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Title: Group 4 amidinate complexes as olefin polymerisation catalysts
Author: Scott, Richard T. W.
ISNI:       0000 0004 2747 7992
Awarding Body: University of Oxford
Current Institution: University of Oxford
Date of Award: 2012
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This Thesis describes the syntheses, structure and olefin polymerisation capability of a series of group 4 ?1-amidinate-supported complexes. Chapter One introduces metal-catalysed polymerisation of olefins with emphasis on the development of homogeneous molecular catalysts. The evolution of ?post-metallocene? systems, cocatalysts and the chemistry of activation are explored providing context to the work detailed in subsequent chapters. Chapter Two describes the synthesis and characterisation of new titanium cyclopentadienyl-amidinate diene complexes and corresponding B(C6F5)3-activated zwitterionic compounds. Their performance in small-scale ethylene-propylene-diene monomer (EPDM) copolymerisation is compared to that of a related dialkyl initiator. Some underlying chemistry of the diene/zwitterionic species is explored particularly in relation to the reversibility of zwitterion formation (activation). Chapter Three details the synthesis and characterisation of a congeneric series of cyclopentadienyl-amidinate group 4 complexes. Combined crystallographic and DFT studies provide an insight into the nature of the amidinate-metal interaction as well as the bonding and conformational preference of the diene complexes described in Chapters Two and Three. The performance of these precatalysts in ethylene homo- and ethylene-propylene (EP) copolymerisation experiments is presented along with preliminary activation experiments giving enhanced understanding of the nature of the active species. Chapter Four describes the synthesis and characterisation of a series of chelating cyclopentadienyl-amidinate complexes. Structural characterisation of these compounds combined with DFT calculations provide useful comparisons with the related non-ansa precatalysts. The EP and EPDM polymerisation performance of the bridged complexes is compared to a representative non-chelated precatalyst. Chapter Five contains experimental details and characterising data for new compounds described in this Thesis. CD Appendix provides crystallography .cif files.
Supervisor: Mountford, Philip Sponsor: Engineering and Physical Sciences Research Council
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Organometallic Chemistry