Synthesis and characterization of hafnium and molybdenum bifunctional initiators for the preparation of triblock copolymers

Chapter 1. Three monofunctional mixed alkyl hafnium complexes containing the (MesNpy)2 ligand ([(MesitylNCH2)2CMe(2-CsH4N)]2) were synthesized. (MesNpy)Hf(Neo)R ((2b), R = Me; Neo = CH2CMe2Ph) and (MesNpy)Hf(CH2TMS)(R), ((3b), R = Me and (4b), R = i-Bu)) were activated with {Ph3C} {B(C6F5)4} and one alkyl group was selectively removed in all cases. The kinetics of activated 4b were studied and the resulting complex was an initiator for the living polymerization of 1-hexene, with the exception of a slight initiation effect. Five linker molecules were investigated for the preparation of bifunctional hafnium mixed alkyl complexes. One complex synthesized, disilyl[(MesNpy)HfMe]2 (disilyl(X)2 = X-CH2SiMe2(CH2)5SiMe2CH2-X) was activated with {Ph3C} {B(C6F5)4} and the methyl groups were successfully removed to form {disilyl[(MesNpy)Hf]2} {B(C6F5)4}2. This complex was also a living catalyst for the polymerization of a-olefins.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemistry.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Gabert, Andrea 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/1721.1/40971

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/40971