototype arrays are incorporated within infant blankets for in vivo studies. This work presents the first fully functional, printed coils for 1.5- and 3-T clinical scanners

The exopolyhedral ligand orientation (ELO) in 3-(nitrato-κO)-3,3-bis(triphenylphosphane-κP)-3-rhoda-1,2-dicarba-closo-dodecaborane(11) dichloromethane 2.2-solvate

In the title compound, [Rh(C2H11B9)(NO3)(C18H15P)2]·2.2CH2Cl2, studied as a 2.2-solvate of what was assumed to be dichloromethane, the nitrate ligand liesciswith respect to both cage C atoms. Accordingly, the compound displays a pronounced preferred exopolyhedral ligand orientation (ELO) which is traced to both the greatertransinfluence of the cage B over the cage C atoms and the greatertransinfluence of the triphenylphosphane ligands over the nitrate ligand. The overall molecular architecture therefore agrees with that of a number of similar 3-L-3,3-L′2-3,1,2-closo-MC2B9H11species in the literature.</jats:p