Title

Phosphinimide complexes of titanium: Synthesis and reactivity studies of a new family of organometallic compounds.

Date of Award

2000

Degree Type

Dissertation

Degree Name

Ph.D.

Department

Chemistry and Biochemistry

First Advisor

Stephan, Douglas W.,

Keywords

Chemistry, Inorganic.

Rights

CC BY-NC-ND 4.0

Abstract

A series of phosphinimine compounds have been synthesized with a view to designing a new ligand system to effect stoichiometric and catalytic organic transformations. The first type of metal complex contained both a Cp and a phosphinimide ligand {CpTi[NPR3]} which, when combined, would sterically and electronically mimic the Cp2Ti family of compounds. The second type of complex was based on a linked ligand system in which a Cp and a phosphinimide, or two phosphinimide moieties were joined to form chelated metal complexes. Phenyl derivatized titanium-phosphinimide compounds were shown to incorporate unsaturated organic substrates to form metallacyclic compounds. Polymerization experiments were carried out employing both aluminum- and boron-based co-catalysts. Some of the titanium-phosphinimides proved to be very active catalysts. Cationic titanium-phosphinimide complexes were isolated and the crystal structure of CpTiMe[NP(t-Bu)3][MeB(C6F5) 3] 95 was shown to be zwitterionic in nature. Some titanium-phosphinimide complexes were titrated with MAO to elucidate possible catalyst activation and deactivation pathways. It was determined that reaction of trimethylaluminum with certain titanium-phosphinimide alkyls produced carbide cluster complexes through C-H bond activation. Crystal structures of these clusters showed the carbide carbon atoms in four or five coordinate geometries. In addition, spectroscopic evidence suggested that upon cation generation the unsaturated end of a pendant-olefin titanium-phosphinimide complex was intramolecularly coordinated to the metal. Furthermore, the previously isolated zwitterion 95 effected coordination and insertion of a variety of simple alkyne molecules.Dept. of Chemistry and Biochemistry. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2000 .S74. Source: Dissertation Abstracts International, Volume: 65-07, Section: B, page: 3460. Adviser: Douglas W. Stephan. Thesis (Ph.D.)--University of Windsor (Canada), 2000.