Early transition metal catalysts for the living polymerization of olefins and alkynes

Zirconium and Hafnium Ziegler-Natta catalysts containing the [(2,6- C12C6H3NCH2CH2)2NMe]2- ([ArciN2NMe]2') ligand were prepared and employed in the polymerization of 1-hexene. Hafnium Ziegler-Natta catalysts containing the [(2,6- X2C6H3NHCH2)2C(CH3)(2-C5H4N)] ([Arx2NPy]2-) (X = Cl or F) ligand were also prepared for use in 1-hexene polymerization studies. Compounds of the type [Ligand]MR2 (R = Me, i-Bu) were activated with {Ph3C}{B(C6F5)4}, B(C6F5)3, or {PhNMe2H}{B(C6F5)4} to yield monoalkyl cationic initiators paired with a weakly coordinating anion. Rates of consumption of 1-hexene were monitored, decomposition pathways studied, and living behavior assessed. Catalysts containing the ([ArcN2NMe]2-) ligand were more stable than those containing the analogous ([MesN2NMe]2-) ligand; however, living behavior was only observed for zirconium catalysts. Substitution of the mesityl amido substituents in [ArylNpy]2- hafnium complexes with aryl groups containing chlorines or fluorines (especially the latter) in the ortho positions was found to be detrimental to the development of living olefin polymerization catalysts of this general type. The catalytic activity steadily decreased in the order aryl = Mes > 2,6-Cl2C6H3 > 2,6-F2C6H3 and 1,2 and 2,1 -hydride elimination increased in the order aryl = Mes < 2,6-Cl2C6H3 < 2,6-F2C6H3.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemistry.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2006

Author dc:creator

• Adamchuk, Jennifer

Advisor dc:contributor.advisor

• Richard R. Schrock.

• Chemistry.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/34499

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/34499