Early transitional metal alkyl, alkylidene, and alkylidyne chemistry

CHAPTER 1. Zirconium and hafnium complexes of several new unsymmetric diamide ligands have been prepared and their proficiency in olefin polymerization reactions evaluated. The first set of supporting ligands examined are diamido-donor ligands that contain ethylene/o-phenylene "arms" and a phenyl-substituted amine donor in the central position. These ligands are derived from the triamines, [MesitylNH-o-C6H4N(Ph)CH2CH2NHMesityl] (H2[MesNNPhMes]) and [t- Bud6-NH-o-C6H4N(Ph)CH2CH2NHMesityl] (H2[t-BuNNPhNMes]). The Zr and Hf complexes that can be isolated include [MesNNPhNMes]MX2 (M = Zr or Hf, X = NMe2, Cl, or Me) and [t- BuNNPhNMes]MX2 (M = Zr or Hf, X = NMe2, Cl, Me). The structures of [MesNNPhNMes]ZrMe2, [t-BuNNPhNMes]ZrMe2, and a dimeric species with the formula [MesitylN-o-C6H4NCH2CH2NMesityl]Zr2(NMe2)5 are reported. Abstraction of a methyl group in [MesNNPhNMes]MMe2 (M = Zr or Hf) with [Ph3C][B(C6F5)4] gives rise to cationic complexes which are active initiators for the polymerization of 1-hexene. Similar activation of [t- BuNNPhNMes]MMe2 (M = Zr or Hf) gives rise to dimeric monocations that eventually break-up and react further to yield cationic monomethyl species. In all cases the poly[1-hexene] produced in the presence of the monometallic cations was found to be atactic.

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

• Tonzetich, Zachary John

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/1721.1/39672

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/39672