Off-campus UMass Amherst users: To download dissertations, please use the following link to log into our proxy server with your UMass Amherst user name and password.
Non-UMass Amherst users, please click the view more button below to purchase a copy of this dissertation from Proquest.
(Some titles may also be available free of charge in our Open Access Dissertation Collection, so please check there first.)
New group 4 complexes and their use as homogeneous polymerization catalysts for the production of polyolefins
Tetrahydro-2-methylbenz[e]indanone (5) and tetrahydro-2-methyl benz[f]indanone (11) were produced from the reaction of 2-bromoisobutyryl bromide with tetralin, contrary to what has been previously published in the literature. Indanones 5 and 11 were readily converted into their corresponding indene derivatives tetrahydro-2-methylbenz[e]indene (6) and tetrahydro-2-methylbenz[f]indene (12), respectively. Two new half sandwich titanium trichlorides based on 6 and 12 were synthesized and were shown to polymerize styrene to s-PS with activities in the low 107 range. ^ Two efficient synthetic routes to the novel titanatrane complexes, indenyl titanatrane (19) and 2-methylbenz[e]indenyl titanatrane ( 20) have been presented. These new titanatranes along with the known titanatranes, Cp titanatrane (17) and Cp* titanatrane ( 18) were tested as potential catalyst precursors for the polymerization of styrene and ethylene. Complex 17 was a very efficient catalyst for the polymerization of ethylene at 0°C, exhibiting a 100 fold increase over its corresponding trichloride derivative (CpTiCl3) Complex 18 proved to be the most versatile catalyst producing very high activities in the polymerization of styrene and moderate activities in the polymerization of ethylene. ^ A new versatile synthetic route to substituted alkyl bridged bis-indanones and bis-indenes was developed. In addition, these bis-indenes can be employed as useful ligands in the synthesis of ansa-titanocenes. Ansa-titanocene complexes 22 and 63 were active in catalyzing the polymerization of olefins when activated by MAO, exhibiting activities of ca. 1 × 107 for the polymerization of ethylene and ca. 1.5 × 104 in catalyzing the polymerization of propylene. ^ Four new C1 symmetric metallocenes containing a substituted indenyl moiety were synthesized. Metallocenes 68– 70 and 72 were active for both the polymerization of ethylene and propylene when activated with MAO. In general, diphenylsilylene-bridged catalysts produce polymers of higher molecular weights than do dimethylsilylene-bridged catalysts. Overall, one obtains a higher activity but polymers of lower molecular weights with ethylene-bridged catalysts versus silylene-bridged catalysts. ^ In addition, four new C1 symmetric metallocenes containing 2,7-disubstituted fluorenyl moieties were synthesized. Three of the four metallocenes, 86–88, were highly active for the polymerization of both ethylene and propylene. In general, the most sterically hindered catalysts were more active and produced polymers of higher molecular weights than do their less hindered counterparts. ^
John J Esteb,
"New group 4 complexes and their use as homogeneous polymerization catalysts for the production of polyolefins"
(January 1, 2001).
Doctoral Dissertations Available from Proquest.