The aim of this project has been to develop the field of group 4 indenyl metallocene complexes based upon highly methylated ligands. Previous studies have shown that these compounds can be extremely active ethylene polymerisation catalysts, and, as such, are of both significant academic and commercial interest <strong>Chapter One</strong> introduces metallocene chemistry, discussing developments within the field and the effects of permethylation on indenyl rings. A synopsis of the rise of the ansa-bridge is provided, in addition to highlights from recent zirconocene chemistry. A feature on olefin polymerisation is included, spanning heterogeneous catalysts, homogeneous metallocenes and post metallocenes, as well immobilised complexes and their supports. <strong>Chapter Two</strong> charts updates to syntheses of bridged and unbridged permethylindenyl ligands. The developments have allowed for their use as viable industrial procedures. <strong>Chapter Three</strong> is an account of the group 4 organometallic chemistry of the indenyl ligands from Chapter Two. Four bridged metallocenes, including rac-SBI*ZrCl<sub>2</sub> and meso-EBI*Zr(CH<sub>2</sub>Ph)<sub>2</sub>, are reported. In addition, six unbridged analogues comprising rac/meso-Ind<sup>#</sup><sub style='position: relative; left: -.8em;'>2</sub>MCl<sub>2</sub> (M = Zr, Hf) and rac/meso-Ind<sup>#</sup><sub style='position: relative; left: -.8em;'>2</sub>(CH<sub>2</sub>Ph)<sub>2</sub> are described as well as a half-metallocene. The complexes are characterised by single crystal X-ray diffraction and variable temperature NMR spectroscopy. DFT calculations have been performed, with representations of their optimised geometries and frontier MOs given. <strong>Chapter Four</strong> describes a reliable, reproducible procedure for immobilising group 4 complexes on the surface of solid supports; in total 19 catalysts are prepared. In addition to SSMAO, two new inorganic supports (LDHMAO and Solid MAO) are utilised. The latter has never previously been described in the academic literature. These catalysts have been characterised by IR, UV/visible and solid-state NMR spectroscopy in addition to SEM imaging. Zr K-edge EXAFS experiments were conducted and exceptionally clear data are reported. <strong>Chapter Five</strong> investigates the aforementioned complexes as both solution- and slurry-phase ethylene polymerisation catalysts. Numerous parameters are tested including temperature and time dependence and all of the catalysts produce high molecular weight polymer in the range 150-300,000 daltons. The activity of rac SBI*ZrCl<sub>2</sub> in solution exceeds 22,500 kg<sub>PE</sub>/mol<sub>Zr</sub>/h/bar, and 7,500 kg<sub>PE</sub>/molZr/h/bar immobilised on Solid MAO. meso-EBI*Zr(CH<sub>2</sub>Ph)<sub>2</sub> displays double the activity of its dichloride analogue. 1-hexene co polymerisation is carried out as part of a high throughput screening study and activities in excess of 30,000 kg<sub>PE</sub>/molZr/h/bar are reported. Scale-up polymerisation runs are also disclosed. The resultant polymer has been characterised by GPC, as well as X-ray diffraction, SEM, <sup>13</sup>C NMR and IR spectroscopy. <strong>Chapter Six</strong> provides the experimental details and characterising data for the previous chapters. An Appendix consists of crystal structure data while the Electronic Appendix contains the CIFs, DFT output files and the raw polymerisation data.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:647682 |
| Date | January 2015 |
| Creators | Arnold, Thomas Allan Quartermaine |
| Contributors | O'Hare, Dermot |
| Publisher | University of Oxford |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://ora.ox.ac.uk/objects/uuid:66107287-43c0-4158-88d0-8d71dd2a1b23 |
Page generated in 0.0018 seconds